System and method for residential gray water recycling

Abstract

A recycling system treats residential gray water for re-use as non-potable water. The system is appliance sized and powered by a standard electrical outlet. The system may have a prefilter, a collection tank, a foam separator, a submerged biofilter, a filter, a supply tank, a disinfection system and / or a delivery pump. A process may include screening, collection, sedimentation, foam separation, biological filtration, filtration, storage, disinfection and / or delivery. A multi-purpose reactor may include the foam separator and a submerged biofilter, optionally with multiple fixed beds that may be separately backwashed. A media filter may be in a separate vessel downstream of the multi-purpose reactor. Flow through the biofilter may be downwards in responsive to delivery of treated water by a pump downstream of the filter. A controller may provide calculations or alerts or automatically implement a vacation mode. The system may have a communication module and ancillary systems.

Description

SYSTEM AND METHOD FOR RESIDENTIAL GRAY WATER RECYCLING RELATED APPLICATIONS

[0001] This application claims the benefit of, and priority from, United States Provisional Application No. 63 / 779,932, filed on March 28, 2025; United States Provisional Application No. 63 / 779,958, filed on March 28, 2025; United States Provisional Application No. 63 / 779,967, filed on March 28, 2025; United States Provisional Application No. 63 / 779,975, filed on March 28, 2025; and United States Provisional Application No. 63 / 804,994, filed on May 13, 2025, all of which are incorporated by reference.FIELD

[0002] This specification relates to residential gray water recycling.BACKGROUND

[0003] U.S. Patent Number 8,377,291, Gray Water Recycling Apparatus and Methods, describes a water recycling system that can be used for reclaiming and recycling gray water to provide water for landscaping or sanitary facilities such as a toilet. The water recycling system includes a tank, an influx pipe with a filter screen, and a pump. The filter screen covers an opening in the bottom of the influx pipe. The part of the influx pipe containing the filter screen is sloped. At least some influent water passing through the influx pipe falls through the filter screen to be collected in the tank. Any excess influent water continues past the filter screen and flows through the influx pipe to an external sanitary drain. When filtered water is drawn from the tank for use, a portion of it is sprayed against the bottom of the screen to force material off the filter screen and into the influx pipe.

[0004] US Patent Number 10,138,138, System and Method of Graywater Recovery and Reuse, describes a device with an inlet connected to a source of graywater, a filter for filtering the graywater, a tank for holding the filtered graywater, a system for disinfecting the filtered graywater, and a pump fordischarged the disinfected water to a toilet. The device includes a controller for operating the system and responding to various alarms or status conditions.

[0005] US Patent Number 11,879,236, Intake Filter for Water Collection System with Pressure Activated Backwash Valve, describes an intake filter for use, for example, in a system that collects graywater from baths or showers for re-use in toilet flushing.

[0006] US Patent Number 12,146,302, Residential Gray Water Recycling System, describes systems for the treatment and reuse of gray water and related processes. An exemplary system collects gray water from baths and showers and treats it for use in toilet flushing. Influent bathing water passes through a prefilter to remove larger particles and flows into a gray water collection tank. Collected gray water is filtered through a membrane designed to remove suspended solids. Membrane permeate passes through a sorbent media to remove soluble organics and then flows into a permeate tank. A chemical agent is used to disinfect water in one or more parts of the system and optionally to clean the membranes. A control system manages the operation of system. The system operates in a generally daily cycle with permeation dispersed over a material time, for example 4 or 8 hours or more.

[0007] US Patent Application Publication Number 2008 / 0173581, Waste Water Treatment Process System, describes an aerated biological filtration system. A treatment vessel has a circulating filter bed and a static filter bed. An aeration system diffuses air through the circulating bed.

[0008] US Patent Application Publication Number 2021 / 0147251, Gray Water Treatment Systems and Methods of Treating Gray Water, describes a gray water treatment system with three tanks. Gray water being treated is circulated between two of the tanks. In the first tank, some contaminants are removed by overflowing the tank. The gray water is also treated by aerobic bacterial digestion. The third tank is used to store treated water.

[0009] NSF / ANSI Standard 350 establishes effluent quality criteria for, among other things, onsite residential gray water treatment systems used toprovide non-potable (i.e. toilet flushing) water. The test requires significant reductions in total suspended solids (TSS), chemical and biological oxygen demand (CBODs) and pathogens among other things. The challenge water used for the test includes large organic molecules (e.g. from shampoo and soap) as well as solids and a small amount of residential wastewater.INTRODUCTION

[0010] This specification describes a gray water recycling system and process. The system and process may be used, for example, for treating residential bathing and / or laundry water for re-use in toilet flushing or other non-potable uses such as irrigation. The following paragraphs describe various features of the system and process. However, an invention may involve only a subset of the features in this summary, or a subset of features in this summary combined with one or more features in the detailed description to follow.

[0011] In some embodiments, a gray water recycling system receives gray water, for example bathing or laundry gray water, from a gray water drain of a house and sends treated water to a toilet supply line of the house. The house could be, for example, a detached house, a semi-detached house, a townhouse or a row house. The house may be occupied by a single family or other group of 1-6 people. The system may be provided in an appliance sized package and placed in a garage, basement, or mechanical room of the house. The system may be powered by a standard 1800-Watt electrical outlet.

[0012] In some embodiments, a process may include one or more of screening, collection, sedimentation, foam separation, biological filtration, filtration (e.g. non-biological filtration), storage, disinfection and delivery. The process may treat the gray water to NSF / ANSI 350 standards.

[0013] In some embodiments, the gray water treatment includes foam separation and biofiltration. In foam separation, alternatively called foam fractionation, bubbles are introduced into the gray water. The presence of surfactants in the gray water, for example from soap or shampoo, results in foamgeneration when the water is aerated. This foam, along with any contaminants trapped in the foamate, is discharged to waste. Biofiltration uses microorganisms attached to a media to remove contaminants by a combination of filtration and biological digestion. Optionally, the biofiltration includes flowing the gray water downwards in a single pass through a submerged and aerated fixed bed bioreactor. Optionally, additional non-biological filtration, for example media filtration, depth filtration or surface filtration, may occur downstream of the biofiltration. The additional filtration may capture small solid particles or fragments of biofilm that are released from, or pass through, the biofilter.

[0014] In some embodiments, influent gray water is collected upstream of the foam separation and treated water is stored downstream of the biofiltration. A foam separation effluent may flow downwards by gravity to a biofilter. The flow of gray water through the biofilter may be intermittent and controlled by a pump downstream of the bioreactor. The instantaneous or maximum flow rate through the bioreactor may be in the range of 2-10 gallons per hour. Flow through the biofilter may be responsive to delivery of the treated gray water, for example the flow may start when a water lever in the supply tank is low and stop when the water level in the supply tank is high.

[0015] In some embodiments, a system may have one or more of a prefilter, a collection tank, a foam separator, a submerged biofilter, a non-biological filter, a supply tank, a disinfection system and a delivery pump. In some embodiments, a foam separator and a submerged biofilter are combined in a multi-purpose reactor, with the foam separator in an upper part of the multipurpose reactor. The submerged biofilter may have two vertically spaced apart media beds.

[0016] In some embodiments, the non-biological filter is a media filter downstream of the biofilter. The system may have a supply tank downstream of the media filter. A pump downstream of the biofilter, and optionally downstream of the media filter, moves gray water through the biofilter and the media filter.

[0017] In some embodiments, the system has a collection tank upstream of the foam separator. The collection tank may have a volume in the range of 35-60 gallons. There may be a prefilter upstream of the collection tank. The prefilter may have a fine screen, for example with openings between 0.5 and 5 mm. A total volume of the collection tank and the supply tank may be 100 gallons or less.

[0018] The specification also describes a domestic gray water treatment device having a reactor body, a gray water inlet in communication with an upper part of the body, a foamate outlet in communication with the upper part of the body, and a gray water outlet in communication with a lower part of the body. The device also has a first media bed within the body at an elevation between a) a lower of the gray water inlet and the foamate outlet and b) the gray water outlet. The device also has a first gas sparger configured to release gas into the body above the first media bed and below the foamate outlet, optionally also below the gray water inlet. In some embodiments, the foamate outlet is above the gray water inlet. In some embodiments, the device has a second gas sparger configured to release a gas into the body below the first media. In some embodiments, the device also has a first waste outlet in communication with the body above the first media bed and below the lower of the gray water inlet and the foamate outlet. In some embodiments, the first gas sparger and the first waste outlet share a common tube in communication with the body. In some embodiments, the device has a second media bed below the first media bed and above the gray water outlet. In some embodiments, the device has a third gas sparger between the first media bed and the second media bed and optionally a second waste outlet between the first media bed and the second media bed, which may share a common tube in communication with the body with the third gas sparger. In some embodiments, the device has an access port between the first media bed and the second media bed. In some embodiments, the device has a third waste outlet in communication with the lower part of the body, optionally wherein the third waste outlet is located in a sump at the bottom of the tank, and optionally wherein the third waste outlet is at a lower elevation than thegray water outlet. In some embodiments, the device has a cap. Optionally, the foamate outlet is in the cap and surfaces of the cap may converge towards the foamate outlet. In some embodiments, the first media bed rests on a partition supported by indents of the body. In some embodiments, the reactor body is elongated and vertically oriented, for example the body may have a width that is 25% or less of its height. In some embodiments, the device is combined with a media filter, which is optionally in a separate vessel.

[0019] This specification also describes a process for treating gray water, optionally in a device as described in the paragraph above. The process includes flowing gray water downwards through a media bed, providing bubbles in the water above the media bed, removing foam above the media bed and removing treated gray water below the media bed. In some embodiments, the gray water flows downwards in the reactor body intermittently, optionally in one pass. In some embodiments, air upwards through the media bed periodically to release solids from the media bed and water containing the released solids is removed from above the media bed. In some embodiments, the gray water flows downwards through multiple media beds, and optionally the multiple media beds are backwashed at different times. In some embodiments, the gray water is drawn through the media bed or beds by a downstream pump. In some embodiments, a free water surface is maintained within a selected range above the media bed or beds.

[0020] This specification also describes a reactor for a gray water recycling system having a foam separation unit and a fixed bed biological reactor. In some embodiments, the reactor has a vertically oriented body, for example having a width that is 25% or less of its height. In some embodiments, the foam separation unit is in an upper part of the reactor and the fixed bed biological reactor is below the foam separation unit. In some embodiments, the fixed bed biological reactor has an upper media bed and a lower media bed. Some embodiments have a gray water inlet and a foam outlet near the top of the reactor and an effluent outlet near the bottom of the reactor. In some embodiments, the reactor has a first air pump in communication with the foamseparation unit and a second air pump in communication with the fixed bed biological reactor. In some embodiments, the first air pump has a variable speed. In some embodiments, the second air pump has a variable speed.

[0021] This specification also describes a tank for a multi-purpose reactor for a gray water recycling system. In some embodiments the tank has a vertically elongated body having a set of indents, a porous plate supported on the indents for supporting a media bed, a fitting in the side of the body above the set of indents, a fitting near the bottom of the tank, a fitting near the top of the tank and a removable cap at the top of the tank. In some embodiments, the tank has a second set of indents, a second porous plate supported on the second set of indents for supporting a second media bed and a second fitting in the side of the body above the second set of indents. Some embodiments have an access port in the side of the body between the sets of indents. In some embodiments, the fitting in the side of the body is connected to an open ended pipe segment extending into the body. Some embodiments have a sump at the bottom of the tank. Optionally there is a fitting connected to the sump below the fitting near the bottom of the tank. In some embodiments, the cap has a sloped surface terminating in second fitting near the top of the tank.

[0022] This specification also describes a process of treating gray water including flowing the gray water intermittently downwards in single pass through a fixed bed bioreactor having multiple vertically separated media beds or a foam separation reactor above a fixed bed bioreactor or through a foam separation reactor above a fixed bed bioreactor having multiple vertically separated media beds. In some embodiments, the foam separation reactor and the fixed bed bioreactor are aerated. In some embodiments, suspended solids are filtered as the gray water flows downwards through the fixed bed bioreactor. In some embodiments, foam containing contaminants is separated from the gray water. In some embodiments, the fixed bed bioreactor is backwashed. In some embodiments, the fixed bed bioreactor has multiple beds and the multiple beds are backwashed at different times.

[0023] This specification also describes a media filter. The media filter has a filter body; a lower screen; an outlet below the lower screen and in communication with the body via the lower screen; an upper screen; and inlet above the upper screen and in communication with the body via the upper screen; and, a media bed between the lower screen and the upper screen. In some embodiments, the media bed has spherical glass beads, optionally 0.5 to 2 mm in diameter. In some embodiments, there is a headspace between the media bed and the upper screen. In some embodiments, the media filter has a cap attached to the filter body, and the upper screen is in the cap and the inlet is in communication with the cap. In some embodiments, there is a media filter pump, wherein the outlet is connected to an inlet of the media filter pump. In some embodiments, there is a pressure transducer between the outlet and the media filter pump. In some embodiments, there is a three-way valve in communication with the inlet. Some embodiments have an air pump and a water pump in communication with the outlet for backwashing the media bed with air and water.

[0024] This specification also describes a method of treating gray water including flowing the gray water downwards through a media bed and backwashing the media bed. In some embodiments, the media bed is part of a media filter as described above. In some embodiments, backwashing the media bed includes flowing air or an air / water mixture upwards through the media bed. In some embodiments, backwashing also includes flowing water upwards through the media bed. In some embodiments, gray water is drawn through the media bed by a downstream pump. In some embodiments, backwashing is trigged by a pressure signal from a sensor in communication with the inlet of the pump.

[0025] This specification also described a gray water recycling system having a bioreactor and a media filter downstream of the bioreactor. In some embodiments, the media filter is as described above. In some embodiments, gray water is drawn from the bioreactor and through the media filter by a pump, optionally a pump downstream of the media filter. In some embodiments thebioreactor is a vertically oriented fixed bed bioreactor and the gray water flows downwards through the fixed bed bioreactor. In some embodiments, the media filter is vertically oriented and the gray water flows downwards through the media filter. In some embodiments, the top of the media filter is located below a minimum water level in the bioreactor and / or at 60% of the height of the bioreactor or lower. In some embodiments, the pump is located below the media filter. Some embodiments have a pressure sensor on the inlet side of the pump connected to a controller adapted to perform a backwash of the media filter when a selected pressure is detected.

[0026] This specification also describes a process for treating domestic gray water including collecting gray water from a residence, treating the collected gray water and delivering the treated gray water back to the residence. The process also includes monitoring one or more attributes of the collection or delivery of the gray water, and producing one or more outputs, alerts or predictions (e.g. determinations or assessments) based on the one or more attributes. In some embodiments, the predictions include determining whether a period of time during which the residence is not regularly occupied has started or ended. Such a period of time may be called a vacation for convenience although there may be other reasons why the residence is not occupied.

[0027] In some embodiments, the one or more attributes include delivery attributes related to the pressure, rate, volume, time and / or frequency of gray water delivery. Optionally, the delivery attributes are obtained directly from a signal from an output meter or indirectly from one or more of a supply pump (i.e. a signal indicating operation of the supply pump) or a supply tank (i.e. signals indicating a change in the volume of water in a supply tank). In some embodiments, the beginning of a vacation is predicted by gray water not being delivered for a selected period of time, for example 24-72 hours. Some embodiments include producing an output indicating the cumulative amount of gray water delivered over a period of time. Some embodiments include producing an alert indicating a leak downstream of the supply pump, for example a leak in a toilet. In some embodiments, the downstream leak alert is indicatedby delivery of gray water with an increased rate (e.g. volume per day) or frequency relative to a selected value or above an observed prior value, or by delivery of gray water during a selected time or during a time previously observed to involve no or minimal delivery. In some embodiments, the downstream leak alert is indicated by delivery of gray water with a decreased rate (e.g. volume per minute) or frequency relative to a selected value or below an observed prior value. In some embodiments, the one or more attributes include collection attributes related to the time, volume and / or rate of gray water collection. In some embodiments, the one or more collection attributes, for example the collection of a selected amount of gray water, are used for predicting the end of a vacation.

[0028] This specification also describes a system for treating domestic gray water having a collection tank, one or more treatment units, a supply tank, a supply pump and a controller. In some embodiments, one or more additional pumps and / or valves and / or tanks are used as part of the treatment units. The controller is connected to one or more sensors and adapted to monitor one or more attributes of the collection and / or delivery of the gray water. The terms sensor may include any device capable of producing a signal, which might be called a sensor, probe, transducer, switch or meter etc. The controller is also adapted to produce one or more outputs, alerts or predictions. In some examples, the controller is configured to predict (i.e. determine) the beginning or end of a vacation by way of the one or more of the attributes.

[0029] In some embodiments, the system has a pressure transducer in communication with the collection tank. In some embodiments, the controller is adapted to determine a volume of water added to the collection tank by way of signals from the pressure transducer. In some embodiments, the controller is adapted to drain the collection tank after predicting the beginning of a vacation. In some embodiments, the controller is adapted to predict the ending of a vacation by way of receipt of a specified volume of water in the collection tank, which may be determined by signals from the pressure transducer. In some embodiments, the system has an outlet meter downstream of the supply pump.In some embodiments, the controller is adapted to calculate an amount of gray water delivered based on signals from the outlet meter, signals related to operation of the supply pump or signals related to the removal of water from the supply tank. In some embodiments, the controller is adapted to predict a leak downstream of the supply pump based on signals from the outlet meter, supply pump, pressure transducer or supply tank. Some embodiments have a fresh water make-up connection in communication with the supply tank. Some embodiments have a make-up water meter in communication with the fresh water make-up connection. Optionally, the controller is adapted to subtract a calculation of the volume of make-up water from the calculation of the amount of gray water delivered. In some embodiments, the controller is adapted to calculate the amount of make-up water based on signals from one or more of the make-up water meter and signals related to the addition of water to the supply tank. In some embodiments, the controller is adapted to implement a vacation mode, communicate an alert regarding a downstream leak, and / or communicate a calculation of gray water delivered over a period of time.

[0030] This specification also describes a gray water recycling system having a controller. In some embodiments, the controller is connected to instrumentation such as probes, sensors, switches, transducers or meters. In some embodiments, the controller is connected to electrically actuated devices such as valves and pumps. In some embodiments, the controller has a Wi-Fi or other type of communication module allowing connection to an internet router and / or direct communication to a diagnostic device, which may be a general purpose computer such as a smartphone. In some embodiments, the controller also has a human machine interface panel. In some embodiments, the controller is adapted to transmit one or more error codes, alerts or warnings. In some embodiments, the controller is adapted to calculate and transmit a water savings value and optionally a make-up water usage value. In some embodiments, the controller enables remote operation of one or more of the electrically actuated devices of the gray water recycling system. In some embodiments, the controller enables remote sensing of one or more of the instrumentation elements of thegray water recycling system. In some embodiments, the gray water recycling system also has an application program. In some embodiments, the controller is adapted to detect a toilet leak, for example by monitoring a treated water outlet meter. In some embodiments, the controller is adapted to determine a water savings value, for example by subtracting a reading from a make up water meter from a reading from a treated water outlet meter.

[0031] This specification also describes a process of predicting a vacation in a house having a gray water recycling system by detecting a lack of flow of treated water to the house for a predetermined period of time, for example 24 hours. In some embodiments, an end to the vacation is predicted by a collection tank being re-filled. In some embodiments, a prefilter and / or a media filter are backwashed after predicting a vacation. In some embodiments, a collection tank is drained after predicting a vacation. In some embodiments, chlorine is maintained in the supply tank after and while vacation is predicted to be occurring. In some embodiments a biological reactor is aerated during a vacation. Some embodiments include backwashing a media filter, backwashing a biological reactor, and / or purging a biological reactor after predicting the end of the vacation.

[0032] This specification also describes a process for treating domestic gray water including suspended solids removal by filtration, soap removal by foam separation, and organics removal by aerobic digestion. Some embodiments also include screening to remove hair. Some embodiments also include grit removal by sedimentation. Some embodiments also include chlorination. In some embodiments, suspended solids filtration occurs in a biofilm media bed, in a non-biological media bed, or both. Some embodiments have media bed filtration downstream of the aerobic digestion. In some embodiments, organics removal occurs in a fixed bed bioreactor. In some embodiments, water moves through a fixed bed bioreactor intermittently in one pass. In some embodiments, the process treats water to NSF 350 standards.

[0033] This specification also describes a system for treating domestic gray water having a foam separation reactor and a fixed bed biofilm reactor, optionally contained in one multi-purpose reactor. In some embodiments, the system also includes one or more of a media filter downstream of the fixed bed biofilm reactor, a supply tank downstream of the media filter, a collection tank upstream of the foam separation reactor and a prefilter upstream of the collection tank. In some embodiments, the total volume of the supply tank and the collection tank is 100 gallons or less. In some embodiments, the system is an appliance sized unit and consumes a peak of no more than 1800 Watts of electrical power.

[0034] This specification also describes a prefilter. The prefilter has a filter body having a graywater inlet, an effluent outlet and a screen between the graywater inlet and the effluent outlet. In some embodiments, the prefilter also has a backwashing fluid inlet and a backwashing outlet. In some embodiments, the prefilter also has a flapper valve, wherein the flapper valve can move between a first position covering the backwashing outlet and a second position covering the effluent outlet. In some embodiments, the flapper valve has a magnet. In some embodiments, the system has a magnetic sensor system adapted to provide a signal indicating the that the flapper valve is in one of the positions. Optionally, when the flapper valve falls by gravity to the first position, the magnetic sensor system provides a signal to a controller indicating that the flapper valve is in the first position. Optionally, the magnetic sensor system includes a permanent magnet attached to the flapper valve and a sensor on the outside of the prefilter body. In some embodiments another magnet on the filter body repels the magnet on the flapper valve to push the flapper valve away from the second position. In some embodiments, the prefilter has a removable cap at the top of the filter body. In some embodiments, the prefilter has a manual drain operable to drain water from the filter body. In some embodiments, the prefilter has a buffer tank above the prefilter body in communication with the greywater inlet. In some embodiments, the prefilter has a water detection probe in a side channel of the buffer tank. Optionally, the side channel is angled upwards andaway from the buffer tank. Optionally, the side channel creates an air pocket that is in communication with a portion of the water detection probe when the buffer tank is filled with water. Optionally, the screen has angled holes pointing upwards and towards the backwashing outlet.

[0035] This specification also describes a collection tank for a gray water recycling system. In some embodiments, the collection tank has a volume of 35-60 gallons. In some embodiments, the collection tank has a sump connected to a purge pump. In some embodiments, the collection tank has a fitting for connection to a purge pump below a fitting for connection to a feed pump. In some embodiments, the collection tank is connected to the outlet or a prefilter and / or the inlet of a reactor.

[0036] This specification also describes a reactor for a gray water recycling system having a foam separation unit and a fixed bed biological reactor. In some embodiments, the reactor has a vertically oriented body, for example having a width that is 25% or less of its height. In some embodiments, the foam separation unit is in an upper part of the reactor and the fixed bed biological reactor is below the foam separation unit. In some embodiments, the fixed bed biological reactor has an upper media bed and a lower media bed. Some embodiments have a gray water inlet and a foam outlet near the top of the reactor and an effluent outlet near the bottom of the reactor. In some embodiments, the reactor has a first air pump in communication with the foam separation unit and a second air pump in communication with the fixed bed biological reactor. In some embodiments, the second air pump has a variable speed.

[0037] This specification also describes a tank for a multi-purpose reactor for a gray water recycling system. In some embodiments the tank has a vertically elongated body having a set of indents, a porous plate supported on the indents for supporting a media bed, a fitting in the side of the body above the set of indents, a fitting near the bottom of the tank, a fitting near the top of the tank and a removable cap at the top of the tank. In some embodiments, the tank hasa second set of indents, a second porous plate supported on the second set of indents for supporting a second media bed and a second fitting in the side of the body above the second set of indents. Some embodiments have an access port in the side of the body between the sets of indents. In some embodiments, the fitting in the side of the body is connected to an open ended pipe segment extending into the body. Some embodiments have a sump at the bottom of the tank. Optionally there is a fitting connected to the sump below the fitting near the bottom of the tank. In some embodiments, the cap has a sloped surface terminating in a second fitting near the top of the tank.

[0038] This specification also describes a process of treating gray water including flowing the gray water intermittently downwards in single pass through a fixed bed bioreactor having multiple vertically separated media beds, or through a foam separation reactor above a fixed bed bioreactor, or through a foam separation reactor above a fixed bed bioreactor having multiple vertically separated media beds. In some embodiments, the foam separation reactor and the fixed bed bioreactor are aerated. In some embodiments, suspended solids are filtered as the gray water flows downwards through the fixed bed bioreactor. In some embodiments, foam containing contaminants are separated from the gray water. In some embodiments, the fixed bed bioreactor is backwashed. In some embodiments, the fixed bed bioreactor has multiple beds and the multiple beds are backwashed at different times.

[0039] This specification also describes a media filter. The media filter has a filter body; a lower screen; an outlet below the lower screen and in communication with the body via the lower screen; an upper screen; and inlet above the upper screen and in communication with the body via the upper screen; and, a media bed between the lower screen and the upper screen. In some embodiments, the media bed has spherical glass beads, optionally 0.5 to 2 mm in diameter. In some embodiments, there is a headspace between the media bed and the upper screen. In some embodiments, the media filter has a cap attached to the filter body, and the upper screen is in the cap and the inlet is in communication with the cap. In some embodiments, there is a media filterpump, wherein the outlet is connected to an inlet of the media filter pump. In some embodiments, there is a pressure transducer between the outlet and the media filter pump. In some embodiments, there is a backwash outlet in communication with the inlet. Some embodiments have an air pump and a water pump in communication with the outlet for backwashing the media bed with air and water.

[0040] This specification also describes a method of treating gray water including flowing the gray water downwards through a media bed and backwashing the media bed. In some embodiments, the media bed is part of a media filter as described above. In some embodiments, backwashing the media bed includes flowing air or an air / water mixture upwards through the media bed. In some embodiments, backwashing also includes flowing water upwards through the media bed. In some embodiments, gray water is drawn through the media bed by a downstream pump. In some embodiments, backwashing is trigged by one or more attributes such as a pressure signal from a sensor in communication with the inlet of the pump, length of time the pump has been running, calculated volume of water that has flowed through the media filter, and length of time since a backwash.

[0041] This specification also described a gray water recycling system having a bioreactor and a media filter downstream of the bioreactor. In some embodiments, the media filter is as described above. In some embodiments, gray water is drawn from the bioreactor and through the media filter by a pump downstream of the media filter. In some embodiments the bioreactor is a vertically oriented fixed bed bioreactor and the gray water flows downwards through the fixed bed bioreactor. In some embodiments, the media filter is vertically oriented and the gray water flows downwards through the media filter. In come embodiments, the top of the media filter is located at 60% of the height of the bioreactor or lower. In some embodiments, the pump is located below the media filter. Some embodiments have a pressure sensor between the media filter and the pump connected to a controller adapted to perform a backwash of the media filter when a selected pressure is detected.

[0042] This specification also describes a chlorination system for treated water, for example in a gray water recycling system having a water tank; a chlorine recirculation loop having an inlet connected to the water tank, an outlet connected to the water tank and a recirculation pump; a chlorine tank; and, a chlorine supply pump connected to the chlorine tank and the water tank. This specification also describes a dye injection system for adding a dye to treated gray water. Some embodiments have a water supply pump downstream of the water tank; a dye tank; and, a dye pump having an inlet connected to the dye tank and an outlet connected to pipe connecting the water tank to an inlet of the water supply pump.

[0043] This specification also describes a process of chlorinating treated gray water including recirculating the treated gray water around a water tank while adding a chlorine solution to the water tank. In some embodiments, the gray water recirculates at a flow rate greater than the chlorine solution is added to the water tank. In some embodiments, a dye is added to water flowing from the water tank to a supply pump.

[0044] This specification also describes a gray water recycling system having a controller. In some embodiments, the controller is connected to instrumentation such as probes, sensors, switches, transducers or meters. In some embodiments, the controller is connected to electrically actuated devices such as valves and pumps. In some embodiments, the controller has a Wi-Fi communication module allowing connection to an internet router and / or direct communication to a diagnostic device, which may be a general purpose computer such as a smartphone. In some embodiments, the controller also has a human machine interface panel. In some embodiments, the controller is adapted to transmit one or more error codes, alerts or warnings. In some embodiments, the controller is adapted to calculate and transmit a water savings value and / or a water usage value. In some embodiments, the controller enables remote operation of one or more of the electrically actuated devices of the gray water recycling system. In some embodiments, the controller enables remote sensing of one or more of the instrumentation elements of the gray waterrecycling system. In some embodiments, the gray water recycling system also has an application program. In some embodiments, the controller is adapted to detect a toilet leak by monitoring when and / or how much treated gray water is delivered to toilets. In some embodiments, the controller is adapted to determine a water savings value by subtracting a volume of make-up water from a volume of water delivered to toilets.

[0045] This specification also describes a process of predicting a vacation in a house having a gray water recycling system by detecting a lack of flow of treated water to the house for a predetermined period of time, for example 24 hours. In some embodiments, an end to the vacation is predicted by a collection tank being re-filled. In some embodiments, a prefilter and / or a media filter are backwashed after predicting a vacation. In some embodiments, a collection tank is drained after predicting a vacation. In some embodiments, a supply tank is chlorinated after predicting a vacation. In some embodiments a biological reactor is aerated after during a vacation. Some embodiments include backwashing a media filter, backwashing a biological reactor, and / or purging a biological reactor after predicting the end of the vacation.

[0046] In some embodiments, the system or process includes other combinations or sub-combinations of the apparatus features or process steps described above, optionally combined with one or more features in the detailed description to follow.BRIEF DESCRIPTION OF THE FIGURES

[0047] Figure 1 is a schematic drawing of a gray water recycling system installed below the showers and bathtubs of a house.

[0048] Figure 2 is a schematic drawing of a gray water recycling system installed on the same level as the showers and bathtubs of a house.

[0049] Figure 3 is an isometric view of the outside of a gray water recycling system showing the connections.

[0050] Figure 4 is an isometric view of the gray water recycling system of Figure 3 without outer covers removed to show the physical arrangement of internal parts.

[0051] Figure 5 is a schematic process and instrumentation drawing of a gray water recycling system.

[0052] Figure 6 is an isometric drawing of a prefilter and adjacent piping.

[0053] Figure 7 is an isometric drawing of the prefilter of Figure 6.

[0054] Figure 8 is an isometric cutaway drawing of the prefilter of Figure 6.

[0055] Figure 9 is another isometric cutaway drawing of the prefilter of Figure 6.

[0056] Figure 10 is a front view of a multi-purpose reactor.

[0057] Figure 11 is a side view of the multi-purpose reactor of Figure 10.

[0058] Figure 12 is a section view of the multi-purpose reactor of Figure 10.

[0059] Figure 13 is an isometric view of the multi-purpose reactor of Figure 10.

[0060] Figure 14 is an isometric view of a media filter.

[0061] Figure 15 is a sectional view of the media filter of Figure 13.DETAILED DESCRIPTION

[0062] The following detailed description relates to an exemplary embodiment, described in detail to help the reader make and use the claimed inventions. Features of the exemplary embodiment are not part of any claim invention unless recited in the claim. Various features described below are optional and may be deleted or replaced with generally equivalent features.Overview

[0063] This specification describes a gray water recycling system and process. The system and process are useful, for example, in treating gray water from bathing (e.g. bathtubs or showers) for re-use in toilet flushing in a singlefamily residence. Optionally, other types of gray water such as laundry water may be treated. Optionally, the treated gray water may be used for other non-potable purposes, such as irrigation. The following paragraphs describe various features of the system and process. However, an invention may involve only a subset of the features in this summary, or a subset of features in this summary combined with one or more features in the detailed description to follow.

[0064] A typical household uses similar amounts of bathing water and toilet flushing water. However, bathing water is produced at a high rate in a concentrated timed period, mostly in the morning, whereas toilet flushing is dispersed throughout the day. The system described herein has two water holding tanks, referred to as a collection tank and a supply tank, to allow for a separation in time between the collection of bathing water and the provision of toilet flushing water.

[0065] The collection tank may have a volume of 35 to 60 gallons. Tank volumes given herein are given in U.S. gallons and describe the maximum volume of water that can be held in the tank, which may be less than the total air capacity of the tank. The total volume of both tanks may be 100 gallons or less, preferably 80 gallons or less. The entire system can be provided in an appliance sized package powered by a single electrical outlet. An embodiment has been tested and meets NSF / ANSI 350 standards for residential graywater recycling.

[0066] In a process, influent gray water is treated with a combination of foam separation, filtration (i.e. solids separation) and biological digestion. Optionally, filtration and biological digestion may occur together in a biofilter, for example a fixed bed downflow bioreactor. Optionally, additional filtration may also be provided by a (non-biological) media filter. Optionally, these processesare preceded by screening and / or sedimentation. Optionally, treated water may be disinfected, for example by chlorination.

[0067] A system may include one or more of a prefilter, a collection tank, a foam floatation unit, a biofilter, a media filter, a supply tank and a chlorination system. Optionally, gray water passes through these units in the order that they are listed in this paragraph.

[0068] The prefilter has a screen, for example with holes in the range of 0.02 to 0.2 inches in width or diameter. The prefilter also has a flapper valve, optionally moved by water and / or air. A sensor, optionally a hall effect sensor, verifies flapper valve operation. A screening chamber opens from the top and has a manual drain valve to facilitate maintenance. An overflow sensor is provided in a side channel of an influent pipe. The screen is backwashed periodically. In some embodiments, angled holes in the prefilter screen direct hair to a drain during backwashing. Optionally, a controller may backwash the screen at the start of vacation mode and reduce or stop backwashing during a vacation mode.

[0069] The collection tank provides a buffer volume such that downstream treatment does not need to match the flow rate of influent water. Grit and sand also collect in a sump at the bottom of the collection tank that can be drained to a purge pump. Optionally, the purge pump is an open impeller pump. The purge pump also removes water containing solids from the biofilter. Optionally, gray water in the collection tank is aerated periodically.

[0070] The foam separation unit and the biofilter may be combined into one reactor unit. The reactor has a vertically oriented tank. A foam separation column is provided in an upper part of the tank. Foam separated effluent flows downwards to the biofilter. A bed expansion area of the biofilter may overlap with the foam separation column.

[0071] The media bed may be divided into multiple segments. Each segment is supported on a media bed partition, which optionally rests on an indent molded into the tank. Dual purpose pipes, which function as an aeratorand a drainpipe, may be provided at the top of each bed segment. The pipe may have an open end. An upper pipe above an upper segment of the media bed provides bubbles for foam separation and drains water after backwashing the upper media bed segment. A lower pipe, located between the upper and lower media bed segments, provides bubbles for backwashing the upper media bed segment and drains water after backwashing the media bed segments. Air can also be provided through a port at the bottom of the tank for backwashing the lower media bed segment. The lower pipe and the bottom of the tank are connected to a first blower (i.e. an air pump), which is optionally a variable speed blower. The blower operates at low speed for aeration and high speed for backwashing. The media bed partitions may disperse air flowing through them. The upper pipe is connected to a second blower, which is optionally a variable speed blower. Optionally, one or more of the dual purpose pipes and the port at the bottom of the tank may be replaced by a combination of a drainpipe and an aerator.

[0072] The bottom of the tank may provide a sump for removal of settled solids and draining. A mid-height access port allows for placement and removal of a lower media bed. A removable cap allows for placement and removal of an upper media bed. The cap is shaped to direct foam to a drain. The media has a specific density greater than 1.

[0073] Water flows vertically downwards through the reactor in a single pass. Suspended solids are filtered as the water flows downwards through the media beds. The flow rate is controlled by a downstream pump that draws water out of the reactor at a predetermined rate but only while there is storage capacity in the supply tank and water in the reactor is above a minimum level. Aeration above the media beds provides foam separation to remove soaps and some solids. This aeration also pre-oxygenates influent water. The media bed is also aerated periodically at a higher rate for bed fluidizing and backwashing. The media bed segments are backwashed individually at different times. Solids released during backwash are drained from the drainpipes or dual purpose pipes.The media bed is kept submerged and aerated except during periodic drain downs.

[0074] Water flows from the bottom of the reactor to a (non-biological) media filter. The media filter may have a bed of spherical glass beads or other similar media. The media may have a size in the range of 0.02 to 0.1 inches. The media is contained between upper and lower screens. A gap between the top of the bed and the upper screen provides expansion room for fluidization

[0075] The media filter is placed downstream of the multi-purpose reactor. Optionally, the top of the media filter is below the minimum water level in the multi-purpose reactor. Water is drawn from the reactor into the filter by a pump. Optionally, the pump is downstream of the filter. Water flows downwards through the media bed to an outlet at the bottom of the media filter. Optionally, the pump is below the outlet of the media filter.

[0076] A pressure sensor on the inlet side of the pump is used to trigger backwashing on an as needed basis. Backwashing may include an air only backwash and / or an air / water backwash before a final water backwash.

[0077] Water leaving the media filter is collected in a supply tank. A chlorination system has a chlorine recirculation loop having an inlet connected to the water tank, an outlet connected to the water tank and a recirculation pump. The chlorination system also has a chlorine tank and a chlorine supply pump connected to the chlorine tank and the supply tank or the chlorine recirculation loop. A water supply pump downstream of the supply tank supplies water for toilet flushing on demand.

[0078] A chlorination process includes recirculating treated gray water in the recirculation loop and adding chlorine into the supply tank. Recirculating the treated gray water mixes the chlorine with the gray water. Optionally, the gray water recirculates at a flow rate greater than the chlorine being added.

[0079] Optionally, the system has a dye tank. A dye pump having an inlet connected to the dye tank and an outlet connected to pipe connecting the watertank to an inlet of the water supply pump. Dye is added to water flowing from the water tank to a supply pump.

[0080] The system controller is connected to all of the instrumentation (for example probes, sensors, transducers, switches and meters) of the grey water recycling system. The system controller is also connected to all of the valves of the gray water recycling system, except for any valves indicated to be manual valves. Controlled valves are electrically actuated valves, for example solenoid valves or motorized valves. The controller is also able to turn on and off any air or liquid pumps except, optionally, for a supply pump which may operate according to a separate pump controller with a pressure switch.

[0081] The system controller also includes a wi-fi communication module that provides connection to an internet router. An application program on the homeowner's smartphone or other computer receives data from the system and may permit operation of parts of the system. Data may include, for example, a water savings calculation, service codes, and / or alerts. Water savings is determined by subtracting any influent make up water flow from treated water supplied to toilets. A leaky toilet may be indicated by, for example, continuous of unexpected operation of the supply pump, unexpected pressure loss measured by a pressure sensor and / or an above normal amount of water being supplied to toilets. The controller may send an alert to the homeowner when a leaky toilet is indicated. Data such as alerts may also be available to service providers. Data such as water savings may be provided to the system supplier for aggregate use, for example to calculate the total water savings from multiple homes.

[0082] Optionally, the system also has a human machine interface (HMI) to provide data and / or accept instructions. The HMI includes a panel visible to the homeowner or service technician. Technicians may also use direct wi-fi or cabled communication to communicate with a controller of the system, for example to retrieve more error codes or operate individual components for diagnostic purposes.

[0083] The system automatically determines the beginning and end of vacations in the household and enters and exits a vacation mode. The system determines the start of a vacation mode by the lack of operation of the supply pump for an extended period of time, for example 24-72 hours. The end of a vacation is determined by the collection tank receiving more than a selected amount of gray water. The system automatically does various steps on the start of vacation, for example one or more of backwashing the intake filter, backwashing the media tank, and draining the collection tank. After these shut down steps, water consuming steps are put on hold but the biological media bed remains aerated and chlorine may be refreshed in the supply tank. At the end of a vacation, the controller activates various steps, for example the media filter is backwashed, the biological media bed is backwashed and purged.

[0084] The further description below relates to an exemplary embodiment, described in detail to further enable the invention. Various details of the exemplary embodiment are not essential to any claimed invention and not part of any claim unless recited in the claim. Various features described below are optional and may be deleted or replaced with generally equivalent features.Installation

[0085] Figure 1 shows a house 10 with a gray water recycling system 12. Gray water collected for example from a bathtub or shower 20 flows through gray water drain 22 to the gray water recycling system 12. The gray water recycling system 12 delivers treated water under pressure to a toilet 24 through a pressurized toilet supply line 28. A waste drain line 30 connects the gray water recycling system 12 to a sanitary drain system 32. Sanitary drain system 32 is connected to a sewer, septic system or other wastewater treatment system in or outside of the house 10. The gray water recycling system is also connected to a potable water supply line 34 and a vent stack 36. Optionally, waste laundry water may also be treated in the gray water recycling system 12.

[0086] Figure 2 shows another house 10 with the gray water recycling system 12 at about the same elevation as the bathtub or shower 20 such that gray water cannot drain by gravity to the gray water recycling system 12. In this example, the gray water drain 22 is connected to a sump pit 38. A sump pump 40 in the sump pit 38 delivers gray water to the gray water recycling system 12.Component Packaging and Connections

[0087] Figure 3 shows an isometric view of the gray water recycling system 12. In the example shown, the gray water recycling system is 79 inches high, 33 inches wide and 24 inches deep. The size of the gray water recycling system 12 may vary, but it is preferably not more than 15% higher, not more than 25% larger in footprint area and not more than 50% larger in volume. The gray water recycling system 12 has a size on the order of various other household appliances or mechanical devices and may be moved through ordinary residential doorways, and down a stairway if required, using ordinary manual moving carts, dollies or straps. The gray water recycling system 12 may be located, for example, in a garage, basement or mechanical room of a house 10.

[0088] The gray water recycling system 12 has a make-up freshwater connection 50, typically a 1 / 2 inch or % inch connection, for connection to the potable water supply line 34. The gray water recycling system 12 has a vent connection 52, typically a 11 1 ” or 2” connection, for connection to the vent stack 36. The gray water recycling system 12 has a toilet supply connection 54, typically a 1 / 2 inch or % inch connection, for connection to the toilet supply line 28. The gray water recycling system 12 has a gray water inlet connection 56, optionally a 1 7 - 2 inch connection, for connection to the gray water drain 22. The gray water recycling system 12 has a system drain connection 58, optionally a 1 72- 2 inch connection, for connection to the sanitary drain system 32.

[0089] Figure 4 is an isometric view of the gray water recycling system 12 with outer covers removed to show the arrangement of the main components. The main components include a reactor 60, a supply tank 62, a display 64, apower supply 66, a controller 68, a prefilter 70, a collection tank 72, a media filter 74 and a chlorine tank 76.

[0090] The gray water recycling system 12 is powered by plugging into a standard 15 amp, 120 volt electrical outlet. The gray water recycling system 12 can also be connected to a local wireless network for further connection to the internet. The internet connection facilitates data collection and sending alerts. Via an internet web page, various valves and pumps of the gray water recycling system 12 can also be operated manually for commissioning, startup, testing, or diagnostic procedures.Water Treatment System and Process

[0091] Figure 5 is a schematic process and instrumentation drawing for the gray water recycling system 12. The primary flow of water through the gray water recycling system 12 is from the graywater inlet connection 56 to the prefilter 70 to the collection tank 72 to the reactor 60 to the media filter 74 to the supply tank 62 and to the toilet supply connection 54. All valves, pumps and instrumentation (e.g. probes, sensors, switches, transducers, and meters) are connected to the controller 68 unless stated otherwise. Lines shown in Figure 5 may be rigid pipes or flexible hoses as appropriate and connected using appropriate fittings.

[0092] The prefilter 70 screens the incoming gray water. The prefilter 70 retains large or fibrous contaminants such as trash and hair. Backwashing the prefilter 70 removes the contaminants retained on the screen through the system drain connection 58.

[0093] Screened gray water flows from the prefilter 70 to a collection tank 72. The collection tank 72 provides a buffer volume so that the reactor 60 is not required to process gray water at the instantaneous rate that it is produced in the house 10. For example, the instantaneous or maximum treatment rate of the reactor 60 may be 2-10 gallons per hour. In contrast, the EPA estimates that a shower has a typical flow rate of 2.1 gallons per minute, or about 125 gallons perhour. A shower may last for over 8 minutes and in a typical single-family residence there may be an average of two showers per day, both taken in the morning. While low flow showerheads with flow rates of 1.6 gallons per minute are becoming more common, storage in the collection tank 72 is still required since treatment of one day’s worth of shower water in the reactor 60 can require several hours or more. A lower collection tank 72 volume and a higher treatment rate would increase the required size of the supply tank 62 and provide less effective treatment. Although the instantaneous or maximum treatment rate of the reactor 60 may be 2-10 US gallons per hour, flow through the reactor 60 is also affected by toilet flushing as discussed below, which beneficially tends to distribute the biological process over the entire day and reduce the average treatment rate relative to the instantaneous or maximum treatment rate. Optionally, the collection tank 72 may have a size in the range of 35-60 gallons. The collection tank may be aerated periodically to avoid anoxic or anaerobic conditions.

[0094] In addition to storing water, the collection tank 72 also provides grit removal by sedimentation. Grit includes small particles of dense material such as sand. Grit settles in reasonably calm water, which is provided by the collection tank 72 other than at times when gray water is actively flowing into it or when the gray water is being aerated. Accumulated grit is drained periodically from the bottom of the collection tank 72 and removed through the system drain connection 58. Optionally, a settling cycle is completed to ensure the water is calm allowing grit to settle prior to draining the accumulated grit.

[0095] The reactor 60 provides a foam separation unit 110 upstream of a fixed bed biological reactor 112. The foam separation unit 110 uses air bubbles to float contaminants to the top of the reactor 60. Foam containing the contaminants collects above a free water surface in the reactor 60. As the foam accumulates, it passes through a reactor overflow line 114 leading to the system drain connection 58. The foam separation unit 110 removes surfactant materials such as soap and shampoo. Some dissolved and suspended solids are alsoremoved with the foam. The volume of the reactor 60 may be in the range of 20-40 gallons.

[0096] The fixed bed biological reactor 112 contains particles, for example particles of a plastic medium with a high surface area to volume ratio. Biofilms grow on the particles and consume contaminants, for example surfactants and organics, in the gray water. The fixed bed biological reactor 112 is aerated so that the biofilm is at least primarily aerobic. However, anaerobic regions may exist in the biofilm, for example in regions of the biofilm adjacent the particles.

[0097] Gray water normally flows downwards through the reactor 60. The particles in the fixed bed biological reactor 112 also act as a media filter to remove suspended solids. Captured solids, and some excess biofilm, are removed periodically by backwashing the fixed bed biological reactor 112. The backwashing water with entrained contaminants is removed through ports 116 and flow to the system drain connection 58.

[0098] The reactor 60 provides a combination of foam separation, media filtration and biological treatment. Additional media filtration is provided by the downstream media filter 74. Media filter 74 contains a relatively small medium, for example particles of sand, glass or foamed glass. The media filter 74 thereby provides additional, or polishing, suspended solids removal by filtration. Solids retained in the media filter 74 are released by backwashing to a media filter overflow line 120 connected to the system drain connection 58. Separating the media filter 74 from the reactor 60 facilitates packaging the treatment units into the desired form factor of the gray water recycling system 12. Separating the media filter 74 from the reactor 60 also allows the reactor 60 to be backwashed separately from the media filter 74. Separately backwashing multiple small units within the gray water recycling system 12, preferably at different times, helps with keeping the maximum power required to operate the gray water recycling system 12 below the maximum power of a standard electrical outlet, for example 1,800 Watts.

[0099] Flow through the reactor 60 and the media filter 74 is controlled primarily by a media filter pump 138 downstream of the media filter 74. The media filter pump 138 operates at a predetermined rate when on, for example at 2-10 gallons per hour. During normal operation, the media filter pump 138 is turned on whenever there is water at a predetermined level above the fixed bed biological reactor 112 and storage capacity in the supply tank 62. A feed pump 134 upstream of the reactor 60 pumps water from the collection tank 72 to the reactor 60 in batches as required to keep a water level in the reactor 60 within a desired range above the predetermined level. The feed pump 134 and the media filter pump 138 are thereby separately controlled but cooperate to provide a flow of water through the reactor 60 while keeping the fixed bed biological reactor 112 immersed.

[0100] Although the instantaneous rate of the media filter pump 138 may be, for example, 2-10 gallons per hour, the average flow rate through the reactor 60 (averaged over 24 hours) is less since it is limited by available storage capacity in the supply tank 62, which in turn is a function of toilet flushing. Considering the essentially plug flow movement of water downwards through the reactor 60 and media filter 74, and the retention of untreated water in the collection tank 72, a significant amount of untreated water is unlikely to break through to the supply tank 62.

[0101] Water drawn through the reactor 60 and media filter 74 is pumped to the supply tank 62. Water in the supply tank 62 is disinfected. In the example shown, disinfection is by way of chlorination. Alternatively, disinfection can be provided by ultraviolet radiation or ozonation. However, chlorination advantageously provides residual chlorine in the treated water that can prevent reinfection of the treated water beyond the supply tank 62, for example as the treated water flows through a toilet supply line 28 or sits in a toilet 24.

[0102] Toilet flushing requires an average of 33 gallons per household per day. However, while toilet flushing may also have a morning peak, it is typically more evenly dispersed throughout the day compared to bathing. The averageflushing volume is 2.6 gallons per flush, although low flush toilets that use 1.28 to 1.6 gallons per flush are becoming common. In some households, toilet flushing in the morning, i.e. 6 am to 9 am, could require 6-15 gallons over 1-2 hours. The supply tank 62 size is sufficient for several toilet flushings. For example, the supply tank 62 may hold 20-40 gallons.

[0103] A supply pump 80 delivers treated water from supply tank 62 to the toilet supply connection 54. However, by manipulation of the appropriate valves, treated water may also flow to the media filter 74 or to the prefilter 70 for backwashing.

[0104] A first air pump 82 and a second air pump 84 can be activated, in combination with operation of appropriate valves, to deliver air selectively to the media filter 74, the reactor 60, the collection tank 72 or the prefilter 70. The air may be used for backwashing, for foam separation, of for adding oxygen to the gray water.

[0105] In combination, the gray water recycling system 12 provides a combination of multiple treatment units and processes. The gray water recycling system 12 treats water using a combination of multiple processes including: coarse screening to remove trash and hair; grit removal by sedimentation; soap removal by foam separation; suspended solids removal by filtration; organic removal by aerobic digestion; and, disinfection by chlorine. Suspended solids filtration can occur by downflow through a biofilm media bed and / or through a (non-biological) media bed. Optionally, at least some suspended solids filtration occurs downstream of aerobic digestion to remove any biomass that might be released by the upstream reactor. Parts of the gray water recycling system will be described in more detail belowPrefilter

[0106] Referring to Figure 6, gray water enters through the gray water inlet connection 56 and flows to the prefilter 70. The prefilter 70 separates solids such as hair, soap pieces and other debris from the gray water. Filtered gray waterflows from the prefilter 70 to the collection tank 72 through an outlet at the back of the prefilter 70 (not visible in Figure 6) that will be described further below.

[0107] A section of the influent piping upstream of the prefilter 70 and below a prefilter bypass pipe 152 functions as a prefilter buffer tank 150. In some embodiments, the prefilter buffer tank 150 has a volume of about 0.5 gallons. If the prefilter 70 is partially fouled, such that gray water does not flow through the prefilter at the rate that the gray water is received, the prefilter buffer tank 150 will temporarily retain a volume of gray water. The prefilter buffer tank 150 thereby allows more time for the incoming gray water to pass through the prefilter 70.

[0108] If the prefilter 70 becomes significantly clogged, a free water surface of the gray water may reach the level of the prefilter bypass pipe 152. The gray water overflows through the prefilter bypass pipe 152 to a waste stack 154 connected to the system drain connector 58. Before the gray water reaches the level of the prefilter bypass pipe 152, it will also reach a water detection probe 156. The water detection probe 156 sends a signal to the controller 68 indicating that influent gray water is backing up in the prefilter bypass tank 150, which in turn indicates that the prefilter 70 is becoming clogged. In some embodiments, the water detection probe 156 is located in a side channel 188 of the prefilter buffer tank 150. The side channel 188 is angled upwards and away from the prefilter buffer tank to inhibit contact with raw water flowing downwards through the prefilter buffer tank 150. In some embodiments, the angled side channel 188 creates an air pocket when the free surface of the gray water reaches the prefilter bypass pipe 152 preventing buildup of material on the walls of the bypass which can falsely set off a water detection probe.

[0109] After receiving the signal, the controller 68 implements a prefilter 70 backwash. During the backwash, to be described further below, backwash water with entrained solids flows from the prefilter 70 to the waste stack 154 through a prefilter backwash connector 158.

[0110] Referring to Figures 7 to 9, the prefilter 70 has a prefilter body 160 and a prefilter cap 162. The prefilter cap 162 is removable to allow access to the inside of the prefilter body 160 for assembly or maintenance. When attached, the prefilter cap 162 is sealed to the prefilter body. The prefilter cap 162 is attached to the top of the prefilter body 160 such that the prefilter cap 162 can be removed even with some gray water in the prefilter body 160 without spilling the gray water.

[0111] The prefilter 70 has a prefilter inlet 164, a prefilter backwash outlet 166 and a prefilter effluent outlet 168. The prefilter inlet 164 is connected to and receives gray water from the bypass tank 150. The prefilter backwash outlet 166 is connected to and releases backwash water to the prefilter backwash connector 158. The prefilter effluent outlet 168 is connected to and releases filtered gray water to the collection tank 72.

[0112] The prefilter 70 also has a prefilter manual drain 170 with a prefilter manual valve 172. If the prefilter 70 becomes clogged and does not become cleared with a backwash, gray water will remain backed up in the bypass tank 150. Opening the prefilter manual valve 172 allows gray water to be drained from the prefilter buffer tank 150. The prefilter cap 162 can then be removed to service the prefilter 70 with minimal gray water spillage. Optionally, the prefilter manual drain 170 may be connected through a pipe (not shown) to the waste stack 154. In another option, the prefilter manual drain 170 is placed in communication with a bucket before opening the prefilter manual valve 172.

[0113] As shown in Figures 7 to 9, the prefilter 70 is in an operating configuration. Gray water entering through the prefilter inlet 164. One side of a dual flapper valve 176 covers the prefilter backwash outlet 166. The gray water passes through a screen 174 and leaves the prefilter 70 through the prefilter effluent outlet 168. The screen 174 retains solids on its upper surface.

[0114] When water is detected at the water detection probe 156, the controller 68 optionally waits for a predetermined period of time, for example 5 or 10 minutes, and then implements a backwash. During the backwash, water issprayed through a prefilter backwash water inlet 178 and optionally air is injected through a prefilter air inlet 180. In some embodiments, air and backwash water are provided together. Optionally, air, water and / or a mixture of air and water can be provided separately in various sequences.

[0115] Referring to Figure 5, backwashing water is provided by opening a prefilter backwash valve 182. Opening the prefilter backwash valve 182 reduces the pressure on the outlet of the supply pump 80, which turns on the supply pump 80 as described further below. Supply pump 80 pumps treated water from the supply tank 62 to the prefilter backwash water inlet 178. Air is pumped from the first air pump 82 to the prefilter air inlet 180 by appropriate actuation of the intervening valves.

[0116] Returning to Figures 7 to 9, the backwashing air and / or water impinges on the dual flapper valve 176 which causes the dual flapper valve 176 to rotate. One part of the dual flapper valve 176 covers the prefilter effluent outlet 168. The other part of the dual flapper valve 176 uncovers the prefilter backwash outlet 166. Backwashing water and / or air flows in a reverse direction through the prefilter screen 174 and to the prefilter effluent outlet 168. Solids retained on the prefilter screen 174 are thereby removed. After a predetermined time, the controller 68 closes the prefilter backwash valve 182 and stops the flow of air to the prefilter 70 to end the backwash.

[0117] In some embodiments, the prefilter screen 174 has holes with an opening size of, for example 0.02-0.2 inches. Optionally, the holes in the prefilter screen 174 may be angled upwards and towards the side of the prefilter 70 having the prefilter backwash outlet 166 to help with moving solids in the required direction.

[0118] After a backwash, the dual flapper valve 176 falls by gravity back to the position shown in Figures 8 and 9. Optionally, the dual flapper valve 176 is fitted with a magnet 184. In some embodiments, a magnet placed on the prefilter body 160 is used to push the dual flapper valve 176 to the position shown in Figures 8 and 9, which may be an alternative to, or in addition to, the dual flappervalve 176 falling by gravity. When the magnet 184 is used, optionally a magnet sensor 186 on the prefilter body 160 senses when the dual flapper valve 176 has returned to its normal operating position and send a signal to the controller 68. The controller 68 sends an alert if it does not receive a signal indicating that the dual flapper valve 176 has returned to its normal operating position after a backwash.

[0119] In addition to backwashing triggered by fouling of the prefilter screen 174, optionally the controller 68 backwashes the prefilter 70 at predetermined time intervals and / or after the controller detects that a predetermined amount of water has passed through the prefilter 70, which may be sensed by the arrival of the prefiltered water in the collection tank 72.Collection Tank

[0120] The prefiltered water flows by gravity to the collection tank 72. A collection tank pressure transducer 130 near the bottom of the collection tank 72 communicates with the controller 68. Signals from the collection tank pressure transducer 130 allow the controller 68 to calculate the volume of water in the collection tank 72. The collection tank pressure transducer 130 also allows the controller 68 to detect the addition of any new incoming water, which is indicated by a rapid increase in the signal from the collection tank pressure transducer 130.

[0121] As discussed above, an average household may have two showers in the morning, each using about 16 gallons of water. The collection tank 72 is sized to hold at least a significant portion of morning shower water for processing later. For example, the collection tank 72 may have a volume of 35-60 gallons. The bottom of the collection tank has sloping walls forming a sump.

[0122] In some embodiments, water stored in the collection tank 72 is periodically aerated by way of the second air pump 84 to oxygenate the gray water and to help keep the gray water in an aerobic state.

[0123] Grit and sand settle and collect in the sump at the bottom of the collection tank 72. The settled solids can be removed by a purge pump 132 in communication with the collection tank 72. The purge pump 132 is optionally an open impeller pump able to handle solids. The purge pump 132 may also be used to remove solids from the reactor 60.

[0124] The collection tank 72 is purged (e.g. partially or completely drained) periodically. The frequency of the collection tank 72 purge may be determined by a length of time (for example once a week) or by a specified volume of water that has entered the collection tank 72 as sensed by the controller 60, or by a combination of elapsed time and volume of water. Optionally, after the time for a purge has arrived, the controller 68 may wait for a new input of gray water to be detected or for a minimum water level in the collection tank 72 to be detected. The controller 68 may also cease aeration for a period of time to help allow the grit to settle. The controller 68 opens a collection tank valve 136 and causes the purge pump 132 to pump water from the collection tank 72 to the system drain 58. The purge pump 132 may remove a predetermined volume of water or reduce the pressure (water level) in the collection tank 72 to a predetermined amount.

[0125] A feed pump 134 (alternatively called a transfer pump) pumps water from the collection tank 72 to the reactor 60. A pipe fitting on the collection tank 72 connected to the feed pump 134 may be located above a pipe fitting connecting the sump to the purge pump 132, for example by at least 1” center to center, to inhibit settled solids from flowing to the reactor 60.Multi-purpose Reactor

[0126] Referring to Figure 5, the reactor 60 receives gray water from the collection tank 72 through the top of the reactor 60. The gray water is treated as it flows downwards intermittently through the reactor 60 in a single pass. Treated water leaves the bottom of the reactor 60 and flows to the media filter 74. The reactor 60 may have a volume in the range of 20 to 40 gallons.

[0127] The reactor 60 is connected to the first air pump 82 and the second air pump 84. The second air pump 84 is smaller than the first air pump 82. The second air pump 84 creates bubbles from the upper port 116 in the foam separation unit 110. Optionally, bubbles are only provided from the upper port 116 while water is moving through the reactor 60, e.g. when a media filter pump 138 is on. This aeration provides foam separation and removes, for example soaps, surfactants and some solids. Air from the second air pump also oxygenates influent water before the influent water flows downwards into the fixed bed biological reactor (FBBR) 112.

[0128] The first air pump 84 also operates, optionally substantially continuously, to provide bubbles from the lower port 116 and optionally through a reactor drain 118 for biological treatment in the FBBR 112. The FBBR 112 may be aerated to provide aerobic conditions throughout at least most of the FBBR 112 at least most of the time to provide aerobic digestion of contaminants in the gray water. While anaerobic zones may exist in some parts of the FBBR 112, and can assist for example with biological nitrogen removal, the FBBR 112 is sufficiently aerated to avoid creating noticeable amounts of hydrogen sulfide or other odorous gasses.

[0129] The flow of water through the reactor 60 is intermittent. While water is flowing, there is generally plug flow, although there may be some mixing caused by aeration as described further below. While water is not flowing, aeration also causes some mixing. However, solids in the gray water are retained as the gray water moves downwards through the FBBR 112. The aeration does not re-suspend solids that have been trapped in the FBBR 112. The retained solids are released and removed during backwashing.

[0130] The first air pump 82 has a variable speed drive. When operated at low speed, the FBBR 112 is aerated but not fluidized. When the first air pump 82 operates at a higher speed, part of the FBBR 112 can be fluidized and backwashed. As discussed further below, the FBBR 112 contains two media beds. Backwashing is done periodically, for example once per week, and / orbased on the volume of water processed through the FBBR 112, optionally at night. During a backwash, the first air pump 82 is operated at the higher rate, which fluidizes one of the FBBR 112 beds and releases trapped solids from fluidized FBBR 112 bed. To end the backwash, the first air pump 82 is turned off, a purge valve 190 connected to a port 116 above the backwashed bed is opened and a purge pump 132 is turned on to pump the water with accumulated solids to flow to the system drain connection 58. The reactor 60 thereby provides suspended solids filtration in addition to foam separation and biological digestion.

[0131] The two FBBR 112 beds are backwashed at different times to reduce the airflow required relative to the amount of air that would be required to fluidize both of the FBBR 112 beds at the same time. This allows the first air pump 82 to be smaller, and to reduce the peak power requirement of the gray water recycling system 12. Backwashing the FBBR 112 beds separately also avoids significantly depleting the microbial population in the FBBR 112 as a whole.

[0132] Referring to Figures 10 to 13, the reactor 60 has a body 250. The body 250 may be made, for example, of molded plastic. The body 250 is vertically elongated. For example the body 250 may extend through 80% or more of the height of the gray water recycling system 12 while having a width (which may be a diameter) that is 25% or less of its height.

[0133] A pair of lower indents 182 at the bottom of the body 250 support a lower partition 254. The partition 254 is a porous plate and supports a lower media bed 256. A pair of upper indents 258 near the middle elevation of the body 250 support an upper partition 260. The upper partition 260 is a porous plate and supports an upper media bed 262.

[0134] The FBBR 112 of the reactor 60 is thereby provided with multiple, vertically spaced apart, media beds. There is a vertical gap between the top of the lower media bed 256 and the upper media bed 262. The foam separation unit 110 acts as a headspace above the upper media bed 262. Each media bed 256, 262 therefore has room for expansion during backwashing.

[0135] Fittings 264 connect to ports 116 (see Figure 5) above but near the top of each media bed 256, 262. The ports 116 perform a dual purpose of acting as an aerator and a drain. Optionally, each port 116 may be an open ended pipe segment without a diffuser. The absence of a diffuser inhibits fouling when the port 116 is used as a drain pipe. The partitions 254, 260 helps to diffuse air supplied from below them.

[0136] The bottom of the body 250 is formed to provide a sump 266. The sump 266 is connected to the reactor drain 118. The sump 266 collects some solids which may be purged from the reactor 60 periodically, for example prior to backwashing the lower media bed 256. A reactor effluent fitting 268 is located at the bottom of the body 250 but above the elevation of the reactor drain 118. The reactor effluent fitting 268 is connected by a pipe to the media filter 74. A gray water inlet 276 is provided near the top of the body 250.

[0137] An access port 270 allows for placement and removal of the media of the lower media bed 256. The media may be removed, for example by a wet vacuum. A removable reactor cap 272 allows for placement and removal of upper media bed 262. The reactor cap 272 may be shaped to duct foam to a foamate outlet 274 connected to the reactor overflow line 114. For example, the cap may have a sloped surface leading to the foamate outlet 274.Media Filter

[0138] Referring to Figures 14 and 15, the media filter 74 has a media bed that traps solids that pass through the reactor 60, as well as any biofilm fragments that are released from the reactor 60. The media may have a size in the range of 0.02 to 0.1 inches. In some embodiments, the media bed contains spherical glass beads or foamed glass beads.

[0139] The media filter 74 has a filter body 220. A lower end of the filter body 220 is connected to an effluent outlet 224, in the example shown by way of an optional reducing adapter 222. An upper end of the body 220 is connected to a filter inlet 230 and a filter waste outlet 232. As in the example shown, theseconnections are optionally made through an optional flange 226, cap 228 and 3-way valve 234.

[0140] The media filter 74 has a lower screen 236 and an upper screen 238. A media bed is contained between the lower screen 236 and the upper screen 238. In some embodiments, the screens 236, 238 are made of stainless steel wire cloth. The media bed (not shown) does not fill the entire volume between the screen 236, 238 to provide room for the media bed to expand during backwashing. As in the example shown, the upper screen 238 is optionally located in the cap 228, which is removable.

[0141] Referring to Figure 5, water is drawn out of the reactor 60 and through a media filter 74 by the media filter pump 138. A media filter pressure transducer 240 on the suction side of the media filter pump 138 provides a signal responsive to the accumulation of solids in the media filter. The media filter 74 is backwashed when a predetermined pressure, for example -2 psi, is reached.

[0142] To minimize the use of backwash water, backwashing includes an air only backwash and / or an air / water backwash before a final water backwash. Water for backwashing is provided by the supply pump 80 from the supply tank 62 after the appropriate valves are opened. For example, opening a media filter backwash valve 242 and closing a media filter effluent valve 244 causes a reduction in pressure at the outlet of the supply pump 80. The reduction in pressure is sensed by the supply pump pressure switch 162 and turns on the supply pump 80 which causes water to flow backwards through the media filter 74. Air for backwashing is provided by the first air pump 82 which, after opening appropriate valves, flows backwards through the media filter 74. The air and / or water fluidizes the media bed and release trapped solids which are sent, with appropriate positioning of the 3-way valve 234, to the filter waste outlet 232 and the system drain connection 58.

[0143] As mentioned above, the media filter 74 is placed downstream of the reactor 60 and water is drawn through the reactor 60 and the media filter 74 by the media filter pump 138 downstream of the media filter 74. Accordingly,water is drawn through the media filter 74 by suction. In some embodiments, the media filter 74 is mounted at a low position relative to the reactor 60. In some embodiments, the top of the media filter 74 is below the minimum water level in the reactor 60 and / or at 60% of the height of the reactor 60 or lower. In some embodiments, the media filter pump 138 is also mounted in a low position relative to the reactor 60. In some embodiments, the media filter pump 138 is also placed below the filter outlet 224. Placing the media filter pump 138 downstream of the reactor 60 avoids having solids flow through the media filter pump 138. Alternatively, the media filter pump 138 could be located between the reactor 60 and the media filter 74.Supply Tank

[0144] Treated effluent water is pumped from the media filter 74 to the supply tank 62. The supply tank 62 can store enough water, for example 20-40 gallons, for several toilet flushings. A supply tank pressure transducer 128 attached to the supply tank 62 allows the controller 68 to determine the water level in the supply tank 62.

[0145] Treated water is delivered from the supply tank 62 for use, for example to flush toilets, by a supply pump 80. A pressure switch 142 is in communication with the outlet of the supply pump 80. The pressure switch 142 turns on the supply pump 80 whenever the outlet pressure drops below a preselected minimum, for example 30 psi, and turns off the supply pump 80 whenever the outlet pressure exceeds a preselected maximum, for example 50 psi. Flushing a toilet lowers the pressure at the supply pump 80 outlet and thereby causes the supply pump 80 to deliver water from the supply tank 62 until the toilet tank is refilled. Optionally, a pressure sensor / transducer that is in communication with the outlet of the supply pump 80 and the controller 68 can be used instead of, or in addition to, the pressure switch 142. In this configuration, the controller 68 can vary the speed of the supply pump 80 based on the outlet pressure. For example, the speed of the supply pump 80 can be increased as its outlet pressure approaches the minimum pressure and decreased as its outletpressure approaches the maximum pressure. The supply pump 80 is also used to provide water for backwashing the prefilter 70, media filter 74 and reactor 60 (via the pre-filter 74).

[0146] If the water level in the supply tank 62 drops below a minimum level, potable water is added through the make up freshwater connection 50 by opening a freshwater make up valve 140 until the minimum water level is reached. The freshwater make-up valve 140 is separated from the supply tank 62 by an air-gap, not shown in Figure 5.

[0147] The flow of water delivered to toilets by the supply pump 80 is measured by a treated water outlet meter 106. Any make up freshwater that enters the supply tank 62 is measured by a make up water meter 108. The controller 68 calculates water saved by the gray water recycling system 12 by subtracting readings from the make up water meter 108 from readings from the treated water outlet meter 106. In some embodiments, other methods are used to measure the volume of make-up water delivered to supply tank 62 or the volume of water delivered to toilets. For example, operation of the supply pump 80 or changing volume in the suppl tank 62, optionally in combination with valve settings, can be used.

[0148] In some embodiments a water hammer arrester 192 and check valve 194 are provided between the supply pump 80 and the toilet supply connection 54.Chlorination and Dyeing

[0149] Referring to Figure 5, chlorine (e.g. as provided in a sodium hypochlorite solution) is added to treated gray water in the supply tank 62 to disinfect the treated water and to prevent the growth of bacteria which may enter the supply tank 62 through the vent connection 52 for example. The chlorine is stored in a chlorine tank 76, which may be filled when required by a homeowner or service technician. The controller 68 calculates the dosing volume andfrequency as a function of the volume and timing of water received into the supply tank 62.

[0150] An upper-level sensor 92 indicates when the chlorine tank 76 is partially empty, which causes the controller 68 to send an alert that the chlorine should be added. A lower-level sensor 94 indicates when the chlorine tank 76 is essentially empty, which causes the controller 68 to send a corresponding alert and optionally to activate freshwater and gray water bypass valves (not shown) and to put the gray water recycling system 12 into an idle mode.

[0151] The chlorine may be provided at a high concentration, for example as in liquid chlorine for use in swimming pools. The concentrated chlorine reduces the volume required of the chlorine tank 76. Optionally, the chlorine tank 76 may be large enough for 6-12 months or more of operation of the gray water recycling system 12.

[0152] A chlorine pump 96 pumps chlorine from the chlorine tank 76 into the top of the supply tank 62. A chlorine recirculation pump 100 draws treated gray water from near the bottom of the supply tank 62, through the recirculation loop 98, and discharges it near the top of the supply tank 62.

[0153] The chlorine pump 96 adds a relatively small flow of chlorine, for example a drip feed from a peristaltic pump, into the top of the supply tank 62. Water flowing in the recirculation loop 98 dilutes and mixes incoming chlorine as it enters the supply tank 62. The circulation pump 100 may also be operated to mix the contents of the supply tank 62 at other times.

[0154] In some jurisdictions a dye, typically a blue dye, must be added to treated water to indicate that the water is not potable. However, some dyes can react with chlorine under some conditions. If required, a dye is added from a dye tank 102 by way of a dye pump 104. The dye pump 104 is optionally a peristaltic pump. The dye pump 104 is connected downstream of the supply tank 62 inhibit contact with chlorinated water in the supply tank 62. The dye pump 104 is connected on the suction side of the supply pump 80 and activated with the supply pump 80. In this way, blue dye is diluted in flowing water for rapid dilutionand then mixed with the flowing water as it passes through the supply pump 80. These features also reduce contact time between chlorine and dye..Controller

[0155] The controller 68, optionally called a controller system, optionally include multiple controller boards each having their own microprocessor. The multiple controller boards are in communication with each other, with one controller board acting as the main logic controller and the other controller boards acting to operate equipment connected to them. The controller 68 monitors some or all the instrumentation in the gray water recycling system 12, for example the water detection probes, sensors, pressure switches, pressure transducers, level switches and water meters, and activates some or all of the various pieces of equipment, such as pumps and valves, shown in Figure 5. The controller 68 also activates the various pumps and valves in the gray water recycling system 12. For some functions, the controller 68 may involve a programmed algorithm and / or data stored in memory to perform the function. Other functions, for example the operation of a pump by a pressure switch, may be performed by non-programmed circuitry.

[0156] The controller 68 is powered by the power supply 66, which may include a transformer and / or AC to DC converter. The power supply 66 also supplies power to the pumps, valves and instrumentation that require power, as determined by relays or other switches of the controller 68. The controller 68 also sends information to, and optionally receives information from, the display 64.

[0157] The controller 68 may be programmed to perform various calculations. For example, the controller can calculate the volume of water held in each tank 62, 72 and the volume of water that has been added to or removed form each tank 62, 72 over various periods of time. The controller 68 can also calculated the amount of fresh water that has been added to the gray water recycling system 12 using signals received from the make up water meter 108.The controller can also calculate the amount of water that has been sent to toilets using signals received from the treated water outlet meter 106.Communications

[0158] The controller 68 includes a communication module, for example a Wi-Fi communication module connected to an Internet router in the house 10. The controller 68 is able to detect malfunctions and relay alerts to a homeowner. Information from the controller 68 may be first collected on a backend server, which optionally also allows information to be sent to a service technician or the system supplier. The system supplier may use anonymized or aggregated data, for example to provide a calculation of total water savings from multiple houses 10.

[0159] A homeowner may access the server through an application program (app) on a smartphone or other computer. The app allows the homeowner to receive data, for example a water savings calculation, service codes or status codes. The app may also send alerts or alarms the homeowner.

[0160] Water savings is determined by the controller 68 based on the calculated volume of water sent to toilets with adjustments for the calculated volume of water added to the supply tank 62. The controller 58 also monitors for excessive operation of the supply pump 80. A leaky toilet may be detected by the controller 68 by monitoring the supply pump 80 and / or treated water meter 106 by, for example, detecting a noticeable increase in the number of times that the supply pump 80 is activated or flow is detected through the treated water outlet meter 106 in a day, in particular during typical low use times, for example between midnight and 4 am, and / or by an increase in operation of the supply pump 80 or the total volume of water flowing through the treated water outlet meter 106 in a day. The controller 68 causes an alert to be sent to the homeowner when a leaky toilet is detected.

[0161] The graywater recycling system 12 also has a human machine interface (HMI) such as display 64 (Figure 4). The display 64 includes a panelvisible to the homeowner. The display 64 may present various forms of data including alarms and alerts.

[0162] Technicians may use the panel 64 to perform diagnostic tests or alter settings in the controller 68. Optionally, technicians may also have direct wi-fi communication with the controller 68. Using the panel or Wi-Fi communication, technicians are able to retrieve more detailed error codes or operate individual components of the gray water recycling system for diagnostic purposes etc.Vacation Prediction and Mode

[0163] The controller 68 is programmed to predict (i.e. sense) that the house 10 is not in use for an extended period of time, for example because the occupants may have left on vacation, based on signals received from one or more components of the gray water recycling system 12. The relevant components may be instrumentation of the gray water recycling system 12. An input from the user is not required. Similarly, the controller 68 is programmed to predict that the house 10 has returned to ordinary use, for example because the occupants may have returned from vacation, based on signals received from one or more components of the gray water recycling system 12. Automatic vacation sensing, rather than relying on a user to enter a vacation setting, is more convenient for the user and also does not rely on the user who could forget to put the gray water recycling system 12 into a vacation mode.

[0164] Although there may be other reasons for a house to be unused for a period of time, periods of non-use are referred to as vacations for convenience. Upon predicting a vacation, the controller 68 automatically performs various steps and then puts the gray water recycling system 12 into an idle or standby condition. This condition may be called vacation mode for convenience. Upon predicting the end of a vacation, the controller 68 automatically performs various steps and then puts the gray water recycling system 12 back into an ordinary operating mode. The vacation mode and ordinary operating mode are conditionswherein the controller 68 applies different aspects of its programming to the operation of the gray water recycling system 12.

[0165] In some examples, the start of a vacation mode is predicted when the controller 68 has not received a signal indicating a flow of water through the treated water outlet meter 106 for a selected time. The selected time may be, for example, in the range of 24 to 72 hours.

[0166] After predicting a vacation, the controller 68 performs various steps before putting the gray water recycling system 12 into vacation mode. In some embodiments, these steps can include one or more of backwashing the prefilter 70, backwashing the media tank 74 and draining the collection tank 72.

[0167] While in vacation mode, water consuming steps are stopped or reduced. The reactor 60 continues to be aerated during vacation mode to avoid producing anaerobic conditions which might generate hydrogen sulfide gas. Chlorine in the supply tank 62 may be refreshed periodically, for example every 1 to 4 hours.

[0168] In some examples, the end of a vacation mode is predicted by the collection tank 72 receiving more than a specified amount of water, for example an amount in the range of about 4-11 gallons. Operation of the supply pump 80 is not used to indicate the end of a vacation mode due to the high potential for false indications. For example a dog walker, contractor, or person checking on a house 10 during a vacation may flush a toilet a few times. In the event that toilets are flushed several times during a long vacation, the supply tank 62 can be refilled from the freshwater makeup connection 50. The end of a vacation mode is also not triggered by any amount of water being received in the collection tank 72 (i.e. by the receipt of 3 gallons or less) due to the potential for false indications.

[0169] After predicting the end of a vacation, the controller 68 performs various steps to bring the gray water collection system 12 out of the vacation mode. In some embodiments, the media filter 74 is backwashed. The reactor 60 is also backwashed. Optionally, the reactor 60 may be partially or fully purged(i.e. partially or fully drained and refilled). After these steps, the controller 68 returns to the ordinary operating mode, which is described throughout the other sections of this detailed description.Example - NSF / ANSI 350 Testing

[0170] A Greyter Water Systems Inc. Model GH30-0-Y residential graywater treatment system, which is substantially as described herein, was submitted for testing under NSF / ANSI Standard 350 for Onsite Residential and Commercial Water Reuse Treatment Systems (2023 edition). The system was tested for treating bathing water for reuse in toilet flushing in Class R (residential). The test included twenty weeks of dosing at design flow and a six-week stress loading sequence including power failure, vacation and water efficiency stress tests. The test design flow was 50 gpd divided into 30 gallons from 7 am to 10 am, 10 gallons from 11 am to 2 pm and 10 gallons from 6 pm to 9 pm. The system exceeded the performance required by the standard.Recap of Some Features

[0171] In some embodiments, a gray water recycling system treats residential gray water, for example bathing and / or laundry water, for re-use as non-potable water, for example for toilet flushing and / or irrigation. A system for a single family residence is provided in an appliance sized package powered by a standard electrical outlet. The system has one or more of a prefilter, a collection tank, a foam separator, a submerged biofilter, a filter, a supply tank, a disinfection system and a delivery pump. A process includes one or more of screening, collection, sedimentation, foam separation, biological filtration, filtration, storage, disinfection and delivery. A multi-purpose reactor may include the foam separator and the submerged biofilter. A media filter may be in a separate vessel downstream of the multi-purpose reactor. Flow of gray water through the biofilter may be intermittent and responsive to delivery of treated gray water.

[0172] In some embodiments, a submerged bioreactor may have multiple fixed beds that may be separately backwashed. The reactor may have a vertically oriented tank. Water flows vertically downwards through the reactor in a single pass. Water may be drawn from the bioreactor into the filter by a pump downstream of the filter.

[0173] In some embodiments, a system may have a controller adapted to provide various calculations and / or alerts and / or to automatically implement a vacation mode. The system may also have a communication module allowing connection to an internet router or other communications device. Data or alerts may be transmitted to a customer, a service organization or a supplier.

[0174] In some embodiments, influent gray water is treated with a combination of foam flotation, separation and biological digestion. Filtration and biological digestion may occur together in a biofilter. Additional filtration may also be provided by a media filter. Additional process may include screening, sedimentation and disinfection. A system may include one or more of a pre-filter, a collection tank, a foam separation unit, a biofilter, a media filter, a supply tank and a chlorination system.

[0175] In some embodiments, a Wi-Fi communication module allows connection to an internet router. Data may be transmitted to a customer, a service organization or a supplier. Data may include water usage and savings and alerts relating to the system or to indicate a leaky toilet. The system is able to detect vacations and enter and exit a vacation mode without input form the user.

[0176] In some embodiments, a system has a multi-purpose biological reactor that provides foam flotation followed by suspended solids filtration and aerobic digestion in a fixed bed biofilm reactor (FBBR). The reactor is housed in a vertically oriented tank with the foam flotation area above the FBBR. A media bed of the FBBR includes two segments that may be separately backwashed. Water flows vertically downwards through the reactor in a single pass. Aeration in the foam floatation area removes soaps and oxygenates the water before itreaches the FBBR. The biological reactor is followed by a media filter. Water is drawn from the bioreactor into the filter by a pump downstream of the filter.

[0177] In some embodiments, water is pre-filtered before entering a collection tank. The pre-filter has a screen that is backwashed automatically when water is sensed accumulating behind the screen. Grit and sand passing through the screen collect at the bottom of the collection tank. A purge pump removes the collected solids periodically. Treated water is held in a supply tank. A chlorination system adds chlorine relatively slowly to treated water flowing in a recirculation loop around a supply tank. A dye is added if required into water flowing from the supply tank to a supply pump.

Claims

CLAIMSWe claim:

1. A process for treating domestic gray water comprising steps of, receiving bathing, and optionally laundry, gray water from a house; treating the gray water by,foam separation andbiofiltration; and,delivering the treated gray water to one or more fixtures, optionally including one or more toilets, of the house.

2. The process of claim 1 further comprising filtration, for example media filtration, downstream of the biofiltration.

3. The process of claim 1 or 2 further comprising one or more of screening, sedimentation and delivery.

4. The process of any of claims 1 to 3 wherein biofiltration comprises flowing the water downwards in a single pass through a submerged and aerated fixed bed bioreactor, optionally at a flow rate in the range of 2-10 gallons per hour.

5. The process of claim 4 wherein a foam separation effluent flows downwards by gravity to the fixed bed bioreactor.

6. The process of any of claims 1 to 5 comprising collecting influent gray water upstream of the foam separation and storing treated water downstream of the biofiltration.

7. The process of any of claims 1 to 6 wherein flow through the biofilter is controlled by a pump downstream of the bioreactor.

8. The process of any of claims 1 to 7 wherein flow through the biofilter is responsive to delivery of the treated gray water, for example the flow starts in response to a low water height signal from a supply tank and stops in response to a high water level signal from a supply tank.

9. The process of any of claims 1 to 8 consuming a peak of no more than 1800 Watts of electrical power.

10. The process of any of claims 1 to 9 wherein the gray water is treated to NSF / ANSI 350 standards.

11. A system for treating domestic gray water comprising a foam separator and a submerged biofilter.

12. The system of claim 11 wherein the submerged biofilter comprises two or more vertically spaced apart media beds.

13. The system of claim 12 wherein the foam separator is above the media beds.

14. The system of any of claims 11 to 13 comprising a media filter downstream of the biofilter.

15. The system of any of claims 1 to 14 comprising a pump downstream of the biofilter and optionally downstream of the media filter.

16. The system of any of claims 11 to 15 comprising a collection tank upstream of the foam separator, the collection tank optionally having a volume in the range of 35-60 gallons.

17. The system of claim 15 comprising a prefilter upstream of the collection tank.

18. The system of any of claims 11 to 17 comprising a supply tank, optionally wherein a total volume of the collection tank and the supply tank is 100 gallons or less or 80 gallons or less.

19. The system of any of claims 11 to 18 packaged in an appliance sized unit.

20. The system of any of claims 11 to 19 connected to a gray water drain of a house and a toilet supply line of the house.

21. A domestic gray water treatment device comprising,a reactor body;a gray water inlet in communication with an upper part of the body;a foamate outlet in communication with the upper part of the body;a gray water outlet in communication with a lower part of the body;a first media bed within the body at an elevation between a) a lower of the gray water inlet and the foamate outlet and b) the gray water outlet; and,a first gas sparger configured to release gas into the body above the first media bed and below the foamate outlet.

22. The device of claim 21 wherein the first gas sparger is configured to release the gas below the gray water inlet.

23. The device of claim 21 or 22 wherein the foamate outlet is above the gray water inlet.

24. The device of any of claims 21 to 23 comprising a second gas sparger configured to release a gas into the body below the first media.

25. The device of any of claims 21 to 24 comprising a first waste outlet in communication with the body above the first media bed and below the lower of the gray water inlet and the foamate outlet.

26. The device of claim 25 wherein the first gas sparger and the first waste outlet share a common tube in communication with the body.

27. The device of any of claims 21 to 26 having a second media bed below the first media bed and above the gray water outlet.

28. The device of claim 27 having a third gas sparger between the first media bed and the second media bed.

29. The device of claim 28 having a second waste outlet between the first media bed and the second media bed.

30. The device of claim 29 wherein the third gas sparger and the second waste outlet share a common tube in communication with the body.

31. The device of any of claims 27 to 29 having an access port between the first media bed and the second media bed.

32. The device of any of claims 21 to 31 having a third waste outlet in communication with the lower part of the body, optionally wherein the third waste outlet is located in a sump at the bottom of the tank, optionally wherein the third waste outlet is at a lower elevation than the gray water outlet.

33. The device of any of claims 21 to 32 comprising a cap, wherein the foamate outlet in the cap.

34. The device of claim 33 wherein surfaces of the cap converge towards the foamate outlet.

35. The device of any of claims 21 to 34 wherein the first media bed rests on a partition supported by indents of the body.

36. The device of any of claims 21 to 35 wherein the reactor body is elongated and vertically oriented.

37. The device of claim 36 wherein the body has a width that is 25% or less of its height.

38. The device of any of claims 21 to 37 combined with a media filter.

39. The device of claim 38 wherein the media filter is in a separate vessel.

40. A process for treating gray water comprising,providing a media bed in a reactor body;flowing gray water downwards in the reactor body through the media bed; providing bubbles in the water above the media bed;removing foam from upper part of the body above the media bed; and, removing treated gray water from a lower part of the body below the media bed.

41. The process of claim 40 wherein the gray water flows downwards in the reactor body intermittently, optionally in one pass.

42. The process of claim 40 or 41 comprising flowing air upwards through the media bed to release solids from the media bed and removing water containing released solids from above the media bed.

43. The process of claim 42 wherein comprising providing multiple media beds in the reactor body and backwashing the multiple beds at different times.

44. The process of any of claims 40 to 43 comprising drawing the gray water through the media bed by a downstream pump.

45. The process of claim 44 comprising maintained free water surface in the body within a selected range above the media bed.

46. A process for treating domestic gray water comprising,collecting gray water from a residence;treating the collected gray water;delivering the treated gray water back to the residence;monitoring one or more attributes of the collection and / or delivery of the gray water; and,producing one or more outputs and / or alerts and / or predicting the beginning and / or end of a period of time during which the residence is not regularly occupied (e.g. a vacation) by way of the one or more of the attributes.

47. The process of claim 46 wherein the one or more attributes include delivery attributes related to the rate, volume, time and / or frequency of gray water delivery back to the residence.

48. The process of claim 46 or 47 wherein the delivery attributes are obtained from signals received from one or more of a supply pump, an outlet meter or a supply tank.

49. The process of any of claims 46 to 48 wherein the beginning of the period of time during which the residence is not regularly occupied is predicted by one or more delivery attributes, for example by gray water not being delivered to the residence for a selected period of time.

50. The process of claim 49 wherein the period of time is in the range of 24-72 hours.

51. The process of any of claims 46 to 50 comprising producing an output indicating the cumulative amount of gray water delivered to the residence over a period of time.

52. The process of any of claims 46 to 51 comprising producing a downstream (e.g. toilet) leak alert.

53. The process of claim 52 wherein the downstream leak alert is indicated by one or more of delivery of gray water with an increased rate (e.g. volume per day) or frequency above a selected value or above an observed prior value, or delivery of gray water during a selected time or during a time previously observed to involve no or minimal delivery, or delivery of gray water at a reduced rate, or frequency below a selected value or below an observed prior value, or a slow pressure loss over time.

54. The process of any of claims 46 to 53 wherein the one or more attributes include collection attributes related to the time, volume and / or rate of gray water collection.

55. The process of claim 54 comprising using the one or more collection attributes to predict the end of a period of time during which the residence is not regularly occupied, for example the collection of a selected amount of gray water after predicting the of a period of time during which the residence is not regularly occupied.

56. A system for treating domestic gray water comprising,a collection tank;one or more treatment units; a supply tank;a supply pump; and,a controller,wherein the controller is connected to one or more sensors and adapted to monitor one or more attributes of the collection and / or delivery of the gray water; and,wherein the controller is adapted to produce one or more outputs and / or alerts and / or predict the beginning and / or end of a period of time during which the residence is not regularly occupied (e.g. a vacation) by way of the one or more of the attributes.

57. The system of claim 56 wherein the one or more sensors comprises a pressure transducer in communication with the collection tank.

58. The system of claim 57 wherein the controller is adapted to determine a volume of water added to the collection tank by way of signals from the pressure transducer.

59. The system of any of claims 56 to 58 wherein the controller is adapted to drain the collection tank after predicting the beginning of a period of time during which the residence is not regularly occupied.

60. The system of any of claims 56 to 59 wherein the controller is adapted to predict the beginning of a period of time during which the residence is not regularly occupied by way of receipt of a specified volume of water in the collection tank and / or signals from the pressure transducer.

61. The system of any of claims 56 to 60 further comprising an outlet meter downstream of the supply pump.

62. The system of any of claims 56 to 61 wherein the controller is adapted to calculate an amount of gray water delivered based on signals from the outlet meter, signals related to operation of the supply pump and / or signals related to the removal of water from the supply tank.

63. The system of any of claims 56 to 62 wherein the controller is adapted to predict a leak downstream of the supply pump based on signals from the outlet meter and / or signals related to operation of the supply pump and / or signals related to the removal of water from the supply tank and / or signals related to pressure downstream of the supply pump.

64. The system of any of claims 56 to 63 further comprising a fresh water make-up connection and a make-up water meter in communication with the supply tank.

65. The system of claim 64 wherein the controller is adapted to subtract a volume of water indicated by the make-up water meter from the calculation of the amount of gray water delivered.

66. The system of any of claims 56 to 65 wherein the controller is adapted to implement a vacation mode, communicate an alert regarding a downstream leak, and / or communicate a calculation of gray water delivered over a period of time.

67. A gray water recycling system comprising,instrumentation such as probes, switches, transducers or meters; electrically actuated devices such as valves and pumps; anda controller connected to the instrumentation and electrically actuated devices, wherein the controller has a communication module allowing connection to an internet router.

68. The gray water recycling system of claim 67 further comprising a human machine interface panel.

69. The gray water recycling system of claim 67 or 68 wherein the communication module also enables direct communication to a diagnostic device.

70. The gray water recycling system of any of claims 67 to 69 wherein the controller is adapted to transmit one or more error codes, alerts or warnings.

71. The gray water recycling system of any of claims 67 to 70 wherein the controller is adapted to calculate and transmit a water savings value.

72. The gray water recycling system of any of claims 67 to 71 wherein the controller enables remote operation of one or more of the electrically actuated devices of the gray water recycling system.

73. The gray water recycling system of any of claims 67 to 72 wherein the controller enables remote sensing of one or more of the instrumentation elements of the gray water recycling system.

74. The gray water recycling system of any of claims 67 to 73 further comprising an application program.

75. The gray water recycling system of any of claims 67 to 74 wherein the controller is adapted to detect a toilet leak by monitoring a treated water outlet meter.

76. The gray water recycling system of any of claims 67 to 75 wherein the controller is adapted to determine a water savings value by subtracting a reading from a make up water meter from a reading from a treated water outlet meter.

77. A process of predicting a vacation in a house having a gray water recycling system comprising detecting a lack of flow of treated water to the house for a predetermined period of time.

78. The process of claim 77 further comprising predicting an end to the vacation by a collection tank being re-filled.

79. The process of claim 77 or 78 further comprising backwash a prefilter and / or a media filter after predicting a vacation.

80. The process of any of claims 77 to 79 further comprising draining a collection tank and / or chlorinating a supply tank after predicting a vacation.

81. The process of any of claims 77 to 80 comprising aerating a biological reactor after predicting a vacation82. The process of any of claims 77 to 81 comprising backwashing a media filter, backwashing a biological reactor, and / or purging a biological reactor after predicting the end of the vacation.

83. A media filter for treating gray water comprising,a filter body;a lower screen;an outlet below the lower screen and in communication with the body via the lower screen;an upper screen;an inlet above the upper screen and in communication with the body via the upper screen; and,a media bed between the lower screen and the upper screen.

84. The media filter of claim 83 wherein the media bed has spherical glass beads, optionally 0.02 to 0.1 inches in diameter.

85. The media filter of claims 83 or 84 having a headspace between the media bed and the upper screen.

86. The media filter of any of claims 83 to 85 comprising a cap attached to the filter body, wherein the upper screen is in the cap and the inlet is in communication with the cap.

87. The media filter of any of claims 83 to 86 comprising a media filter pump, wherein the outlet is connected to an inlet of the pump.

88. The media filter of claim 87 having a pressure transducer between the outlet and the media filter pump.

89. The media filter of any of claims 83 to 88 having a backwashing water outlet in communication with the inlet.

90. The media filter of any of claims 83 to 89 having an air pump and a water pump in communication with the outlet for backwashing the media bed with air and water.

91. A method of treating gray water comprising,flowing the gray water downwards through a media bed; and, backwashing the media bed,wherein backwashing the media bed comprises flowing air or an air / water mixture upwards through the media bed.

92. The method of claim 91 further comprising flowing water upwards through the media bed.

93. The method of claim 91 or 92 comprising drawing the gray water through the media bed by a downstream pump.

94. The method of claim 93 wherein the backwashing is trigged by a pressure signal from a sensor in communication with the inlet of the pump.

95. The method of any of claims 91 to 94 wherein the media bed is part of a media filter as claimed herein.

96. A prefilter for a graywater collection system comprising,a filter body having a graywater inlet, an effluent outlet, a backwashing fluid inlet and a backwashing outlet;a screen between the graywater inlet and the effluent outlet; and a flapper valve, wherein the flapper valve can move between a first position covering the backwashing outlet and a second position covering the effluent outlet; and,a magnet on the flapper valve; and,a sensor system, the sensor system adapted to provide a signal indicating the that the flapper valve is in one of the positions and / or,a second magnet on the filter body adapted to push the flapper valve away from the second position.

97. The prefilter of claim 96 wherein the flapper valve falls by gravity to the first position, and wherein the magnetic sensor system is adapted to provide a signal indicating that the flapper valve is in the first position.

98. The prefilter of claim 96 or 97 wherein the sensor system comprises a permanent magnet attached to the flapper valve and a magnet sensor on the outside of the prefilter body.

99. A prefilter for a graywater collection system comprising, a filter body having a graywater inlet and an effluent outlet;a screen between the graywater inlet and the effluent outlet; and, a removable cap at the top of the filter body.

100. The prefilter of claim 99 further comprising a manual drain, operable to drain water from the body.

101. The prefilter of claim 99 or 100 having a buffer tank above the prefilter body in communication with the greywater inlet.

102. A prefilter for a graywater collection system comprising,a filter body having a graywater inlet and an effluent outlet;a screen between the graywater inlet and the effluent outlet;a buffer tank above the prefilter body in communication with the greywater inlet; and,a water detection probe in a side channel of the buffer tank.

103. The prefilter of claim 102 wherein the side channel is angled upwards and away from the buffer tank.

104. The prefilter of claim 102 or 103 wherein the water detection probe is in communication with an air pocket when the buffer tank is filled with water.

105. A collection tank for a gray water collection system having a volume of 35-60 gallons, a sump having a fitting for connection to a purge pump, and a fitting for connection to a feed pump above the fitting for connection to the purge pump.

106. The collection tank of claim 105 in communication with an air pump.

107. The collection tank of claim 105 or 106 connected to the outlet of a prefilter, wherein the prefilter is connected to a graywater inlet.

108. A chlorination system for treated water, for example in a gray water recycling system, comprising,a water tank;a chlorine recirculation loop having an inlet connected to the water tank, an outlet connected to the water tank and a recirculation pump;a chlorine tank;a chlorine supply pump connected to the chlorine tank and the water tank.

109. The chlorination system of claim 108 wherein the chlorine supply pump drips water into the water tank, optionally through air in a headspace of the tank.

110. The chlorination system of claim 108 or 109 further comprising,a water supply pump downstream of the water tank;a dye tank;a dye pump having an inlet connected to the dye tank and an outlet connected to pipe connecting the water tank to an inlet of the water supply pump.

111. A chlorination process, for example for chlorinated treated gray water, comprising the steps of,recirculating the treated gray water around a water tank; and,adding a chlorine solution to the water tank.

112. The process of claim 111 wherein the chlorine is dripped into gray water in the water tank, optionally though air, while recirculating the gray water.

113. The process of claim 111 or 112 further comprising adding a dye to water flowing away from the water tank.

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