Systems and methods for wastewater heat recovery

Abstract

Described herein are systems and methods for wastewater heat recovery, including a system for heat recovery, the system comprising: (i) a heat exchanger configured to heat water with thermal energy recovered from a wastewater stream being treated by a wastewater treatment system in fluid communication with the heat recovery system; and (ii) a device configured to control the flow rate of the wastewater within the heat recovery system based at least in part on real-time sensor data.

Description

[Technical Field]

[0001] cross reference This application claims priority to U.S. Provisional Application No. 63 / 371,698, filed August 17, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The use of hot water within a building, including hot water used for showers, toilets, and clothes washing, increases the temperature of the wastewater stream. This hot water is a valuable heat source for other uses within the building. Heat recovery modules convert the heat in the wastewater into usable heat for uses such as preheating water for a boiler or hot water tank. Current heat recovery technologies sometimes employ the use of heat pumps. Heat pump technology uses electricity and a reverse refrigeration cycle to transfer heat from one location to another. However, heat pumps can be expensive, requiring high capital costs and complex setup. An alternative option is a heat exchanger, a passive technology product that does not require any external energy source. Heat exchangers facilitate the transfer of internal thermal energy between two fluids without mixing the two fluids. Heat exchangers can be used to transfer thermal energy from a wastewater stream to another source, such as a building's hot water supply. A heat exchanger requires the wastewater to be at a high enough temperature to heat the building's water loop. However, current heat exchanger systems can have insufficient heat recovery performance when integrated with wastewater treatment systems. For example, raw wastewater has the highest amount of heat energy before treatment, but poor water quality and the presence of impurities can lead to high operating costs. Treated water is of high quality, but its heat energy is lost during transport through the wastewater treatment system, resulting in poor heat recovery performance. Summary of the Invention

[0003] There is a need for a low-cost heat recovery system that does not significantly compromise heat recovery performance. There is also a need for a heat recovery system that can be easily and conveniently integrated with new or existing wastewater treatment systems. The present disclosure provides systems and methods for recovering heat and energy present in wastewater. Wastewater, which may be elevated in temperature due to hot water use throughout a building, provides a valuable but underutilized source of thermal energy. The methods and systems described herein can convert the heat and energy present in the wastewater into usable energy. In some cases, the recovered energy may be used for other purposes within the building, including preheating water for a boiler or hot water tank.

[0004] Various advantages of the embodiments described herein include providing efficient and cost-effective on-site wastewater heat recovery for buildings (e.g., commercial and residential buildings, food and industrial processing facilities) or other entities, capturing heat for use in generating hot water for various domestic and industrial process uses or space heating, generally conserving water and energy, and ease of integration.

[0005] Described herein is an improved system for wastewater heat recovery. In one aspect herein, a system is provided that includes: (i) a heat exchanger configured to heat water with thermal energy recovered from a wastewater stream being treated by a wastewater treatment system in fluid communication with the heat recovery system; and (ii) a device configured to control a flow rate of the wastewater through the heat recovery system based at least in part on real-time sensor data.

[0006] In some embodiments, the wastewater is at least partially treated by a wastewater treatment system before entering the heat recovery system. In some embodiments, the heat exchanger comprises a plate-and-frame heat exchanger. In some embodiments, the wastewater is treated by the wastewater treatment system after exiting the heat recovery system. In some embodiments, the heat exchanger comprises a shell-and-tube heat exchanger. In some embodiments, the system further comprises a screening system. In some embodiments, the device is configured to control a flow rate of the wastewater based at least in part on a temperature of the wastewater stream. In some embodiments, the device is configured to increase the flow rate of the wastewater when the temperature of the wastewater stream exceeds a threshold value. In some embodiments, the device is configured to decrease the flow rate of the wastewater when the temperature of the wastewater stream falls below a threshold value. In some embodiments, the device is configured to control a flow rate of the wastewater based at least in part on a demand for heated water. In some embodiments, the device is configured to increase the flow rate of the wastewater through the heat recovery system when the demand for heated water exceeds a threshold value. In some embodiments, the device is configured to increase the flow rate of the wastewater through the heat recovery system when the demand for heated water exceeds a threshold value.

[0007] In some embodiments, the system further comprises a wastewater holding tank. In some embodiments, the device is configured to control the flow rate of the wastewater based at least in part on the amount of wastewater present in the wastewater holding tank. In some embodiments, the device is configured to stop when the amount of wastewater present in the wastewater holding tank falls below a threshold level. Alternatively or additionally, the pump is configured to stop when the temperature of the wastewater tank falls below a predetermined threshold.

[0008] In some embodiments, the heat recovery system is housed within a complete skid-mounted system. In some embodiments, the complete skid-mounted system is configured to be added to an existing wastewater treatment system. In some embodiments, the system is located at a location within the wastewater source. In some embodiments, the wastewater source is a building and the system is located in the foundation of the building. Alternatively, the system can be located at any suitable location inside or outside the building. In some embodiments, the system is fully automated. Optionally, at least a portion of the wastewater used by the heat recovery system is not completely treated by the wastewater treatment system. Optionally, the device is a pump. Optionally, the device is a valve. Optionally, the wastewater source is a building and the system is located outside the building. Optionally, the wastewater source is a building and the system is located remotely from the building.

[0009] Incorporation by Reference All publications, patents, and patent applications mentioned herein are incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In the event that the publications and patents or patent applications incorporated by reference conflict with the disclosure contained herein, the present specification is intended to supersede and / or take precedence over any such conflicting material. [Brief explanation of the drawings]

[0010] The novel features of the invention are specifically set forth. The features and advantages of the present invention will be better understood by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also referred to herein as "figure" and "FIG.")

[0011] [Figure 1] FIG. 1 is a diagram of an integrated wastewater treatment and heat recovery process, according to some embodiments. [Figure 2]FIG. 1 is a process flow diagram of an integrated wastewater treatment and heat recovery process, according to some embodiments. [Figure 3] FIG. 1 is a diagram of a system for treating 30,000 gallons of wastewater per day incorporating wastewater heat recovery, according to some embodiments. [Figure 4] FIG. 1 is a diagram of a system for treating 37,000 gallons of wastewater per day incorporating wastewater heat recovery, according to some embodiments. [Figure 5] FIG. 1 is a diagram of a system for treating 50,000 gallons of wastewater per day incorporating wastewater heat recovery, according to some embodiments. [Figure 6A] FIG. 1 is a diagram of a shell-and-tube heat exchanger, according to some embodiments. [Figure 6B] 1 is a cross-sectional view of a shell-and-tube heat exchanger according to some embodiments. [Figure 7] FIG. 1 is a diagram of a plate-and-frame heat exchanger, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0012] While various embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It is understood that various alternatives to the embodiments of the invention described herein may be employed.

[0013] The present disclosure provides systems and methods for recovering heat and energy present in wastewater. The wastewater can originate from a source such as a building or any other type of structure. In some embodiments, the wastewater source can be a municipal sewer. The building can be a residential building, a commercial building, an industrial building, or any other type of building. The water source can be a high-density building or other structure. A high-density source can have multiple water consumption sources. A high-density source can have at least 5, 10, 15, 20, 30, 40, 50, 70, 100, or more water consumption sources within the structure. Examples of wastewater sources can include, but are not limited to, apartment buildings, townhouses, single-family homes, office buildings, educational facilities, manufacturing facilities, medical facilities, government facilities, stores, or any other type of structure. The wastewater source can be a group of buildings. In some cases, the wastewater source is a campus, a neighborhood, or a city. In some embodiments, the wastewater source can comprise a multi-family housing unit, such as an apartment building. In some embodiments, an apartment may include any number of apartment units. For example, an apartment may include 10 units, 20 units, 50 units, 100 units, 250 units, 500 units, 750 units, 1000 units, 5000 units, or any other number of units. Examples of water consumption sources may include toilets, sinks, showers, washing machines, dishwashers, cooling towers, and irrigation systems, among others. Wastewater from one or more water consumption sources or one or more wastewater sources may be collected on-site or near the wastewater source.

[0014] In some embodiments, heat recovery systems may employ the use of heat exchangers integrated with improved control mechanisms, which may reduce operating costs by optimizing portions of the process. Wastewater often experiences elevated temperatures as a result of the uses for which it is used. For example, hot water used for showering, cooking, cleaning, washing clothes, etc. may increase the temperature of the wastewater stream. As the heated wastewater travels through a building and undergoes treatment or heads toward a sewer, the temperature of the stream may decrease until it reaches ambient temperature. As such, the thermal energy in the wastewater stream is lost and cannot be recovered. The systems and methods herein recover the thermal energy stored in the wastewater stream and convert it into a usable heat source for various applications with improved performance.

[0015] In some embodiments, the heat recovery system herein may be applied at the level of a wastewater treatment system. The heat recovery system may be coupled to the wastewater treatment system and dynamically adapt to the wastewater treatment process to recover heat from treated, untreated, or partially treated wastewater within the wastewater treatment system. The overall efficiency of the heat recovery and wastewater treatment may be improved by avoiding unnecessary treatment of unusable wastewater while recovering the energy of such water for heat recovery. In some embodiments, the integrated heat recovery and wastewater treatment system may include an automatic control system configured to maximize system uptime and heat recovery capacity by timing and recovering extraction of wastewater streams. Details of the automatic control are described below.

[0016] The wastewater treatment and heat recovery systems provided herein may be located substantially on-site. This advantageously reduces heat loss due to transportation. In some examples, portions of the wastewater treatment and heat recovery system may be located on-site, but may also be located at a remote central treatment facility. Optionally, separation of the wastewater into a waste solids component and a separated water component may occur on-site at or near the wastewater source (e.g., a building). Separation may occur as a decentralized system. The solid waste may be treated on-site or near the wastewater source and / or at a remote treatment facility. The separated water component may undergo treatment on-site or near the wastewater source. Heat recovery may occur substantially on-site. The recovered heat may be used for on-site applications.

[0017] An on-site activity may occur at a location that is within the wastewater source (e.g., a building). The location may be partially within the wastewater source. The location may also be physically outside the wastewater source but operably connected to the wastewater source such that the location is within the location of the wastewater source or connected to the wastewater source. For example, an on-site activity may occur on the same property as the wastewater source. An on-site activity may occur beneath the wastewater source. An on-site activity may occur underground. In some cases, an activity may occur near the site. For example, an activity (e.g., wastewater heat recovery) may occur within 3 blocks, 2 blocks, 1 block, 100 feet, 50 feet, 40 feet, 30 feet, 20 feet, or 10 feet of the wastewater source (e.g., a building) or the property where the wastewater source is located. For example, an activity (e.g., wastewater heat recovery) may occur more than 1 mile from the wastewater source (e.g., a building) or the property where the wastewater source is located.

[0018] In some embodiments, the amount of wastewater flowing through the wastewater heat recovery system is between about 5,000 gallons / day and about 1,000,000 gallons / day, and any amount less than 5,000 gallons / day or greater than 1,000,000 gallons / day. In some embodiments, the amount of water flowing through the wastewater heat recovery system is between about 5,000 gallons / day and about 1,000,000 gallons / day. In some embodiments, the amount of water flowing through the wastewater heat recovery system is between about 5,000 gallons / day and about 20,000 gallons / day, between about 5,000 gallons / day and about 60,000 gallons / day, between about 5,000 gallons / day and about 100,000 gallons / day, between about 5,000 gallons / day and about 500,000 gallons / day, between about 5,000 gallons / day and about 1,000,000 gallons / day, between about 20,000 gallons / day and about 60,000 gallons / day, between about 20,000 gallons / day and about 100,000 gallons / day, between about 20,000 gallons / day and about 100,000 gallons / day, between about 20,000 gallons / day and about 100,000 gallons / day, gallons / day to about 500,000 gallons / day, about 20,000 gallons / day to about 1,000,000 gallons / day, about 60,000 gallons / day to about 100,000 gallons / day, about 60,000 gallons / day to about 500,000 gallons / day, about 60,000 gallons / day to about 1,000,000 gallons / day, about 100,000 gallons / day to about 500,000 gallons / day, about 100,000 gallons / day to about 1,000,000 gallons / day, or about 500,000 gallons / day to about 1,000,000 gallons / day. In some embodiments, the amount of water flowing through the wastewater heat recovery system is about 5,000 gallons / day, about 20,000 gallons / day, about 60,000 gallons / day, about 100,000 gallons / day, about 500,000 gallons / day, or about 1,000,000 gallons / day. In some embodiments, the amount of water flowing through the wastewater heat recovery system is at least about 5,000 gallons / day, about 20,000 gallons / day, about 60,000 gallons / day, about 100,000 gallons / day, or about 500,000 gallons / day. In some embodiments, the amount of water flowing through the wastewater heat recovery system is up to about 20,000 gallons / day, about 60,000 gallons / day, about 100,000 gallons / day, about 500,000 gallons / day, or about 1,000,000 gallons / day.

[0019] FIG. 1 illustrates an example of an integrated wastewater heat recovery and wastewater treatment system. Wastewater can enter through valve 1. In some cases, this valve is a three-way valve. In one direction, the wastewater can be directed through the integrated heat recovery and wastewater treatment system. In the other direction, the wastewater can be directed to a sewer, bypassing the wastewater treatment and heat recovery system. This valve can be adjusted manually or automatically. The three-way valve can be used to divert the wastewater to a sewer if the wastewater treatment system is undergoing maintenance or if an error occurs within the system. As the wastewater enters the treatment system, it can flow through a screening unit, such as microscreen 2. This screening unit (e.g., microscreen 2) can be used to filter and collect solids present in the wastewater.

[0020] The wastewater may then enter the pre-treatment tank 3. Optionally, the pre-treatment tank 3 may be equipped with a sensor. In some examples, the sensor may include a temperature sensor that measures the temperature of the water in the pre-treatment tank. The temperature sensor may be located anywhere in the tank, at the inlet / outlet of the tank, etc. In some examples, the sensor may include a sensor for measuring the water level in the pre-treatment tank. Optionally, at least a portion of the water in the pre-treatment tank may be used in a heat recovery system to exchange heat with building water to be heated. Optionally, at least a portion of the water in the pre-treatment tank may be pumped to the heat recovery system. A sensor for measuring the water level may beneficially protect the pump. Any suitable sensor for sensing the water level may be utilized. For example, the sensor may be a contact or non-contact device. A non-contact sensor may be an ultrasonic or hydrostatic sensor. Sensor data regarding the temperature and / or water level in the tank may be processed by a controller of the heat recovery system to control pumps in the heat recovery system and to trigger alarms and / or other actions in the heat recovery system and / or the wastewater treatment system.

[0021] The wastewater may be filtered of solids and then flow through a series of treatment and disinfection processes. The wastewater may enter a membrane bioreactor ("MBR") process skid 4. MBR processes may include membrane processes such as microfiltration and ultrafiltration in combination with biological wastewater treatment processes, activated sludge processes.

[0022] Additionally, the wastewater may flow through an oxic tank 5 and / or an anaerobic tank 6 for further treatment. For example, nitrogen and phosphorus removal may occur through microbial degradation within the tanks. The treated wastewater may then flow to UV and / or chlorine input for disinfection and then into the reclaimed water tank 7. In some embodiments, a heat recovery system may be located near the reclaimed water tank. The reclaimed water tank may also be referred to interchangeably as a treated water storage tank or holding tank throughout this specification.

[0023] The heat recovery system may be in fluid communication with the reclaimed water tank 7. In some embodiments, the reclaimed water tank 7 may be equipped with sensors to measure the temperature or level or other conditions of the treated wastewater. The temperature and / or water level sensors may be the same as those described above.

[0024] The wastewater may enter the heat recovery portion of the process through a heat recovery unit (system) 8. The heat recovery unit 8 may comprise a heat exchanger or a series of heat exchangers. The thermal energy present in the treated wastewater may be transferred to another fluid using the heat recovery unit 8. In some embodiments, the heat recovery unit 8 may comprise a pump or valve 9 for controlling the flow within the heat recovery system. Optionally, a pump or valve may be used to control the treated wastewater flowing into the heat exchanger. Optionally, a pump or control valve may be used to control the flow of building water that is heated in the heat exchanger. After passing through the heat recovery unit 8, the wastewater may be returned to the reclaimed water tank 7 via a pipe. Optionally, a control valve 801 may be integrated into the pipe. Optionally, the control valve 801 may be used to control the flow of wastewater within the heat recovery system.

[0025] FIG. 2 schematically illustrates an example of an integrated wastewater heat recovery and wastewater treatment system. The system may be located on-site (e.g., within a building) or external to the structure. In some embodiments, the integrated heat recovery and wastewater treatment system is located in the building's foundation. Wastewater, including sewage (blackwater), ashwater, or process wastewater, may flow from the building into the integrated wastewater heat recovery and wastewater treatment system. The wastewater may flow into the integrated wastewater heat recovery and wastewater treatment system through building retrofit pipes. Wastewater from a building may originate from sources such as industrial processes, flush toilets (WCs or "toilets"), urinals, bathtubs, showers, or sinks. Other sources may include, for example, dishwashers and washing machines. The wastewater may be heated by use within the building. For example, the wastewater may be heated for showering, laundry, or dishwashing. Wastewater containing sewage (blackwater) may flow from the building through one or more pipes and through a microscreen or other screening process. The microscreen may separate solid waste from the blackwater. Solid waste may be sent to an off-site facility. The remaining wastewater, free of solid waste, may then flow to an equalization storage tank. Ashwater (wastewater not containing human waste) may flow from the building via one or more pipes, bypassing the screening and flowing directly to the equalization storage tank. In some cases, multiple equalization storage tanks (also called holding tanks) are used. The equalization or holding tank (or tanks) will typically be designed to manage the peak flow of the system to which the tank is attached. From the equalization storage or holding tank, the wastewater stream may flow to a heat recovery system. The heat recovery system may include one or more pumps and heat exchangers. The heat exchanger may be used to facilitate heat transfer from the heated wastewater to another water stream. The other water stream may be domestic water. The heated domestic water exits the heat exchanger and flows to a domestic hot water storage tank or may flow directly for use within the building. In some embodiments, the wastewater stream exits the equalization storage tank and enters a treatment and disinfection process. The treatment and disinfection process may include an anaerobic process, an aerobic process, an MBR process, UV disinfection, ozone contact, activated carbon, chlorine disinfection, or a combination thereof.The treatment and disinfection process may produce waste activated sludge (WAS). The waste activated sludge may exit the wastewater treatment process and enter a sewer. The treated wastewater may exit the treatment process and undergo reverse osmosis, if desired. The reverse osmosis process may produce a reverse osmosis concentrate. The reverse osmosis concentrate stream may backflow into the building or enter a sewer. The treated wastewater may exit the reverse osmosis process and enter a treated water storage tank. If reverse osmosis is not required, the treated wastewater may flow directly from the treatment and disinfection process to a treated water storage tank. The treated water storage tank may also be filled with municipal water as needed. The treated wastewater may be reused on-site or off-site. Optionally, the treated wastewater stream may flow to a heat recovery system. The heat recovery system may include one or more pumps and heat exchangers. The heat exchanger may be used to facilitate heat transfer from the treated wastewater to another water stream. The other water stream may be domestic water. The heated domestic water exits the heat exchanger and flows to a domestic hot water storage tank or may flow directly for use within the building.

[0026] According to various embodiments, multiples of any of the components of the integrated heat recovery and wastewater treatment system may be provided. In various alternative embodiments, the wastewater treatment and heat recovery system may include fewer or more components than those described above. For example, any one or any combination of the components described above may be provided in multiples (e.g., multiple equalization storage tanks, multiple heat exchangers, multiple pumps, etc.). In some embodiments, one or more components may be eliminated from the system. For example, in one embodiment, the equalization storage tank may be omitted. In alternative embodiments, the wastewater treatment and heat recovery system may include any of several other configurations, combinations of components, sizes, shapes, etc., such as, but not limited to, one or more of the components or aspects described above in connection with FIG. 2.

[0027] Before entering the treatment process, wastewater may first pass through a screening process. In some embodiments, wastewater may pass through the screening process before heat recovery. In some embodiments, wastewater may pass through the screening process after heat recovery. The screening process may be used to remove solid materials above a size threshold. For example, the screening process may remove material larger than the size of a grain of sand or a golf ball. In some embodiments, the screening process may remove material having a largest dimension (e.g., length, width, height, diagonal, diameter) of approximately 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 7 mm, or 10 mm or greater. This material may include inorganic or organic solid materials. The screening process may remove inorganic matter improperly flushed down the toilet. For example, the screening process may be used to remove inorganic matter such as children's toys, packaging, or other materials improperly flushed down the toilet. Optionally, the screening process may utilize one or more screens. The screen may be selected from the group consisting of a coarse screen, a fine screen, and a microscreen. In some cases, a single screen may be used to capture larger solid materials. Alternatively, multiple screens may be provided in series or parallel. Once removed from the wastewater, the larger solid materials may be discharged to a sewer or periodically collected. In another example, once removed from the wastewater, the larger solid materials may be periodically disposed of or processed off-site for reuse as a soil conditioner. Once the larger solid materials are screened out of the wastewater, a valve may be used to redirect the wastewater flow to a heat exchanger. In some cases, at least a portion of the wastewater may not pass through a screening process before entering the wastewater treatment and heat recovery processes described herein.

[0028] One or more pumps may be used to move the heated wastewater through the heat exchanger. The heat exchanger may be located proximate to the wastewater treatment system. Alternatively, the heat exchanger may be located any distance from the wastewater treatment system. In some embodiments, heat recovery may occur prior to wastewater treatment. In some embodiments, the temperature of the heated wastewater stream is from about 65°F to about 90°F before entering the wastewater treatment system. In some embodiments, the temperature of the wastewater stream prior to entering the wastewater treatment system is from about 65°F to about 70°F, from about 65°F to about 72°F, from about 65°F to about 75°F, from about 65°F to about 78°F, from about 65°F to about 80°F, from about 65°F to about 85°F, from about 65°F to about 90°F, from about 70°F to about 72°F, from about 70°F to about 75°F, from about 70°F to about 78°F, from about 70°F to about 80°F, from about 70°F to about 85°F, from about 70°F to about 90°F , about 72°F to about 75°F, about 72°F to about 78°F, about 72°F to about 80°F, about 72°F to about 85°F, about 72°F to about 90°F, about 75°F to about 78°F, about 75°F to about 80°F, about 75°F to about 85°F, about 75°F to about 90°F, about 78°F to about 80°F, about 78°F to about 85°F, about 78°F to about 90°F, about 80°F to about 85°F, about 80°F to about 90°F, or about 85°F to about 90°F. In some embodiments, the temperature of the wastewater stream before entering the wastewater treatment system is about 65°F, about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, about 85°F, or about 90°F. In some embodiments, the temperature of the wastewater stream before entering the wastewater treatment system is at least about 65°F, about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, or about 85°F. In some embodiments, the temperature of the wastewater stream before entering the wastewater treatment system is at most about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, about 85°F, or about 90°F.

[0029] Once the wastewater stream exits the wastewater treatment and heat exchanger, one or more pumps may move the wastewater through the wastewater treatment system. In some embodiments, valves or pumps are used to direct the wastewater to the wastewater treatment system.

[0030] The heat recovered from the wastewater can be transferred to on-site or nearby heating needs. The recovered heat can facilitate heating of spaces and / or water on-site. In some embodiments, the recovered thermal energy can be converted to another form of energy. For example, the recovered thermal energy can be converted to mechanical energy, electrical energy, or a combination thereof. In some embodiments, the thermal energy recovered from the wastewater can be used in an on-site wastewater treatment process. In some cases, the thermal energy recovered from the wastewater can reduce the energy input required for the wastewater treatment process.

[0031] In some embodiments, the heat recovered from the wastewater may be used for on-site heating of domestic water. In other embodiments, the heat recovered from the wastewater may be used for on-site heating of treated wastewater (reclaimed or reused water). The temperature of the domestic cold water before the introduction of the recovered heat may be approximately 40°F, 45°F, 50°F, 55°F, 60°F, 65°F, 70°F, or 75°F. The heat recovered from the wastewater may be transferred to heat the domestic water to a temperature of approximately 60°F, 70°F, 80°F, 90°F, 100°F, 110°F, or 120°F. The domestic water may flow through a heat exchanger configured for heat transfer between two fluids. In some embodiments, the domestic cold water enters the heat exchanger at a first input location and the hot wastewater enters the heat exchanger at a second input location. The heat exchanger may facilitate heat transfer between the two fluids. In some embodiments, the heat energy present in the hot wastewater is transferred to cold domestic water to raise the temperature of the domestic water. In some embodiments, this heated domestic water is used on-site for domestic use. For example, this heated domestic water can be used for laundry, showering, washing clothes, etc.

[0032] In some embodiments, heat recovery system 200 may include heat exchanger 201, pump 203, and controller 205. In some cases, pump 203 may be a variable frequency drive (VFD) pump or a single-speed pump. The pump may include a motor controller that drives the electric motor by varying the frequency and voltage supplied to the electric motor, allowing the pump to operate at variable speeds (e.g., a range of flow rates) without using an additional gearbox or switching to a different electric motor. VFD pumps can adjust pump operation on the fly to accommodate uneven wastewater densities. This beneficially reduces pump power consumption, reducing costs and increasing energy efficiency. A flow control valve may be used to adjust the pump discharge flow rate instead of changing the pump motor speed.

[0033] The controller 205 may perform flow control within the heat recovery system 200. In some embodiments, the controller 205 is operatively coupled to a motor controller for the pump 203 and may automatically adjust the speed or other operation of the pump (e.g., switch it on / off). In some embodiments, the controller 205 may control the flow based on sensor data. For example, the sensor data may include the temperature of the wastewater (e.g., treated or partially treated), and the controller may execute a proprietary or non-proprietary control algorithm that adjusts the speed and activation timing of the pump. The control algorithm may maximize heat recovery while reducing the cost of the system.

[0034] In some embodiments, the controller and / or control algorithm may be part of a process control system that is integrated into the wastewater treatment and heat recovery system to optimize heat recovery, control the timing of wastewater flow, or a combination thereof. Sensors located at the tank, inlet / outlet of the heat exchanger 201 may also be part of the process control system. Data captured by the sensors may be transmitted via cable or wirelessly to the controller or process control system.

[0035] In some cases, the control algorithm may control the flow or operation of the heat recovery system based at least in part on the status of the wastewater treatment process and / or the building's water demand. In some cases, the control algorithm may be executed by a process control system to cooperatively control both the wastewater treatment process and the heat recovery to improve the overall performance of the integrated wastewater treatment and heat recovery. The collection and flow of wastewater through the building's network may depend on the water demand and use at a given time. More hot water may flow into the wastewater collection system at certain times of the day. For example, building occupants may take hot showers at the start of the day, causing a large amount of hot wastewater to flow into the wastewater treatment system in the morning. Similarly, an increase in hot water flow may be the result of increased use of washing machines and dishwashers. In some cases, a building's demand for non-potable water is less than the amount of wastewater being supplied to the integrated heat recovery and wastewater treatment system, so a portion of the building's wastewater flow may be diverted to a sewer. The process control system may execute control algorithms to prioritize and automatically determine when wastewater diversion to a sewer is needed to maximize heat recovery while balancing the building's non-potable supply needs. For example, when a building's non-potable supply needs fall below a threshold, the building's wastewater flow may be diverted to a sewer without unnecessary treatment. In some cases, the control algorithm may be able to anticipate and / or forecast building hot water demand and dynamically adjust wastewater diversion (e.g., time frame, amount, etc.) based on the predicted demand. The overall efficiency of heat recovery and wastewater treatment may be improved by avoiding unnecessary treatment of unusable wastewater while recovering the energy of such water for heat recovery.

[0036] In some cases, the process control system can control heat recovery to maximize heat recovery capacity and maximize uptime. During times when heat recovery capacity is limited or nonexistent, the system may automatically adjust the flow rate in the heat recovery system 200, such as by controlling the speed of the pump 203 or shutting it off, to conserve energy and limit component wear. In some cases, based on real-time sensed water temperature or water level in the tank, the system may determine heat recovery capacity and adjust (e.g., ramp down or shut down) the pump based on heat recovery capacity. For example, if heat recovery capacity falls below a threshold, the pump may be shut off.

[0037] The process control system may include sensors for measuring temperature, pressure, flow rate, or additional process / operating parameters. Temperature sensing may occur at the wastewater holding tank, at the water source to be preheated, at the inlet and / or outlet of the heat exchanger, or at any other point in the wastewater treatment and heat recovery process. Temperature sensing may be used to track system efficiency. Temperature sensing may also be used to enable control of pump speed, thereby enabling heat extraction. As described above, heat recovery operations may be controlled based on real-time temperature and / or hot water demand. For example, during periods when a building needs more hot water, pump speed may be increased to meet the increased heat recovery demand, and may be decreased when the building needs a decrease.

[0038] Optionally, if the wastewater temperature in the holding tank rises above a predetermined threshold, the controller 205 may command the pump to increase its speed until the temperature returns to a predetermined range. Optionally, if the wastewater temperature in the holding tank falls below a predetermined threshold, indicating insufficient heat recovery capacity, the controller 205 may command the pump to reduce speed or shut down, thereby reducing operating costs and minimizing wear and tear on components when heat recovery potential is low.

[0039] In some cases, the process control system may measure on-site demand for domestic hot water. In some cases, these measurements may be made in real time. Building or site water demand may be measured using an in-line flow meter for continuous, real-time data collection. In some cases, the domestic hot water temperature setpoint may be determined automatically through an in-line thermocouple. In some cases, the domestic hot water temperature setpoint is set by an operator. The domestic hot water need temperature setpoint may vary based on the building's hot water need, the time of day, and the season, among various other factors. An operator may set the temperature setpoint. This temperature setpoint may be adjusted to accommodate changing hot water demand, weather conditions, and seasons, among other factors. In some cases, the process control system may control the wastewater treatment process and / or heat recovery operations based on the expected domestic hot water demand. This forecast may be made based on historical data and / or real-time sensor data. Domestic hot water demand may be forecast for a future forecast horizon, such as 10 minutes, 20 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, etc.

[0040] The process control system may be capable of automatic operation. In some embodiments, the process control system may protect a pump from operating in a low-water condition based at least in part on water level sensor data. This may maximize system operation time or uptime and reduce operating costs. The water level in the tank may be measured using an in-line device located in the tank. Optionally, the in-line device contacts the wastewater in the tank. Optionally, the in-line device does not contact the wastewater in the tank. Optionally, the water level in the tank may be measured using a hydrostatic device. The hydrostatic device may include a displacer, a bubbler, or a differential pressure transmitter, or a combination thereof. Optionally, the water level in the tank is measured using an ultrasonic device. Optionally, the water level in the tank is measured using a laser or radar level transmitter. By continuously measuring the water level in the tank, the number of water level points for alarms and actions may be unlimited by programming within the control system. When a low-water condition is detected, the automatic control system may slow down the pump or shut off the pump entirely. In some cases, the pump suction height can determine the low-low cutoff value, as this is the physical point at which the pump is sucking in air instead of pumping water. In one example, the low cutoff point may be approximately 10 inches from the bottom of the tank. The low cutoff value is customizable and can be adjusted to suit a particular application or the physical dimensions of the component.

[0041] The heat recovery system may include one or more pumps 203 that move the hot wastewater stream to one or more heat exchangers 201. The hot wastewater stream may enter the one or more heat exchangers before wastewater treatment. In some embodiments, the heat exchanger 201 may be a shell-and-tube heat exchanger. FIGS. 6A and 6B illustrate a shell-and-tube heat exchanger. A shell-and-tube heat exchanger allows two fluids to exchange heat in thermal contact. In some embodiments, the first fluid is hot wastewater. In some embodiments, the second fluid is domestic chilled water. In some embodiments, the second fluid is a circulating fluid such as ammonia, water, a water-glycol mixture, or a refrigerant. The heat captured in the circulating fluid can be utilized for various on-site applications. In some embodiments, the two fluids include hot wastewater and a circulating fluid from the building to be heated. One fluid flows outside the tubes, and the second fluid flows through the tubes. The fluids can be in a gas phase, a liquid phase, or a combination thereof. Fluids can be single-phase or two-phase. Shell-and-tube heat exchangers can operate in parallel, cross-flow, or counter-flow configurations. A parallel-flow configuration is when the shell-and-tube fluids enter the heat exchanger on the same side and flow in parallel to opposite ends. A counter-flow heat exchanger is when the shell-and-tube fluids enter the heat exchanger at both ends. The fluids flow in opposite directions and exit at both ends of the heat exchanger. In a cross-flow shell-and-tube heat exchanger, the fluids flow perpendicular to each other at approximately a 90° angle. Figure 6A shows a shell-and-tube heat exchanger with two inlets and two outlets; each fluid begins at its corresponding inlet and exits the device at its corresponding outlet. The tube-side flow passes through the tubes (held in place by metal plates known as tubesheets) and exits through the tube outlets. Similarly, the shell-side flow begins at the shell inlet, passes through the tubes, and exits through the shell outlets. The amount of thermal mixing that occurs between the shell-side fluid and the fluid in the tubes is maximized by baffles. The shell-and-tube heat exchanger may be a U-tube heat exchanger, a fixed tubesheet exchanger, or a floating head heat exchanger.

[0042] In some embodiments, one or more heat exchangers may be plate-and-frame heat exchangers. FIG. 7 illustrates an example of a plate-and-frame heat exchanger. A plate-and-frame heat exchanger may include two end members that hold multiple heat transfer plates together. A plate-and-frame heat exchanger enables heat transfer between two fluids using multiple heat transfer plates. In some embodiments, the first fluid is hot wastewater. In some embodiments, the second fluid is cold domestic water. In some embodiments, the second fluid is a circulating fluid such as ammonia, water, a water-glycol mixture, or a refrigerant. The heat captured in the circulating fluid can be utilized for various field applications. In some embodiments, one or more pumps move the second fluid through the heat exchanger. The two fluids may flow through alternating channels in a countercurrent flow. The fluids may be in a gas phase, a liquid phase, or a combination thereof. The fluids may be single-phase or two-phase. The plates may be corrugated to create turbulence in the fluid as it flows through the heat exchanger. This turbulence can increase the amount of heat transferred between the two fluids. The plates may be constructed of stainless steel, titanium, aluminum, copper, Hastelloy, Avesta 254 SMO, Avesta 254 SLX, or any material ductile enough to be formed into a compression plate. The plates may be between 0.5 and 2.5 mm thick, or may be less than 0.5 mm or greater than 2.5 mm thick. The heat transfer plates may be separated by gaskets that seal the plates and direct fluid flow between them. The gaskets can prevent mixing of the two fluids in the event of internal damage to the heat exchanger. The heat transfer plates may be brazed together using a brazing material. The brazing material may include copper, nickel, silver, aluminum, or gold, or a combination thereof.

[0043] After exiting the heat exchanger and before entering the wastewater treatment, the wastewater stream may have a temperature of about 60°F to about 75°F. After exiting the heat exchanger and before entering the wastewater treatment, the wastewater stream may have a temperature of about 60°F to about 62°F, about 60°F to about 64°F, about 60°F to about 65°F, about 60°F to about 66°F, about 60°F to about 68°F, about 60°F to about 70°F, about 60°F to about 72°F, about 60°F to about 74°F, about 60°F to about 75°F, about 62°F to about 64°F, about 62°F to about 65°F, about 62°F to about 66°F, about 62°F to about 68°F, about 62°F to about 70°F, about 62°F to about 72°F, about 62°F to about 74°F, about 62°F to about 75°F, about 64°F to about 65°F, about 64°F to about 66°F, about 64°F to about 68°F, about 64°F to about 70°F, about 64°F to about 72°F, about 64°F to about 74°F, about 64°F to about 75°F, about 65°F to about 66°F, about 65°F to about 68°F, about 65°F to about 70°F, about 65°F to about 72°F, about 65°F to about 74°F, about 65°F to about 75°F, about 66°F to about 68°F, about 66°F to about 70°F, about 66°F to about 72°F, about 66°F to about The temperature may be about 74°F, about 66°F to about 75°F, about 68°F to about 70°F, about 68°F to about 72°F, about 68°F to about 74°F, about 68°F to about 75°F, about 70°F to about 72°F, about 70°F to about 74°F, about 70°F to about 75°F, about 72°F to about 74°F, about 72°F to about 75°F, or about 74°F to about 75°F. After exiting the heat exchanger and before entering the wastewater treatment, the wastewater stream may have a temperature of about 60°F, about 62°F, about 64°F, about 65°F, about 66°F, about 68°F, about 70°F, about 72°F, about 74°F, or about 75°F.

[0044] In some embodiments, the amount of energy extracted from the thermal wastewater is between about 500,000 BTU / day and about 100,000,000 BTU / day, or any amount less than 500,000 BTU / day or greater than 100,000,000 BTU / day. In some embodiments, the amount of energy extracted from the thermal wastewater is between about 500,000 BTU / day and about 100,000,000 BTU / day. In some embodiments, the amount of energy extracted from the thermal wastewater is between about 500,000 BTU / day and about 1,000,000 BTU / day, between about 500,000 BTU / day and about 5,000,000 BTU / day, between about 500,000 BTU / day and about 20,000,000 BTU / day, between about 500,000 BTU / day and about 50,000,000 BTU / day, between about 500,000 BTU / day and about 100,000,000 BTU / day, between about 1,000,000 BTU / day and about 5,000,000 BTU / day, between about 1,000,000 BTU / day and about 20 ... between about 50,000,000 BTU / day, between about 1,000,000 BTU / day and about 100,000,000 BTU / day, between about 5,000,000 BTU / day and about 20,000,000 BTU / day, between about 5,000,000 BTU / day and about 50,000,000 BTU / day, between about 5,000,000 BTU / day and about 100,000,000 BTU / day, between about 20,000,000 BTU / day and about 50,000,000 BTU / day, between about 20,000,000 BTU / day and about 100,000,000 BTU / day, or between about 50,000,000 BTU / day and about 100,000,000 BTU / day. In some embodiments, the amount of energy extracted from the thermal wastewater is about 500,000 BTU / day, about 1,000,000 BTU / day, about 5,000,000 BTU / day, about 20,000,000 BTU / day, about 50,000,000 BTU / day, or about 100,000,000 BTU / day. In some embodiments, the amount of energy extracted from the thermal wastewater is at least about 500,000 BTU / day, about 1,000,000 BTU / day, about 5,000,000 BTU / day, about 20,000,000 BTU / day, or about 50,000,000 BTU / day.In some embodiments, the amount of energy extracted from the heated wastewater is up to about 1,000,000 BTU / day, about 5,000,000 BTU / day, about 20,000,000 BTU / day, about 50,000,000 BTU / day, or about 100,000,000 BTU / day. Once the wastewater stream exits the heat exchanger, one or more pumps may move the wastewater through a wastewater treatment system. In some embodiments, a valve is used to divert the wastewater to the wastewater treatment system.

[0045] Upon entering the wastewater treatment system, the wastewater may be held in a holding tank. In some cases, if the treatment process reaches its limit, the holding tank may be used to hold the excess wastewater in a bay. In some cases, a three-way valve may be used as an emergency bypass to a sewer. For example, if the treatment process reaches its limit and the holding tank is full, excess wastewater from a building may be released to a sewer using an emergency bypass.

[0046] Various embodiments of the wastewater treatment systems and methods described herein provide wastewater treatment with improved efficiency and water and energy use. In some embodiments, the treated solid waste can be used as fertilizer or soil amendment. Wastewater separated from the solid waste during the treatment process can be treated and disinfected for use in toilets, cooling towers, clothes washing, irrigating landscaping, or other environmentally safe applications. Various embodiments may be used in any of a number of settings and locations to provide efficient and effective wastewater treatment.

[0047] The terms "waste," "wastewater," and "sewage" may be used interchangeably in this application and should be construed as interchangeable unless specifically stated to have a particular meaning.

[0048] In some embodiments, heat recovery may occur after wastewater treatment. As the wastewater exits the wastewater treatment system, a valve may be used to redirect the wastewater stream to one or more heat exchangers. One or more pumps may be used to move the heated wastewater through the one or more heat exchangers. The heat exchangers may be located close to the outlet of the wastewater treatment system or at a distance. In some embodiments, heat recovery may occur before and after wastewater treatment. In some embodiments, the temperature of the heated wastewater stream after exiting the wastewater treatment system is about 65°F to about 90°F. In some embodiments, the temperature of the wastewater stream after leaving the wastewater treatment system is from about 65°F to about 70°F, from about 65°F to about 72°F, from about 65°F to about 75°F, from about 65°F to about 78°F, from about 65°F to about 80°F, from about 65°F to about 85°F, from about 65°F to about 90°F, from about 70°F to about 72°F, from about 70°F to about 75°F, from about 70°F to about 78°F, from about 70°F to about 80°F, from about 70°F to about 85°F, from about 70°F to about 90°F , about 72°F to about 75°F, about 72°F to about 78°F, about 72°F to about 80°F, about 72°F to about 85°F, about 72°F to about 90°F, about 75°F to about 78°F, about 75°F to about 80°F, about 75°F to about 85°F, about 75°F to about 90°F, about 78°F to about 80°F, about 78°F to about 85°F, about 78°F to about 90°F, about 80°F to about 85°F, about 80°F to about 90°F, or about 85°F to about 90°F. In some embodiments, the temperature of the wastewater stream after exiting the wastewater treatment system is about 65°F, about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, about 85°F, or about 90°F. In some embodiments, the temperature of the wastewater stream after exiting the wastewater treatment system is at least about 65°F, about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, or about 85°F. In some embodiments, the temperature of the wastewater stream after exiting the wastewater treatment system is at most about 70°F, about 72°F, about 75°F, about 78°F, about 80°F, about 85°F, or about 90°F.

[0049] In some embodiments, the heat recovery system herein may be provided as a package that can be advantageously integrated into an existing wastewater treatment system. In some cases, the heat recovery system may have a small footprint, such as a complete skid-mounted system. This complete skid-mounted system can be integrated into an existing wastewater treatment process where heat recovery is desired. In some embodiments, the heat recovery system may include the pumps, heat exchangers, sensors, and controllers described above and may be coupled to the wastewater treatment system in a plug-and-play manner without requiring replacement of the wastewater treatment system. This may facilitate easy integration of the system into a building. In some cases, the integrated wastewater treatment and heat recovery system is installed in the building foundation. Alternatively, reconfiguration of one or more components of the existing wastewater treatment system may be required to couple to the heat recovery system. For example, the skid-mounted heat recovery system may include all required sensors and instrumentation. The sensors and instrumentation can be tested prior to installation and delivery to the installation site. In some cases, the temperature sensors (or other sensors) of the existing wastewater treatment system may be utilized by the heat recovery system. For example, a controller for the heat recovery system may communicate with a control system for the wastewater treatment system to retrieve sensor data or other wastewater treatment condition data and control pumps or operation of the heat recovery system.

[0050] In some cases, the heat recovery systems herein may provide the flexibility to be custom designed to fit existing wastewater treatment sites. For example, the heat recovery system may be configured to be scaled up or down relative to the flow capacity of the existing wastewater treatment system. For example, the heat recovery system may be scaled up by increasing the speed or size of the pumps to meet the flow capacity of the existing wastewater treatment.

[0051] In some cases, the functionality or management of the heat recovery system can be automatically integrated into the management software of the wastewater treatment system, e.g., a supervisory control and data acquisition ("SCADA") system. This software may allow an operator to set the heat exchanger configuration, view real-time status of both the heat recovery system and the WWTP (wastewater treatment plant), and control the system.

[0052] In some embodiments, the software may provide an operator interface that allows an operator to configure the heat exchanger system when setting and / or modifying the configuration of the heat exchanger system during operation. Control algorithms may be executed to control the pumps of the heat recovery system, the valves of the wastewater treatment system, and other components of the system for safety, heat recovery efficiency, and / or cost reduction purposes as described elsewhere herein. Alternatively or additionally, an operator may configure the heat recovery system by directly setting system parameters (e.g., flow rates or pump speeds).

[0053] In some embodiments, the integrated systems herein may provide an operator interface that allows an operator to access real-time status and data regarding the system. For example, data collected from the wastewater treatment and heat recovery systems may be displayed on a control panel. Real-time information may allow an operator to track heat recovery and other system statistics.

[0054] In some cases, the software may be capable of announcing alarms (e.g., system malfunction, pump stall, low water level in a tank, etc.) in real time. In some cases, the operator interface provided by the system may allow the operator to customize rules for activating alarms. For example, the operator may set thresholds to activate alarms, reminder / alarm frequency, and / or alarm notification channels (e.g., messages, emails, in-app messages, etc.).

[0055] In some cases, the operator interface may include a control panel that allows an operator to control at least a portion of the operating parameters. For example, an operator may be able to manually shut down the heat recovery system through the control panel when there is little heat available for recovery or when the system requires maintenance.

[0056] In some embodiments, the software may provide a customer interface. A customer may be an individual or business utilizing the wastewater heat recovery system. For example, a customer may be an owner of an apartment building in which the wastewater heat recovery system is installed. A customer may be a university that utilizes a wastewater heat recovery system to recover heat from wastewater throughout the university campus. The customer interface may allow the customer to view certain operational or performance statistics. In some cases, the customer interface displays the amount of heat or energy recovered from the wastewater heat recovery system. The customer interface may display cost savings associated with the installation and operation of the wastewater heat recovery system. The customer interface may display data in real time or as an average over a given period of time. In some cases, the customer may not be able to modify operational parameters through the customer interface.

[0057] For example, the control panel may be a customer-facing dashboard that displays the real-time status of the system and / or provides the customer with an overview of how the system is performing. In some cases, the customer-facing dashboard may include reporting functionality. In some cases, only authorized users may be allowed to edit process parameters via this dashboard.

[0058] In some embodiments, the integrated wastewater treatment and heat recovery system is fully automated. The process control system can be fully automated with controls that can be manually overridden by the system operator. For example, an operator may control the system through a supervisory control and data acquisition ("SCADA") system, allowing the operator to force pumps on and off, adjust pump speeds, change the opening ratio of control valves, and perform various other system operations. The operator can always return the entire system or individual components to automatic operation. For troubleshooting purposes, in-line sensors can be manually set to specific values. This advantageously allows for equipment replacement without interrupting system operation. Additionally, this functionality can be used to diagnose whether automatic functions are operating.

[0059] In some embodiments, the heat recovery system and / or WWTP may communicate with a remote cloud via a gateway, the building's internet service, or a cellular network. For example, the gateway may be connected to a wide area network (e.g., the internet) or cloud using any possible TCP / IP or UDP-based backhaul, such as Ethernet, Wi-Fi, or cellular. The gateway may be equipped with a radio front-end capable of listening to several MHz of RF radio spectrum at a time and / or configured to listen to all network traffic transmitted within that spectrum. In some cases, the gateway may use a synchronous frequency hopping scheme.

[0060] In some cases, the user interface may be provided as a cloud application, such as an administration console or analytics portal, that can be accessed by users, operators, managers, auditors, or third-party entities.

[0061] In some cases, a graphical user interface (GUI) or user interface provided by the system herein may be rendered on a display of a user device. The display may or may not be a touchscreen. The display may be a light-emitting diode (LED) screen, an organic light-emitting diode (OLED) screen, a liquid crystal display (LCD) screen, a plasma screen, or any other type of screen. The display may be configured to show a user interface (UI) or graphical user interface (GUI) rendered through a mobile application or a cloud application (e.g., via an application programming interface (API) running on the user device). Similarly, a GUI may also be provided by a local computing system, or the GUI may be provided on a display of a wearable device, personal device, or user device in a building. The GUI may be rendered through an application running on the user device (e.g., via an application programming interface (API)). The user device may be a computing device configured to perform one or more operations consistent with embodiments of the present disclosure. Examples of user devices may include, but are not limited to, a mobile device, a smartphone / cell phone, a tablet, a personal digital assistant (PDA), a laptop or notebook computer, a desktop computer, a virtual reality system, an augmented reality system, a microphone, or any electronic device.

[0062] The controller, process control system, and various other methods herein may be implemented in hardware, software, or a combination of both. In some embodiments, the controller or process control system may include one or more processors, such as a programmable processor (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a general-purpose processing unit, or a microcontroller) in the form of a fine-grained space architecture such as a field programmable gate array (FPGA), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), and / or one or more Advanced RISC Machine (ARM) processors. In some embodiments, the processor may be a processing unit of a computer system.

[0063] Those skilled in the art will appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate such interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality.

[0064] The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic controller (PLC) device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a DSP in combination with a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0065] The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by one or more processors, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. Alternatively, the processor and the storage medium may reside as discrete components in a user terminal.

[0066] In accordance with the description herein, suitable computing devices include, by way of non-limiting example, server computers, desktop computers, laptop computers, notebook computers, subnotebook computers, netbook computers, netpad computers, set-top computers, media streaming devices, handheld computers, Internet appliances, mobile smartphones, tablet computers, personal digital assistants, video game consoles, and communications media. Those skilled in the art will also recognize that selected televisions, video players, and digital music players, with optional computer network connectivity, are suitable for use with the systems described herein. Suitable tablet computers, in various embodiments, include those having booklet, slate, and convertible configurations known to those skilled in the art.

[0067] In some embodiments, a computing device includes an operating system configured to execute executable instructions. An operating system is software, including, for example, programs and data, that manages the device's hardware and provides services for application execution. Those skilled in the art will recognize that suitable server operating systems include, by way of non-limiting example, FreeBSD, OpenBSD, NetBSD®, Linux®, Apple® Mac OS X Server®, Oracle® Solaris®, Windows Server®, and Novell® NetWare®. Those skilled in the art will recognize that suitable personal computer operating systems include, by way of non-limiting example, Microsoft® Windows®, Apple® Mac OS X®, UNIX®, and UNIX-like operating systems such as GNU / Linux®. In some embodiments, the operating system is provided by cloud computing. Those skilled in the art will also recognize that suitable mobile smartphone operating systems include, by way of non-limiting example, Nokia® Symbian® OS, Apple® iOS®, Research In Motion® BlackBerry OS®, Google® Android®, Microsoft® Windows Phone® OS, Microsoft® Windows Mobile® OS, Linux®, and Palm® WebOS®.Those skilled in the art will also recognize that suitable media streaming device operating systems include, by way of non-limiting example, Apple TV®, Roku®, Boxee®, Google TV®, Google Chromecast®, Amazon Fire®, and Samsung® HomeSync®. Those skilled in the art will also recognize that suitable video game console operating systems include, by way of non-limiting example, Sony® PS3®, Sony® PS4®, Microsoft® Xbox 360®, Microsoft Xbox One, Nintendo® Wii®, Nintendo® Wii U®, and Ouya®.

[0068] In some embodiments, the systems, media, devices, and methods disclosed herein comprise one or more non-transitory computer-readable storage media encoded with a program including instructions executable by an operating system of a networked computing device. In further embodiments, the computer-readable storage medium is a tangible component of the computing device. In still further embodiments, the computer-readable storage medium is optionally removable from the computing device. In some embodiments, computer-readable storage media include, by way of non-limiting example, CD-ROMs, DVDs, flash memory devices, solid-state memories, magnetic disk drives, magnetic tape drives, optical disk drives, distributed computing systems such as cloud computing systems and services, and the like. In some cases, the programs and instructions are encoded on the medium permanently, nearly permanently, semi-permanently, or non-transitoryly.

[0069] In some embodiments, the platforms, systems, media, and methods disclosed herein include at least one computer program, or the use thereof. A computer program includes a sequence of instructions that is executable by one or more processors of a computing device's CPU and that are written to perform specified tasks. The computer-readable instructions may be implemented as program modules, such as functions, objects, application programming interfaces (APIs), computing data structures, etc., that perform particular tasks or implement particular abstract data types. In light of the disclosure provided herein, those skilled in the art will recognize that computer programs may be written in various versions of various languages, such as PLC ladder logic code.

[0070] The functionality of the computer-readable instructions may be combined or distributed as desired in various environments. In some embodiments, a computer program includes one instruction sequence. In some embodiments, a computer program includes multiple instruction sequences. In some embodiments, a computer program is provided from one location. In other embodiments, a computer program is provided from multiple locations. In various embodiments, a computer program includes one or more software modules. In various embodiments, a computer program includes, in part or in whole, one or more web applications, one or more mobile applications, one or more stand-alone applications, one or more web browser plug-ins, extensions, add-ins, or add-ons, or combinations thereof.

[0071] In some embodiments, the computer program comprises a web application. In light of the disclosure provided herein, those skilled in the art will recognize that web applications, in various embodiments, utilize one or more software frameworks and one or more database systems. In some embodiments, the web application is built on a software framework such as Microsoft® .NET or Ruby on Rails (RoR). In some embodiments, the web application utilizes one or more database systems, including, by way of non-limiting example, relational, non-relational, object-oriented, associative, and XML database systems. In further embodiments, suitable relational database systems include, by way of non-limiting example, Microsoft® SQL Server, mySQL™, and Oracle®. Those skilled in the art will also recognize that web applications may be written in one or more versions of one or more languages. Web applications may be written in one or more markup languages, presentation definition languages, client-side scripting languages, server-side coding languages, database query languages, or combinations thereof. In some embodiments, a web application is written in part in a markup language such as Hypertext Markup Language (HTML), Extensible Hypertext Markup Language (XHTML), or eXtensible Markup Language (XML). In some embodiments, a web application is written in part in a presentation definition language such as Cascading Style Sheets (CSS). In some embodiments, a web application is written in part in client-side scripting such as Asynchronous Javascript and XML (AJAX), Flash® Actionscript, Javascript, or Silverlight®.In some embodiments, the web application is written in part in a server-side coding language such as Active Server Pages (ASP), ColdFusion®, Perl, Java™, JavaServer Pages (JSP), Hypertext Preprocessor (PHP), Python™, Ruby, Tcl, Smalltalk, WebDNA®, or Groovy. In some embodiments, the web application is written in part in a database query language such as Structured Query Language (SQL). In some embodiments, the web application integrates an enterprise server product such as IBM® Lotus Domino®. In some embodiments, the web application includes a media player element. In various further embodiments, the media player element utilizes one or more of many suitable multimedia technology products, including, by way of non-limiting examples, Adobe® Flash®, HTML 5, Apple® QuickTime®, Microsoft® Silverlight®, Java®, and Unity®.

[0072] In some embodiments, the computer program comprises a mobile application provided to the mobile computing device. In some embodiments, the mobile application is provided to the mobile computing device at the time of manufacture. In other embodiments, the mobile application is provided to the mobile computing device via a computer network as described herein.

[0073] Given the disclosure provided herein, mobile applications are created using hardware, languages, and development environments known in the art and techniques known to those skilled in the art. Those skilled in the art will recognize that mobile applications are written in a variety of languages. Suitable programming languages ​​include, by way of non-limiting example, C, C++, C#, Objective-C, Java™, Javascript, Pascal, Object Pascal, Python™, Ruby, VB.NET, WML, and XHTML / HTML with or without CSS, or combinations thereof.

[0074] Suitable mobile application development environments are available from several sources. Commercially available development environments include, but are not limited to, Airplay SDK, alcheMo, Appcelerator®, Celsius, Bedrock, Flash Lite, .NET Compact Framework, Rhomobile, and WorkLight Mobile Platform. Other development environments are available free of charge, but are not limited to, Lazarus, MobiFlex, MoSync, and Phonegap. Mobile device manufacturers also distribute software development kits, including, but not limited to, the iPhone® and iPad® (iOS) SDK, Android™ SDK, BlackBerry® SDK, BREW SDK, Palm® OS SDK, Symbian SDK, webOS SDK, and Windows® Mobile SDK.

[0075] Those skilled in the art will recognize that several commercial forums are available for the distribution of mobile applications, including, by way of non-limiting example, the Apple® App Store, Google® Play, Chrome Webstore, BlackBerry® App World, App Store for Palm devices, App Catalog for webOS, Windows® Marketplace for Mobile, Ovi Store for Nokia® devices, Samsung® Apps, and Nintendo® DSi Shop.

[0076] In some embodiments, the computer program comprises a stand-alone application, which is a program that runs as an independent computer process rather than as an add-on, e.g., a plug-in, to an existing process. Those skilled in the art will recognize that stand-alone applications are often compiled. A compiler is a computer program that converts source code written in a programming language into binary object code, such as assembly language or machine code. Suitable compiled programming languages ​​include, but are not limited to, C, C++, Objective-C, COBOL, Delphi, Eiffel, Java™, Lisp, Python™, Visual Basic, and VB.NET, or combinations thereof. Compilation is often performed, at least in part, to create an executable program. In some embodiments, the computer program comprises one or more executable compiled applications.

[0077] In some embodiments, the computer program includes a web browser plug-in (e.g., an extension). In computing, a plug-in is one or more software components that add specific functionality to a larger software application. Software application manufacturers support plug-ins to allow third-party developers to extend the application, facilitate the easy addition of new features, and reduce the application's size. When supported, plug-ins allow customization of the software application's functionality. For example, plug-ins are commonly used in web browsers to play video, generate interactivity, scan for viruses, and display specific file types. Those skilled in the art will be familiar with several web browser plug-ins, including Adobe® Flash® Player, Microsoft® Silverlight®, and Apple® QuickTime®. In some embodiments, the toolbar includes one or more web browser extensions, add-ins, or add-ons. In some embodiments, the toolbar includes one or more explorer bars, tool bands, or desk bands. The various functionalities, methods, and control algorithms described herein can be implemented in an application platform, software, hardware, or any combination of the foregoing.

[0078] In view of the disclosure provided herein, one of ordinary skill in the art will recognize that several plug-in frameworks are available that allow for the development of plug-ins in a variety of programming languages, including, by way of non-limiting example, C++, Delphi, Java™, PHP, Python™, and VB.NET, or combinations thereof.

[0079] A web browser (also called an Internet browser) is a software application designed for use with networked computing devices to search, present, and traverse information resources on the World Wide Web. Suitable web browsers include, by way of non-limiting example, Microsoft® Internet Explorer®, Mozilla® Firefox®, Google® Chrome, Apple® Safari®, Opera Software® Opera®, and KDE Konqueror. In some embodiments, the web browser is a mobile web browser. Mobile web browsers (also called microbrowsers, minibrowsers, and wireless browsers) are designed for use on mobile computing devices, including, by way of non-limiting example, handheld computers, tablet computers, netbook computers, subnotebook computers, smartphones, music players, personal digital assistants (PDAs), and handheld video game systems. Suitable mobile web browsers include, by way of non-limiting example, Google® Android® Browser, RIM BlackBerry® Browser, Apple® Safari®, Palm® Blazer, Palm® WebOS® Browser, Mozilla® Firefox® for mobile, Microsoft® Internet Explorer® Mobile, Amazon® Kindle® Basic Web, Nokia® Browser, Opera Software® Opera® Mobile, and Sony® PSP™ Browser.

[0080] In some embodiments, the platforms, systems, media, and methods disclosed herein include software, server, and / or database modules, or the use thereof. In light of the disclosure provided herein, software modules are created by techniques known to those skilled in the art using machines, software, and languages ​​known in the art. The software modules disclosed herein are implemented in numerous ways. In various embodiments, a software module comprises a file, a section of code, a programming object, a programming structure, or a combination thereof. In further various embodiments, a software module comprises multiple files, multiple sections of code, multiple programming objects, multiple programming structures, or a combination thereof. In various embodiments, one or more software modules include, by way of non-limiting examples, a web application, a mobile application, and a standalone application. In some embodiments, a software module is within one computer program or application. In other embodiments, a software module is within more than one computer program or application. In some embodiments, a software module is hosted on one machine. In other embodiments, a software module is hosted on multiple machines. In further embodiments, a software module is hosted on a distributed computing platform, such as a cloud computing platform. In some embodiments, the software modules are hosted on one or more machines in one location, while in other embodiments, the software modules are hosted on one or more machines in more than one location. [Example]

[0081] Example 1: Energy Recovery from 30,000 Gallons / Day of Wastewater The heat recovery system herein may reduce costs without compromising performance. As illustrated in FIG. 3, an apartment building may have approximately 30,000 gallons / day of wastewater available for heat recovery. Hot water used for showering, cooking, cleaning, washing clothes, etc. may increase the temperature of the wastewater stream. The temperature of the wastewater may be approximately 75°F. The 30,000 gallons / day of wastewater may flow to the apartment building's foundation and enter the wastewater treatment and heat recovery process. The thermal energy stored in the hot wastewater may be recovered and used to heat domestic water used in the apartment building. The amount of energy available for extraction from the wastewater stream is calculated using the formula Q=m×C×(T1-T A -T2), where Q is the thermal energy, m is the mass flow rate of the wastewater (250,200 lbs / day), C is the specific heat of water (1 BTU / lb / °F), T1 is the input temperature of the wastewater stream (75°F), and T A is the heat exchanger approach temperature of 5°F, and T2 is the domestic water input temperature. Assuming a domestic water input temperature (T2) of 60°F, the energy available for extraction from the wastewater stream is 2,502,000 BTU / day or 733 kWh / day. Assuming a hot water demand of 20 gal / capita / day, an apartment building with 540 units and two occupants per unit could have a total hot water demand of 21,600 gal / day. Therefore, the energy recovered from the wastewater can heat domestic water by providing 116 BTU / gal.

[0082] Example 2: Energy Recovery from 37,000 Gallons / Day of Wastewater As illustrated in Figure 4, an apartment building may have approximately 37,000 gallons / day of wastewater available for heat recovery. Hot water used for showering, cooking, cleaning, washing clothes, etc. may increase the temperature of the wastewater stream. The temperature of the wastewater may be approximately 75°F. The 37,000 gallons / day of wastewater may flow to the apartment building's foundation and enter the wastewater treatment and heat recovery process. The thermal energy stored in the hot wastewater may be recovered and used to heat domestic water used in the apartment building. The amount of energy available for extraction from the wastewater stream is calculated using the formula Q = m × C × (T - T A-T2), where Q is the thermal energy, m is the mass flow rate of the wastewater (308,580 lbs / day), C is the specific heat of water (1 BTU / lb / °F), T1 is the input temperature of the wastewater stream (75°F), and T A is the heat exchanger approach temperature of 5°F, and T2 is the domestic water input temperature. Assuming a domestic water input temperature (T2) of 60°F, the energy available for extraction from the wastewater stream is 3,085,800 BTU / day or 904 kWh / day. Assuming a hot water demand of 20 gal / capita / day, an apartment building with 540 units and two occupants per unit could have a total hot water demand of 21,600 gal / day. Therefore, the energy recovered from the wastewater can heat domestic water by providing 143 BTU / gal.

[0083] Example 3: Energy Recovery from 50,000 Gallons / Day of Wastewater As illustrated in Figure 5, an apartment building may have approximately 50,000 gallons / day of wastewater available for heat recovery. Hot water used for showering, cooking, cleaning, washing clothes, etc. may increase the temperature of the wastewater stream. The temperature of the wastewater may be approximately 75°F. The 50,000 gallons / day of wastewater may flow to the apartment building's foundation and enter the wastewater treatment and heat recovery process. The thermal energy stored in the hot wastewater may be recovered and used to heat domestic water used in the apartment building. The amount of energy available for extraction from the wastewater stream is calculated using the formula Q = m × C × (T - T A -T2), where Q is the thermal energy, m is the mass flow rate of the wastewater (417,000 lbs / day), C is the specific heat of water (1 BTU / lb / °F), T1 is the input temperature of the wastewater stream (75°F), and T Ais the heat exchanger approach temperature of 5°F, and T2 is the domestic water input temperature. Assuming a domestic water input temperature (T2) of 60°F, the energy available for extraction from the wastewater stream is 4,170,000 BTU / day or 1,222 kWh / day. Assuming a hot water demand of 20 gal / capita / day, an apartment building with 540 units and two occupants per unit could have a total hot water demand of 21,600 gal / day. Therefore, the energy recovered from the wastewater can heat domestic water by providing 193 BTU / gal.

[0084] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the present invention be limited by the specific examples provided herein. While the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the invention. Furthermore, it is to be understood that all aspects of the present invention are not limited to the specific descriptions, configurations, or relative proportions set forth herein, depending upon a variety of conditions and variables. It is to be understood that various alternatives to the embodiments of the present invention described herein may be employed in practicing the invention. Therefore, it is contemplated that the present invention also encompasses any and all such alternatives, modifications, variations, or equivalents. The following claims define the scope of the invention, and it is intended that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. 1. A heat recovery system comprising: (i) a heat exchanger configured to heat water with thermal energy recovered from a wastewater stream being treated by a wastewater treatment system in fluid communication with the heat recovery system; (ii) a device configured to control a flow rate of wastewater within the heat recovery system based at least in part on real-time sensor data.

2. The heat recovery system of claim 1 , wherein the wastewater is at least partially treated by the wastewater treatment system before entering the heat recovery system.

3. The heat recovery system of claim 2 , wherein the heat exchanger comprises a plate-and-frame heat exchanger.

4. The heat recovery system of claim 1 , wherein the wastewater is treated by the wastewater treatment system after exiting the heat recovery system.

5. The heat recovery system of claim 4 , wherein the heat exchanger comprises a shell-and-tube heat exchanger.

6. The heat recovery system of claim 1 further comprising a screening system.

7. The heat recovery system of claim 1 , wherein the device is configured to control a flow rate of the wastewater stream based at least in part on a temperature of the wastewater stream.

8. The heat recovery system of claim 7 , wherein the device is configured to increase the flow rate of the wastewater stream when the temperature of the wastewater stream exceeds a threshold value.

9. The heat recovery system of claim 7 , wherein the device is configured to reduce the flow rate of the wastewater stream when the temperature of the wastewater stream falls below a threshold value.

10. The heat recovery system of claim 1 , wherein the device is configured to control the flow rate of the wastewater through the heat recovery system based at least in part on a demand for heated water.

11. The heat recovery system of claim 1 , wherein the device is configured to increase the flow rate of the wastewater through the heat recovery system when a demand for heated water exceeds a threshold.

12. The heat recovery system of claim 1 , wherein the device is configured to reduce the flow rate of the wastewater through the heat recovery system when a demand for heated water falls below a threshold.

13. The heat recovery system of claim 1 further comprising a wastewater holding tank.

14. The heat recovery system of claim 13 , wherein the device is configured to control a flow rate of the wastewater based at least in part on an amount of wastewater present in the wastewater holding tank.

15. 14. The heat recovery system of claim 13, wherein the device is configured to shut down when the amount of wastewater present in the wastewater holding tank falls below a threshold level.

16. The heat recovery system of claim 1 housed within a complete skid-mounted system.

17. The heat recovery system of claim 16 , wherein the complete skid-mounted system is configured to be coupled to an existing wastewater treatment system.

18. The heat recovery system of claim 1 , located at a location within a wastewater source.

19. The heat recovery system of claim 1 , wherein the wastewater source is a building and the heat recovery system is located within the building.

20. 20. The heat recovery system of claim 19, located in the foundation of the building.

21. The heat recovery system of claim 1 , wherein at least a portion of the wastewater used by the heat recovery system is not completely treated by the wastewater treatment system.

22. The heat recovery system of claim 1 , wherein the device is a pump.

23. The heat recovery system of claim 1 , wherein the device is a valve.

24. The heat recovery system of claim 1 , wherein the wastewater source is a building and the heat recovery system is located outside the building.

25. The heat recovery system of claim 1 , located remotely from a source of wastewater.

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