Precision monitoring of fluid levels and smart control of pumps for wastewater vessels

Abstract

A device, system and method for precise and reliable monitoring and control of fluid levels within wastewater vessels are provided The device comprises a tubular probe with a submerged end and a reading end. A pressure generating unit exerts brief, high-intensity pressure bursts exceeding expected hydrostatic pressure by a significant factor (e.g., 5 to 25 times). After a predetermined delay, the pressure reading unit determines the actual hydrostatic pressure. A control unit, informed by this data, activates a fluid displacement pump if the hydrostatic pressure exceeds a set maximum. This system offers enhanced accuracy and efficiency in wastewater level management, particularly in scenarios where buildup or other factors may interfere with traditional monitoring methods.

Description

[0001] Title

[0002] Precision monitoring of fluid levels and smart control of pumps for wastewater vessels

[0003] Technical field

[0004] The present invention relates to devices for monitoring and controlling fluid levels within vessels, such as tanks, reservoirs, or wells. More particularly, the invention relates to a system for accurately determining fluid levels in wastewater vessels and automatically controlling wastewater displacement pumps based on the determined level.

[0005] Background

[0006] The precise measurement and control of liquid levels within aggressive environments, such as closed sewage tanks, poses a significant challenge. The prevalent technology for controlling submersible pumps in these applications relies on level switches. These level switches have several inherent disadvantages:

[0007] Cost: Level switches are relatively expensive components.

[0008] Installation and Maintenance: They require precise installation and electrical connections, increasing labor costs and potential points of failure. Additionally, their placement within the hazardous environment of e.g., sewage tanks or wells makes maintenance difficult and poses health risks due to exposure to harmful pathogens and bacteria.

[0009] Limited Functionality: Level switches primarily provide discrete on / off signals for pump control, lacking the ability for continuous monitoring or sophisticated control strategies. Alternative methods like echo sounders or radar, while available, have not found widespread commercial adoption for pump control in sewage tanks, likely due to cost and complexity considerations.

[0010] Another alternative method for measuring fluid levels in wastewater include the utilization of pneumatic systems such as "bubblers”, meaning systems utilizing a pressure generating unit in gaseous communication with a pressure sensor and a tubular probe i.e., a flexible tube, having one end submerged in the wastewater. These so called "bubblers” continuously feed the tubular probe with air and the pressure reading unit continuously take measurements. The actual hydrostatic pressure is then derived from the difference between a known fed pressure and the measured pressure. However, traditional measurement utilizing such pneumatic systems, such as bubblers, face several challenges that can compromise their reliability and performance. The continuous feeding or air into the probe result in relatively high energy consumption and wear and tear on pressure reading sensors. In the harsh environment of vessels filled with waste water, traditional probes are susceptible to clogging caused by a variety of factors. Physical obstructions, such as debris or sedimentation, can block the probe and hinder accurate readings. Additionally, biofilm buildup and chemical precipitation can constrict the probe's interior, further impeding fluid flow. These kinds of obstructions can lead to inaccurate measurements, system malfunctions, and even damage to the pressure monitoring components. This highlights the need for innovative solutions to improve accuracy and robustness for fluid level monitoring within wastewater management systems.

[0011] Furthermore, the accuracy of pneumatic systems can be compromised by their sensitivity to environmental factors within the wastewater vessel. Temperature variations can alter the physical properties of the fluid and the air within the system, leading to fluctuations in pressure readings. Additionally, turbulence, such as that caused by air escaping the bubbler, can introduce further instability in the pressure measurements. This inherent sensitivity translates to imprecise measurements, which can negatively impact the control and efficiency of wastewater pumps.

[0012] Summary

[0013] According to a first aspect of the present invention there is proposed a device for monitoring and controlling a fluid level of a wastewater vessel. The device includes the following components:

[0014] A tubular probe having a submerged probe end and a reading probe end. The submerged probe end is adapted to be submerged into the wastewater vessel.

[0015] A pressure generating unit arranged to be in fluid communication with the reading probe end.

[0016] A pressure reading unit arranged to measure pressure at the reading end of the tubular probe. a control unit having a power outlet for providing power to a fluid displacement pump arranged to displace wastewater from the wastewater vessel, wherein the control unit is configured to: control the pressure generating unit such as to exert a brief pressure burst to the reading end of the tubular probe, preferably the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3, most preferably by a factor between 5 to 25; determine an actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit subsequent to a predetermined time delay following the end of the brief pressure burst; and, supply power to the power outlet if the actual hydrostatic pressure exceeds a predetermined maximum pressure.

[0017] The powerful, short pressure bursts effectively dislodge clogs and debris within the tubular probe and thus enable for a self-cleaning function. This eliminates the need for manual cleaning, ensuring consistent accuracy and reducing maintenance requirements. Furthermore, installation of the device is made easy since it does not rely on precision in relation to its placement within the wastewater vessel as opposed to conventional level switch based monitoring system.

[0018] Meaning that the device enables for non-professionals to install the device since installation only requires the user to put the submerged probe end into the wastewater vessel so that the submerged probe end is below a minimum fluid level. Preferably, the tubular probe is made with a small diameter, i.e., a diameter below 10 mm which allows for installation of the tubular probe via existing power conduits leading to the fluid displacement pump.

[0019] Further, by means of the brief pressure burst, it may be facilitated or allowed for achieving a relatively high accuracy in the determining of the actual hydrostatic pressure by the acquiring of a pressure reading from the pressure reading unit. This is at least due to that by the brief pressure burst, any surface tension within the tubular probe which may be caused by any fluid within the tubular probe and which might result in an inaccurate pressure reading by the pressure reading unit, may be reduced or even eliminated.

[0020] The term "wastewater vessel" as used herein refers to any container, tank, reservoir, or other structure designed for temporary or long-term holding of wastewater. Wastewater encompasses a wide range of sources, including: blackwater, i.e., wastewater containing human waste from toilets and similar sources; greywater, i.e., wastewater from sinks, showers, laundry, and similar household or commercial uses; and surface runoff i.e., water that flows over land surfaces, including rainwater and / or stormwater from developed areas (urban runoff) or runoff from agricultural fields.

[0021] The pressure generating unit is directly responsible for creating the short, high-pressure burst used to clear clogs within the tubular probe. Common examples include air pumps, air compressors, or specialized pneumatic actuators. It is preferable that the pressure generating device is an air pump since these are typically smaller, cheaper and more energy efficient within the context of this application. The control unit directs the pressure generating unit, receives and interprets readings from the pressure reading unit, determines fluid levels, and activates energy supply to the fluid displacement pump based on pre-programmed logic.

[0022] The device for monitoring and controlling a fluid level may, but need not necessarily, include the fluid displacement pump. The control unit is configured to control the energy supply, and hence the operation, of such a pump if one is present within the system. This allows flexibility in the device's implementation. Meaning that the device could be a standalone monitoring and control unit used with existing pumping systems, or it could be an integrated device incorporating both the monitoring / control functionality and the fluid displacement pump itself.

[0023] The term "hydrostatic pressure” refers to the pressure exerted by a column of fluid due solely to its height and density, under the influence of gravity. The expected hydrostatic pressure at any given depth depends on the expected fluid level and the expected density of the waste water. The control unit may for example use a pre-calculated estimate or continuous measurement to determine expected hydrostatic pressure. Alternatively, a first expected hydrostatic pressure is set by the user upon installation, and subsequent expected hydrostatic pressure are based on historical pressure readings.

[0024] How the predetermined maximum pressure is determined depends on the specific use case. To avoid potential errors in determination of the predetermined maximum pressure it is preferable that a professional inputs a predetermined maximum pressure upon installation of the device. However, if for example the device is sold directly to consumers to be used for a sewage well for a single household the predetermined maximum pressure could be inputted to the device via an interface display on the device, or inputted through a mobile application in communication with the device. In such scenarios it is critical to ensure the consumer has a correct understanding and is led to make relevant considerations for choosing the predetermined maximum pressure, for a sewage well this could entail inputting the depth of the sewage well and the type of fluid displacement pump. Such settings for inputting the predetermined hydrostatic pressure are facilitated by the system displaying the pressure both digitally and analogously in millimeters of water column (mmH20), which can be directly translated to fluid height.

[0025] The device may in embodiments comprise several tubular probes and / or pressure sensing units as to increase reliability by providing redundancy in case of a tubular probe and / or pressure sensor unit failure. In a preferred embodiment the tubular probe has an inner diameter less than 10 mm. The optimal inner diameter of the tubular probe involves a trade-off between several factors. The main factors being:

[0026] Blockage Risk: Smaller diameters increase susceptibility to blockages by debris or sludge in the wastewater. A larger diameter mitigates this risk.

[0027] Pressure Burst Effectiveness: Smaller diameters aid in rapid pressure build-up during the brief pressure burst, potentially improving the accuracy of subsequent hydrostatic readings.

[0028] Sensor Sensitivity: The pressure reading unit must be sensitive enough to detect pressure changes within the expected range for a given probe diameter. Larger diameters may necessitate a more sensitive sensor to maintain accuracy.

[0029] Flow Restriction: An excessively small diameter could restrict liquid flow into and out of the probe, potentially hindering dynamic readings and system response time.

[0030] The proposed interval in this embodiment has been developed by empirical testing over long periods of time, e.g., 1 to 10 years, in aggressive environment such as sewage wells, for tubular probes having a length between 1-8 meters and using 12v air pumps as the pressure generating unit At an inner diameter within the interval of 2 mm to 6 mm there has been found to be an especially beneficial tradeoff between blockage risk, sensor sensitivity and pressure burst effectiveness. The proposed diameter enables for a weaker 12v air pump to be used and for the tubular probe to be installed via existing conduits used for power transmission to the fluid displacement pump in the sewage well.

[0031] In one proposed embodiment the control unit is further configured to: control the pressure generating unit such as to exert a brief pressure burst to the reading end of the tubular probe, preferably the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3, most preferably by a factor between 5 to 25; determine a actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit subsequent to a predetermined time delay following the end of the brief pressure burst; supply power to the power outlet if the actual hydrostatic pressure exceeds a predetermined maximum pressure; and, stop power supply to the power outlet if the actual hydrostatic pressure less than a predetermined minimum pressure.

[0032] In one preferred embodiment the device further comprises a check valve arranged to prevent - or at least reduce - fluid flow (which may be referred to as backflow) from the reading end of the tubular probe to the pressure reading unit. By preventing backflow from the reading end of the tubular probe to the pressure reading unit (partly or completely), the checkvalve may facilitate or allow for a relatively high accuracy in the measuring of pressure at the reading end of the tubular probe. The check valve enhances the overall reliability and long-term accuracy of the fluid level monitoring system. It minimizes the risk of measurement errors caused by contamination or debris entering the pressure generating unit.

[0033] The pressure reading unit may alternatively be referred to as a pressure sensor. The pressure reading unit or pressure sensor may for example comprise or be constituted by a digital pressure sensor. The pressure reading unit or pressure sensor may be configured so as to have temperature compensation implemented therein. Temperature compensation in pressure sensors is as such known in the art.

[0034] In one embodiment the control unit is configured to identify an uncontrolled inflow of fluid (e.g., a leak causing runoff water to enter or excess of inflow caused by a malfunctioning toilet or shower) into the wastewater vessel. The uncontrolled inflow may be identified by determining if pressure readings retrieved over a recent time period deviates from a baseline profile based on historical pressure readings for the wastewater vessel, preferably the baseline profile is further based on historical rainfall and / or historical pressure readings from another wastewater vessel. An inflow of wastewater may be caused by a number of factors such groundwater infiltration, overflow from connected systems forcing wastewater back into the vessel, structural damages and ruptured or loose pipes. Consequences of inflow leaks include: overflow resulting in environmental contamination, system imbalance causing operational failure in a wastewater treatment facility in fluid communication with the fluid displacement pump. Deviations from a baseline may be determined by any Time-Series Trend Analysis which is suitable for the specific scenario, such as Statistical Process Control (SPC) Techniques, machine learning and data mining algorithms or Change Point Detection Algorithms.

[0035] Additionally, or alternatively, the uncontrolled inflow may be identified by monitoring and analyzing a number of start / stop cycles of the power outlet (and hence the fluid displacement pump) over a defined time period. This method may be employed to achieve uncontrolled inflow detection redundancy and / or confirm an uncontrolled inflow detected through pressure differences or catching leaks when pressure-based detection is inconclusive. The detection of anomalies in start / stop cycles provide valuable signals even if they don't directly pinpoint leaks. Anomalies could be used to detecting pump wear, changes in inflow patterns, or impending overflow situations. The monitoring and analysis of start / stop cycle of the power outlet and hence the fluid displacement pump may for example work in the following way:

[0036] (a) Establishing a Baseline: During normal operation, the system establishes a baseline pattern of starts / stops for the fluid displacement pump. Alternatively, a baseline may be predetermined by a professional installing the device. This baseline may based on factors known prior to installation, such as: wastewater vessel size, typical inflow rates, predetermined maximum fluid level, and / or pump capacity. Alternatively, or additionally, the baseline may be based on historical start / stop cycles, which may be complemented by historical rainfall and / or historical pressure readings. The baseline could also be based on historical stop / start cycles and / or pressure readings for wastewater wells having similar characteristics, such as well size, geographical location and / or typical inflow.

[0037] (b) Monitoring Deviations: The system continuously monitors the number of times the pump starts and stops over a set period (e.g., hourly, daily). Significant deviations from the established baseline act as indicators of potential problems, including leaks.

[0038] (c) Leak Detection Logic: Here's how the system interprets deviations in start / stop cycles to signal a leak:

[0039] More frequent cycles: If the pump starts and stops much more frequently than normal, this suggests a faster-than-anticipated rise in fluid level. A possible cause is an unexpected inflow source, such as a leak.

[0040] Less frequent cycles: Significantly fewer pump cycles might mean the vessel isn't filling as quickly as expected. Though less common, this could signal a leak causing fluid outflow.

[0041] This way of detecting uncontrolled inflow offers enhanced simplicity, redundancy and adaptability since: it relies on readily available data (pump's on / off state) and requires relatively basic calculations; complements pressure-based leak detection to improve overall system reliability; and, since baselines can be dynamically adjusted to account for seasonal changes in usage or shifts in the system's environment

[0042] By including rainfall data into the analysis, it is possible to indicate the type of uncontrolled inflow. Two typical scenarios of uncontrolled inflow are: leaks in conduits causing rainfall to enter the wastewater vessel; and, malfunctioning wastewater unit such as a toilet or shower causing the wastewater unit to constantly direct fluid to the wastewater vessel. By incorporating rainfall data, the device may determine if the uncontrolled inflow correlates with rainfall patterns and thus if the uncontrolled inflow is due to leaks causing rainfall water to enter the wastewater vessel.

[0043] According to a preferred embodiment of the first aspect, the control unit is housed in an enclosure having an ambient air inlet. The pressure generating unit is arranged so that an air conditioning pathway (i.e., a flow of air) is formed between the inlet of the pressure generating unit and the ambient air inlet of the control unit enclosure. This air pathway serves two important functions:

[0044] 1. Thermal Management: The air conditioning pathway is in thermal communication with at least parts of the control unit expected to constitute the most heated hot spot In one embodiment, it is proposed that the pathway is in thermal communication with at least parts of the circuit controlling the fluid displacement pump arranged inside of the control unit, since this part traditionally constitutes the most heated hot spot However, the ambient air inlet and inlet of the pressure generating unit may be arranged as air pathways for additional or alternative parts depending on where expected hot spots are positioned.

[0045] 2. Moisture Reduction: The air circulation within the pathway promotes moisture removal from the control unit enclosure. This helps to prevent condensation and potential damage to electronic components. The inlet of the pressure generating unit might be one of several inlets, and the specific arrangement depends on factors like the pressure generating unit type, the tubular probe diameter, and the size / airflow characteristics of the air conditioning pathway. Due to the preferably high pressure used in the brief pressure burst, a large tubular probe diameter would likely confer that only a part of the inlet of the pressure generating unit is arranged to form the air pathway. This helps to avoid creating an unnecessarily large airflow resistance that the pressure generating unit has to overcome.

[0046] In one embodiment the control unit is adapted to determine the rate of fluid displacement by:

[0047] (a) Supplying power to the power outlet; i.e., initiating the fluid displacement pump by supplying power thereto; and,

[0048] (b) acquiring a first pressure reading from the pressure reading unit;

[0049] (c) acquiring a second pressure reading subsequent to a time delay following the first pressure reading; and,

[0050] (d) determine the amount of fluid displaced based on the first pressure reading, second pressure reading and the time delay.

[0051] In variations of this embodiment the control unit may be configured to acquire multiple pressure readings during the time delay between the first and second pressure readings. This approach may involve the following: (c) After acquiring the first pressure reading, the control unit takes a series of additional pressure readings at predetermined intervals within the time delay.

[0052] (e) The control unit analyzes the collected pressure readings to determine a more dynamic rate of fluid displacement This might involve techniques such as: averaging the readings to reduce the impact of noise or fluctuations; and / or fitting a curve to the readings to model the pressure change over time.

[0053] Multiple readings can help to identify and mitigate errors caused by isolated inaccurate readings or temporary disturbances in the system. It also enables for identifications of fluctuations in rate of fluid displacement during one pump cycle. Taking multiple readings may increase the computational demands on the control unit Therefore, it's not always desirable to acquire multiple readings.

[0054] In another embodiment the rate of fluid displacement may be determined based on pump cycle(s) performed by the fluid displacement pump. A pump cycle is associated with start fluid level which may correspond to the predetermined maximum hydrostatic pressure invention; and a stop fluid level which may correspond to the minimum hydrostatic pressure. The rate of displaced fluid may be determined based on: the cross-section of the wastewater vessel (e.g., the inner circumference of a sewage well); and the time elapsed during the cycle, i.e., the time it took for the fluid displacement pump to move the actual fluid level from the start to the stop fluid level. Knowing the wastewater vessel's cross-sectional area and the change in fluid level during the cycle, the volume of wastewater displaced can be calculated as: Volume = Area of Vessel * (Start Level - Stop Level). The time taken for this cycle is recorded. Dividing the displaced volume by the cycle time gives the fluid displacement rate: Rate = Volume / Time. It is further possible to calculate a total volume of wastewater pumped over a specific period by summing the volume of each pump cycle within the period. An average flow rate of the fluid displacement pump may be determined by dividing the total pumped volume by the duration of the specific period.

[0055] The flow rate may be for example be used to detect abnormal conditions. For example, the device may be further configured to compare the measured pump time for each cycle with historical data to establish a baseline for normal operation. If the pump time for a cycle is significantly longer than the baseline, it may indicate a blockage or other issue in the discharge line. The device may further monitor the number of pump cycles per day and compare it to historical data. A significant increase in the number of cycles may indicate an abnormal inflow, such as a leak in a nearby property or excessive rainwater infiltration into the sewer system.

[0056] In embodiment the device uses both of two proposed methods of determining the flow rate. In one embodiment the control unit is adapted to acquire pump information relating to the fluid displacement pump, wherein said pump information comprises at least one of:

[0057] The operational runtime, i.e., the total time the pump is actively pumping fluid. The operational runtime provides insights into wear-and-tear, thereby enabling scheduling of preventive maintenance of the fluid displacement pump.

[0058] Start, stop and timestamps thereof, i.e., the exact date and time the pump begins and ends each pumping cycle. These start, stop and timestamps enable analysis of pump usage patterns, allowing for optimization of system control for improved efficiency.

[0059] Rate of fluid displacement and timestamps thereof, i.e., the amount of fluid the pump moves per unit of time (e.g., liters per minute) and the corresponding timestamps. The rate of fluid displacement and timestamps allow for detection of changes in pump performance, indicating potential issues like clogging or leaks.

[0060] Volume of fluid displacement and timestamps thereof, i.e., the total amount of fluid moved during a given pumping cycle and the timestamps for the start and end of that cycle. The volume of fluid displacement may be determined based on the rate of fluid displacement as well as operational runtime of the fluid displacement pump. The volume of fluid displacement and timestamps facilitate water level management and tracking of overall system throughput

[0061] Power consumption data, i.e., the amount of electrical power used by the fluid displacement pump. Power consumption data helps identify periods of inefficient operation, potentially stemming from system faults or increased pump resistance. In some embodiments the control unit may be further configured to acquire additional information from communication with the fluid displacement pump. This information may include:

[0062] Fault or error codes, meaning that if the pump has a self-diagnostic system, the control unit could gather any error codes or fault indicators.

[0063] Temperature readings or other sensor data if the fluid displacement pump comprises sensors.

[0064] The communication module may alternatively or additionally be adapted to transmit information. In one embodiment the transmitted information includes at least one of the following: An alert indicating a predetermined maximum or minimum fluid level in the wastewater vessel; i.e., a signal that the water level has reached a critical high or lowpoint. Overflow or underflow conditions in a wastewater vessel can cause environmental hazards or equipment damage. In case of overflow due to a failure or excessive inflow of wastewater, this alert may for example enable for rapid response and thus prevent overflow. A minimum fluid level may be beneficial in scenarios where there is a risk of damage due to the fluid displacement pump running dry

[0065] An alert indicating the occurrence of a leak causing inflow of fluid into the wastewater vessel; i.e., a warning that the system has detected abnormal fluid entry.

[0066] An alert indicating the occurrence of a deviation in the rate at which fluid is displaced by the fluid displacement pump; i.e., a signal that the pump's performance has changed significantly from its normal range. This alert provides early warning of potential pump issues such as clogs, mechanical wear, or decreased power supply efficiency. Thereby enabling proactive detection of potential malfunctions or inefficiencies of the fluid displacement pump.

[0067] An alert indicating the occurrence of an overcurrent condition in the power supply of the control unit; i.e., a warning of a potential electrical issue within the system. This alert helps protect the system's electrical components and allows for troubleshooting and potential prevention of future faults.

[0068] Pump information; i.e., data such as operational runtime, start / stop times, power consumption, etc. This information may be transmitted by the communication module for each or any operational runtime time or pumping cycle of the fluid displacement pump. This information might for example be of interest to maintenance providers, system integrators and regulatory agencies. For example, service companies can use pump data to remotely assess pump health, schedule preventive maintenance visits, and arrive on-site with the necessary parts and expertise, minimizing equipment downtime. Companies managing larger wastewater networks can utilize pump information to optimize overall system performance, balance loads across multiple systems, and improve resource allocation based on real-time needs. Furthermore, pump operation data may in some cases demonstrate compliance with operational standards and support environmental reporting requirements. Present and / or historical fluid levels in the wastewater vessel; i.e., current and past readings of the fluid level. This information might for example be utilized by upstream systems, Downstream Systems and / or Environmental Monitoring systems. For example facilities contributing wastewater can adjust their own outflow rates based on real-time fluid levels in the receiving vessel, preventing backlogs and overflows within the entire network. Treatment plants or other facilities receiving outflow can anticipate incoming volumes, making adjustments to their processes, chemical treatments, or staffing needs in advance. Environmental agencies can use historical fluid level data to track long-term trends, assess the effectiveness of wastewater management systems, and identify potential areas of concern.

[0069] Expected future fluid level in the wastewater vessel; i.e., a prediction or projection of the fluid level based on current trends and historical data. Depending on the scenario this information may be used by emergency services, public notification systems or urban planners. For example, predicted overflow risks may provide early warning to emergency responders, allowing for proactive measures to protect people and property or to contain potential contamination. Additionally, communities can be alerted in advance when maintenance operations might impact wastewater services, or if predicted heavy inflows suggest a risk of temporary disruptions. Urban planners or infrastructure developers can utilize predicted wastewater loads to assess future capacity needs, design system expansions, or coordinate other related infrastructure projects.

[0070] In one embodiment it is suggested that the device further comprises a communication module adapted to receive at least one of the following:

[0071] Expected amount of rainfall for the area at which the fluid to be controlled is positioned. If the device receives a forecast indicating the amount of rain predicted for the area where the wastewater vessel is located, it enables anticipation of potential increases in fluid levels. instructions from a wastewater treatment facility in fluid communication with the fluid displacement pump. In other words, the device may receive direct commands from a connected wastewater treatment facility. Thereby allowing for remote control and integration into a larger management system. operational status of a wastewater treatment facility in fluid communication with the fluid displacement pump. For example, if the device monitors the operational status of the wastewater treatment facility it may acquire information that could be used to trigger preventative fluid displacement pump actions or alert operators to potential issues downstream. operational status of a wastewater vessel in fluid communication with the fluid displacement pump. The wastewater vessel may for example be a holding tank, or sewage well used to manage fluctuations in the flow of wastewater. It may function as to temporarily store excess wastewater during peak inflow periods, preventing overflows and ensuring a more consistent flow rate to downstream treatment processes.

[0072] Additionally, in some embodiments the wastewater vessel may allow for some mixing and preliminary treatment of wastewater, helping to homogenize the composition of the fluid before it enters the main treatment facility.

[0073] In one embodiment the control device comprises a pretreatment unit adapted to dispense a chemical compound, bio-additive or enzyme into the suspension to be controlled.

[0074] The pretreatment unit can dispense various additives designed to enhance the overall treatment process of the wastewater. For instance, coagulants and flocculants can be employed to promote the aggregation and sedimentation of suspended solids, improving their subsequent removal.

[0075] These additives may include inorganic compounds like alum or ferric chloride, as well as organic polymers such as polyaluminum chloride or chitosan.

[0076] The choice of specific coagulants or flocculants depends on factors like the wastewater pH and the nature of the suspended solids. To break down complex organic matter in the wastewater, enzymes can be introduced. Examples include lipase for fats, cellulase for cellulose, and protease for proteins. Importantly, enzymes operate optimally within specific temperature and pH ranges, so these environmental factors must be considered during their selection.

[0077] Additionally, nutrients might be dispensed to support the growth of beneficial bacteria that naturally aid in the breakdown of organic substances. These nutrients can include nitrogen- and phosphorus-based compounds. Careful dosing is essential with nutrients, as excessive amounts can lead to environmental concerns if the treated wastewater is discharged.

[0078] Precise control of additive release from the pretreatment unit is critical to ensure a consistent and efficient treatment process. The optimal dosing control strategy will depend on the specific wastewater characteristics, treatment goals, and the capabilities of the overall system. The system may implement various dosing strategies, including: Proportional Dosing: With this method, the additive dosage is directly linked to the measured flow rate of the wastewater. This approach ensures a consistent additive-to- wastewater ratio, which can be especially useful if the flow rate of the wastewater fluctuates significantly. Reliable flow measurement devices are necessary for successful proportional dosing.

[0079] Time-Based Dosing: In this strategy, additives are released at predetermined time intervals (e.g., every hour, or every few hours). Time-based dosing offers simplicity but might lead to inefficiencies if there are substantial changes in wastewater composition, or if flow rates vary widely over time.

[0080] Event-Based Dosing: This method relies on specific events within the wastewater system to trigger additive release. For example, the pretreatment unit might dispense additives when the wastewater level reaches a certain height, ensuring targeted treatment. Eventbased dosing requires reliable sensors to detect the relevant triggering events.

[0081] In one preferred embodiment the device employs proportional dosing wherein the pretreatment unit is configured to dispense a fixed amount of additives immediately prior to initiation of the fluid displacement device. The fixed amount being determined as proportional to a volume of wastewater corresponding to the predetermined maximum hydrostatic pressure. In this preferred embodiment it is preferable that the additive is a flocculant

[0082] The pretreatment unit may be configured to deliver additives through the existing tubular probe designed for pressure-based level measurement This can for example be achieved through methods including the use of the Venturi effect generated by the purge flow through the probe, or through the integration of a dedicated dosing pump and channel within or alongside the tubular probe.

[0083] In a second aspect of the present invention there is proposed a wastewater management system comprising: a plurality of devices for monitoring and controlling fluid levels of a plurality of wastewater vessels, respective device comprising: a tubular probe having a submerged probe end and a reading probe end. The submerged probe end is adapted to be submerged into a wastewater vessel among the plurality of wastewater vessels. a pressure generating unit arranged to be in fluid communication with the reading probe end. a pressure reading unit arranged to measure pressure at the reading end of the tubular probe. a control unit having a power outlet enabling power transmission to a fluid displacement pump arranged to displace wastewater from the wastewater vessel among the plurality of wastewater vessels. The control unit is configured to: control the pressure generating unit such as to exert a brief pressure burst to the reading end of the tubular probe, the brief pressure burst exceeds a expected hydrostatic pressure by a factor of at least 3, preferably by a factor between 5 to 25; and, determine an actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit subsequent to a predetermined time delay following the end of the brief pressure burst; a central processing unit adapted to acquire information comprising: operational status and / or instructions from a wastewater treatment facility in fluid communication with respective fluid displacement pump arranged to displace wastewater from respective wastewater vessel among the plurality of wastewater vessels; and, the fluid level in respective wastewater vessel among the plurality of wastewater vessels;

[0084] The central processing unit is further adapted to transmit instructions to the plurality of devices based on the acquired information. The instructions being determined so that respective fluid level in respective wastewater vessel does not exceed a predetermined maximum level, and so that said wastewater treatment facility is supplied with a rate of wastewater falling within a predetermined rate interval having a maximum value and a minimum value.

[0085] The central processing unit may acquire either or both of operational status and / or instructions from a wastewater treatment facility. Operational status may for example include capacity, active treatment process or fault codes. Capacity refers to information including current available capacity (in liters or a similar measure), percentage utilization, or predicted time-to-full under varying inflow scenarios. Active Treatment Processes refers to information relating to the specific treatment stages that are operational (e.g., primary sedimentation, biological treatment, disinfection), which may be especially relevant for smaller wastewater treatment facilities. Instructions within this context may refer to maximum inflow rate limits, emergency shutdown requests or temporary hold commands. Meaning that the wastewater treatment facility may set dynamic upper bounds on the acceptable inflow rate, either in general or tailored to individual wastewater vessels. Or that the facility may request temporary pauses on wastewater inflow to specific vessels, potentially for maintenance or to isolate a particular section of the system. The central processing unit employs a decision-making process to optimize the wastewater management system. This decision logic preferably incorporates a blend of real-time measurements and predictive analysis. Specifically the central processing unit may consider:

[0086] Fluid level in the wastewater vessel: Current fluid levels within individual wastewater vessels, providing the primary indicator of potential overfill risk.

[0087] Historical inflow data: Statistical analysis of inflow patterns helps anticipation of fluctuations based on time of day, weather events, or other relevant factors.

[0088] Predictive model: The central processing unit may utilize a predictive model, potentially incorporating external data like weather forecasts, to proactively estimate inflow surges. The central processing unit’s primary objective is to activate the fluid displacement pumps proactively to prevent wastewater vessel overflow. Additionally, the central processing unit monitors and regulates the wastewater flow rate sent to the treatment facility. The flow rate is preferably calculated as a moving average over a defined period (e.g., 10 minutes or 1 hour) to balance responsiveness with data smoothing. The acceptable flow rate range is represented by an interval with maximum and minimum values. This interval may be set by the wastewater treatment facility, acting as either a strict operational limit or as a target for the central processing unit optimization algorithms.

[0089] Preferably, the system follows a clear prioritization hierarchy such as:

[0090] (a) Prevent Wastewater Vessel Overflow: The prevention of wastewater overflow in the wastewater vessel is paramount

[0091] (b) Maintain Flow Rate Within Interval: The system strives to keep the wastewater flow rate within the designated interval, as long as this does not conflict with priority (a).

[0092] (c) Minimize Energy Consumption: When feasible, the central processing unit may optimize respective fluid displacement pump operation to reduce energy usage within the constraints of the higher priorities.

[0093] In the rare event of a predicted tank overflow that cannot be resolved while respecting the flow rate interval, the central processing unit may temporarily exceed the interval maximum as a protective measure. Such events would preferably trigger alerts or follow a defined escalation procedure to ensure prompt response.

[0094] According to a third aspect of the present invention there is proposed a method for monitoring and controlling a fluid level of a wastewater vessel, the method utilizing a device comprising: a tubular probe having a submerged probe end adapted to be submerged into the wastewater vessel and a reading probe end; a pressure generating unit in fluid communication with the reading probe end; a pressure reading unit arranged to measure pressure at the reading end of the tubular probe; a control unit having a power outlet for power transmission to a fluid displacement pump configured to displace wastewater from the wastewater vessel.

[0095] The proposed method comprises the steps of:

[0096] (a) Controlling the pressure generating unit to exert a brief pressure burst to the reading end of the tubular probe, preferably the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3;

[0097] (b) Determining an actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit after a predetermined time delay following the end of the brief pressure burst; and

[0098] (c) Supplying power from the control unit to the fluid displacement pump if the actual hydrostatic pressure exceeds a predetermined maximum pressure.

[0099] The control unit may comprise components such a microprocessor, a memory module, a power supply, input / output ports for communication with the pressure generating unit, pressure reading unit, and fluid displacement pump, and a housing to enclose the components. There may be provided a check valve (and / or another component capable of providing the same or similar functionality as a check valve), which may be arranged to prevent backflow from the reading end of the tubular probe to the pressure reading unit. Such a check valve may enhance the overall reliability and long-term accuracy of the fluid level monitoring system and may minimize the risk of measurement errors caused by contamination or debris entering the pressure generating unit Such a check valve may be arranged within the housing and / or comprised in the control unit.

[0100] The steps of the method may be performed by the control unit Meaning that the control unit may be programmed with instructions to:

[0101] (a) Receive pressure readings from the pressure reading unit

[0102] (b) Compare received pressure readings with a predetermined maximum pressure.

[0103] (c) If the received pressure reading exceeds the predetermined maximum pressure, send a control signal to activate the fluid displacement pump. (d) Calculate fluid displacement targets based on current inflow data from the wastewater treatment facility.

[0104] (e) Adaptively adjust the activation and duration of the fluid displacement pump based on the calculated fluid displacement targets.

[0105] In one embodiment according to the third aspect it is proposed that the method further comprises identification of an uncontrolled inflow of fluid into the wastewater vessel by determining if pressure readings and / or pump cycles over a recent time period deviate from a baseline profile based on historical pressure readings and / or pump cycles for the wastewater vessel. In one embodiment utilizing pressure readings the method further comprising the steps of:

[0106] (a) Retrieving a plurality of pressure readings from the pressure reading unit at different points over a recent time period;

[0107] (b) Establishing a baseline profile based on historical pressure readings for the wastewater vessel;

[0108] (c) Comparing the retrieved pressure readings with the baseline profile; and

[0109] (d) Identifying a leak causing an inflow of fluid into the wastewater vessel if the comparison reveals deviations from the baseline profile.

[0110] In one embodiment according to the third aspect it is proposed that the method further comprises the steps of:

[0111] (a) Initiating fluid displacement by supplying power to the fluid displacement pump;

[0112] (b) Acquiring a first pressure reading from the pressure reading unit;

[0113] (c) Waiting for a predetermined time delay;

[0114] (d) Acquiring a second pressure reading from the pressure reading unit; and

[0115] (e) Determining the rate of fluid displacement based on the first pressure reading, the second pressure reading, and the predetermined time delay.

[0116] In another embodiment according to the third aspect it is proposed that the method comprises:

[0117] (a) determining a fluid displacement rate of the fluid displacement pump, wherein the rate is determined based on at least one pump cycle performed by the fluid displacement pump, wherein a pump cycle comprises: a start fluid level associated with a predetermined maximum hydrostatic pressure; and a stop fluid level associated with a predetermined minimum hydrostatic pressure;

[0118] (b) calculating a volume of wastewater displaced during the pump cycle based on a cross-sectional area of the wastewater vessel and a height difference between the start fluid level and the stop fluid level;

[0119] (c) measuring the time elapsed during the pump cycle; and

[0120] (d) determining the fluid displacement rate by dividing the calculated volume by the measured cycle time.

[0121] In one embodiment according to the third aspect it is proposed that the method further comprises:

[0122] (a) Acquiring operational status data from a wastewater treatment facility. The operational status data include at least a current inflow capacity of the waste water treatment facility or information which may be used to determine a current inflow capacity;

[0123] (b) Determining the current fluid level in the wastewater vessel by acquiring a pressure reading from the pressure reading unit;

[0124] (c) Calculating a fluid displacement target based on the current inflow capacity and the current fluid level; and

[0125] (d) Initiating fluid displacement pump operation if the calculated fluid displacement target is reached.

[0126] The proposed embodiment enables for the frequency of fluid displacement pump cycles to be adaptively adjusted based on the current inflow capacity. This ensures a consistent, manageable flow to the wastewater treatment facility while preventing overflow in the wastewater vessel. For example, the system may prioritize shorter pump cycles in scenarios where the current inflow capacity is low and the fluid level in the wastewater vessel is high. This approach removes smaller amounts of wastewater more frequently, preventing overflow in the wastewater vessel while minimizing flow to the treatment facility. As the inflow capacity increases, the system may utilize longer pump cycles with extended intervals between them, enabling larger displacements without compromising the treatment facility's capacity. The adaptive method enables the incorporation of safety buffers to calculate displacement targets, ensuring that even sudden changes in inflow capacity or fluid level do not lead to overflow. The Current inflow capacity of the wastewater treatment facility represents the maximum rate at which the wastewater treatment facility can safely process additional inflow at a given time. This could be expressed as a volume per unit time (e.g., liters per hour). The facility might communicate this directly or the device might calculate it based on operational status data. The duration of the fluid displacement pump cycle refers to the length of time the fluid displacement pump remains actively pumping wastewater during a single activation cycle.

[0127] In most cases it is preferable that the duration of the fluid displacement pump cycle is adjusted based on the current inflow capacity to prevent overflow in the wastewater vessel. However, in certain scenarios it is beneficial to keep the duration of the fluid displacement pump cycle constant and adapt the fluid displacement target to the fixed cycle duration, or within a predetermined cycle duration interval.

[0128] In one variation of this embodiment the method may further analyze historical pressure readings from the wastewater vessel to refine its adaptive control. For example, the algorithm may identify recurring patterns of inflow surges or extended periods of low inflow. By incorporating this historical data, it is possible to proactively adjust the fluid displacement target and pumping frequency to anticipate potential overflow risks or optimize flow rates to the wastewater treatment facility. Additionally, the algorithm may reference historical rainfall data, if available, to improve its predictions of potential inflow surges.

[0129] In another embodiment according to the third aspect it is proposed that the method further comprises channeling airflow generated by the pressure generating unit through a cooling pathway within the control unit enclosure to manage the temperature of the fluid displacement pump control circuit

[0130] In accordance with one or more embodiments of the present invention, a plurality of values of the actual hydrostatic pressure may be determined by acquiring pressure readings from the pressure reading unit at a plurality of successive time instants or during a plurality of successive periods of time. Fluid levels in the wastewater vessel may be determined based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels may correspond to a respective one of the plurality of successive time instants or the plurality of successive periods of time. Any change in the fluid level in the wastewater vessel may be determined based on the determined fluid levels. If it is determined that the fluid level in the wastewater has changed by a selected percentage, the pressure generating unit may be controlled to exert a brief pressure burst to the reading end of the tubular probe, wherein the brief pressure burst may exceed an expected hydrostatic pressure by a factor of at least 3. The above-mentioned operations of determining and controlling the pressure generating unit may for example be carried out by the control unit, which may be configured to carry out any or each of these operations. The selected percentage may be between (e.g., about) 5% and (e.g., about) 10%, or possibly more than 10%. By means of such configurations, which may be implemented in any of the embodiments of the present invention described herein, reliability and / or accuracy of the fluid level monitoring system may be increased. This is at least due to that by the brief pressure burst, any surface tension within the tubular probe which may be caused by any fluid within the tubular probe and which might result in an inaccurate pressure reading by the pressure reading unit, may be reduced or even eliminated.

[0131] In accordance with one or more other embodiments of the present invention, a plurality of values of the actual hydrostatic pressure may be determined by acquiring pressure readings from the pressure reading unit at a plurality of successive time instants or during a plurality of successive periods of time. Fluid levels in the wastewater vessel may be determined based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels may correspond to a respective one of the plurality of successive time instants or the plurality of successive periods of time. Any change in the fluid level in the wastewater vessel may be determined based on the determined fluid levels. If it is determined that the fluid level in the wastewater has not changed, the pressure generating unit may be controlled to exert brief pressure bursts to the reading end of the tubular probe based on a selected schedule or with a selected periodicity, wherein each of the brief pressure bursts may exceed an expected hydrostatic pressure by a factor of at least 3. The above-mentioned operations of determining and controlling the pressure generating unit may for example be carried out by the control unit, which may be configured to carry out any or each of these operations. By means of such configurations, which may be implemented in any of the embodiments of the present invention described herein, reliability and / or accuracy of the fluid level monitoring system may be increased. This is at least due to that by the brief pressure burst, any surface tension within the tubular probe which may be caused by any fluid within the tubular probe and which might result in an inaccurate pressure reading by the pressure reading unit, may be reduced or even eliminated.

[0132] In the context of the present application, by a brief pressure burst it may be meant a pressure burst having a duration of (e.g., about) one or a few seconds or more, e.g., between (e.g., about) 1 s and (e.g., about) 8 s or more, or between e.g., about) 1 s and (e.g., about) 10 s or more. According to one or more application examples, the pressure burst may have a duration between (e.g., about) 5 s and (e.g., about) 10 s or more, such as (e.g., about) 8 s. The pressure generating unit may be controlled such that the brief pressure burst exerted to the reading end of the tubular probe has such a duration. The duration of the brief pressure burst may be different depending on when during the operation of the device (e.g., at what stage during the operation of the device) the pressure generating unit is controlled to exert the brief pressure burst to the reading end of the tubular probe. For example, in connection with or during start of operation of the device, or re-start of operation of the device, the pressure burst may have a duration of, e.g., between (e.g., about) 5 s and (e.g., about) 10 s or more, such as (e.g., about) 8 s. As also indicated in the following description with reference to the figure, in connection with or during an extended period of time of operation of the device (e.g., at a stage of operation of the device following a start-up stage of operation of the device), the pressure burst may have a duration of (e.g., about) 1 s, or (e.g., about) 1.5 s or possibly longer.

[0133] Brief description of the figure

[0134] Figure 1 shows one embodiment according to the present invention.

[0135] Detailed description

[0136] The following figure descriptions illustrate practical application of possible embodiments according to the present invention as to facilitate understanding.

[0137] Figure 1 illustrates the operation of a wastewater management system according to an embodiment of the present invention. Depicted components include:

[0138] Enclosure 10 which in the illustrated example houses the control unit, pressure generating unit, pressure reading unit, and power outlet

[0139] Tubular probe 11: depicted as a flexible tube with an outer diameter of 4 mm allowing it to be installed via existing power conduits. The submerged probe end 111 in the wastewater vessel 20 is arranged close to the bottom of the wastewater vessel 20. The reading end 112 is connected to the control unit via the enclosure 10.

[0140] Fluid displacement pump 60, which in the first illustrated example is a submerged sewage pump 60 located at the bottom of the wastewater vessel 20 and responsible for pumping out wastewater. A power cable 12 responsible for transferring power to the sewage pump is connected to the power outlet in the enclosure 10.

[0141] Waste water vessel 20 which in the illustrated example is a sewage well 20 with a depth of 1.6 meters and a diameter of 0.5 meters. In the example the top of the sewage well 20 is aligned with the ground surface level 25. The dotted lines 22, 23 and 24 represent fluid levels. The predetermined maximum pressure 24 is in the example illustrated as an alert level 24 arranged ata height of 0.65 meters measured from the bottom of the sewage well 20. Below the alert level 24 there is illustrated a pump activation level 24 arranged at the height 0.55 meters, the pump activation level 24 refers to a preset sewage height / volume threshold triggering the sewage pump 60 to start. The pump deactivation level 23 represents a preset pressure threshold triggering pump stop. In the example the deactivation level is arranged at a height of 0.15 meters.

[0142] Consequently, one pump cycle in this example constitutes a fluid level decrease from the pump activation level 24 to the pump deactivation level 23. Meaning that, if the level rises above the pump activation level 24 the system will start the sewage pump 60. The sewage pump 60 will run until the current sewage level 21 drops to the pump deactivation level 23.

[0143] The minimum fluid level 22 is in this example the same level as the pump deactivation level 23. If the current sewage level 21 drops below this the sewage pump 60 is prevented to start due to risk of dry running. Additionally, if the current sewage level 21 falls below the minimum fluid level 22, the system may trigger an alarm.

[0144] The actual hydrostatic pressure 21 is illustrated as a current sewage level 21 and is depicted as being in between the pump activation level 24 and the pump deactivation level 23.

[0145] The wide lines represent the flow of sewage in the illustrated embodiment. The incoming wastewater 40 is directed into the sewage well 20. In this example the waste water consists of untreated domestic sewage. The sewage is fed to the wastewater treatment facility 50 via a conduit 41 connecting the sewage pump 60 to the wastewater treatment facility 50, which in the example is a municipal wastewater treatment plant 50, i.e., a large-scale centralized wastewater treatment plant 50 receiving waste water from multiple sources.

[0146] It is to be understood that while specific heights from the bottom of the sewage well 20 and specific depth and diameter of the sewage well 20 have been provided in the foregoing, these are merely for illustrating and facilitating understanding of one or more embodiments of the present invention and are not to be considered to be limiting the scope of the embodiments of the present invention in any way. Rather, as a skilled person will understand in the light of the disclosure of the embodiments of the present invention herein, the heights from the bottom of the sewage well 20 and depth and diameter of the sewage well 20 provided in the foregoing are exemplifying and each or any of them may - according to one or more other embodiments of the present invention - differ from those provided in the foregoing and may differ for different configurations of the sewage well 20. Further, while the tubular probe 11 has been described as a flexible tube with an outer diameter of 4 mm, it is to be understood that the tubular probe 11 does not necessarily need to be flexible, and that a tube which may be included or constitute the tubular probe 11 may have another outer diameter than 4 mm, which may be larger or smaller than 4 mm.

[0147] For the depicted scenario the system performs probe rinsing (i.e., exerting a brief pressure burst) six times per day (every four hours) using the air pump. If system detect a significant increase in the hydrostatic pressure between scheduled probe rinses this may be due to the current sewage level 21 rising a certain amount, due to a significant temperature change or due to another factor such as a leak in the tubular probe 11. To verify that the current sewage level 21 has changed, an unscheduled probe rinse is preferably performed when a significant increase in hydrostatic pressure is detected between scheduled probe rinses.

[0148] As described in the foregoing, fluid levels in the wastewater vessel may be determined based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels may correspond to a respective one of the plurality of successive time instants or the plurality of successive periods of time. Any change in the fluid level in the wastewater vessel may be determined based on the determined fluid levels, and if it is determined that the fluid level in the wastewater has changed by a selected percentage, the pressure generating unit may be controlled to exert a brief pressure burst to the reading end of the tubular probe. In accordance with such configurations and according to an example, when or whenever the current sewage level 21 has changed (increased or decreased) by at least a selected percentage at the end of a certain period of time compared to the sewage level at the start of that period of time, a probe rinse, e.g., using an air pump, may be carried out. The selected percentage may be between (e.g., about) 5% and (e.g., about) 10%. According to an example, the selected percentage may be (e.g., about) 10%, or possibly more than 10%. As per the foregoing description, the probe rinse may be carried out by controlling the pressure generating unit to exert a brief pressure burst to the reading end 112 of the tubular probe 11. In such as well as in other situations, the pressure generating unit may be controlled such that the pressure burst lasts (e.g., about) 1 s, or (e.g., about) 1.5 s or possibly longer. By means of such configurations, which may be implemented in any of the embodiments of the present invention described herein, reliability and / or accuracy of the fluid level monitoring system may be increased. This is at least due to that by the brief pressure burst, any surface tension within the tubular probe 11 which may be caused by any fluid within the tubular probe 11 and which might result in an inaccurate pressure reading by the pressure reading unit, may be reduced or even eliminated.

[0149] If the sewage pump 60 fails to lower the current sewage level 21 to the pump deactivation level 23 within a predetermined time, such as one minute, the system may trigger an alarm and stop the pump. In one variation the system won’t restart the sewage pump 60 until a manual reset has been performed as to avoid malfunction. To reset the alarm and restart the pump, the user may for example cycle the main switch off and on. In another variation the system may make two attempts to lower the current sewage level 21 before triggering alarm and / or deactivation of the sewage pump 60. In another preferred embodiment the system may perform a diagnosis at the second attempt in which the system performs rinsing of the tubular probe before the second activation of the sewage pump 60 and then register pressure readings over a set time interval. The results may be presented to a technician and / or used to perform automatic diagnosis.

[0150] If the pump fails to lower the current sewage level 21 to the pump deactivation level 23 even after a restart, the alarm preferably persists, and the pump remains deactivated. If the current sewage level 21 rises above the pump activation level 24 the system may trigger an alarm, even if the pump is running.

[0151] In the illustrated embodiment the volume of wastewater pumped out of the sewage well can be monitored and calculated. Since the pump activation level 24, the pump deactivation level 23 as well as the diameter of the sewage well 20 are typically known it is possible to define the amount of wastewater displaced during each sewage pump 60 cycle. In this example each cycle displaces around 93 liters.

[0152] By recording the start and stop times of each pump cycle, along with the known volume displacement per cycle, the total volume over a set period (e.g., per day), i.e., the average rate of fluid displacement may be easily determined.

[0153] The average fluid displacement may then be utilized to gain insight into the operational function of the sewage pump 60. For example, a longer-than-normal pump time may indicate blockages or potential pump problems. Additionally, more frequent or less frequent cycles than what might be considered normal can reveal changes in wastewater inflow. This can be due to leaks, weather- related infiltration, and / or other factors.

[0154] In accordance with the embodiment of the present invention illustrated in Figure 1, there may be provided a check valve (and / or another component capable of providing the same or similar functionality as a check valve), which may be arranged to prevent fluid flow from the reading end 112 of the tubular probe 11 to the pressure reading unit. By preventing backflow from the reading end 112 of the tubular probe 11 to the pressure reading unit (partly or completely), the check valve may facilitate or allow for a relatively high accuracy in the measuring of pressure at the reading end 112 of the tubular probe 11. Thereby, such a checkvalve may enhance the overall reliability and long-term accuracy of the fluid level monitoring system and may minimize the risk of measurement errors caused by contamination or debris entering the pressure generating unit. Further in accordance with the embodiment of the present invention illustrated in Figure 1, the check valve, which is schematically illustrated at reference numeral 115, may be included within the enclosure 10.

[0155] As described in the foregoing, fluid levels in the wastewater vessel may be determined based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels may correspond to a respective one of the plurality of successive time instants or the plurality of successive periods of time. Any change in the fluid level in the wastewater vessel may be determined based on the determined fluid levels, and if it is determined that the fluid level in the wastewater has not changed, the pressure generating unit may be controlled to exert brief pressure bursts to the reading end of the tubular probe based on a selected schedule or with a selected periodicity. In accordance with such configurations and according to an example, in case the current sewage level 21 does not change, or essentially does not change (e.g., it has changed only by less than 1%, or by less than 0.5%), during an extended period of time (e.g., several hours, or one day or more), probe rinses, e.g., using an air pump, may be carried out based on a selected schedule or with a selected periodicity. As per the foregoing description, each of the probe rinses may be carried out by controlling the pressure generating unit to exert a brief pressure burst to the reading end 112 of the tubular probe 11. The said probe rinses which may be carried out based on a selected schedule or with a selected periodicity may be carried out once every 30 minutes, or once every hour, for example. In such as well as in other situations, the pressure generating unit may be controlled such that the each or any of the pressure bursts lasts (e.g., about) 1 s, or (e.g.., about) 1.5 s or possibly longer. By means of such configurations, which may be implemented in any of the embodiments of the present invention described herein, reliability and / or accuracy of the fluid level monitoring system may be increased. This is at least due to that by the brief pressure burst, any surface tension within the tubular probe 11 which may be caused by any fluid within the tubular probe 11 and which might result in an inaccurate pressure reading by the pressure reading unit, may be reduced or even eliminated.

[0156] Another aspect of the present invention will now be presented and discussed also in relation to figure 1. In this aspect the wastewater treatment facility 50 is an on-site treatment plant 50, i.e., a decentralized waste water treatment facility 50 receiving wastewater from one source.

[0157] Traditionally when installing on-site treatment plant, the size of the on-site treatment plant is chosen by assessing the load, i.e. how many people and wastewater units are generating the incoming wastewater. Each type of wastewater unit (e.g., a toilet, or shower) has a specific standard flow. All standard flows are added up to a total standard flow. Since not all units are used at the same time, the sum is converted to a so-called probable flow. While this probable flow is always less than the total standard flows, it is most often unrealistically large, resulting in an unreasonably large treatment plant

[0158] The present invention solves this problem since the wastewater vessel 20 may function as a "equalization tank” 20. Due to the purpose of enabling equalization the equalization tank 20 is normally larger than the typical sewage well, e.g., six cubic meters.

[0159] This is especially beneficial for premises where the number of people varies greatly at different times, such as meeting rooms and conference rooms. In this case, the equalization tank 20 can be used before the wastewater pipe is connected to the on-site treatment plant 50. The wastewater pump 60 is then placed in the equalization tank 20 and the wastewater pump 60 is controlled to pump just the right amount of wastewater to the on-site treatment plant 50.

[0160] The right amount is the amount that the on-site treatment plant 50 is designed for to achieve optimal operation. As the level in the equalization tank 20 decreases, the pump time / pump volume decreases so that the wastewater supply to the on-site treatment plant 50 does not suddenly stop, which leads to a poorer treatment result The system thus enables for the wastewater treatment to be an ongoing process without any sudden interruptions.

[0161] The system allows for a much smaller size of treatment plant since this can be used with a higher efficiency.

[0162] The control of the wastewater pump 60 may in some cases be carried out in the same way as in the sewage well 20. In other cases, the pump cycle duration may be more adaptive so that high wastewater levels in the equalization tank 20 result in more frequent pumping and / or longer pump cycle duration. While low levels result in less frequent pumping and / or shorter pump cycle duration.

[0163] In conclusion, a device, system and method for precise and reliable monitoring and control of fluid levels within wastewater vessels are provided. The device comprises a tubular probe with a submerged end and a reading end. A pressure generating unit exerts brief, high-intensity pressure bursts exceeding expected hydrostatic pressure by a significant factor (e.g., 5 to 25 times). After a predetermined delay, the pressure reading unit determines the actual hydrostatic pressure. A control unit, informed by this data, activates a fluid displacement pump if the hydrostatic pressure exceeds a set maximum.

[0164] Although the present invention has been described above by referring to particular embodiments, it should be understood that modifications and variations could be made to the sole structure without departing from the intended scope of invention.

Claims

Claims1. A device for monitoring and controlling a fluid level of a wastewater vessel, the device comprising: a tubular probe having a submerged probe end and a reading probe end, wherein the submerged probe end is adapted to be submerged into a wastewater vessel: a pressure generating unit arranged to be in fluid communication with the reading probe end; a pressure reading unit arranged to measure pressure at the reading end of the tubular probe; a control unit having a power outlet for providing power to a fluid displacement pump arranged to displace wastewater from the wastewater vessel, wherein the control unit is configured to: control the pressure generating unit such as to exert a brief pressure burst to the reading end of the tubular probe, wherein the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3, preferably by a factor between 5 to 25; determine an actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit subsequent to a predetermined time delay following the end of the brief pressure burst; and, supply power to the power outlet if the actual hydrostatic pressure exceeds a predetermined maximum pressure.

2. The device according to claim 1, wherein the control unit is adapted identify a uncontrolled inflow of fluid into the wastewater vessel, wherein said uncontrolled inflow is identified by determining if pressure readings retrieved over a time period deviates from a baseline profile based on historical pressure readings for the wastewater vessel, preferably the baseline profile is further based on historical rainfall and / or historical pressure readings from another wastewater vessel.

3. The device according to any of the preceding claims, wherein the control unit is housed in an enclosure having a ambient air inlet, and wherein the pressure generating unit is arranged so that an air pathway is formed between the inlet of the pressure generating unit and the ambient air inlet of the control unit enclosure, preferably the air pathway is in gaseous communication with at least parts of the circuit controlling the fluid displacement pump arranged inside of the control unit4. The device according to any of the preceding claims, wherein the control unit is adapted to determine the rate of fluid displacement by:(a) initiating the fluid displacement pump by supplying power to the power outlet; and,(b) acquiring a first pressure reading using the pressure reading unit;(c) acquiring a second pressure reading subsequent to a time delay following the first pressure reading; and,(d) determine an amount of fluid displaced based on the first pressure reading, second pressure reading and the time delay.

5. The device according to any of the preceding claims, wherein the control unit is adapted to acquire pump information relating to the fluid displacement pump, wherein said pump information comprises at least one of: the operational runtime; start, stop and timestamps thereof; rate of fluid displacement and timestamps thereof; volume of fluid displacement and timestamps thereof; wherein the volume of fluid displacement is determined based on the rate of fluid displacement as well as operational runtime of the fluid displacement pump.

6. The device according to any preceding claim, wherein the device further comprises a communication module adapted to transmit at least one of the following: an alert indicating a predetermined maximum fluid level or minimum fluid level in the wastewater vessel; an alert indicating the occurrence of an uncontrolled inflow of fluid into wastewater vessel, preferably the uncontrolled inflow has been identified according to the means defined in claim 2; an alert indicating the occurrence of a deviation in the rate at which fluid is displaced by the fluid displacement pump, preferably the rate of fluid displacement is determined according to the means defined in claim 4; an alert indicating the occurrence of an overcurrent condition in the power supply of the control unit; pump information as defined in claim 5; present and / or historical fluid levels in the wastewater vessel; expected future fluid level in the wastewater vessel.

7. The device according to any of the preceding claims, wherein the device further comprises a communication module adapted to receive at least one of the following:expected amount of rainfall for the area at which the fluid to be controlled is positioned; instructions from a wastewater treatment facility in fluid communication with the fluid displacement pump; operational status of a wastewater treatment facility in fluid communication with the fluid displacement pump; operational status of a second wastewater vessel in fluid communication with the fluid displacement pump.

8. The device according to any of the preceding claims, wherein the control device comprises a pretreatment unit adapted to dispense a chemical compound, bio-additive or enzyme into the wastewater vessel.

9. The device according to any one of the preceding claims, further comprising a check valve arranged to reduce or prevent fluid flow from the reading end of the tubular probe to the pressure reading unit.

10. The device according to any one of the preceding claims, wherein the control unit is configured to: determine a plurality of values of the actual hydrostatic pressure by acquiring pressure readings from the pressure reading unit at a plurality of successive time instants or during a plurality of successive periods of time; determine fluid levels in the wastewater vessel based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels corresponds to a respective one of the plurality of successive time instants or the plurality of successive periods of time; determine any change in the fluid level in the wastewater vessel based on the determined fluid levels; and if it is determined by the control unit that the fluid level in the wastewater has changed by a selected percentage, control the pressure generating unit to exert a brief pressure burst to the reading end of the tubular probe, wherein the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3.

11. The device according to any one of the preceding claims, wherein the control unit is configured to:determine a plurality of values of the actual hydrostatic pressure by acquiring pressure readings from the pressure reading unit at a plurality of successive time instants or during a plurality of successive periods of time; determine fluid levels in the wastewater vessel based on the determined plurality of values of the actual hydrostatic pressure, wherein each of the determined fluid levels corresponds to a respective one of the plurality of successive time instants or the plurality of successive periods of time; determine any change in the fluid level in the wastewater vessel based on the determined fluid levels; and if it is determined by the control unit that the fluid level in the wastewater has not changed, control the pressure generating unit to exert brief pressure bursts to the reading end of the tubular probe based on a selected schedule or with a selected periodicity, wherein each of the brief pressure bursts exceeds an expected hydrostatic pressure by a factor of at least 3.

12. A wastewater management system comprising: a plurality of devices for monitoring and controlling fluid levels of a plurality of wastewater vessels, wherein each device is a device according to any of the preceding claims; a central processing unit adapted to acquire information comprising: operational status and / or instructions from a wastewater treatment facility in fluid communication with respective fluid displacement pump arranged to displace wastewater from respective wastewater vessel among the plurality of wastewater vessels; and, the fluid level in respective wastewater vessel among the plurality of wastewater vessels; wherein the central processing unit is further adapted to transmit instructions to the plurality of devices based on acquired information, said instructions being determined so that respective fluid level in respective wastewater vessel does not exceed a predetermined maximum level, and so that said wastewater treatment facility is supplied with a rate of wastewater falling within a predetermined rate interval having a maximum value and a minimum value.

13. A method for monitoring and controlling a fluid level of a wastewater vessel, the method utilizing a device comprising: a tubular probe having a submerged probe end adapted to be submerged into the wastewater vessel and a reading probe end; a pressure generating unit in fluid communication with the reading probe end;a pressure reading unit arranged to measure pressure at the reading end of the tubular probe; a control unit having a power outlet for power transmission to a fluid displacement pump configured to displace wastewater from the wastewater vessel; wherein the method comprising the steps of:(a) controlling the pressure generating unit to exert a brief pressure burst to the reading end of the tubular probe, wherein the brief pressure burst exceeds an expected hydrostatic pressure by a factor of at least 3;(b) determining an actual hydrostatic pressure by acquiring a pressure reading from the pressure reading unit after a predetermined time delay following the end of the brief pressure burst; and(c) supplying power from the control unit to the fluid displacement pump if the actual hydrostatic pressure exceeds a predetermined maximum pressure.

14. The method of claim 13, wherein the device is a device according to any of claims 1 to 12.

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