Abstract:
A forecast-integrated automated control system for combined greywater-stormwater storage and reuse. A simple and reliable approach for managing greywater and stormwater collection at a household or community level is provided, allowing for the near-continuous monitoring and adjustment of water quantity and quality in a combined greywater-stormwater storage tank based on monitored feedback/output from individual, tank-specific sensors and/or sensors located elsewhere in the water collection system. Use of the forecast-integrated automated control system for combined greywater-stormwater storage and reuse enables optimization of the water quality and quantity collected in the storage tank, reduce the amount of stormwater discharged to municipal sewers, and assure/demonstrate regulatory compliance for control of stormwater runoff through the integration of a low impact development best management practices.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    n/a 
       BACKGROUND OF THE INVENTION 
       [0002]    Water is a scarce resource in the arid West of the United States, and recent droughts in the Midwest and the South have elevated the issue of water scarcity to a national level. Existing water sources will face increasing strain due to population growth and climate change, and financial and regulatory barriers will prevent the development of new sources. One method to alleviate water scarcity is stormwater capture. Stormwater can be used for non-potable applications such as irrigation, laundry, and toilet flushing to significantly reduce domestic municipal water consumption. However, in arid regions of the US, rain comes in short, intense storms only a few months out of the year, and the duration and intensity of these storms require large storage tank volumes for stormwater capture to be financially feasible. One solution is to integrate stormwater capture with greywater capture. Greywater is a reliable source of water for domestic reuse, and includes water from washbasins, laundry, and showers (kitchen sinks and water for toilet flushing are considered blackwater). Combining greywater-stormwater in the same collection system allows for a much smaller storage tank. 
         [0003]      FIG. 1  shows a schematic of a typical combined greywater-stormwater storage system for domestic use  10 . These systems capture stormwater runoff  12  from building roofs  34  and other impervious surfaces  36  such as parking lots and greywater from washbasins  14 , laundry machines  16 , and showers  18  and store the collected water in the same storage tank  20 , typically installed under the house, outside, or underground. Other systems route the captured stormwater directly to a combined or separate storm sewer  22 . Many of these systems include some sort of treatment process  24  for the greywater prior to storage, such as filtration or disinfection. Water stored in the tank  20  can then be used for toilets  28 , irrigation or other domestic non-potable uses  26 . An overflow pipe  30  at the top of the storage tank allows excess stormwater or greywater to overflow to a municipal sewerage system  32  or onsite wastewater treatment system (not shown). 
         [0004]    Unfortunately, a number of problems exist with currently available combined stormwater-greywater storage systems. One of the major drawbacks of greywater storage is that water quality in the tank degrades quickly after prolonged storage. Potable water  40  may be used to dilute the greywater, but this is not a desirable use of a limited resource. Although a combined stormwater-greywater system can alleviate this problem by diluting greywater  42  with higher quality stormwater  12 , the currently available systems are unable to predict when rainfall events will occur in order to empty the tank  20  of old, poor quality water to make room for new water. As a result, many impurities remain in the tank even after rainfall events. 
         [0005]    A secondary purpose of stormwater capture may be to reduce the intensity and duration of stormwater flow into the municipal sewer system and receiving waters. Heavy rainfall leads to a dramatic increase in the volume of wastewater sent to wastewater treatment plants in combined sewer areas, and these increases can overwhelm the capacity of the plant and lead to the unintended discharge of raw sewage to natural water bodies. Current combined greywater-stormwater systems are unable to regulate the volume of water entering sanitary sewers because they may be filled to capacity at the time of a storm. 
         [0006]    Lastly, new infrastructure projects are required to implement Best Management Practices (BMPs) for low impact development in many states throughout the United States. These BMPs often require new developments to entrain 85% of stormwater runoff generated from a newly developed site. Although current combined greywater-stormwater storage systems capture rainfall, they cannot be relied upon to prevent stormwater from entering sewers and therefore do not meet low impact development requirements for new infrastructure. Most critically, existing systems do not utilize digital weather forecasting information in order to anticipate the likely volume of future precipitation, e.g., rain or snowmelt, that may be added to the storage tank during a current or future precipitation event and act on this information to manipulate the volume maintained in the storage tank. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    The problems with current combined greywater-stormwater capture and reuse systems identified above can be addressed using a forecast-integrated automated control system for combined greywater-stormwater storage and reuse, as described herein. 
         [0008]    The presently disclosed system and method provide a simple and reliable approach for managing greywater and stormwater collection at a household or community level, and allows for the near-continuous monitoring and adjustment of water quantity and quality in a combined greywater-stormwater storage tank based on monitored feedback/output from individual, tank-specific sensors and/or sensors located elsewhere in the water collection system. Use of the forecast-integrated automated control system for combined greywater-stormwater storage and reuse allows an owner, operator, or technician to optimize the water quality and quantity collected in the storage tank, reduce the amount of stormwater discharged to municipal sewers, and assure/demonstrate regulatory compliance for control of stormwater runoff through the integration of a low impact development BMP. 
         [0009]    The invention pertains to a forecast-integrated automated control system for combined greywater-stormwater capture and reuse. The system is comprised of six primary components that together provide an efficient and robust solution to the complex optimization of combined greywater-stormwater storage: a combined greywater-stormwater storage tank; greywater and stormwater collection systems; a stormwater runoff bypass system; a greywater bypass system; a tank drawdown valve or pump system; and a forecast-integrated control system. 
         [0010]    A discussion of these six individual components is presented below, followed by a description of the fully integrated system and methods implemented therewith. 
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       [0011]    Embodiments of the present invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which: 
         [0012]      FIG. 1  is a block diagram illustrating the state of the art in discrete greywater and stormwater systems; 
         [0013]      FIG. 2  is a block diagram illustrating a combined greywater/stormwater system with forecast-integrated control, as disclosed herein; 
         [0014]      FIG. 3  is a schematic illustration of connections provided to a controller of the system of  FIG. 2 ; 
         [0015]      FIG. 4  is a flowchart depicting basic operations of the method implemented by the combined greywater/stormwater system with forecast-integrated control; 
         [0016]      FIG. 5  is a flowchart depicting a storage tank drawdown subroutine of the method of  FIG. 4 ; 
         [0017]      FIG. 6  is a flowchart depicting a storage tank water quality monitoring subroutine of the method of  FIG. 4 ; and 
         [0018]      FIG. 7  is a flowchart depicting a greywater management subroutine of the method of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    This application claims priority of U.S. Prov. Pat. Appl. No. 62/069,604, filed Oct. 28, 2015, which is incorporated herein in its entirety. 
         [0020]    Disclosed is a forecast-integrated automated control system  102  for combined greywater-stormwater capture and reuse, a combined greywater-stormwater capture and re-use system  100  incorporating such a control system, and methods of use implemented by the controller and the combined system. The combined system is comprised of six primary functional components: a combined greywater-stormwater storage tank  120 ; greywater and stormwater collection systems  142 ,  112 ; a stormwater runoff bypass system  150 ; a greywater bypass system  152 ; a storage tank drawdown valve  154  and/or pump system  156 ; and the forecast-integrated control system  102 , the latter also being referred to simply as the controller. Each of these components is discussed separately herein, followed by a description of the integrated system and methods. 
         [0021]    The storage tank  120  is a tank, or functionally similar storage volume, intended to store both stormwater runoff  112  and greywater  142 . Stormwater runoff is typically collected from building roofs  134  and other impervious surfaces  136  such as parking lots. The tank preferably has two separate inlets: one for the greywater collection system  142  and one for the stormwater collection system  112 . The tank is of conventional construction and is sized according to the predicted requirements of the respective installation, taking into consideration factors such as historical stormwater and/or greywater volumes as a factor of time, predicted trends in such volumes resulting from factors such as climate change, re-use requirements/opportunities, available space, and the ability of an interconnected storm and/or sanitary sewer to absorb bypass volumes from the integrated system. An overflow pipe  130  at or near the top of the tank allows excess water to flow from the tank into the municipal sewer  132  when the tank maximum capacity is reached. Inputs from one or more sensing devices  160  are employed by the controller to estimate the volume of combined greywater and stormwater within the storage tank. The controller is then capable of controlling the operating status of one or more controllable water pumps, drain valves, and/or auxiliary bypass discharge valves, discussed subsequently. Exemplary sensing devices are discussed below. 
         [0022]    The greywater and stormwater collection systems  142 ,  112  are drainage and/or plumbing systems of contemporary construction that connect greywater and stormwater runoff, respectively, to the storage tank  120 . The greywater and/or stormwater collection systems optionally include a treatment step, e.g. filtration, by a respective treatment system prior to storage. In  FIG. 2 , a greywater treatment system  162  is illustrated. While not shown, a similar treatment system can be disposed between a stormwater runoff bypass valve  164  and the storage tank, or after a stormwater runoff bypass valve  164 , in a respective bypass flow path  150 . A bypass system  170 ,  168  within each collection system  142 ,  112 , discussed below, allows the greywater and/or stormwater to flow directly to the tank, to a treatment process  162 , and/or to a municipal sanitary or storm sewer  132 ,  122 , depending on the water level in the system storage tank and predicted volumes of greywater and/or stormwater to be received in a future time interval. 
         [0023]    The stormwater runoff bypass system  170  includes an active or passive bypass flow path  150  configured to enable the selective diversion of stormwater runoff directly to a storm sewer  122  or on-site stormwater treatment system (not illustrated) instead of to the storage tank  120 . The controller  102  manages the operation of a respective drain valve  164  of the bypass system leading to the stormwater runoff bypass flow path  150 , taking into consideration factors such as sensor  160  input(s) indicative of storage tank water level and storage tank water quality parameters, and weather forecasts predicting the volume of water that may enter the tank over a given time period. Other information that the controller may take into consideration in the selective operation of the stormwater runoff bypass valve includes Hydromodification Management (HM) Best Management Practices (BMPs) for an associated stormwater runoff system. The constituent valve is an automatic, remote controlled valve of conventional construction. 
         [0024]    The greywater bypass system  170  is an active or passive bypass flow path  152  configured to enable the selective diversion of greywater directly to a sanitary sewer  132  instead of to the storage tank  120 . Similar to the stormwater runoff bypass system  168  described above, the controller  102  manages the operation of the respective greywater bypass drain valve  166  leading to the greywater bypass flow path  152 , taking into consideration factors such as sensor  160  input(s) indicative of storage tank water level and storage tank water quality parameters, weather forecasts predicting the volume of water that may enter the tank over a given time period, and predicted or actual indications of available capacity of an associated sewage treatment system fed by the respective sanitary sewer. Greywater may be diverted away from the storage tank if the tank is already full or if the controller predicts a large storm is coming. 
         [0025]    The configuration of each of the greywater bypass system  170  and the stormwater runoff bypass system  168  by the controller  102  may be handled discretely or may be handled in a coordinated fashion. For example, if feedback indications received by the controller suggest the HM BMP for a given runoff system would be exceeded if additional stormwater runoff were to be routed through the respective bypass system, the stormwater runoff bypass valve  164  is configured to route stormwater to the storage tank while the greywater bypass system  170  is actuated instead if one or more sensors  160  provide indications to the controller that available storage tank  120  capacity is insufficient for receiving both stormwater runoff and greywater inflows. 
         [0026]    Further, the controller  102  is able to respond to changing conditions over time. Thus, while sufficient storage tank  120  capacity may exist at the onset of a precipitation event, if conditions change from a prediction model, one or both bypass systems  170 ,  168  may be enabled to prevent over-filling the storage tank. 
         [0027]    The storage tank drawdown valve  154  and/or pump system  156  is a selectively operable system for controlling the water level in the storage tank  120  by discharging stored water (i.e., combined greywater and stormwater) from the storage tank to the sanitary sewer  132  (or a combined sanitary/stormwater sewer) or to an acceptable on-site use, such as washing machines  116 , toilets  128 , irrigation, decorative fountains, or other non-potable use  126 . The storage tank drawdown valve  154  is of conventional construction. The drawdown pump system  156  in one embodiment comprises a conventional pump and associated pressure tank with pump switch. Both the drawdown valve  154  and pump system  156  are remotely and automatically operated by the controller  102 , based on water quantity and quality in the tank, weather forecasts, and other optional inputs that can include associated sewer treatment facility available capacity, HM BMPs, etc. The controller may be programmed to estimate the timing and volume of non-potable water demand or available capacity, such as for landscape irrigation, based upon pre-programmed predictions and/or calculated from historic use data recorded by the controller or otherwise provided to it, and to optimize the balance between creating room for greywater and/or stormwater runoff capture in the storage tank and maintaining supply for non-potable reuse. The drawdown valve may discharge to the municipal sanitary sewer if the controller determines there is a need to make room for incoming stormwater runoff, or it may supply stored water for domestic non-potable reuse. The controller is designed to efficiently capture, transmit, and store water quantity and quality sensor information associated with the storage tank, process and analyze these data, evaluate attainment of optimization goals, and ultimately transmit signals to control/adjust the storage tank drawdown valve and/or pump system. 
         [0028]    The forecast-integrated control system  102  in one embodiment is a controller and all related hardware and software for actuating the storage tank drawdown valve  154  and/or pump system  156 , the greywater bypass system  170 , and the stormwater runoff bypass system  168 . The control system may be comprised of a field Internet Gateway Device (IGD) or Devices (IGDs) that include microcontrollers and Internet Protocol (IP)-based communications hardware and software interfaces that facilitate bi-directional communication with internet-based web services (e.g., cloud-based control systems and Application Programming Interfaces (APIs)). Other physical configurations are envisioned and employable. 
         [0029]    A block diagram illustrating the control system  102  and the network of communications pathways to which it interfaces is shown in  FIG. 3 . A controller IGD is comprised of a microprocessor  202 , local memory  204 , communications interfaces  206 , and a power supply  208 , the latter being an interface to an external power source and/or internal battery power. The communications interfaces enable a data pathway to and from the internet-based web services and weather forecasts  210  and cloud-based algorithm and data storage  212 . In addition to the sensors  160  associated with the storage tank  120 , described in greater detail herein, other sensors  214  may be employed for providing data to the controller, such as atmospheric or soil temperature, humidity and pressure sensors. Control applications, as previously described, include storage tank drawdown control  220 , greywater bypass valve control  222 , stormwater bypass valve control  224 , and potable water refill valve control  226 . Additionally, a local interface  228  may be provided to enable local control, reconfiguration, programming and data readout of the controller. 
         [0030]    By means of site-specific algorithms made available to the controller  102  via internet-based web services, the control system is able to integrate weather forecast information into the control logic running locally on the controller in order to make available adequate storage volume in the storage tank  120  needed to effectively control stormwater runoff or achieve some similar site specific water control objective (e.g., reduce environmental impacts of the system, conserve water, etc.) The forecast-integrated control system predicts an expected time-dependent volume of water being added to or to be added to the system as well as a prediction of onsite water use and/or capacity for use, and the controller operates the storage tank drawdown valve  154  and/or pump system  156  to draw down the tank and/or activate at least one of the greywater and stormwater runoff bypass valves  166 ,  164  to divert either greywater or stormwater away from the storage tank to provide adequate storage volume for the predicted precipitation. Preferably, the precipitation forecast device or service provides weather precipitation data from an internet-connected resource source  210  such as the World Wide Web, internet-based web services, a local area network (LAN), a wide area network (WAN), and/or a dedicated weather data server or web service. 
         [0031]    The site-specific algorithms may be individually coded for each location, or may take the form of a template into which various site-specific input data are loaded. Such input data may include storage tank  120  maximum capacity, the identification of sensors associated with the storage tank  160 , greywater collection system (not shown), stormwater runoff collection system (not shown), soil or atmospheric hygrometers, thermometers, atmospheric barometers  214 , etc., data relating to HM BMPs for an associated runoff system, and inputs from an associated sanitary sewer  132 , storm sewer  122  and/or downstream sewage treatment facility (not shown) as to free capacity. Further, such algorithms may have baseline storage tank profiles that control storage tank capacity based upon factors such as historic environmental data, subject to modification based upon forecast data received by the controller. For example, a location may typically experience, on a year-to-year basis, very little precipitation for nine months of the year. During those months, the controller, executing the respective algorithm, provides less capacity for stormwater runoff unless a newly received forecast indicates more stormwater may be received. However, during the other three months of the calendar year, rain storms are more frequent and so the storage tank is configured to receive more stormwater runoff in the absence of forecast data, and subject to modification by newly received forecast data. 
         [0032]    The site-specific algorithms can also be customized to take into consideration, in addition to the other inputs discussed above, the storage tank  120  water quality and possible need for purging and refilling to address contents of increasing turbidity and stagnation. Sensors associated with the storage tank  160  and providing input to the controller  102  can include temperature, turbidity, conductivity, oxidation reduction potential, nitrate concentration, etc. Such sensor data may also be used by the controller in determining the suitability of the storage tank contents for local non-potable use, such as irrigation. 
         [0033]    The controller algorithm may also enable the prediction of a number of water quality parameters (e.g., biological oxygen demand, fecal coliform concentration, total suspended solids, and dissolved oxygen levels) based upon one or more of how much stormwater runoff has entered the tank in a given time period versus how much greywater has entered the tank in the same time period, the recycle rate of the water, and easy to measure surrogate parameters like temperature and conductivity. 
         [0034]    Additionally the controller algorithm is capable of responding to pre-programmed predictions of greywater production based on previous use patterns; as water is added to the tank over time, the controller uses machine learning processes to estimate how much greywater to expect and integrates this with the weather forecast for more accurate predictions of required storage capacity. Alternatively, such greywater production predictions are factored into the respective algorithm prior to being programmed into the respective controller. 
         [0035]    The integration of the six primary functional components of the forecast-integrated greywater-stormwater capture and reuse system  100 , individually described above, is shown schematically in  FIG. 2 . 
         [0036]    Initially, the stormwater running off from roofs and impervious surfaces  134 ,  136  and greywater from washbasins  114 , showers  118 , and laundry machines  116  is plumbed to the combined greywater-stormwater storage tank  120  that fills until a defined level is reached. The controller monitors water level and water quality parameters within the storage tank via plural sensors  160  disposed in conjunction with the storage tank. As the water level reaches maximum capacity for the storage tank or some other predefined level below that threshold, the controller either i) diverts incoming greywater to the sanitary sewer  132  by actuation of the greywater bypass valve  166 , ii) actuates the storage tank drawdown valve  154  to direct stored water to the sanitary sewer, or iii) actuates the drawdown pump system  156  to drain stored water from the storage tank and to direct it for non-potable use. The controller may be programmed to supply stored water for re-use applications at regular times and volumes, and it may ensure that adequate water quantity and quality is available for the re-use application from data gathered by sensors within the tank. 
         [0037]    A basic method of operation is described with reference to  FIG. 4 . Initially, the controller  102  is provided with an algorithm  300  for implementing the combined greywater/stormwater control system with forecast integration. The controller is connected to a precipitation forecast source  302  and, using tank-located sensors  160 , establishes the free capacity within the storage tank  304 . In the event a storm is predicted, the controller determines the expected volume of stormwater runoff that may be produced  306 . The controller then compares the free capacity to the runoff prediction  308 . If the expected volume is greater than the free capacity within the tank, the controller determines  310 , on the basis of the algorithm, whether to actuate the stormwater runoff bypass valve  164 , actuate the greywater bypass valve  166 , actuate the storage tank drawdown valve  154 , actuate the drawdown pump system  156  to drain the storage tank  120 , or some combination thereof. 
         [0038]    In  FIG. 5 , a further sub-routine of the algorithm, executed by the controller  102 , determines if the free capacity of the storage tank  120  is substantially zero or whether drawdown is otherwise required  330 , such as due to predicted rainfall and/or predicted greywater inflow. If so, the controller, executing the algorithm, determines  332  whether to actuate the stormwater runoff bypass system  168 , actuate the greywater bypass system  170 , actuate the tank drawdown valve  154 , actuate the drawdown pump system  156 , or some combination thereof. 
         [0039]    In  FIG. 6 , a further sub-routine of the algorithm, executed by the controller  102 , compares data from sensors  160  disposed in conjunction with the storage tank  120  to acceptable water quality thresholds  340 . As previously discussed, such measures may include temperature, turbidity, conductivity, oxidation reduction potential, nitrate concentration, etc. If the stored water quality is determined to be below acceptable levels  342 , the controller uses the algorithm to determine  344  whether to drawdown the storage tank to the respective sanitary sewer  132  via actuation of the drawdown valve  154  or to non-potable uses via actuation of the drawdown pump system  156 . 
         [0040]    Water quality parameter levels may be set on the controller so that when these values are exceeded, the controller drains the tank to flush out the poor quality water. The levels may be based on state/municipal-level regulatory limits for greywater reuse. 
         [0041]    In  FIG. 7 , a further sub-routine of the algorithm, executed by the controller  102 , includes providing the controller with a forecast of a volume of greywater to be expected  350 , such as based on historical analysis. The controller establishes  352  the free capacity of the storage tank  120  on the basis of input from tank-mounted sensors  160  and a predetermined acceptable water level within the storage tank. Then, the controller compares  354  the expected volume of greywater to the free capacity within the tank. If the expected volume of greywater exceeds the free capacity, the controller then determines  356  whether to actuate the greywater bypass system  170 , drawdown the storage tank to the respective sanitary sewer  132  via actuation of the drawdown valve  154  or to non-potable uses via actuation of the drawdown pump system  156 , or some combination thereof. 
         [0042]    Information collected by the controller is processed and various reports, plots, notifications, and visual representations are automatically generated and available to the homeowner/operator via web connected cloud-based web dashboards  210  or the local user interface  228 . 
         [0043]    Various operations described are purely exemplary and imply no particular order. Further, the operations can be used in any sequence when appropriate and can be partially used. With the above embodiments in mind, it should be understood that additional embodiments can employ various computer-implemented operations involving data transferred or stored in computer systems. These operations are those requiring physical manipulation of physical quantities. Usually, though not necessarily, these quantities take the form of electrical, magnetic, or optical signals capable of being stored, transferred, combined, compared, and otherwise manipulated. 
         [0044]    Any of the operations described that form part of the presently disclosed embodiments may be useful machine operations. Various embodiments also relate to a device or an apparatus for performing these operations. The apparatus can be specially constructed for the required purpose, or the apparatus can be a general-purpose computer selectively activated or configured by a computer program stored in the computer. In particular, various general-purpose machines employing one or more processors coupled to one or more computer readable media, described below, can be used with computer programs written in accordance with the teachings herein, or it may be more convenient to construct a more specialized apparatus to perform the required operations. 
         [0045]    The procedures, processes, and/or modules described herein may be implemented in hardware, software, embodied as a computer-readable medium having program instructions, firmware, or a combination thereof. For example, the functions described herein may be performed by a processor executing program instructions out of a memory or other storage device. 
         [0046]    The foregoing description has been directed to particular embodiments. However, other variations and modifications may be made to the described embodiments, with the attainment of some or all of their advantages. It will be further appreciated by those of ordinary skill in the art that modifications to the above-described systems and methods may be made without departing from the concepts disclosed herein. Accordingly, the invention should not be viewed as limited by the disclosed embodiments. Furthermore, various features of the described embodiments may be used without the corresponding use of other features. Thus, this description should be read as merely illustrative of various principles, and not in limitation of the invention. 
         [0047]    Many changes in the details, materials, and arrangement of parts and steps, herein described and illustrated, can be made by those skilled in the art in light of teachings contained hereinabove. Accordingly, it will be understood that the following claims are not to be limited to the embodiments disclosed herein and can include practices other than those specifically described, and are to be interpreted as broadly as allowed under the law.