Patent Application
20230264980
Agricultural runoff includes rainwater plus any particulate debris and dissolved materials that the rainwater may entrain as it traverses either the soil surface or the soil profile before entering drainage pipes. Both surface runoff and subsurface drainage from agricultural fields typically flow into artificially constructed drainage ditches or other surface water bodies. Given that the fields this drainage originates from typically receive external nutrient inputs; agricultural runoff and drainage can constitute a significant form of non-point source pollution. Agricultural non-point source phosphorus pollution in particular is often the primary cause of harmful algal blooms in surface water bodies. While many agricultural conservation practices have been installed to mitigate surface runoff, there are few practices available that mitigate dissolved phosphorus loading from runoff and tile drainage.
One solution to the introduction of phosphorus pollution in the drain water is provided by a tile system in which water runoff from tiles or soil is diverted to an area that has been filled with a layer of iron slag or iron enhanced sand to capture the runoff. The tiles are typically large networks of drainage conduits embedded in soils. The drainage conduits are designed to divert runoff water into the areas containing the filter media to filter the water runoff for up to about 10 years. The filter areas are difficult to maintain and media replacement after ten years is often impractical.
In view of the above, a system for treating water runoff is provided. In example systems, a water runoff treatment device includes a primary receptacle and a secondary receptacle separated by a barrier having at least one treatment port to permit water to pass from the primary receptacle to the secondary receptacle. A runoff water inlet is formed on one side of the primary receptacle. The runoff inlet is connected to a drainage conduit to receive drain flow into the primary receptacle. At least one treatment tank comprising a treatment medium is mounted over a corresponding one of the treatment ports in the primary receptacle. The at least one treatment tank includes a treatment tank opening configured to receive water in the primary receptacle for treatment by the treatment medium. The at least one treatment tank is connected to the treatment port to pass treated water into the secondary receptacle. At least one drain port is formed in the secondary receptacle to pass treated water out of the secondary receptacle and into a flow of treated water.
In one aspect, a single water runoff treatment device may be used to treat water runoff from a network of drainage conduits. The drainage conduits may include a series of openings on an upper surface of the drainage conduits to capture water runoff. The water runoff may be directed to an outlet drainage conduit attached to the water runoff treatment device.
In another aspect, multiple water runoff treatment devices may be connected to corresponding outlet drainage conduits to treat the water runoff. The treated water runoff may flow from the water runoff treatment device into a pool or stream of treated water runoff.
Water that flows through soil in fields of agriculture or fields having other uses may contain high levels of soluble phosphorus. The water becomes water runoff that eventually drains into water supplies including lakes and reservoirs. Phosphorus has been identified as a primary cause of harmful algal blooms in surface water bodies. Described below are systems and apparatuses for treating water runoff to substantially mitigate the buildup of phosphorus in surface water bodies.
It is noted that the system 200 in
The water runoff treatment device 120 in
In example implementations, the treatment tanks 122 are configured in size and with filter media having a desired density such that the untreated water contacts the filter media for a desired amount of time before it exits through the treatment ports 150. The treated water collects in the secondary receptacle 142 and flows out through drain ports 152 formed on one or more sides of the secondary receptacle 142. The treated water 130 may flow out and collect or flow into the surrounding ecosystem to eventually flow into the surface water bodies. The treated water 130 flows with a substantially reduced level of phosphorus thereby mitigating the algal blooms in the surface water bodies. The primary receptacle 140 in
In example implementations, the housing portion 180 forming the primary receptacle 140 and the secondary receptacle 142 may be made of a molded thermoplastic. In other implementations, other suitable materials may be used where such materials provide sufficient support and durability in environments in which the device is in contact with soil, water and other materials.
It is noted that while the examples illustrated in the figures and described in the specification are cylindrical in shape, the treatment tanks described herein may take any other suitable shape. In other implementations, the treatment tanks may be cube-shaped, or tanks having rectangular cross-sections or any other suitable shape. Similarly, the treatment ports of the treatment tanks opening to the secondary receptacle may be circular or any other suitable shape.
In one example implementation, the gasket housing 220 includes a ring clamp configured to secure the treatment tank over the treatment port. In another implementation, the gasket housing 220 includes a push-in gasket seal configured to secure the treatment tank over the treatment port. In another example implementation, the gasket housing 220 includes a threaded mechanism to secure the treatment tank over the treatment port. That is, the treatment tank 122 may be screwed into a fitting on the treatment port 150. The gasket housing 220 may also include a twist and lock mechanism to secure the treatment tank over the treatment port.
The example implementation in
In another implementation, the at least one treatment tank 122 may be fixedly attached over the corresponding one treatment ports and configured to support removable bags containing treatment media. In this way, the filter media my be replenished over time by simply replacing the bag of filter media.
In example implementations, the treatment media includes engineered media having high sorption capacity. In one example, the engineered media includes activated alumina. In another example, the engineered media includes engineered iron or aluminum oxide materials. The engineered filter media may be provided in a density and volume that allows for the water runoff to contact the engineered media for a desired length of time. The area of the treatment ports, the volume of the treatment tanks, the number of treatment tanks in each water runoff treatment device, and the geometry of the inlet 132 and drain ports 152 may be adjusted to allow for the water runoff to contact the filter media for a desired length of time. In example implementations, the water runoff treatment devices 120 may be configured to allow for the water runoff to contact the filter media for about 1 to 2 minutes. In larger areas of soil through which water runoff passes, multiple water runoff treatment devices may be installed at multiple outlet drainage conduits to suitably treat the water runoff.
It is noted that example implementations described herein are configured for treatment of water runoff to capture phosphorus. The filter media used in the treatment tanks is engineered to capture phosphorus. The treatment tanks may be configured to capture other materials in addition or instead of phosphorus as may be desired in specific implementations.
The disclosure provided herein describes features in terms of preferred and exemplary embodiments thereof. Numerous other embodiments, modifications and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure.
