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STATE WATER RESOURCES CONTROL BOARD -6- <br /> ORDER <br /> 6- <br /> ORDER WQ 2014-0153-DWQ <br /> GENERAL WASTE DISCHARGE REQUIREMENTS <br /> FOR SMALL DOMESTIC WASTEWATER TREATMENT SYSTEMS <br /> Wastewater percolated from a pond to the subsurface has the potential to <br /> degrade groundwater quality to an unacceptable extent. Reducing the amount <br /> of wastewater percolated by lining a pond with a synthetic or low permeability <br /> liner can control the percolation rate, but an alternative method of wastewater <br /> disposal may be required. Land application (discussed below) is often selected <br /> as the method to dispose of the wastewater from lined ponds. <br /> Overloading a wastewater pond with Biochemical Oxygen Demand (BOD) <br /> constituents can result in nuisance odor generation. Source control of BOD <br /> constituents, additional pretreatment prior to discharge to the pond, or <br /> mechanical aeration of wastewater in the pond are typically used to prevent a <br /> pond from generating nuisance odors. <br /> Burrowing animals can result in rapid failure of a containment berm. The <br /> population of such animals should be promptly controlled and repairs to the <br /> containment completed as soon as possible. <br /> b. When land application of wastewater is selected as a disposal method, <br /> adequate acreage must be available to allow application rates that will not <br /> create nuisance conditions (e.g. vectors, nuisance odors, off-site discharge) or <br /> degrade groundwater quality to an unacceptable extent. <br /> Crops are often grown and harvested from a land application area (LAA) to take <br /> up wastewater constituents such as nitrogen and dissolved solids, as well as <br /> maintain roots which promote wastewater infiltration rates. When climatic <br /> conditions are favorable, double cropping an LAA can increase the uptake of <br /> wastewater constituents. <br /> Hydraulic loading of an LAA must be controlled to prevent off-site wastewater <br /> discharge; if wastewater is not disinfected prior to land application, storm water <br /> that falls on the LAA must be contained to prevent the potential migration off- <br /> site of pathogenic organisms. LAAs are sometimes equipped with a tailwater <br /> control system that allows for reapplication of wastewater to the LAA or <br /> returning tailwater to a wastewater pond. <br /> c. Subsurface disposal areas may be constructed as leachfields or when <br /> conditions allow, seepage pits. If seepage pits are employed, they are often <br /> located at the end of a leachfield distribution pipe to maximize shallow <br /> distribution of wastewater. <br /> If conditions are not favorable for traditional leachfield construction, an at-grade, <br /> or an above grade (mound) system may be used. Typically, at-grade and <br /> above grade systems are dosed using a dosing pump and pump controller. <br /> Dosed systems use relatively small diameter pipe to distribute the wastewater <br /> to zones within the dispersal area. Even in well operated systems, some <br /> suspended solids will be pumped into the distribution piping. Cleanouts or a <br /> flushing system on the distribution piping are required to remove the solids that <br /> will accumulate if the emitters are small enough diameter to prevent suspended <br /> solids from passing through the distribution equipment. Gravelless trench <br /> systems which do not use gravel, typically use distribution piping and a dosing <br /> September 23, 2014 <br />