Definitions:
       |
"BOD" means biochemical oxygen demand, typically expressed in mg/L.
"CBOD5" means carbonaceous biochemical oxygen demand, typically expressed in mg/L. "FC" means fecal coliform, typically expressed in number colonies/100 ml. "O&G" (formerly referred to as FOG) means oil and grease, a component of sewage typically originating from food stuffs (animal fats or vegetable oils) or consisting of compounds of alcohol or glycerol with fatty acids (soaps and lotions), typically expressed in mg/L. "TSS" means total suspended solids, a measure of all suspended solids in a liquid, typically expressed in mg/L. "Bed" means a soil dispersal component consisting of an excavation with a width greater than three feet. "Design flow" means the maximum volume of sewage a residence, structure, or other facility is estimated to generate in a twenty-four-hour period. It incorporates both an operating capacity and a surge capacity for the system during periodic heavy use events. The sizing and design of the on-site sewage system components are based on the design flow. "Drain field" see subsurface soil absorption system (SSAS) and soil dispersal component. "Drainrock" means clean washed gravel or crushed rock ranging in size from three-quarters inch to two and one-half inches. "Effluent" means liquid discharged from a septic tank or other on-site sewage system component. "Failure" means a condition of an on-site sewage system or component that threatens the public health by inadequately treating sewage or by creating a potential for direct or indirect contact between sewage and the public. Examples of failure include: (a) Sewage on the surface of the ground; (b) Sewage backing up into a structure caused by slow soil absorption of septic tank effluent; (c) Sewage leaking from a sewage tank or collection system; (d) Cesspools or seepage pits where evidence of ground water or surface water quality degradation exists; (e) Inadequately treated effluent contaminating ground water or surface water; or (f) Noncompliance with standards stipulated on the permit. "Fecal coliform" means bacteria common to the digestive systems of warm-blooded animals that are cultured in standard tests. "Gray water" means sewage from bathtubs, showers, bathroom sinks, washing machines, dishwashers, and kitchen sinks. It includes sewage from any source in a residence or structure that has not come into contact with toilet wastes. "Infiltrative surface" means the surface within a treatment component or soil dispersal component to which effluent is applied and through which effluent moves into original, undisturbed soil or other porous treatment media. "On-site sewage system" (OSS) means an integrated system of components, located on or nearby the property it serves, that conveys, stores, treats, and/or provides subsurface soil treatment and dispersal of sewage. It consists of a collection system, a treatment component or treatment sequence, and a soil dispersal component. An on-site sewage system also refers to a holding tank sewage system or other system that does not have a soil dispersal component. "Pressure distribution" means a system of small diameter pipes equally distributing effluent throughout a SSAS "Proprietary product" means a sewage treatment and distribution technology, method, or material subject to a patent or trademark "Public domain technology" means a sewage treatment and distribution technology, method, or material not subject to a patent or trademark "Record drawing" means an accurate graphic and written record of the location and features of the OSS that are needed to properly monitor, operate, and maintain that system "Reserve area" means an area of land approved for the installation of a conforming system that is protected and maintained for replacement of the OSS upon its failure. "Restrictive layer" means a stratum impeding the vertical movement of water, air, and growth of plant roots, such as hardpan, claypan, fragipan, caliche, some compacted soils, bedrock and unstructured clay soils. "Septic tank" means a watertight treatment receptacle receiving the discharge of sewage from a building sewer or sewers, designed and constructed to permit separation of settleable and floating solids from the liquid, detention and anaerobic digestion of the organic matter, prior to discharge of the liquid. "Sewage" means any urine, feces, and the water carrying human wastes, including kitchen, bath, and laundry wastes from residences, buildings, industrial establishments or other places. "Sewage quality" means contents in sewage that include: (a) CBOD5, TSS, and O&G; (b) Other parameters that can adversely affect treatment. Examples include pH, temperature, and dissolved oxygen; (c) Other constituents that create concerns due to specific site sensitivity. Examples include fecal coliform and nitrogen. "Soil log" means a detailed description of soil characteristics providing information on the soil's capacity to act as an acceptable treatment and dispersal medium for sewage. "Subsurface soil absorption system" (SSAS) means a soil dispersal component of trenches or beds containing either a distribution pipe within a layer of drainrock covered with a geotextile, or an approved gravelless distribution technology, designed and installed in original, undisturbed, unsaturated soil providing at least minimal vertical separation as established in "On-site Sewage Systems Chapter 246-272A WAC", with either gravity or pressure distribution of the treatment component effluent. "Timed dosing” means delivery of discrete volumes of sewage at prescribed time intervals. "Trench" means a soil dispersal component consisting of an excavation with a width of three feet or less. "Water table" means the upper surface of the ground water, whether permanent or seasonal. (Definitions from: On-site Sewage Systems Chapter 246-272A WAC) apps.leg.wa.gov/wac/default.aspx?cite=246-272A |