Individual Sewage Disposal System: An individual sewage disposal system is a subsurface sewage disposal system designed and constructed to treat sewage in a manner that will retain most of the solid waste in a water-tight tank and to discharge the liquid portions to an adequate disposal area. Septic Tank: A septic tank is a water-tight receptacle which receives the discharge of sewage from a building sewer or part thereof, and is designed and constructed so as to permit settling of solids from the liquid, digestion of organic matter by detention, and discharge of the liquid portion into a disposal area.. The tank is generally designed to provide a 2-day retention time for wastewater settling to occur. Heavy solids sink to the bottom forming a layer of “sludge” while light solids and fats/grease form a floating “scum layer”. Disposal Trench: Disposal trenches are shallow ditches with vertical sides and flat bottoms partially filled with a satisfactory filtering material in which a single distribution line has been laid, covered with top soil and a suitable vegetative cover. Disposal Bed: A disposal bed consists of an area from which the entire earth contents have been removed and the excavation filled with a satisfactory drainage & treatment material in which distribution lines have been laid and the entire area covered in topsoil and a suitable vegetative growth.. The size of the disposal bed will depend on the anticipated volume of water to be produced from the home and the soil conditions at the site. Seepage Pit: A seepage pit is a covered pit with open jointed lining through which septic effluent or laundry waste may seep or leach into the surrounding soil. Distribution Box: The distribution box lies between the septic tank and disposal area. And serves to evenly distribute the wastewater evenly amongst the drain lines. Ensuring even distribution of the wastewater is crucial in maintaining the longevity of the disposal area. Conventional Treatment Systems: Refers to the standard gravity flow design, which consists of a septic tank, a distribution box and a drainfield (disposal bed). Mounded and Filled Systems: These systems are common solutions to overcoming shallow depth to ground water table or other restrictive features, where site conditions allow for the use of conventional treatment systems. The onsite treatment components are installed within the mound of fill. Some systems require an effluent pump & pump tank be installed. Advanced (Alternative) Treatment Systems: Advanced treatment systems differ from conventional systems in a number of ways. The primary difference being that they further treat the wastewater before it is dispersed to the soil environment. Reducing the “strength” of the wastewater or solids, fats and greases that are suspended in the effluent.