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re ' . <br /> d i <br /> 1 i'8lr , <br /> 3b SEPTIC TANK SYSTE:1 EFFECTS ON GROUND WATER U <br /> Q ALTTY <br /> Table 13: Setback Requirements for Orainfields (Cotteral and Norris, <br /> i 1969) <br /> 1 <br /> Seebeck ke•ulrearnta I•et <br /> ! Federal Dblfore <br /> boring Plumbing S� Crnee Sant. Como. ?Urfa <br /> Authority Code county Cru. Cleo. Costa County <br /> Ce�ey Oeunc7 County County <br /> I <br /> Drainfielde To: <br /> r <br /> i \ulldipg. <br /> S e 3 s l0 1D <br /> Property line. S 10 <br /> �! <br /> W11. S 10 S ID s 5 <br /> 100 SO <br /> 73 100 <br /> 100 SO 100 <br /> i'y C»eke or •tra.m. SO <br /> 20 100 - SO 25 <br /> PoolCur..or erbeMe.nte - <br /> - 20 IS - so xs <br /> - <br /> 25 - - - 25 <br /> weer line. 10 S - <br /> s - 10 <br /> Valk. and drive. - - <br /> ler\a core. - - - S - <br /> 10 - <br /> - - 1D - <br /> considered' prior to-designing the soil absorption system. Three types of <br /> drainfield loading can be utilized, including Continuous ponding, dosing and <br /> .1 resting, and uniform application without pondin method the infiltrative surface is covered at allltim scwith waste ate .poning <br /> This method has the advantage of increasing the effective infiltrative area <br /> !I by submerging the sidewalls of the drainfield trenches. It also increases the <br /> '! hydraulic gradient across the infiltrative surface and this in turn may <br /> increase the infiltration rate. However, since clogging occurs at the <br /> i infiltrative surface there will be no aeration at the surface and this may <br /> cause subsequent problems in terms of both hydraulic flow and biological <br /> ' ' decomposition. <br /> • To overcome some of the concerns <br /> dosing and resting can be utilized. This approach provides reaera on in that <br /> ' i ponding, <br /> • <br /> periods of loading are followed by periods of resting. The resting phaSe <br /> j allows the soil to drain and reaerate, thus encouraging degradation of The <br /> 1 dogging mat which may build up at the infiltrative surface. <br /> The process of alternate dosing and resting of a drainfield can <br /> therefore markedly prolong the effective Iife of the system. For practical <br /> • <br /> • <br /> purposes the resting period required for restoration appears <br /> • <br /> order of several months (Cotteral and Norris, 1969). I unifrm to be on the <br /> application <br /> without ponding the liquid is distributed uniformly over the entire <br /> IL infiltrative surface at a rate lower than that which the soil can accept <br /> - liquid. Therefore, the soil always remains u <br /> conditions prevail at the infiltrative surface. When f these ated and aerobic <br /> prevail,the resistance of the dogging mat is m thse aerobic conditions <br /> minimized. <br /> k- 1__._ _I ______._ <br /> - <br /> • <br />