Agenda - 05-22-1989 - Laserfiche WebLink

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t Pressurized Alternative Wastewater Systems (Septic Tank Effluent Pumping) FULFILLING A NEED CONCEPT DEFINITION . Although many sanitary consulting One of the most difficult problems engineers have had some ex- for today's individual home builder perience with pressure sewers,there and residential developers is finding are others who have had little exposure available land for building homes to the.concept.Therefore,as a start, , • that will readily lend itself to sewage let's define a pressure sewer system. disposal either by on-site systems . or gravity sewers.The price of good A pressure sewer is sometimes land for development has become described as a potable water system so expensive in many areas that it in reverse. By this,we mean a water has forced the individual builder and system will have one inlet pressuri- the residential developers to build zation point and a number of end on what is referred to as undesirable user connections, while a pressure land. These areas can be normally sewer will normally have a pressuriz- described as rocky, contain major ed inlet point at each end user con- elevation differences and may have nection and one discharge outlet at . high water tables. In addition, soil a treatment plant or discharge point. structures in many areas of the The number of end user connections United States do not lend themselves - could be anywhere from a few to to on-site treatment systems, several thousand. A pressure sewer system is made up It is.universally recognized that there of three major segments.They are: is a major need for a more econom- A. Pump package system (basin, ical method of collecting,transport- • pump piping, controls, control ing and treating sewage other than panel,alarm) gravity sewers.This would be espec- B. Servce lines and force mains ially true in areas containing rock, C. Discharge treatment point rough terrain, sparsely settled and high water table areas. There are two primary types of . • pumps used in pressure sewers. One of the most viable alternatives One is referred to as a grinder pump to gravity sewers that has gained a (GP) and the other an effluent pump great deal of attention over the past • (STEP)which is located in or behind several years is the concept of pres- a septic tank. The major difference sure sewer systems.There have been between the two pump types is how over 150 of these systems (100-1500 the solids are handled. connections) installed since 1970 with a large number currently under In the case of GP units, the solids evaluation, design, or installation. are ground into a slurry and pumped Pressure sewers under the US-EPA to a discharge point. With a STEP grants program are defined as alter- pump. the settleable solids and native systems, but not innovative most of the grease accumulation since their performance and reli-. remain in the septic tank. Conse- ability has been proven in over 14 • quently. the STEP pump conveys a years of operation. fairly clear effluent to the discharge point. • - - 1 'CRAIG B.MORGAN AND ASSOCIATES,P.A. ot •