Agenda - 11-23-1987 - Laserfiche WebLink

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i S 1 I em/ / 4 EFFLUENT PUMPING . For maximum corrosion resistance. EQUIPMENT FOR the discharge piping, junction box PRESSURE SEWERS and shutoff valve are made of plastic ✓ materials. Mercury ball level controls In grinder pump pressure sewer are standard. Some engineers speci- + systems there has been only one size ty a redundant check valve to be lo- centrifugal grinder pump (2 hp) avail- cared in service line for added able for installation at the individual protection. An anti-siphoning valve O home. However, in a STEP pressure is added to the internal piping if low sewer, the engineer can choose from heads or negative heads (downhill $ a variety of horsepowers and sizes. runs) are expected to prevent any STEP pumps can be 1/3, .4, 1/2, 1, siphoning action. In most cases, the 1-1/2 and 2 hp, depending on the cover is made of steel so that it can O head and flow requirements.The per- withstand the weight of a riding lawn formance, weight, and cost of the mower. Pump basin covers are nor- O STEP pumps increase as horse- mally installed flush with the ground power increases. The STEP pumps level. An anti-flotation flange held that are available are basically sump by concrete is provided to prevent ♦ pumps, small hp sewage ejectors or the basin from moving upward in modifications thereof. , highwater table areas. 0 One of the drawbacks of currently • available STEP pumps is that they generate much higher flows than PERFORMANCE needed. As an example, a 1/2 hp 4 STEP pump can generate up to 80 Since STEP pumps are pumping a gpm with shut oft heads to 78 feet. clarified liquid from a septic tank, y Since the peak wastewater flow there is usually very little problem generated from an average individual with the pump plugging.The risk of home is no more than 8-15 gpm,you plugging is greater if an old septic 4 can see that the flow rates are much tank is used which is generating higher than needed. The high flow heavy flows and possibly some carry 4 rates make it more difficult to hydrau- over solids due to infiltration. lically design a pressure sewer and will increase pipe sizes. In addition, iAt one time, it was assumed that the high flow rates of the standard a high percentage of old septic tanks effluent pumps can create problems could be utilized as part of a STEP * when discharging into a variable pressure sewer. Now, the consensus gravity sewer system. of opinion is that the majority of old 4 septic tanks should be replaced with new ones. One of the problems Septic tanks can be made of fiber- in using old septic tanks is the owes- * glass,polyethylene or concrete. Con- tion of how do you determine if the crete is the most readily available. tank is leaking. By the time you 4 The most common size used is 1000 pump out the septic tanks, find the gallons,although 500 and 750 gallon leak and repair it (assuming this can ' size tanks have been used in some be accomplished), it may be less pressure systems. In commercial expensive to put in a new septic tank. applications, larger size septic tanks - 4 will be required. Two potential problems associated with STEP systems are corrosion - Variations of an audio and visual and odors. As previously indicated, alarms are used, although the most corrosion can be overcome by popular and cost-effective is a red . choice of materials. Since the septic y flashing alarm light mounted on con- tank is vented through the house trol panel. Most all control panels plumbing system, no outside venting 4 with a disconnect switch are located is required. Care must be taken to outside so they will be easily acces- . insure the cover to the wet well is sible to the serviceman. The prefer- sealed properly. Odors can be a 4 able location of the panel and alarm problem at intermediate pump sta- is on the side of the home or garage tions if vented to atmosphere. This to minimize aesthetic concerns of can be solved by installing an under- the home owner. If desired, the ground venting system. 4 panel can be located at the septic tank/pump basin and mounted on a pedestal. 4 _ __ 3 y CFtA1G B.MORGAN AND ASSOCIATES,P.A.- e 4