_O & M MANUAL - WEST LANE MOBILE HOME PARK

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PCC011.1rol N11:I ford, Of 14 5147,0-1 S30 Tel: (5 13) 831-1165 Fax (>1 3) 965-4812 E-rmar;l: PolconsSC4'aol.co.tt ww'.Poll Lit ionC ontrolsystem.d ono Special Maintenance During Start-up Period Common Problems One of the most common problems during the first few weeks of plant operation is the accumulation of sludge on the hopper slopes of the clarifier (settling tank). However, this problem can be almost completely eliminated by proper care and maintenance procedures. The purpose of the clarifier is to settle out and return the solids that pass through from the aeration tank. One of the characteristics of activated sludge is that it is likely to be stringy and sticky during the early weeks of operation, and as it settles toward the bottom of the tank, may cling to the hopper sides where it cannot be returned by the air lift pump. In several days the continuous build up of sludge will completely fill the lower half of the clarifier. After a short time this spongy mass will form a gas and break up into chunks of sludge that float to the surface of the water and will be discharged with treated water. This solid sludge condition prevents the clarifier from performing properly. With this condition the skimmer and the final discharge weir are all hampered in their operation. In addition, the sludge mass may give off a very strong odor. It is possible for a sludge return pipe to be discharging clear water while there is three or four feet of sludge in the hopper (See Figure 1). This occurs when soft sludge packs solid almost to the hopper bottom except for a narrow clear channel running down through the sludge mass to the pump-intake. Clear surface water is pulled down through this channel and up through the pump without disturbing the sludge mass. Therefore, visual checking of the sludge return discharge is not sufficient. Practices to be Followed for Proper Operation Every day during the first few weeks of operation, the operator should check to see that all equipment is running and to check the clarifier. A long handled small scraper with rubber squeegee is to be used to keep the hopper slopes, which begin about three to five feet below the water level, free from solids build Lip. The operator should gently scrape all around the hopper with a slow, easy, downward motion, just enough to help move the sludge toward the bottom of the hopper where it can be picked up by the airlift sludge return pump. ®o not stir or I pcs,'O m-sp.rniin,startup-1-:i