Project Start Date October 2001        End Date December 2001

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     In the fall of 2001 the Moundsville Wastewater Treatment plant's staff started a major undertaking when they started cleaning their two stage anaerobic digestion system. The primary (anaerobic) digester holds 332,900 gallons and the secondary digester has a volume of 514,630 gallons. This also gave the staff a chance to install seven 14 inch Dezurik plug valves, four 6 inch plug valves, two 4 inch plug valves and installed 2 rebuild valve kits for 12 inch valves. These valves were changed, in  spite of a valve exercise program, due to the difficulty of operations. This will give the staff the ability to do future maintenance on equipment and give them more flexibility in operating the digestion system. Also added to the digesters were new pressure relief equipment along with flame arresters for safety. The staff started by isolating the secondary digester, running the plant's belt press daily on day-turn and afternoon turn. A Godwin 4 inch dri-prime pump was also used to pump additional liquid and sludge from the tanks. The pre determined amount of digester contents was ran through the plant, the bar screens catching the trash and the captor/activated sludge secondaryjy31-008.jpg (46202 bytes)

 

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system removing the added load. The plant's lab monitor the plant processes closely during and after pumping for any adverse effect on the plant. During the entire process the plant's system handled the extra load quite well. The secondary digester was completed first, then put back in service while the primary digester was cleaned. After removing as much sludge from the primary digester with the belt press and rented pump, entry was made by the plant's staff. They found approximately six (6) feet of sand and grit covering the entire diameter of the tank's floor. Removal was completed by the plant's staff using shovels and a large vacuum truck rented from Robinson Pipe Cleaning Company. This part of the job was completed in 5 days. The cleaning of both digesters used approximately sixty (60) 40 yard dumpsters and was sent to a local landfill.jy31-012.jpg (64494 bytes)jy31-014.jpg (41585 bytes)                                     jy31-015.jpg (43462 bytes)