EXPERIMENTS AND RUNNING RESULTS OF THE START UP OF THE PRIMARY DIGISTER IN ‘CZAJKA’ SEWAGE TREATMENT PLANT IN WARSAW
The Warsaw WWTP “Czajka” was designed for the flow of 400000 m3/d. During wastewater treatment 4 800 m3 /d sludge settle down in the primary settling tanks. It’s a mixture of primary and excess activated sludge. The settling tanks are desludged three times a day and the sludge flows by gravity to 4 thickener and is then pumped into 6 digesters, 7 200 m3 volume each. The start up of the digesters took place in 1991. The digesters were filled up with water, heated a bit over the temperature of work and then at once 2 000 m3 of raw sludge was pumped in. After this the content was thoroughly mixed and the feed was started with the amount of 15 m3/d of raw sludge. Gradually increasing the feed the full volumetric loading was reached after 110 days. The analysis of the sludge from the start up period are presented.