WASTE-WATER TREATMENT IN A COMPANY WITH ADVANCED DEMANDS FOR WATER-QUALITY

The result of the North Sea Conference 1987 in London was the 50% redu ction of dangerous and nutritive substances before 1995. To reach that aim the wastewater treatment plants discharging to the river Elbe wer e subjected to more severe discharge standards. In our case the compan y could also use the publicly owned treatment plant of Hamburg and so we were in direct competition with that plant After several conference s with the client and the water authority we began the planning. The t reatment plant also includes removal of nitrogen in the last stage and phosphorus in the biological stage (not only with chemicals). Another difficulty was that only a small area between the dam of the Elbe wit h a street alongside and the offices was available, So we had to plan a very compact treatment plant To avoid the emission of odours the pla nt was completely housed. As in other factories we also had the proble m that on weekends and during the holidays very little water is flowin g to the plant. The sewage system collected the wastewater in one syst em and stormwater in another. Since the area is flat, several pumpstat ions transport the water. So we planned a modular system with sieve sc reen and three SBR reactors to use it further as cascaded activated sl udge tanks with predenitrification and enhanced biological phosphorus removal. The sludge treatment was realized as an aerobic thermophilic process in a separate tank To improve matters we also installed a comp uter for process control. The influent concentrations are higher than municipal wastewater which is conditioned by the separate system of tr ansportation without infiltration water. For example COD influent conc entrations are about 1500 mg/l, NH4-N about 130 mg/l and total phospho rus P-tot, about 17 mg/l. The results we obtained in the plant are pre sented in this paper.