So: build a new one. But how? One, two or three sewage plants? Which solution would result in the best clearing results? Which one at the lowest costs? After weighing various possibilities it was decided to build a central sewage plant. Building costs were estimated at DM 7.8 millions, adding running costs of DM 500,000 a year. Still a lot of money, but after all nobody had turned to us about it, yet.

Then the city of Naumburg was consulted by HPC. Individual component parts of the plant could be arranged in a more space-saving and more effective way. We guaranteed a fixed price of DM 6.5 millions. And we promised that running costs would not exceed DM 380,000 a year.

Construction began in April 1998 (ill.1). One year later the plant was put into operation. That was the quickest start-up in the administrative district. It saved the customer further costs because, as long as the sewage was treated in the old way, the community had to pay sewage fees of DM 300.000 a year. The clearing results of the new plant are distinctly below the authorized limits. Running costs amount to DM 220.000 a year.

Mechanical step:
Combination of fine riddle and grate sand trap with integrated ventilated sand and grease separator.

Biological step:
A rectangular sludge activation basin (ill.2) with forward-inserted biological phosphate elimination, variable operation because of integrated two-track mode, denitrification and nitrification basin, ventilator, a final sedimentation tank with sludge scrapers and dipped waste pipes, gutter piece construction with MID measuring and high-water pump.

Sludge treatment:
Biological sludge degradation (ill.3)by means of planted reed patches, a sludge silo for wet sludge discharge, automated sludge water separation, sludge pit.