SEQUENCING BATCH REACTORS WITH CONTINUOUS INFLOW FOR SMALL COMMUNITIES IN RURAL-AREAS IN BAVARIA

For over two years, special investigations and practical experiences w ere evaluated at small wastewater treatment plants with SBR-technology in rural areas in Bavaria The plants are designed for advanced wastew ater treatment with extended aeration. Plants of this type are suitabl e for small treatment plants, which have to cope with stringent treatm ent requirements and little available land. The machinery and controll ing equipment are constructed with highly sophisticated technology. Th e constant cycles with time fixed process phases have been proved to b e sufficient, but the phases should be optimized and adapted individua lly to an empirically analysed load line for each plant. The compositi on of the biocenosis was stable and efficient. The amount of filamento us bacteria was not high. The biocenosis of the ciliated protozoa was dominated by free-swimming species. Plants with two reactors and cycle durations of 10 hours should have a buffer tank in front of the react ors in order to equalize the loading of each reactor. A polishing pond should always be built before discharge into the receiving body of wa ter. The investment costs are comparatively low but the current energy consumption is higher than in activated treatment plants with continu ous operation. Although the automatically controlled process requires little continuous assistance, skilled operators are needed for operati on, maintenance and manual control. Copyright (C) 1996 IAWQ.