Summary
Initial situation
The Joint Wastewater Treatment Works Bitterfeld-Wolfen (GKW) treats domestic wastewater from 18 communities as well as industrial wastewater from the neighbouring chemical park. This park produces organically highly contaminated waste water with a high salt content of approx. 80 g NaCl per litre. Against the background of an almost complete utilisation of the existing aerobic treatment capacity, an anaerobic waste water treatment process could be realized after tests in laboratory and semi-industrial scale.
Technical solution
Key part of the new plant are sludge bed reactors with upward flow. Sludge pellets form a floating bed and are carried upwards by the adhering biogas in the reactor. A precipitator separates biogas from the pellets, which sink back into the sludge bed. Other important plant components are the downstream biogas processing and storage as well as combined heat and power plants.
Results
The ecological and economical advantages of the anaerobic wastewater treatment process are
- The energy requirement for aeration is eliminated. The resulting biogas is burned in combined heat and power units. Electricity and heat contribute to energy self-sufficiency.
- Due to the higher volumetric loading, the required reactor volumes are considerably smaller than those required for aerobic treatment.
- In relation to the COD load degraded, the excess sludge volume is 90 to 95 % lower than with the aerobic process
The anerobic process can also be used by other methylcellulose producers who still use aerobic processes. The anerobic process is also suitable for refinery waste water or other high-saline problem waste water from the chemical industry, such as mother liquors, saline wash water or waste water from product isolation (crystallisation/salting out processes).
