Pilot Plant Evaluation of Alternative Activated Sludge Systems.

摘要

Step feed,plug flow and complete mix activated sludge systems were compared on a pilot plant scale under similar operating conditions with the same municipal wastewater. The process loading to each system was varied over a wide range during the course of the investigation. Extended periods of steady state operation at constant flow provided extensive data on effluent quality,sludge yield,settling characteristics,etc. at several fixed F/M loadings for each of the system configurations. All systems demonstrated that the variability in carbonaceous effluent quality was mostly influenced by the suspended solids concentrations in the effluent over a wide range of process loadings. Sludge production was the same within experimental error in all systems at comparable SRT's. Analysis of the aggregate data from all systems produced a yield coefficient of 0.79 g VSS/g BOD5applied and a decay coefficient of 0.064/day. The sludge from the complete mix system exhibited the poorest settling characteristics. A step feed system was found to offer the best physical arrangement for secondary treatment of District of Columbia wastewater.