The Biological Treatment of Coke-Oven Effluents: Further Studies on the Role of Organic Inhibitors

摘要

A small-scale activated sludge plant (2.65 liters) was set up with intermittent sludge return and the pH maintained at 7.0 by automatic addition of NaOH. An activated sludge from a works treating a sewage containing a small proportion of gas-purification waste was used and fed continuously with an influent containing 1000 ppm of thiocyanate. The organisms which developed were extremely active. Loadings were about 2.5 times greater than those previously obtained from systems treating coke-oven wastes in the presence of glucose, with no thiocyanate present in the effluent. This high activity was transferred to the treatment of coke-oven liquor (90 per cent) and water (10 per cent). At a retention of 10.8h thiocyanate removal was complete, with a 4h permanganate value loading of 5.04 kg/cu.m./day. The previous highest obtained was 3.0 kg/cu.m./day. On increasing the influent to undiluted liquor a marked deterioration in performance was obtained which after dilution and an increased retention time could not be reversed.