An investigation into the occurrence of sewage fungus in rivers containing papermill effluents—IV. Growth in experimental channels dosed with effluents and pure compounds

Abstract

This is the fourth and final paper in a series of articles describing research undertaken at PIRA during 1978–1980 on the causes and prevention of sewage fungus growth in rivers receiving paper and board mill effluents. This paper describes simulated stream studies in which sewage fungus growths from mixed mill effluents, component effluent streams and mill raw materials were quantified at two paper-mill sites. At the first mill, sewage fungus growth from treated effluent was only light and somewhat less than might have been expected from the measured level of glucose. Cationic starch was a better nutrient than unmodified starch and possible reasons for this are put forward. Individual waste streams at the second mill supported heavy growths of sewage fungus comparable to that from the mixed mill effluent after clarification. As sole sources of organic carbon, fresh or degraded gelatin and melamine formaldehyde resin gave very little sewage fungus growth, but glycerol supported some growth. As the effluent from this mill was considerably more complex than others previously examined, it was concluded that sewage fungus nutrients were provided by degraded organics (largely unidentified) extracted from rags and broke.