This project was directed to evaluating means for increasing BOD removal from primary treatment systems treating pulp and paper wastes. An improved understanding of the optimal conditions for soluble and colloidal BOD removal should permit increasing efficiency in total organic removal. The initial phase surveyed 12 mills to obtain data on total and soluble BOD5, COD, suspended solids and color removal from sedimentation systems. This data was used to select mill effluents for additional study. These laboratory studies showed that, with proper flocculating agents, soluble BOD removal could be markedly increased. Soluble BOD was defined as that organic load passing through a 0.45 micrometer filter. Gel chromatography studies showed that low molecular weight biodegradable residues and colloidal materials were flocculated and removed. Studies with model compounds indicated that increased removal is apparently related to pH of the solution and to functional groups, chain length, branching and solubility of the compound. Chemical costs may range from 3 cents to 10 cents per 1000 gallons. Cost reduction and improved clarifier performance can be achieved by elimination of overflows and spills within the mill that are antagonistic to efficient sedimentation due to dispersant action.

"September 1976." "Grant No. R-803119." Includes bibliographical references (pages 98-99).