AbstractsEngineering

Foam separation of organic and toxic materials in kraft mill effluents

by James Lewis Blazier




Institution: Oregon State University
Department: Civil Engineering
Degree: MS
Year: 1965
Keywords: Sewage  – Purification
Record ID: 1573322
Full text PDF: http://hdl.handle.net/1957/47788


Abstract

Because of the organic nature and the natural foaming characteristics of kraft mill effluents, it was decided to investigate the feasibility of using foam separation as a method of treatment. The treatment efficiency was evaluated by BOD and COD reductions as well as the decrease in toxicity to marine life. Grab samples of the whole mill effluent obtained from a kraft pulp and paper mill were foamed in a column by sparging air through the sample. The effect of adding nonionic, anionic, and cationic surfactants was evaluated. Samples were foamed at 25° C and 40° C to assess the effect of temperature. It was observed that a stable foam would not always be formed, and that the addition of a surface active agent may sometimes be necessary for foam stability. BOD reductions from 15.8 to 35.2 percent and COD reductions from 7.9 to 20.2 percent were obtained. The addition of surface active agents did not materially increase BOD and COD reduction. The bay mussel (Mytilus edulis Linnaeus) was used as the test organism for the toxicity tests. TLm's of 1.8 to 3.7 percent concentration were observed on the untreated waste. TLm's up to 8.4 percent were obtained after foaming. The toxicity reduction factor (ratio of TLm of waste after foaming to TLm of waste before foaming) was used as the measure of toxicity reduction. Reduction factors up to 2.3 were obtained when foamed without the addition of a surfactant and when foamed with Krystallamide LA, a nonionic surfactant. Lower reduction factors were observed when using ionic surfactants. Increasing the temperature did not affect BOD, COD, or toxicity reduction. However, a larger volume of foam was usually generated at the higher temperature.