Pollution of Streams By Pulp-Mill Wastes

The manufacture of wood pulp is a hydro-chemical process; consequently, pulp mills are always located on streams or canals. Large volumes of water are required and the waste waters which contain the spent chemicals and the washings of the pulp, pollute the streams. Whether this pollution does damage down stream depends on many factors, namely, the r elative volumes of waste and of stream flow and the variations in flow; the quality of the river water and the character of the waste.3; the opportunity for mixing, the velocity of the current, the existence of riffles, slack water, aqueous vegetation, re-aeration, sedimentation, and the many factors which bring about the natural purification of streams; and, finally, the use which is made of the river water down stream. These factors are common to all forms of stream pollution resulting from hydro-chemical processes, but there are no two places where the conditions are exactly alike. Every polluted stream has its own set of conditions therefore, generalizations are hazardous. The speaker will only call attention to certain facts regarding pulp-mill wastes and discuss briefly the larger problem of stream pollution by industrial wastes.