Chapter 1 - Theories and practices

Abstract

The first step in minimizing the effects of industrial wastes on receiving streams and treatment plants is to reduce the volume of such wastes. This may be accomplished by classifying wastes, conserving wastewater, changing production to decrease wastes, reusing both industrial and municipal effluents as raw water supplies, and eliminating batch or slug discharges of process wastes. The three main classes of wastes are as follows: wastes from manufacturing processes, waters used as cooling agents in industrial processes, and wastes from sanitary uses. Conservation begins when an industry changes from an “open” to a “closed” system. Concentrated recycled wastewaters are often treated at the end of their period of usefulness, because usually it is impractical and uneconomical to treat the wastewaters as they complete each cycle. Changing production to decrease wastes is an effective method of controlling the volume of wastes, but is difficult to put into practice. It is hard to persuade plant managers to change their operations just to eliminate wastes, whose primary objective is cost savings. Reusing industrial and municipal effluents for raw water supplies is proving a popular and economical method of conservation.