Water purification, effluent treatment and recycling of industrial process streams

The provision of water suitable for drinking is another essential to life. The quality of naturally available water varies greatly from site to site and in many places it may be necessary to remove bacteria, salts, heavy-metal ions and organics desalmation and chlorination are the most cotnmon processes. Moreover, it is again advantageous to monitor the water quality continuously or, at least, routinely. 

Effluent and water treatment, therefore, are essential technologies which are likely to expand and develop considerably in the future. While such processes have a variety of objectives, a common feature is the need to handle a highly variable feed. Typical are the locaUauthority sewage works to be found in every town. Each person produces 2(X)dm day of sewage which, although 

Comminution, sediment ation, sludge digestion or tneineration 

Percolation through activated sludge filters, biological oxidation, nitrilication 

Flotation, coagulation by additives, precipitation (e.g. phosphate, fluoride, heavy metals), flltration 

Stage BOD range/mg cm Mechanical or biological processes Physical or chemical processes 

Primary 400-250 Comminution, sedimentation, sludge digestion or incineration Flocculation by chemical additives, flotation 

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D. Pletcher and F. C. Walsh, Water Purification, Effluent Treatment and Recycling of Industrial Process Streams, Ch.7, Industrial Electrochemistry, Chapman and Hall, London, 1990. 

Water purification, effluent treatment and recycling of industrial process streams... 

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