Man has always generated wastes, materials which were either by-products of his activities, for which he could not find any use, or products which have reached the end of their useful life. While this has been going on throughout the ages, no problem was caused until recent times because of nature’s own waste treatment processes: dispersion, dilution, and degradation. The smoke of the caveman’s fire (even the smoke of last century’s industry) was simply dispersed into the air, swept away by the winds, and, because of its relatively small amount compared to the volume of the atmosphere, it had no noticeable effect on the environment. Wastes dumped into the rivers were washed away quickly and diluted to the point where no effect on water purity could have been observed, had anyone been able to measure it. Wastes left on land decayed by spontaneous chemical process: the balance of nature was preserved.
KeywordsSewage Treatment Waste Treatment Electrostatic Precipitator Treatment Tank Aeration Time
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