Initial stages of processing the sewage physically remove larger objects and materials that can be sedimented or will form flotsam. The sewage passes slowly along 'v'-shaped channels so that the heavier particles can settle and be removed. The remaining sewage contains dissolved organic matter, fine particles - including bacteria, and flotsam continue to the next stage in the process. This image was provided by D. J. Patterson. Copyright: D. J. Patterson, image used under license.
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4. Settlement channels
From the collection
Activated sludge - sewage treatment