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Fig. 7.4 : Schematic diagram of a two-stage anaerobic digester (After Gilbert, 1955)
Oxidation Ponds :
Oxidation Ponds are simple ponds having 1m - 2m deep where partially treated
or raw water are exposed to aerobic conditions for reaction with
micro organisms. However, in case of deeper ponds, anaerobic condition may
prevail where the organic wastes reacts with anaerobic bacteria and releases
CO
2
, methane etc. as shown in Figure. Oxidation Ponds requires large areas
depending upon the volume of raw water and may be used in areas where
adequate land is available.
Fig. 7.5 : Schematic diagram of an oxidation pond (After Gilbert, 1955)
