Oxidation ponds

OXIDATION POND

• An oxidation pond is an artificial pond of controlled design, in which sewage can be retained for sufficient time to satisfy BOD
• Change in character of the sewage and waste matter occur due to the action of both aerobic bacteria and algae.
• The aerobic bacteria use oxygen from the atmosphere whereas algae is active in sunlight.
• The combined action of bacteria and algae is called bacterial-algal-symbiosis
• Due to the dual action, the organic matter in sewage is broken down 
• Oxidation ponds are capable of treating both raw and settled sewage
• The function of oxidation pond is to stabilise organic material
• Efficiency of oxidation ponds depends on temperature which affects biological activity rate and intensity of sunlight
• Surface area of oxidation ponds is kept as large as possible while depth does not play an important role
• Oxidation ponds are kept shallow since sunlight and oxygen may reach the sewage.
• In India, a detention period of 10 to 15 days is sufficient