What will effect to environment if BOD is high of water?

Question

What will effect to environment if BOD is high of water?

Answer 1

Microorganisms such as bacteria are responsible for decomposing organic waste.  When organic matter such as dead plants, leaves, grass clippings, manure, sewage, or even food waste is present in a water supply, the bacteria will begin the process of breaking down this waste.  When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live.  Biological Oxygen Demand (BOD) is a measure of the oxygen used by microorganisms to decompose this waste.  If there is a large quantity of organic waste in the water supply, there will also be a lot of bacteria present working to decompose this waste.  In this case, the demand for oxygen will be high (due to all the bacteria) so the BOD level will be high.  As the waste is consumed or dispersed through the water, BOD levels will begin to decline.  

****When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria.  Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive.

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