Answers

2016-04-28T18:36:08+08:00
The oxygen demand in the pond becomes higher when the algae grows on it. It consumed all the oxygen that affects the aquatic life system. It is commonly called the Algal bloom.
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2016-04-28T21:32:57+08:00
In wastewater only small amount of oxygen can be dissolved in it so if there are organisms in wastewater the oxygen demand will be high because it is needed by these  organisms
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