Question

Environmental Engineering

Water Treatment

Wastewater Treatment

Waste Water Treatment.

A river is used as water resource for a town. During monitoring, high level of NH3 is detected.

A) What are the reasons for this pollution?

B) Is it logical to continue feeding the water treatment system?

C) Can NH3 be removed by regular units in a typical water treatment plant? In summary, how do you solve this problem, explain your reasons.

Answer 1

Ans A) Following are the reasons of Ammonia (NH3) in river :

1) From microbiologiccal decomposition of nitrogenous compound in orgainic matter

2) Fish and some other aquatic organisms excrete ammonia

3) Some industries discharge ammonia in river as their waste

4) Ammonia can also be generated in river by decay of organic waste

Ans B) No, it is not logical to continue feeding the water treatment system because removal of NH3 from water requires process of nitrification but most of the water treatment plant does not designed for this. So, it is required to upgrade the water treatment plant and then continue feeding .

Ans C) No, NH3 cannot be removed by regular units in typical water treatment plant because regular treatment plants are designed for solid removal, sedimentation , reverse osmosis and disinfection only. Removal of ammonia required Nitrification in which ammonia is breaked down into nitrogen with the help of bacterias . The nitrogen generated is then released to atmosphere.

The NH3 can also be removed through activated sludege method but it requires higher capital cost. The conventional activated sludge process which are designed for BOD removal only can also be modified to provide nitrification but required a good amount of investment.