It is not at all clear to me about your question, please, make clear what is your requirement.
Sorry, it was not full question. The right question is here below:
An activated sludge system treating domestic wastewater is operated at a solids retention time of 10 days with a mixed liquor temperature of 18 °C. For many weeks nitrification has occurred, with and effluent NH4-N concentration reported at less than 1.0 mg/L. after some time, the nitrification performance declines with effluent NH4-N concentrations exceeding 10 mg/L. You are requested to investigate the cause of the decline in performance and to make recommendations for actions that will get the discharge quality back to compliance. Describe possible causes for the decline in nitrification efficiency and how you would evaluate the problem.
This sounds like an assignment question given in a class. The answer is readily available in standard textbooks that deal with the topic of biological wastewater treatment.
- I also follow Dr Mohamed Hasnian Isa. It is most probable that initially in the treatment pond, there was sufficient DO (dissolved Oxygen) which accelerated Nitrification in presence of nitrifying bacteria. Along with time, DO content decreased due to continuous biochemical oxidation of organic matter, anoxic condition prevailed in which ammonification started in increased level producing significant amount of Ammonia as observed in the present case. Aeration in the pond could be done to increase the DO level again which can bring down Ammonia content due to aerobic oxidation.
This is a very common practical problem. Often it is from changes in the treated water.
There isn't any question in your current statement. What are you interested in determining?
Gabriel O. Ogbeh, see the clarification of the question by Yemane G. Asfaha 5 days ago in the answer thread.
Explanation by @Henrik Rasmus Andersen is correct. Another reason could be low concentration of heterotrophic substrate in wastewater which can inhibit nitrification. Regards
Vit
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