Study on nitrogen removal performance in conventional mode of CAST process
- Received Date: 01/03/2010
- Accepted Date: 12/10/2009
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Key words:
- biological nitrogen removal /
- cyclic activated sludge technology(CAST) /
- nitrification /
- denitrification /
- municipal sewage
Abstract: The removal performance of organic matter and nitrogen pollutants in conventional mode of CAST reactor with effective volume of 21.6 L feeded with simulation wastewater was studied.The limiting factors of nitrogen removal in the process were analyzed.When the reactor operated 4 h in one period,DO>2 mg/L,MLSS was about 4 000 mg/L,the result showed that COD and ammonia removal could get 90％.It can be found that ammonia nitrogen was removed completely in aerobic zone and nitrate accumulation occurred in a typical cycle.Total nitrogen removal rate was about 69%.Static test showed that the ammonia oxidation rate was 8.0 mg NH+4-N/（g MLSS·h） and the nitrate generation rate was 3.33 mg NO-3-N/（g MLSS·h） in the CAST reactor.Under the above process operating conditions， CAST nitrogen limiting factors were the sludge recycle ratio and SRT.
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