[Half-nitrosofication of dewatering liquid of digested sludge with high ammonia].
The affecting factors and controlling methods of how realizing and maintaining half-nitrosofication of dewatering liquid of digested sludge were investigated in an A/O process. The experimental results showed that the nitritation was obtained in 29 d under bulk liquid temperature of 9-20 degrees C, average DO of 5.4 mg/L, SRT of about 30 d and influent ammonia loading rate of 0.64 kg/(m3 x d). The nitritation with 70% nitrite accumulation efficiency was maintained during 65 d when average FA concentration in A/O reactor was more than 4 mg/L. Furthermore, the half-nitrosofication with effluent ammonia and nitrite ratio of 1:1.32 was obtained. When the ammonia loading rate reduced to 0.19 kg/(m3 x d) (FA < 1 mg/L), the nitritation disappeared, and the high FA as a main factor of maintaining half-nitrosofication was proved again with FISH under the condition of different FA. TN removal concentration was about 91 mg/L under influent COD of 282 mg/L and raw C/N ratio of 0.85 in the A/O system, which due to nitritation saving much carbon sources. The study showed that the half-nitrosofication of the dewatering liquid was obtained and stably maintained when FA was more than 4 mg/L in the A/O reactor by dynamic controlling influent ammonia loading rate and pH value in the system under middle or low temperature, high DO, long SRT.
Zhang
Shu-Jun
SJ
Key Laboratory of Beijing for Water Quality Science and Water Environmental Recovery Engineering, Beijing University of Technology, Beijing 100022, China. lxzsj@tom.com
Meng
Fan-Neng
FN
Lü
Jian
J
Gan
Yi-Ping
YP
Wang
Hong-Chen
HC
Peng
Yong-Zhen
YZ
D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical