Effect of Sludge Retention Time on Nitrifiers' Biomass and Kinetics in an Anaerobic/Oxic Process |
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| Authors: | Tzu‐Yi Pai Terng‐Jou Wan Yung‐Pin Tsai Chwen‐Jeng Tzeng Hsiao‐Hsing Chu Yao‐Sheng Tsai Ching‐Yuan Lin |
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| Affiliation: | 1. Department of Environmental and Safety Engineering, National Yunlin University of Science and Technology, Yunlin, Taiwan.;2. Department of Civil Engineering, National Chi Nan University, Nantou, Taiwan.;3. Water and Environmental Engineering Department, CECI Engineering Consultants, Inc., Taipei, Taiwan.;4. Department of Environmental Engineering and Management, Chaoyang University of Technology, Taichung, Taiwan. |
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| Abstract: | In this study, the effect of sludge retention time on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in an anaerobic/oxic (AO) process, was explored. The results indicated that the growth rate constants of AOB were 0.97, 0.88, and 0.79 d–1, respectively, meanwhile, those of NOB were 1.22, 1.03, and 0.93 d–1, respectively, when the sludge retention time (SRT) was 15 days, 10 days and 5 days. The relation between the growth rate constant and the SRT could be best described using a simple exponential curve and a second type hyperbolic curve. The lysis rate constants for AOB and NOB were 0.13 and 0.18 d–1, respectively. The yield coefficients values of AOB and NOB were 0.22 and 0.21, respectively. The percentage of AOB to mixed liquid suspended solids (MLSS) was 0.64%, 0.53%, and 0.35%, respectively. Meanwhile, the percentage of NOB was 2.24%, 1.87%, and 1.11%, respectively, at SRT values of 15 days, 10 days and 5 days. When the SRT value decreased, the AOB and NOB biomass levels decreased by 12.75 and 47.01 mg L–1, respectively. Meanwhile the removal efficiency of NH4+‐N decreased from 90 to 26%, while the removal efficiency of total nitrogen (TN) decreased from 14 to 8%. |
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| Keywords: | Bacteria Biomass Nitrifying Species Sludge retention time Total nitrogen |
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