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Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal

ZENG Wei, PENG Yongzhen, WANG Shuying

《环境科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 28-32 doi: 10.1007/s11783-007-0005-5

摘要: In order to improve the nitrogen removal efficiency and save operational cost, the feasibility of the alternating aerobic-anoxic process (AAA process) applied in a sequencing batch reactor (SBR) system for nitrogen removal was investigated. Under sufficient influent alkalinity, the AAA process did not have an advantage over one aerobicanoxic (OAA) cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition, which would prolong the total cycling time. On the contrary, the AAA process made the system control more complicated. Under deficient influent alkalinity, when compared to OAA, the AAA process improved treatment efficiency and effluent quality with NH-N in the effluent below the detection limit. In the nitrification, the average stoichiometric ratio between alkalinity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO/mg NH-N. In the denitrification, the average stoichiometric ratio between alkalinity production and NO-N reduction is about 3.57 mg CaCO/mg NO-N. As a result, half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period. That was why the higher treatment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity. If the lack of alkalinity in the influent was less than 1/3 of that needed, there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity. Even if the lack of alkalinity in the influent was more than 1/3 of that needed, the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost.

关键词: bicarbonate alkalinity     sufficient influent     influent alkalinity     detection     alkalinity production    

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

《环境科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 241-246 doi: 10.1007/s11783-008-0040-x

摘要: The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape.

关键词: homogeneous     spherical     influent alkalinity     process     anaerobic treatment    

Comparative experiment on treating digested piggery wastewater with a biofilm MBR and conventional MBR: simultaneous removal of nitrogen and antibiotics

Xiaoyan Song,Rui Liu,Lujun Chen,Tomoki Kawagishi

《环境科学与工程前沿(英文)》 2017年 第11卷 第2期 doi: 10.1007/s11783-017-0919-5

摘要: The BF-MBR displayed higher removal rates of nitrogen, phosphorous and antibiotics. The BF-MBR saved alkali consumption. The removal of antibiotics was influenced significantly by HRT. Membrane filtration greatly contributed to antibiotics removal. A biofilm membrane bioreactor (BF-MBR) and a conventional membrane bioreactor (MBR) were parallelly operated for treating digested piggery wastewater. The removal performance of COD, TN, NH -N, TP as well as antibiotics were simultaneously studied when the hydraulic retention time (HRT) was gradually shortened from 9 d to 1 d and when the ratio of influent COD to TN was changed. The results showed that the effluent quality in both reactors was poor and unstable at an influent COD/TN ratio of 1.0±0.2. The effluent quality was significantly improved as the influent COD/TN ratio was increased to 2.3±0.5. The averaged removal rates of COD, NH -N, TN and TP were 92.1%, 97.1%, 35.6% and 54.2%, respectively, in the BF-MBR, significantly higher than the corresponding values of 91.7%, 90.9%, 17.4% and 31.9% in the MBR. Analysis of 11 typical veterinary antibiotics (from the tetracycline, sulfonamide, quinolone, and macrolide families) revealed that the BF-MBR removed more antibiotics than the MBR. Although the antibiotics removal decreased with a shortened HRT, high antibiotics removals of 86.8%, 80.2% and 45.3% were observed in the BF-MBR at HRT of 5–4 d, 3–2 d and 1 d, respectively, while the corresponding values were only 83.8%, 57.0% and 25.5% in the MBR. Moreover, the BF-MBR showed a 15% higher retention rate of antibiotics and consumed 40% less alkalinity than the MBR. Results above suggest that the BF-MBR was more suitable for digested piggery wastewater treatment.

关键词: Alkalinity     Antibiotics     Biofilm     Digested piggery wastewater (DPW)     Membrane bioreactor    

标题 作者 时间 类型 操作

Process evaluation of an alternating aerobic-anoxic process applied in a sequencing batch reactor for nitrogen removal

ZENG Wei, PENG Yongzhen, WANG Shuying

期刊论文

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

期刊论文

Comparative experiment on treating digested piggery wastewater with a biofilm MBR and conventional MBR: simultaneous removal of nitrogen and antibiotics

Xiaoyan Song,Rui Liu,Lujun Chen,Tomoki Kawagishi

期刊论文