1. College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China;
2. Yangzhou Jieyuan Drainage Company Limited, Yangzhou 225002, China;
3. National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China
A two-sludge system combined anaerobic/anoxic/oxic with moving bed biofilm reactor (A2/O-MBBR) was used to treat real domestic wastewater. By adding sodium acetate to adjust influent carbon/nitrogen ratio (C/N), the transformation and utilization and metabolic pathways of organic matter in the system were investigated. When the influent C/N ratio varied from 3.11 to 6.09, the system all achieved efficient COD removal with the maximum removal of 83.85%. However, from the perspective of VFA and PHAs transformation, the influent C/N ratio should not exceed 5.42. Additionally, the material balance analysis of carbon also revealed that when the influent C/N ratio was below 5.42, COD removal percentage in the A2/O reactor was up to 70.10% and that in the MBBR reactor only accounted for 4.32%~5.89%, where the efficient utilization of carbon source was the key to improve microbial community optimization and enhance denitrification and phosphorus removals under the condition of low C/N ratio. The results of dissolved carbon source component distribution and three-dimensional fluorescence properties manifested that proteins and polysaccharides transformed although COD changed gently along the reactor, in which proteins-like substance was the dominant.
Zhang M, Wang C, Peng Y, et al. Organic substrate transformation and sludge characteristics in the integrated anaerobic anoxic oxic-biological contact oxidation (A2/O-BCO) system treating wastewater with low carbon/nitrogen ratio[J]. Chemical Engineering Journal, 2016,283:47-57.
[2]
Wang Z W, Wu Z C. Distribution and transformation of molecular weight of organic matters in membrane bioreactor and conventional activated sludge process[J]. Chemical Engineering Journal, 2009,150(2):396-402.
[3]
Ilani T, Schulz E, Chefetz B. Interactions of organic compounds with wastewater dissolved organic matter:role of hydrophobic fractions[J]. Journal of Environmental Quality, 2005,34(2):552-562.
[4]
Guo J, Peng Y, Guo J, et al. Dissolved organic matter in biologically treated sewage effluent (BTSE):Characteristics and comparison[J]. Desalination, 2011,278(1-3):365-372.
[5]
Wang X, Wang S, Xue T, et al. Treating low carbon/nitrogen (C/N) wastewater in simultaneous nitrification-endogenous denitrification and phosphorous removal (SNDPR) systems by strengthening anaerobic intracellular carbon storage[J]. Water Research, 2015, 77:191-200.
[6]
Cao G, Wang S, Peng Y, et al. Biological nutrient removal by applying modified four step-feed technology to treat weak wastewater[J]. Bioresource Technology, 2013,128(1):604-611.
Wang Y, Peng Y, Stephenson T. Effect of influent nutrient ratios and hydraulic retention time (HRT) on simultaneous phosphorus and nitrogen removal in a two-sludge sequencing batch reactor process[J]. Bioresource Technology, 2009,100(14):3506-3512.
Zhang M, Peng Y, Wang C, et al. Optimization denitrifying phosphorus removal at different hydraulic retention times in a novel anaerobic anoxic oxic-biological contact oxidation process[J]. Biochemical Engineering Journal, 2016,106:26-36.
Zhang M, Qing Y, Jianhua Z, et al. Enhancement of denitrifying phosphorus removal and microbial community of long-term operation in an anaerobic anoxic oxic-biological contact oxidation system[J]. Journal of Bioscience & Bioengineering, 2016,122(4):456-466.
[14]
Franson M A H. American public health association American water works association water environment federation[M]. Methods, 1995.
[15]
Oehmen A, Keller-Lehmann B, Zeng RJ, et al. Optimisation of poly-β-hydroxyalkanoate analysis using gas chromatography for enhanced biological phosphorus removal systems[J]. Journal of Chromatography A, 2005,1070(1/2):131-136.
[16]
Lowry O H, Rosebrough N J, Farr A L, et al. Protein measurement with the Folin phenol reagent[J]. Journal of Biological Chemistry, 1951,193(1):265-275.
Chuang S H, Ouyang C F. The biomass fractions of heterotrophs and phosphate-accumulating organisms in a nitrogen and phosphorus removal system[J]. Water Research, 2000,34(8):2283-2290.
Wang X, Peng Y, Wang S, et al. Influence of wastewater composition on nitrogen and phosphorus removal and process control in A2O process[J]. Bioprocess & Biosystems Engineering, 2006,28(6):397-404.
[21]
Chen Y, Peng C, Wang J, et al. Effect of nitrate recycling ratio on simultaneous biological nutrient removal in a novel anaerobic/anoxic/oxic (A2/O)-biological aerated filter (BAF) system[J]. Bioresource Technology, 2011,102(10):5722-5727.
[22]
Wachtmeister A, Kuba T, Loosdrecht M C M V, et al. A sludge characterization assay for aerobic and denitrifying phosphorus removing sludge[J]. Water Research, 1997,31(3):471-478.
[23]
Wei Y, Wang S, Ma B, et al. The effect of poly-β-hydroxyalkanoates degradation rate on nitrous oxide production in a denitrifying phosphorus removal system[J]. Bioresource Technology, 2014,170(3):175-182.
[24]
Chen Y, Li B, Ye L, et al. The combined effects of COD/N ratio and nitrate recycling ratio on nitrogen and phosphorus removal in anaerobic/anoxic/aerobic (A2/O)-biological aerated filter (BAF) systems[J]. Biochemical Engineering Journal, 2015,93(10):235-242.
Peng Y, Ge S. Enhanced nutrient removal in three types of step feeding process from municipal wastewater[J]. Bioresource Technology, 2011,102(11):6405-6413.
[27]
Chen Y, Peng C, Wang J, et al. Effect of nitrate recycling ratio on simultaneous biological nutrient removal in a novel anaerobic/anoxic/oxic (A2/O)-biological aerated filter (BAF) system[J]. Bioresource Technology, 2011,102(10):5722-5727.
[28]
Guo J, Sheng F, Guo J, et al. Characterization of the dissolved organic matter in sewage effluent of sequence batch reactor:the impact of carbon source[J]. Frontiers of Environmental Science & Engineering in China, 2011,6(2):1-8.
Sheng G P, Yu H Q. Characterization of extracellular polymeric substances of aerobic and anaerobic sludge using three-dimensional excitation and emission matrix fluorescence spectroscopy[J]. Water Research, 2006,40(6):1233-1239.
[31]
Leenheer J A, Jean-Philippe C. Characterizing aquatic dissolved organic matter[J]. Environmental Science & Technology, 2003, 37(1):18-26.
