外加碳源对AOA-SBR工艺脱氮除磷效果的影响

采用厌氧/好氧/缺氧模式运行的SBR工艺处理模拟城市污水,考察外加碳源乙酸钠和污泥水解酸化上清液对其脱氮除磷效果的影响。模拟城市污水,进水水质COD为400 mg/L、氨氮为60 mg/L、磷酸盐为7 mg/L。结果表明:不投加碳源时,系统对COD、氨氮、磷酸盐的去除率分别为90%、91%、82%;乙酸钠投加量为60 mg/L的条件下,外加乙酸钠系统对COD、氨氮、磷酸盐的去除率分别为93%、100%、100%,磷的去除主要是通过好氧聚磷作用;上清液投加量折合进水COD为30 mg/L时,外加污泥水解酸化上清液系统对COD、氨氮、磷酸盐的去除率分别为97%、99%、95%,系统中出现明显的反硝化除磷现象,反硝化除磷占24%。     

并联式A~2O/MBR反硝化聚磷工艺试验研究

基于反硝化聚磷理论,结合MBR工艺的优点,在传统A2O工艺的基础上提出新型并联式同步脱氮除磷工艺。工艺解决了传统工艺中的碳源不足、硝酸盐氮供需矛盾等问题;通过省去沉淀池,节约了占地面积。针对常规城市污水,研究了不同工艺条件对处理效果的影响。结果表明,当污泥体积回流比为50%,内体积回流比为100%时具有较好的去除效果,COD、NH4+-N、TP和TN去除率分别达到了90%、99%、94.4%和67%。     

双污泥-诱导结晶工艺除磷脱氮试验研究

针对传统污水处理脱氮除磷工艺碳源不足、聚磷菌与硝化菌泥龄矛盾、磷资源无法有效回收利用等问题,开发出"双污泥-诱导结晶"新型工艺,对其去除有机物和脱氮除磷性能进行了考察和分析。结果表明:当进水COD为152～237mg.L-1,TP为3.92～7.68mg.L-1,TN为31.3～50.5mg.L-1,C/N比约为3.91～5.21时,COD、TN和TP平均去除率分别为93.2%、71.2%和95.7%。厌氧段COD去除量约占系统COD去除总量的85.9%。TN的去除主要由缺氧池承担,厌氧池、硝化池、缺氧池、后置曝气池TN去除量约占系统TN去除总量的31.7%、11.4%、54.9%和2.0%。结晶在除磷过程中起着主要作用,结晶除磷量平均约占总除磷量的81.5%。双污泥工艺在系统中的主要作用为辅助化学除磷和脱氮。侧流比是保证系统稳定运行的关键参数。后置曝气池对超越污泥中COD和氨氮的去除有重要作用。     

A2O工艺缺氧生物磷去除

A lab-scale anaerobic-anoxic-oxic (A2O) process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria (DPB), evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen (92.3%, 95.5%, 96% and 79.5%, respectively) could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.     

A2O工艺缺氧生物磷去除

A lab-scale anaerobic-anoxic-oxic （A^2O） process used to treat a synthetic brewage wastewater was investigated. The objectives of the study were to identify the existence of denitrifying phosphorus removing bacteria （DPB）, evaluate the contribution of DPB to biological nutrient removal and enhance the denitrifying phosphorus removal in A^2O bioreactors. Sludge analysis confirmed that the average anoxic P uptake accounted for approximately 70% the total amount of P uptake, and the ratio of anoxic P uptake rate to aerobic P uptake rate was 69%. In addition, nitrate concentration in the anoxic phase and different organic substrate introduced into the anaerobic phase had significant effect on the anoxic P uptake. Compared with conventional A^2O processes, good removal efficiencies of COD, phosphorus, ammonia and total nitrogen （92.3%, 95.5%, 96% and 79.5%, respectively） could be achieved in the anoxic P uptake system, and aeration energy consumption was saved 25%. By controlling the nitrate recirculation flow in the anoxic zone, anoxic P uptake could be enhanced, which solved the competition for organic substrates among poly-P organisms and denitrifiers successfully under the COD limiting conditions. Therefore, in wastewater treatment plants the control system should be applied according to the practical situation to optimize the operation.     

Statistical analysis and optimization of simultaneous biological nutrients removal process in an intermittently aerated SBR

Simultaneous removal of carbon and nutrients from a synthetic wastewater in aerobic/anoxic sequence batch reactor (SBR) was investigated. The experiments were conducted based on a central composite design (CCD) and analyzed using response surface methodology (RSM). Two significant independent variables, cycle time and aeration time, were studied to analyze the process. Five dependent parameters—total COD (TCOD) removal, total nitrogen removal, total phosphorus removal, total Kjeldahl nitrogen removal and effluent nitrate concentration—were monitored as the process responses. The region of exploration for the process was taken as the area enclosed by cycle times (2, 4.25 and 6.5 h) and aeration times (30, 40 and 50 min/h) boundaries. The maximum COD (87.18%) and TKN (78.94%) removal efficiencies were obtained at the cycle time and aeration time of 6.5 h and 50 min/h, respectively. While the maximum TN (71.15%) and phosphorus (68.91%) removal efficiencies were obtained at cycle time of 6.5 h and aeration time of 40min/h. As a result, high cycle time (6.5 h) and moderate aeration time (40min/h) were found to be the optimal region for maximum carbon and nitrogen removal efficiencies.     

Simultaneous removal of nitrogen and phosphorus from swine wastewater in a sequencing batch biofilm reactor

In this study, the performance of a sequencing batch biofilm reactor (SBBR) for removal of nitrogen and phosphorus from swine wastewater was evaluated. The replacement rate of wastewater was set at 12.5%throughout the exper-iment. The anaerobic and aerobic times were 3 h and 7 h, respectively, and the dissolved oxygen concentration of the aerobic phase was about 3.95 mg·L?1. The SBBR process demonstrated good performance in treating swine wastewater. The percentage removal of total chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) was 98.2%, 95.7%, 95.6%, and 96.2%at effluent concentrations of COD 85.6 mg·L?1, NH4+-N 35.22 mg·L?1, TN 44.64 mg·L?1, and TP 1.13 mg·L?1, respectively. Simultaneous nitrification and denitrification phenomenon was observed. Further improvement in removal efficiency of NH4+-N and TN occurred at COD/TN ratio of 11:1, with effluent concentrations at NH4+-N 18.5 mg·L?1 and TN 34 mg·L?1, while no such improvement in COD and TP removal was found. Microbial electron microscopy analysis showed that the fil er surface was covered with a thick biofilm, forming an anaerobic–aerobic microenvironment and facilitating the removal of nitrogen, phosphorus and organic matters. A long-term experiment (15 weeks) showed that stable removal efficiency for N and P could be achieved in the SBBR system.     

Modelling a sequencing batch reactor to treat the supernatant from anaerobic digestion of the organic fraction of municipal solid waste

In this study, a lab‐scale sequencing batch reactor (SBR) has been tested to remove chemical oxygen demand (COD) and NH₄⁺‐N from the supernatant of anaerobic digestion of the organic fraction of municipal solid waste. This supernatant was characterized by a high ammonium concentration (1.1 g NH₄⁺‐N L^?1) and an important content of slowly biodegradable and/or recalcitrant COD (4.8 g total COD L^?1). Optimum SBR operating sequence was reached when working with 3 cycles per day, 30 °C, SRT 12 days and HRT 3 days. During the time sequence, two aerobic/anoxic steps were performed to avoid alkalinity restrictions. Oxygen supply and working pH range were controlled to promote the nitrification over nitrite. Under steady state conditions, COD and nitrogen removal efficiencies of more than 65% and 98%, respectively, were achieved. A closed intermittent‐flow respirometer was used to characterize and model the SBR performance. The activated sludge model ASM1 was modified to describe the biological nitrogen removal over nitrite, including the inhibition of nitrification by unionized ammonia and nitrous acid concentrations, the pH dependency of both autotrophic and heterotrophic biomass, pH calculation and the oxygen supply and stripping of CO₂ and NH₃. Once calibrated by respirometry, the proposed model showed very good agreement between experimental and simulated data. Copyright © 2007 Society of Chemical Industry     

头孢类制药废水中有机污染物的去除特性

为全面研究头孢类制药废水处理过程中有机污染物的去除特性,分析了废水中常规污染物（COD、TOC、氨氮、总氮、总磷）和残留抗生素的去除效率,并采用液液萃取/气相色谱-质谱联用（GC-MS）的方法对有机物进行定性分析。研究结果表明,废水中残留的头孢唑林去除率为99.1%,而COD、TOC、氨氮、总氮和总磷的去除率为50.0%~97.4%,出水均满足《化学合成类制药工业水污染物排放标准》（GB 21904—2008）直接排放要求。GC-MS定性分析得到52种有机污染物,其中酸酯类、胺类、杂环类物质较多,三氯甲烷、苯酚属于水中优先控制污染物;三乙胺、四氢呋喃、N,N-二甲基三甲基乙酰胺、丁酸、2-巯基咪唑、2-巯基-5-甲基-1,3,4-噻二唑等属于头孢类抗生素生产过程中的原料和中间体。以上物质均具有潜在的环境毒性,需要针对这些物质优化处理工艺,并关注其残留浓度和迁移转化过程。     

Development of a correlation to study parameters affecting nitrification in a domestic wastewater treatment plant

BACKGROUND: Nitrification performance of an activated sludge reactor treating weak domestic wastewater was investigated for 11 months. Ammonia nitrogen removals were investigated as a function of wastewater composition and operational conditions. Backward elimination experimental design was used to determine the influence of the most important independent variables on NH₃‐N removal efficiencies. Influent ammonia and biological oxygen demand (BOD₅) concentrations, hydraulic retention time (HRT), mixed liquid suspended solids (MLSS), temperature, pH and dissolved oxygen (DO) concentration were considered as independent variables. This study aimed to find the most important parameters to describe nitrification performance. RESULTS: The presence of nitrification was confirmed by ammonia and nitrate variations throughout the reactor; ammonia oxidizing bacteria (AOB) populations were determined using a fluorescence in situ hybridization (FISH) method. MLSS concentration, influent BOD₅ concentration and temperature were found to be the most influential factors on nitrification performance. The empirical correlation using multiple linear regressions was statistically significant and produced an adjusted coefficient of multiple determinations (R²_adj) of 92.5%. CONCLUSION: Correlation provides a good understanding of the various parameters that affect the nitrification process, and could be extended to other case studies. Using these results, operators can apply proper operational strategies to maintain nitrification in wastewater treatment plants. Copyright © 2007 Society of Chemical Industry     

Performance evaluation of a modified anaerobic/anoxic/oxic (A/O) process treating low strength wastewater

A full scale modified A²/O process which combined pre-anoxic selector and the staging strategy treating low strength wastewater was investigated. In South China, domestic wastewater is always low in strength due to the high level of groundwater and setting of septic tank at the beginning of wastewater collection system. The results suggested that inadequate denitrification could result in deterioration of phosphorus removal. In addition, influent phosphorus concentration had effect on phosphorus removal. The pre-anoxic selector in modified A²/O process changed the distribution of nitrogen denitrified in different tanks. Characteristics of 3-stage aeration tanks were also studied. The simplified design of rectangular aeration tank could also perform as plug flow as conventional channel aeration tank. In 3-stage aeration tanks, mixed liquid suspended solid (MLSS) increased from one tank to another, while specific oxygen uptake rate (SOUR) of sludge, chemical oxygen demand (COD) and total phosphorus (TP) removal rate decreased, however ammonia nitrogen (NH₃-N) and nitrate nitrogen (NO₃-N) reaction rate remained constant. Furthermore, high MLSS concentration was not suitable for treating low strength wastewater. Waste sludge discharge could improve removal efficiency of COD, NH₃-N, and TP. Without waste sludge discharge, nitrite accumulated in settler.     

人工湿地基质材料处理含磷废水静态吸附实验研究

利用烧杯实验考察钢渣、沸石、炉渣、硅藻土对磷的吸附性能及其影响因素,同时研究对氨氮,CODCr吸附情况。结果表明:基质对磷的吸附性能由强到弱依次为钢渣,硅藻土,炉渣,沸石。钢渣180 min内升至30%左右;NH4+-N的吸附性能由强到弱的顺序为:沸石,钢渣,硅藻土,炉渣。沸石180 min内升至80%左右,钢渣次之,达到了40%;CODCr吸附性能强弱顺序:硅藻土,沸石,钢渣,炉渣。硅藻土180 min内可达到50%。钢渣,硅藻土除磷的最佳pH值范围为10～12,另2种基质的最佳pH值范围为6～8;原水磷浓度低于3 mg/L或高于5 mg/L时4种基质磷去除率下降。     

Simultanous removal of high concentration nitrogen and phosphorus from abattoir wastewater by using a sequencing batch reactor

研究了采用序列间歇式活性污泥法（SBR工艺）同步去除屠宰废水中高浓度氮、磷和COD。结果表明,SBR工艺采用分步进水,避免了硝化阶段NO₃-N和NO₂-N的积累,能够提供生物除磷所需的厌氧环境。在温度为35 ℃、污泥龄为14天的条件下,采用两种成分废水作为原水（预发酵废水和屠宰废水混合）,经过3个月的启动,当原水中TP、TN和COD浓度分别为36.5 mg/L、226 mg/L和2615 mg/L时,TP、TN和COD的去除率分别高于96%、95%和95.5%,出水中TP、TN和COD浓度分别低于1.4 mg/L、10.8 mg/L和95 mg/L。     

Treatment of domestic wastewater by subsurface flow constructed wetlands in Jordan

The use of subsurface flow constructed wetlands for treating domestic wastewater in Jordan is described. The objective was to study the performance of subsurface flow constructed wetlands as a low-cost technology for treating domestic wastewater. Results show that subsurface flow constructed wetlands are capable of reducing biochemical oxygen demand (BOD), different forms of nitrogen, total suspended solids (TSS), fecal coliform count (FCC), and total coliform count (TCC). However, removal efficiencies differ from bed to bed and from month to month. Results show that there is strong correlation between BOD₅ removal efficiency and BOD₅ loading in kg/ha, which is defined as BOD₅ loading rate in kg/ha.d multiplied by residence time. The coefficient of determination (R²) for the six beds varied from 0.827 for bed number one to 0.608 for bed number four. Total nitrogen, ammonia nitrogen, and nitrate nitrogen reductions were observed, which suggestthat, nitrification as well as denitrificationtookplace in the beds. TSS reduction was observed in all beds. However, removal efficiency differed from bed to bed and for the same bed from month to month. Total and fecal coliform counts were reduced by one to three logs, because influent was high in total and fecal coliform counts were still high.     

混合型城市污水强化脱氮除磷工艺试验研究

采用膜膜强化集成工艺,对混合型城市污水进行脱氮除磷效果试验研究。试验结果表明,COD、NH3-N、TN及TP去除率分别达到80%、96%、60%及88%,系统平均出水COD为25 mg/L,NH3-N、TN及TP的质量浓度分别为0.9、13、0.44 mg/L。系统运行稳定,各项指标均可达到国家一级A标准(GB 18918-2002)。     

反硝化除磷机理与工艺研究进展

介绍了反硝化除磷机理的研究和发展状况,通过反硝化除磷的特性分析,阐述了反硝化除磷机理.介绍了反硝化除磷工艺的发展状况,通过比较得出单污泥和双污泥系统适合市政污水、低氮源和低C/N污水的脱氮除磷工艺.     

氟化物对火山石基质人工湿地处理废水性能及菌群的影响

构建了以火山石为基质的垂直流人工湿地（VFCW）系统,探究该系统在优化的水力负荷率（HLR）和碳氮比（C/N）条件下对含氟废水的处理性能以及菌群变化。结果显示,HRL 80mL/min、C/N 4.5条件下系统对有机物和氮的去除率较高。10mg/L氟化物处理导致硝酸盐氮（NO₃-N）开始出现累积（去除率为-23.1%）。20mg/L氟化物处理中总氮（TN）的去除率与0mg/L处理相比下降14.5%,NO₃-N累积加重（去除率为-52.2%）。50mg/L氟化物处理中化学需氧量（COD）、氨氮（NH₄-N）和TN的去除率与0mg/L处理相比分别下降10.0%、17.1%和28.4%,NO₃-N累积更加严重（去除率为-96.1%）。氟离子（F^-）主要与系统中钙盐、磷酸盐反应生成氟化钙（CaF₂）和氟磷酸钙[Ca₅F(PO₄)₃]沉淀而去除。50mg/L氟化物处理的菌群组成明显受到了影响,菌群多样性降低,有机物降解菌（Zoogloea）、硝化菌（Nitrospira和Nitrosomonas）和反硝化菌（Thauera、Simplicispira和Dechloromonas）等的相对丰度显著降低（p＜0.05）。比耗氧速率（SOUR）、氨摄取速率（AUR）和硝酸盐还原酶（NaR）活性均随着氟化物浓度增大而下降,在F^-浓度为50mg/L时,分别降低13.7%、18.8%和55.6%。氟化物改变了VFCW系统的菌群结构和活性,导致污染物去除率降低。氟化物对反硝化过程和反硝化菌的影响最大,其次是硝化过程和硝化菌。     

小球藻对奶牛场沼液处理能力及生物质生产的探究

为资源化处理奶牛场沼液、探究小球藻Chlorella vulgaris NIES-227对奶牛场沼液的处理能力以及生物质利用潜力,在柱式光生物反应器中利用小球藻处理沼液占比分别为25%、50%、75%和 100% 4种不同浓度的未灭菌污水。研究结果显示,各浓度污水中总氮、总磷和COD的去除率分别为36.0%～92.5%、42.8%～100%和6.9%～32.2%。在沼液占比为25%的污水中氮磷的去除率最高,氨氮、总氮和总磷的去除效率分别可达99.9%、91.0%和100%。微藻在低浓度沼液（25%～50%）中生长状态良好,在沼液占比为50%的污水中可获得最高生物质产率393.6 mg/(L·d)。但是在高浓度沼液（75%～100%）中微藻生长受到一定抑制,导致氮磷的去除效果变差。培养期间细菌的数量增长显著,促进了COD的去除。各浓度沼液生物质中总脂、总糖和蛋白质含量分别为13.2%～32.2%、12.3%～27.6%和16.2%～30.9%。实验数据表明,低浓度沼液能产生更多高能量组分的生物质,适合用作生物燃料的开发;高浓度沼液能产生含较多蛋白质的生物质,更适合用作动物饲料。     

Electrochemical removal of ammonia,chemical oxygen demand and energy consumption from aquaculture waters containing different marine algal species

Phytoplankton over‐blooming and consequent die‐off is one of the major contributory factors for ammonia and chemical oxygen demand (COD) loadings. In this work, electrolysis technology was applied to determine its ability to remove ammonia and total chemical oxygen demand (TCOD) in both laboratory‐scale batch and continuous systems. Under an initially set voltage of 5 V, a constant current of 0.1 A was applied and different retention times were used for ammonia‐removal experiments. Results showed that these conditions are not satisfactory in removing TCOD loadings contributed by algal cells. However, a retention time of 35.7 min was sufficient to remove 100% ammonia from algal‐uncontaminated waters. Ammonia removals in waters containing Chlorella spp and Isochrysis spp were 87 and 68%, respectively, after 140 min of electrolysis. Energy consumption for ammonia removal in algal‐free water was 50 W mg^?1 of ammonia. For waters containing Chlorella spp and Isochrysis spp energy consumptions were 67 and 85 W mg^?1 of ammonia, respectively. Interestingly, the applied mild electrolysis condition was just sufficient to control excess algal blooming and ammonia without increasing the dissolved COD and chlorine in shrimp grow‐out ponds. This minimizes operating costs due the process requiring less energy. Furthermore, it was also found that electrolysis does not lower alkalinity. Copyright © 2005 Society of Chemical Industry     

Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn²⁺ solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1: 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn²⁺ solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996).