Analysis of the Effect and Influencing Factors of Rural Domestic Sewage Treatment Based on A^(2)O-MBBR Integrated Process

[Objectives] This study was conducted to solve the prominent problems in the treatment of domestic sewage in southern rural areas of China. [Methods] An integrated process treatment mode of anaerobic/anoxic/aerobic moving bed biofilm reactor (A 2O-MBBR) was proposed to analyze and study its operating effect and influencing factors. [Results] The A^(2)O-MBBR mode had good COD removal efficiency and nitrogen and phosphorus removal performance, and the water quality index of the effluent met the Class A standard of GB181918-2002. This mode is suitable for treating rural domestic sewage, and has high treatment effects in different operating periods. In spring, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS reached (83.53 ± 2.15)%, (89.44 ± 4.97)%, (67.36±18.53)%, (88.22±11.21)% and (91.73±2.25)%, respectively;In the autumn period, the average removal rates of COD, NH_(4)^(+)-N, TN, TP and SS were (83.49±2.64)%, (89.26±9.19)%, (66.05±17.00)%, (87.48±9.68)%, and (91.13±2.35)%. [Conclusions] This study provides theoretical reference and technical support for the popularization and application of A^(2)O-MBBR integrated process.

Removal of nitrogen and phosphorus in a combined A^2/O-BAF system with a short aerobic SRT

A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.

Nitrogen removal for low-carbon wastewater in reversed A^2/O process by regulation technology

Full scale experimental study on nitrogen removal for low-carbon wastewater was conducted in reversed A2/O process in Jiguanshi waste water treatment plant in Chongqing,in order to aid the operation and maintenance of similar WWTP. When the proposed measures,such as using 0.1% (volume fraction of wastewater) landfill leachate,shortening HRT by 2/3 in the primary sedimentation tank and controlling DO at 0.5 mg/L in the 3rd section of aerobic zone,are applied,15% of the carbon source can be complemented,the favorable property of activated sludge is achieved,and the nitrogen removal effect is significantly improved. The effluent NH3-N is 2 mg/L and the removal rate is 90%. The effluent TN is 17 mg/L and the removal rate is 54%. The up-to-standard discharge of the effluent is achieved. And after the optimization,the unit electricity consumption also reaches 0.21 kW/h and saves 20%.

A^(2)O-SBR工艺在城镇污水处理厂中的应用

A^(2)O-SBR工艺为A2O工艺与SBR工艺串联组合,为了探究A^(2)O-SBR工艺在城镇污水处理厂的应用效果,分析广西壮族自治区东兴市城东污水处理厂2021年运行情况,结果表明:厂区出水稳定达标排放,A^(2)O-SBR工艺脱氮除磷效果好;COD、NH_(4)^(+)-N、TP平均去除率为87.05%、97.23%、80.86%,最高去除率为97.55%、98.36%、91.21%;出水浓度相对稳定,A^(2)O-SBR工艺对上述三种污染物的去除率也相对稳定,对NH_(4)^(+)-N效果最好,全年去除率稳定达到95%以上;该污水处理厂平均处理成本0.53元/m^(3)。

Anoxic Biological Phosphorus Uptake in A^2O Process

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.

不同运行条件下改进型A^(2)/O工艺脱氮除磷性能研究

为了提升传统A^(2)/O工艺的脱氮除磷效果,采用改进型A^(2)/O工艺,探究不同影响因素对其脱氮除磷效果的影响,并确定了改进型A^(2)/O工艺的最佳运行条件。通过调整消化液回流比、进水分配比、溶解氧(DO)浓度,确定改进型A^(2)/O工艺的最佳运行工况为消化液回流比200%、进水分配比6∶4、DO浓度1.9~2.0 mg/L,该运行条件下,脱氮除磷效果得到有效提升,出水水质能够稳定地达到一级A排放标准。

改良A^(2)O工艺与多级AO工艺在污水处理厂设计中的应用对比

东莞市某污水处理厂现状工程规模为20万m^(3)/d,文章以该工程中的新建三期工程为研究案例,工程规模为10万m^(3)/d。基于相关政策对污水处理厂总氮指标的逐步提升,通过对现状进水水质及其脱氮除氯工艺效率进行分析,对比同等进水水质情况下的改良A^(2)O工艺与多级AO工艺的设计,分析两者不同的设计参数、投资运维费用和生物脱氮除磷效率,总结两种工艺各自的优势及特点,为污水处理厂生化池工艺的选择提供参考。

分配比对分段进水A^2/O工艺脱氮除磷的影响

以低C/N实际污水为研究对象,研究进水分配比对分段进水A^2/O工艺脱氮除磷性能的影响.以稳态条件下建立的物料平衡方程为基础,分析进水分配比对处理过程的影响.结果表明,分段进水A^2/O工艺平均出水CODCr和NH3-N质量浓度基本维持为25.6~41.2mg/L和0.35~1.40mg/L,出水水质较稳定;出水TN、TP受进水分配比的影响明显.根据已建立的物料平衡方程分析发现,当进水分配比由6∶3降低至3∶6时,缺氧单元反硝化脱氮贡献率由36.95%升至83.47%,厌氧单元反硝化脱氮贡献率由43.81%降至12.30%,好氧单元同步硝化反硝化脱氮贡献率由19.24%降至4.23%,缺氧单元反硝化成为去除TN的主要途径,TN总体去除率升高9.95%;缺氧单元缺氧聚磷除磷贡献率由5.20%升至13.00%,好氧单元好氧聚磷除磷贡献率由94.80%降低至87.00%,好氧聚磷为去除TP的主要途径,但TP总体去除率降低5.37%.

低碳源、低能耗型改良A^2/O工艺的脱氮除磷研究

介绍了一种新型的脱氮除磷工艺及其运行情况。该工艺是对传统A2/O工艺的改进(可称为改良型A2/O工艺),它采用了后置反硝化系统以及厌氧池碳源分流技术和回流污泥预缺氧反硝化技术,以提高系统的脱氮除磷效果。研究结果表明:在进水COD≥300 mg/L,TN为40.3 mg/L,TP为3.82 mg/L时,对TN、TP及COD的去除率分别可达70%、86%和88%;当COD<300 mg/L时,对TP的去除效果较差,但对TN和COD的去除率仍分别可达60%和85%;试验期间,污泥沉降性能良好。

A-A^2/O工艺处理低碳源城市污水的除磷脱氮效果

文章以南方某污水处理厂的实际运行情况为例,介绍了A-A2/O工艺在处理低碳源城市污水的效果。运行结果表明,工艺对BOD5、COD、SS的去除效果良好,达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级A标准。对于氮磷去除,出水NH4-N<0.5mg/L,TN<15mg/L,TP<1.5mg/L,但TN平均去除率只有45%左右;TP大多数的去除率在30%～50%之间。造成这种结果的主要原因是碳源不足。为提高除磷脱氮效果,采取了投加PAC来辅助除磷,并提出了进一步的改进措施,供同行参考。

倒置A^2/O工艺的生产性试验研究

为考察倒置A2/O工艺的实际处理效果及影响因素,在某污水处理厂进行了生产性试验。结果表明,对于工业废水占2/3的城市污水而言,倒置A2/O工艺在生产运行中具有较高的去除有机物和脱氮除磷能力;运行中回流比≥2.0,好氧区停留时间为6.0～10.0h,DO为2.0mg/L左右比较合适。整个工艺具有流程简洁、能耗低、运行稳定、抗冲击能力强的特点。

硝化液回流比对A^2/O-BCO工艺反硝化除磷特性的影响

以低C/N城市生活污水为处理对象,重点考察了硝化液回流比对A2/O-BCO(生物接触氧化)工艺脱氮除磷特性的影响.在A2/O反应池水力停留时间(HRT)为8h,污泥回流比为100%条件下,将硝化液回流比分别设定为100%、200%、300%和400%进行试验.结果表明,系统在A2/O中实现了反硝化除磷,具有很好的同步氮磷的去除效果,出水COD浓度均在50mg/L以下.上述不同硝化液回流比下总氮(TN)去除率分别为48.8%、66.5%、75.6%和62.5%,总磷(TP)去除率分别为86.0%、90.3%、91.0%和95.0%.在硝化液回流比为300%时,系统平均出水TN和TP浓度分别为14.96mg/L和0.49mg/L.系统反硝化除磷量随着硝化液回流比的增大略有增加,在硝化液回流比为400%时,反硝化除磷量高达磷总去除量的98%.

倒置A^2/O工艺的原理与特点研究

通过短时厌氧环境的生化特性、厌氧 /缺氧环境倒置效应和小型系统平行对比试验 ,较系统地研究了倒置A2 /O工艺的原理和工艺特点。指出 :①聚磷菌厌氧有效释磷水平的充分与否 ,并不是决定其在后续曝气条件下过度吸磷能力的充分必要条件。推进聚磷菌过度吸磷的本质动力与厌氧区HRT和厌氧环境的厌氧程度有关。在一定范围内 ,厌氧环境的HRT越长 ,厌氧程度越充分 ,聚磷菌的吸磷动力越强。②把常规生物脱氮除磷系统的厌氧、缺氧环境倒置过来 ,可以得到更好的脱氮除磷效果。小型系统平行对比试验表明 ,倒置A2 /O工艺的氮磷脱除功能明显优于常规A2 /O工艺 ,其COD去除能力则与常规A2 /O工艺相当。

污泥龄对A^2/O工艺脱氮除磷效果的影响

污泥龄(SRT)作为活性污泥法设计与运行的参数已显示出比其它参数更加重要。试验以实际生活污水为对象,研究SRT分别为5、10、15、20、25、30d时,系统CODCr、NH4+-N、TN、PO43-P的去除率以及污泥特性的变化,试验期间其它运行参数保持不变。试验结果表明:SRT=15d时系统总体脱氮除磷效果最好,此时CODCr、NH4+-N、TN、PO43-P去除率分别为:93%、98%、81%、82%,并对SRT=15d时系统中氮磷的浓度变化曲线进行分析。

回流比对投料A^2/O工艺脱氮除磷影响的中试研究

试验采用了投料A2/O脱氮除磷工艺在广州市某污水处理厂进行中试,考察了不同混合液回流比及污泥回流比对投料A2/O工艺脱氮除磷的影响。结果表明,混合液回流比对COD、TP和NH3-N影响较小,对TN的去除率影响较大,系统混合液回流比为200%时,系统处理效果最佳;污泥回流比对系统整体功能的影响较大,随污泥回流比的增大,各指标的去去除率随之增大,结合处理效果和能耗情况,污泥回流比为75%时系统效果最佳。

负荷(F/M)对A^2/O工艺脱氮影响的研究

以上海市白龙港城市污水厂初沉池污水为进水,构建A2/O试验系统。调节试验系统有机负荷(F/M),并分析负荷对A2/O工艺脱氮的影响。结果表明,COD去除最佳F/M范围为0.14～0.28gBOD5·gMLSS-1·d-1;BOD5去除最佳F/M范围为0.14～0.22gBOD5·gMLSS-1·d-1;反硝化最佳F/M范围为0.13～0.23gBOD5·gMLSS-1·d-1;硝化最佳F/M范围为0.14～0.28gBOD5·gMLSS-1·d-1。根据分析,F/M介于0.14～0.22gBOD5·gMLSS-1·d-1之间时,A2/O工艺脱氮效果最佳。

A^2/O-曝气生物滤池工艺反硝化除磷

以低C/N生活污水为研究对象,考察了A2/O-曝气生物滤池生化系统的脱氮除磷特性。通过缩短A2/O的泥龄,把硝化过程从A2/O中分离出去,让曝气生物滤池实现硝化;A2/O在短泥龄条件下运行,有利于除磷及反硝化,曝气生物滤池在长泥龄条件下运行,有利于硝化效果的稳定和氨氮的彻底去除;曝气生物滤池回流来的硝化液为A2/O的缺氧区提供了充足的电子受体,为反硝化除磷提供了必要条件。试验结果表明,在HRT为7.5 h,泥龄为15 d,硝化液回流比为400%的条件下,平均进水COD、NH+4-N、TN和TP浓度分别为376、67.9、72.9、6.1 mg.L-1时,系统出水COD、NH+4-N、TN和TP浓度分别为42、0.86、9.6、0.1 mg.L-1,实现了COD和氮磷的同步深度去除;硝化液回流比为200%和400%时,反硝化除磷量分别为1.49、1.64 gTP.(g MLVSS)-1.d-1;序批试验表明,反硝化聚磷菌占聚磷菌的比值为68.2%;泥龄增加,TP去除率下降。

进水C/P比对A^2/O工艺性能的影响

我国当前面临着严重的水体富营养化问题,A2/O工艺是一种有效的同步脱氮除磷工艺,但其中进水C/P比是其运行效果的重要影响因素,为深入考察不同进水C/P比对A2/O工艺运行性能的影响,试验设计了4种进水C/P比(55、45、34、23),研究了A2/O工艺中COD、总氮、磷和污泥特性的变化.实验结果表明,当进水C/P比小于32时,磷的去除效果随C/P比的降低而线性降低;当进水C/P比高于32时,磷的去除效果稳定在90%～98%,出水磷浓度小于0.5mg·L-1.但是C/P比的变化,对COD和总氮的去除率影响较小,平均去除率分别高于90%和75%.而剩余污泥中磷含量则随C/P比的下降而增加.实验发现,不同C/P比系统均存在反硝化除磷现象,可以实现“一碳两用”,有利于氮磷去除效果的提高.

西安市污水处理厂改良A^2／O工艺的运行效果分析

介绍了西安市污水处理厂改良A2/O工艺的特点及运行状况。采用对回流污泥预反硝化及分段进水的方法,减少了硝酸盐对聚磷菌(PAOs)碳源摄取释磷行为的影响,基本满足了反硝化和生物除磷(BPR)对碳源的需求。结果表明,该工艺对COD、NH4+-N、总氮、总磷的去除率分别为91.91%、78.70%、64.20%和95.52%。

短好氧泥龄下A^2/O和BAF联合工艺的脱氮除磷特性

采用小试装置,研究了短好氧污泥龄下A2/O和BAF联合工艺处理低C/N和C/P污水时的脱氮除磷特性。结果表明,通过提高A2/O工艺段的厌氧区有机负荷和缺氧区硝酸盐负荷对反硝化聚磷菌(DPAOs)进行选择和强化后,其在聚磷菌(PAOs)中的比例维持在28%左右,工艺具有部分反硝化除磷能力,能够减少脱氮除磷过程中对碳源的总需求量。但在联合工艺中,好氧除磷仍是主要的除磷方式。在A2/O工艺段内,好氧污泥龄在满足好氧PAOs存活的同时,还必须满足抑制硝化细菌生长的要求,且为了保证工艺对磷的整体去除效果,混合液在好氧区的接触时间须大于30 m in。此外,以保证缺氧区出水中含有1~4 mg/L的硝态氮为原则来控制BAF出水的回流量,可达到较好的脱氮除磷效果。该联合工艺结合了活性污泥工艺和生物膜工艺的优点,运行稳定,出水水质优良,不仅适合于新建污水处理厂,也特别适合于不能脱氮除磷污水处理厂的技术改造。