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.

Kinetics of antimony biogeochemical processes under pre-definite anaerobic and aerobic conditions in a paddy soil

While the transformation of antimony(Sb) in paddy soil has been previously investigated, the biogeochemical processes of highly chemical active Sb in the soil remain poorly understood. In addition, there is a lack of quantitative understanding of Sb transformation in soil. Therefore, in this study, the kinetics of exogenous Sb in paddy soils were investigated under anaerobic and aerobic incubation conditions. The dissolved Sb(V) and the Sb(V) extracted by diffusive gradient technique decreased under anaerobic conditions and then increased under aerobic conditions. The redox reaction of Sb occurred, and Sb bioavailability significantly decreased after 55 days of incubation. The kinetics of Fe and the scanning transmission electron microscopy analysis revealed that the Fe oxides were reduced and became dispersed under anaerobic conditions, whereas they were oxidized and re-aggregated during the aerobic stage. In addition, the redox processes of sulfur and nitrogen were detected under both anaerobic and aerobic conditions. Based on these observations, a simplified kinetic model was established to distinguish the relative contributions of the transformation processes. The bioavailability of Sb was controlled by immobilization as a result of S reduction and by mobilization as a result of Fe reductive dissolution and S oxidation, rather than the p H. These processes coupled with the redox reaction of Sb jointly resulted in the complex behavior of Sb transformation under anaerobic and aerobic conditions. The model-based method and findings of this study provide a comprehensive understanding of the Sb transformation in a complex soil biogeochemical system under changing redox conditions.

Petro-chemical wastewater treatment by biological process

In order to study the feasibility of treating petro chemical wastewater by the combination of anaerobic and aerobic biological process, a research of treating wastewater in UASB reactor and aeration basin has been conducted. The test results shows that under moderate temperature, with 5\^2 kgCOD/(m\+3·d) volumetric load of COD Cr in the UASB reactor and 24h of HRT, 85% removal rate of BOD 5 and 83% of COD \{Cr\} and 1\^34 m\+3/(m\+3·d) volumetric gas production rate can be obtained respectively. The aerobic bio degradability can be increased by 20%—30% after the petro chemical wastewater has been treated by anaerobic process. As Ns=0\^45 kgCOD/(kgMLSS·d), HRT=4h in the aeration tank, 94% removal rate of BOD 5, 93% of COD \{Cr\}, 98\^8% total removal rate of COD \{Cr\} and 99% removal rate of BOD 5 can be reached.

Elucidating the removal mechanism of N,N-dimethyldithiocarbamate in an anaerobic-anoxic-oxic activated sludge system

N,N-Dimethyldithiocarbamate （DMDTC） is a typical precursor of N-nitrosodimethylamine （NDMA）. Based on separate hydrolysis, sorption and biodegradation studies of DMDTC, a laboratory-scale anaerobic-anoxic-oxic （AAO） system was established to investigate the removal mechanism of DMDTC in this nutrient removal biological treatment system. DMDTC hydrolyzed easily in water solution under either acidic conditions or strong alkaline conditions, and dimethylamine （DMA） was the main hydrolysate. Under anaerobic, anoxic or oxic conditions, DMDTC was biodegraded and completely mineralized. Furthermore, DMA was the main intermediate in DMDTC biodegradation. In the AAO system, the optimal conditions for both nutrient and DMDTC removal were hydraulic retention time 8 hr, sludge retention time 20 day, mixed-liquor return ratio 3：1 and sludge return ratio 1：1. Under these conditions, the removal efficiency of DMDTC reached 99.5%; the removal efficiencies of chemical organic demand, ammonium nitrogen, total nitrogen and total phosphorus were 90%, 98%, 81% and 93%, respectively. Biodegradation is the dominant mechanism for DMDTC removal in the AAO system, which was elucidated as consisting of two steps： first, DMDTC is transformed to DMA in the anaerobic and anoxic units, and then DMA is mineralized to CO2 and NH3 in the anoxic and oxic units. The mineralization of DMDTC in the biological treatment system can effectively avoid the formation of NDMA during subsequent disinfection processes.

基于氮元素循环利用的鱼粪生化处理工艺优化

为探究鱼菜共生系统中适宜氮元素高效循环利用的鱼粪生化处理工艺,设置厌氧和好氧两种工艺对鱼粪进行生化处理,每种工艺设置3个反应温度和3个鱼粪浓度,研究不同工艺处理后鱼粪液中氮元素变化规律,以及鱼粪液对生菜生长的影响。结果表明,经厌氧处理后的鱼粪液铵硝比增大,经好氧处理后的鱼粪液铵硝比降至1.0以下,浓度3.0%~3.5%的鱼粪经35°C好氧处理后水培生菜的生长速率最优。最适宜生菜生长的鱼粪生化处理工艺为原鱼粪浓度3.0%~3.5%,经35°C好氧工艺处理10 d。

乳业污水处理工艺研究

本文综合现有主流污水处理工艺的特点,对乳业生产废水特性分析,提出“厌氧+好氧”的生物处理方法。在乳制品综合废水处理中,与其他处理工艺相比,该工艺具有运行稳定、运行成本低以及环境污染风险小等优势。采用该工艺COD、BOD_(5)、SS、NH_(3)-N、pH等均能满足排放标准,且运行成本也较低,可为乳业废水的处理提供参考借鉴。

厌-好氧交替工艺处理辽河油田废水的试验

采用厌－好氧交替（ＡＡＡ）工艺处理适当稀释或原浓度的油田废水，进水ＣＯＤ３６０—９５０ｍｇ／Ｌ，ＣＯＤ去除率均保持在６０％左右．经过厌氧ＵＡＳＢ反应器处理后的废水，再经ＡＡＡ工艺进行处理，在ＨＲＴ８—１２ｈ的条件下，其ＣＯＤ浓度能够从３５０ｍｇ／Ｌ降到１６０—２４０ｍｇ／Ｌ，ＣＯＤ去除率３１％—４８．５％．对于ＣＯＤ浓度为１６０—１８０ｍｇ／Ｌ的废水，采用好氧接触氧化法作为好氧二级处理，其出水ＣＯＤ去除率在５０％—６０％，出水ＣＯＤ浓度一般接近８０ｍｇ／Ｌ左右．

抗生素工业废水生物处理技术的现状与展望

分析了各类抗生素工业废水的水质特征和主要污染因子，综述了目前应用的好氧和厌氧生物处理工艺，在此基础上提出了前处理－厌氧－好氧生物处理的组合工艺路线，并对各工艺的作用和可能采用的技术进行了比较分析，最后指出应重点研究高效低耗复合反应器、除硫脱氮工艺和厌氧毒性试验方法．

厌-好氧交替工艺的生物除磷特性研究

采用模拟配制的生活污水，研究了厌好氧交替工艺对磷和有机污染物的去除效果．结果表明，经过驯化运行等阶段后，在高效除磷阶段运行期间，磷的去除效率在９０％ 以上．总ＣＯＤ 去除率通常大于９０％ ．实验表明ＣＯＤ 主要是在好氧阶段被去除．反应器的有机处理负荷Ｆｒ 达１－２１ —１－５ ｋｇ（ＣＯＤ）／（ｍ３·ｄ） ．这些良好的运行性能与反应器中培养出好氧颗粒活性污泥有关．运行过程中，不必投加外部碳源（ 甲醇或乙酸钠） ，只利用生活污水自身的有机物就能达到如此好的除磷和降解ＣＯＤ 效果，而且该工艺的曝气时间仅为传统活性污泥法的一半．

厌氧-好氧驯化活性污泥生物合成PHA的研究

厌氧 -好氧处理有机污水的活性污泥中含有大量菌胶团菌 ,其形成与菌体胞内聚羟基烷酸酯 (PHA)的积累有关 ,因此有可能利用污水中有机物和活性污泥中多种微生物合成PHA。笔者利用纺织工业废水厌氧 -好氧驯化活性污泥 ,从中提取PHA。分别研究了厌氧过程和好氧过程中供氧量、碳源调节物浓度、培养时间等对菌胶团菌生长和胞内PHA积累的影响 ,测定了所得PHA的分子量、熔点和单体链节组成。

好氧颗粒活性污泥的培养及理化特性研究

研究厌氧－好氧交替工艺中好氧颗粒活性污泥的培养和理化特性．在普通好氧曝气条件下，反应器内培养出了好氧颗粒活性污泥，颗粒直径０．５—１．５ｍｍ，比重１．００７左右，含水率９７％—９８％．ＭＬＳＳ４．０４—６．８８％ｇ／Ｌ，ＳＶＩ２０—４５ｍｌ／ｇ，一般约３０ｍｌ／ｇ．颗粒污泥受阻沉降层的均匀沉降速度ｖｓ约２．１５ｃｍ／ｍｉｎ，临界浓度时沉降速度值ｖ２约０．３５ｃｍ／ｍｉｎ．颗粒污泥的耗氧速率ＯＵＲＷ１．２７ｍｇ／（ｇ·ｍｉｎ），这些理化指标均优于普通的活性污泥．对于ＣＯＤ浓度３７２—５４８ｍｇ／Ｌ、Ｐ浓度９．８４—１３．５７ｍｇ／Ｌ的生活污水，总ＣＯＤ去除率和除Ｐ效率一般分别在９０％以上．

亚硝酸盐对聚磷菌吸磷效果的影响

以厌氧/好氧生化反应器中的聚磷菌为实验对象,探讨了亚硝酸盐对聚磷菌吸磷效果的影响.结果表明:低浓度NO2--N可以作为聚磷菌的电子受体,实现NO2--N型反硝化除磷,但吸磷总量和吸磷速率明显低于NO3--N型反硝化除磷的效果;当NO2--N和NO3--N共存于缺氧环境时,NO2--N对NO3--N型反硝化除磷的除磷总量和速率没有影响,但会降低NO3--N的消耗量;NO2--N型反硝化除磷污泥的好氧吸磷量和速率均低于传统A/O厌氧放磷污泥的效果,但由于它经历了缺氧吸磷和好氧吸磷2个阶段,因此,从吸磷总量或出水水质看,二者相差不大.

抗生素废水生物处理法的研究进展

为了更好地为抗生素废水治理提供工艺参考。笔者在分析抗生素废水特点的基础上,总结了国内外普遍使用的几种抗生素废水生物处理方法:好氧法、厌氧法、好氧-厌氧法以及其他组合工艺,探讨了目前存在的一些问题和解决方法,同时也对抗生素废水生物处理法的应用前景进行了展望。

亲水性塑料弹性填料生物膜法处理模拟废水的研究

通过比较普通塑料弹性填料与亲水性改进后的塑料弹性填料在污水生化处理中的应用效果发现 :亲水性改进的塑料弹性填料在污水的厌氧生化处理中可提高污水处理效率 15 %— 30 % ,在好氧生化处理中可提高污水处理效率5 %— 10 % ,且亲水性改进大大提高了塑料弹性填料的挂膜速度。

O_1/A/O_2工艺处理高浓度焦化废水

焦化废水水质复杂,处理难点在于去除水中高浓度的CODCr、NH3-N和氰化物等。首钢某焦化厂废水处理工程采用以O1/A/O2工艺（预曝气/缺氧/好氧）为核心、前置除油预处理、后置混凝沉淀深度处理工艺,取得了较好的处理效果。运行结果表明：O1/A/O2工艺对CODCr和NH3-N的去除率分别可达95%和89%以上;混凝沉淀采用聚合硫酸铁絮凝剂和PAM助凝剂,加药量分别为600~800 mg/L和1~2 mg/L时,CODCr去除率在50%左右,脱色效果好。经过预处理、生化处理及深度处理后,出水主要污染物指标达到了《污水综合排放标准》的二级排放标准要求。

SBR工艺交替硝化反硝化运行方式的可行性研究

将交替好氧、缺氧运行方式应用于间歇式污水处理系统(SBR工艺),分别在原水碱度充足和碱度不足情况下考察该运行方式的可行性.结果表明:原水碱度充足时,交替硝化反硝化的运行方式在处理效率上并没有体现出优势;原水碱度不足时,交替硝化反硝化与传统硝化反硝化相比,处理效率与出水水质明显提高,出水氨氮可以达到检测水平.当原水碱度的不足量低于所需碱度理论值的1 3时,采取交替硝化反硝化,无需额外补充碱度就可以达到原水碱度充足情况下的处理效率.如果原水碱度的不足量已超过1 3,采取交替硝化反硝化可最大限度节省额外投加碱度的量,降低处理成本,是一种理想的运行方式.

改良型SBR系统处理染料废水的研究

通过试验考察了两种改良型序批式间歇反应器-SBR-系统——“厌氧、好氧”交替运行系统-系统1-和“厌氧+好氧”串联二级系统-系统2-的运行过程,分析了影响系统运行效果的因素,比较了两个系统厌氧阶段、好氧阶段及全过程处理效果的差异,并分析了造成差异的原因.结果表明,两个系统均具有适应能力强、稳定性能好、能够有效地降解污染物的特点;污泥浓度、碳源数量、环境温度均影响系统的运行效果;系统1的厌氧阶段比系统2更有效,系统2的好氧阶段比系统1更有效,系统2的全过程处理效率更高;分析认为生物相组成情况的不同是导致两个系统处理效果差异的主要原因.

水解酸化/AAO工艺的同步脱氮除磷及污泥减量研究

针对传统活性污泥法脱氮除磷效率低、污泥产量高的缺点，提出了水解酸化／缺氧-厌氧-好氧（HAAO）污水、污泥一体化处理工艺，研究了该工艺去除COD、氮、磷和污泥减量的效果及其主要影响因素。试验结果表明，在进水COD为286-425mg／L、NH4^＋ -N为36-58mg／L、PO4^3- -P为4-12mg／L、总水力停留时间为11．5h及无外加碳源和碱度的条件下，系统对COD、NH4^＋ -N、TN、PO4^3- -P的去除率分别可达95％、98％、84％、87％。好氧段的DO浓度、固体停留时间（SRT）和剩余污泥回流比对系统的运行效果有重要影响。将污水和剩余污泥同时进行水解酸化，既可有效地改善污水的可生化性，提高系统对碳源的利用效率，又可实现污泥的减量化，试验条件下系统的污泥减量率达56．5％。

维生素类制药废水处理工艺

将好氧共基质工艺、厌氧-好氧工艺、混凝以及Fenton试剂处理工艺用于维生素类制药废水的处理并加以比较.结果表明:在好氧共基质条件下,葡萄糖人工配水和制药废水的最佳COD浓度比为1∶5;厌氧反应器的串联使用提高了反应器中的生物降解效果,有利于反应器的长期稳定运行;混凝工艺适合作为生化处理的预处理工艺,Fenton试剂则不适于处理此种制药废水.

城市污泥与有机垃圾交替式好氧厌氧堆肥化

为探讨交替好氧厌氧堆肥化过程中城市污水污泥与有机垃圾理化性质和生物毒性的变化规律,将城市污水污泥、城市有机垃圾以及调理剂以3∶3∶1的质量比均匀混合,进行60天的交替好氧厌堆肥化处理,发现堆料中的总有机碳含量从59.62%(质量分数,下同)下降到40.21%,挥发性固体含量从76.47%下降到69.85%,总氮含量从0.94%下降到0.68%,总磷含量则由0.59%上升到0.86%,腐殖质含量最终维持在7%左右的水平,种子发芽率达72.5%.表明堆料成为腐熟的堆肥产品.