碳源性质和COD/NO_3~--N对硝酸盐还原途径的影响

通过批次试验考察了实际工业有机废水的碳源性质和COD/NO_3~--N对硝酸盐还原途径的影响。研究结果表明,木薯酒糟中含有大量的大分子易发酵有机物(如碳水化合物和蛋白质等),更易发生异化硝酸盐还原为铵(DNRA)过程;而葡萄糖合成废水和木薯酒精废水厌氧出水中,硝酸盐还原途径主要是通过反硝化进行的。虽然基质不同,但COD/NO_3~--N对硝酸盐还原途径的影响却呈现出相同的规律,即随着COD/NO_3~--N增大,反硝化所占的比例逐渐减小,DNRA占的比重逐渐增大。     

厌氧生物处理低浓度污水研究进展

厌氧生物处理技术具有节能降耗及回收资源的优点,但在处理低浓度污水（COD<1000mg/L）时,污泥活性较差、处理效率偏低等问题使其应用受到严重限制。为促进厌氧生物处理低浓度污水技术的发展,本文在介绍微生物间电子传递类型和厌氧功能菌的基础上,阐明厌氧生物处理的作用机理;随后基于厌氧消化原理,探讨了温度、pH、挥发性脂肪酸（VFA）和氨氮等因素对厌氧生物处理的影响;接着从厌氧膜生物反应器、厌氧微生物活性及直接种间电子传递三个层面出发,对强化低浓度污水厌氧生物处理的方法进行归纳总结;最后从“耐饥饿”菌种的筛选和微生物活性强化途径角度展望了厌氧生物处理低浓度污水的发展趋势和研究方向,旨在为推广厌氧生物处理低浓度污水、加快污水中有机物的资源化利用提供参考。     

低浓度生活污水厌氧处理的试验研究

该文介绍了厌氧生物污水处理技术在低浓度污水处理领域的研究，并通过实验室静态批量试验，针对广州等南方城市特有的低浓度生活污水（CODCr浓度范围为35～350mg/L）研究了厌氧污泥消化过程对水中总CODCr和溶解性CODCr的去除规律、ORP的变化、影响因素以及边界条件。     

基于ANAMMOX工艺基础上的DEAMOX新型生物脱氮工艺

反硝化氨氧化(DEAMOX)是指在自养反硝化条件下,以硫化物为电子供体,将硝酸盐还原成亚硝酸盐,然后发生以氨氮为电子供体,亚硝酸盐为电子受体的厌氧氨氧化反应。亚硝酸盐的产生和厌氧氨氧化在同一反应器内完成。综述了DEAMOX新型生物脱氮工艺的反应机理、脱氮效果及微生物特性。同时对该工艺的优势及应用前景进行了比较分析。     

亚硝酸盐对厌氧产酸耦合反硝化工艺的影响

以木薯酒精废水为碳源,通过批次实验研究了亚硝酸盐对厌氧产酸耦合反硝化系统的影响。结果表明,投加600 mg·L^-1 后的最终产酸量与空白反应器相差不大,但是投加相同浓度亚硝酸盐后产酸受到严重抑 制,最终产酸量仅为空白反应器的1.8%。而硝酸盐还原过程中厌氧产酸受到抑制可能是由于反硝化中间产物亚硝酸盐的存在,低投加量的亚硝酸盐即可对厌氧产酸产生强烈的抑制作用并具有持续性,且对各产酸组分的影响作用：正丁酸>丙酸>乙酸。随着 的降低,亚硝酸盐的还原率由74.9%降低至22.2%。当游离亚硝酸（free nitrous acid, FNA）浓度为0.05 mg·L^-1以上时,亚硝酸盐还原几乎被完全抑制（90%以上）。此外,随着 的增加,反硝化所占的比例逐渐减小,而DNRA过程（dissimilatory nitrate reduction to ammonium,异化硝酸盐还原为铵）逐渐占优势。     

亚硝酸盐对厌氧产酸耦合反硝化工艺的影响

以木薯酒精废水为碳源,通过批次实验研究了亚硝酸盐对厌氧产酸耦合反硝化系统的影响。结果表明,投加600 mg·L-1 3NO-N-后的最终产酸量与空白反应器相差不大,但是投加相同浓度亚硝酸盐后产酸受到严重抑制,最终产酸量仅为空白反应器的1.8%。而硝酸盐还原过程中厌氧产酸受到抑制可能是由于反硝化中间产物亚硝酸盐的存在,低投加量的亚硝酸盐即可对厌氧产酸产生强烈的抑制作用并具有持续性,且对各产酸组分的影响作用:正丁酸丙酸乙酸。随着2COD/NO-N-的降低,亚硝酸盐的还原率由74.9%降低至22.2%。当游离亚硝酸(free nitrous acid,FNA)浓度为0.05 mg·L-1以上时,亚硝酸盐还原几乎被完全抑制(90%以上)。此外,随着2COD/NO-N-的增加,反硝化所占的比例逐渐减小,而DNRA过程(dissimilatory nitrate reduction to ammonium,异化硝酸盐还原为铵)逐渐占优势。     

硝酸盐去除途径浅析

目前研究发现的硝酸盐去除途径包括反硝化、同化作用、异化硝酸盐还原为铵、硫细菌氧化脱氮、厌氧氨氧化和铁细菌化能自养脱氮。硝酸盐负荷超标的淡水系统中,影响这些途径的因素是什么,现有的认识仍然不完整,需要进一步深入研究。     

碳源对厌氧氨氧化菌活性影响的研究进展

使厌氧氨氧化系统适应碳源成分复杂的环境对推动其应用发展具有重要意义。在深入分析无机碳源、有机碳源对厌氧氨氧化影响的基础上,充分讨论了混合营养型厌氧氨氧化的可行性及影响因素。分析表明,低浓度的小分子有机酸可以刺激厌氧氨氧化菌的有机营养特性,低碳氮比进水诱导可实现混合营养型厌氧氨氧化。     

硝酸盐和硫酸盐对厌氧还原甲基橙性能的影响

以厌氧污泥作为接种物,研究了低浓度硝酸盐和硫酸盐对甲基橙脱色性能的影响。结果表明:①当体系加入6 m M硫酸盐时,驯化的厌氧菌群能同时进行甲基橙脱色和硫酸盐还原,甲基橙脱色速率提高了约2倍,同时生物量提高了1. 24～1. 31倍,COD去除率提高了1. 72～1. 77倍。②当体系加入6 m M硝酸盐时,整个周期中甲基橙最大脱色率只有25. 67%(对照组78. 57%),但体系生物量提高了1.35～1. 44倍,COD去除率提高了1. 72～1. 83倍。硝酸盐作为优先电子受体提高了体系生物量和COD去除率但抑制了甲基橙脱色,而所用浓度硫酸盐对偶氮染料废水生物处理过程具有积极作用。     

我国水体中硝酸盐的污染现状及危害

我国水体中硝酸盐污染日益严重,水体中硝酸盐浓度过高会导致一系列的人类健康和环境风险。饮用水中高浓度的硝酸盐含量会增加人类患有高铁血红蛋白和"蓝婴综合征"的风险。过高的硝酸盐会诱发相邻地表水体的富营养化,藻类在活动过程中会产生毒素和减少水体的溶解氧含量,从而影响该区域的生物多样性。此外,硝酸盐在反硝化过程中会产生温室气体二氧化氮。     

SBR法处理垃圾渗滤液的反硝化过程中NO~-_2积累的研究

The nitrite accumulation in the denitrification process is investigated with sequencing batch reactor (SBR) treating pre-treated landfill leachate in anoxic/anaerobic up-flow anaerobic sludge bed (UASB). Nitrite accumulates obviously at different initial nitrate concentrations (64.9,54.8,49.3 and 29.5 mg&#8226;L－1) and low temperatures, and the two break points on the oxidation-reduction potential (ORP) profile indicate the completion of nitrate and nitrite reduction. Usually, the nitrate reduction rate is used as the sole parameter to characterize the denitrification rate, and nitrite is not even measured. For accuracy, the total oxidized nitrogen (nitrate + nitrite) is used as a measure, though details characterizing the process may be overlooked. Additionally, batch tests are conducted to investigate the effects of C/N ratios and types of carbon sources on the nitrite accumulation during the denitrification. It is observed that carbon source is sufficient for the reduction of nitrate to nitrite, but for further reduction of nitrite to nitrogen gas, is deficient when C/N is below the theoretical critical level of 3.75 based on the stoichiometry of denitrification. Five carbon sources used in this work, except for glucose, may cause the nitrite accumulation. From experimental results and cited literature, it is concluded that Alcaligene species may be contained in the SBR activated-sludge system.     

Simultaneous removal of carbon,nitrogen and phosphorus from wastewater by coupling two-step anaerobic digestion with a sequencing batch reactor

The objective of this study was to develop an integrated process for simultaneous removal of carbon, nitrogen and phosphorus from industrial wastewaters. The process consisted of a-two step anaerobic digestion reactor, for carbon removal, coupled with a sequencing batch reactor (SBR) for nutrient removal. In the proposed process, carbon is eliminated into biogas by anaerobic digestion: acidogenesis and methanogenesis. The volatile fatty acids (VFA) produced during the first step of anaerobic digestion can be used as electron donors for both dephosphatation and denitrification. In the third reactor (SBR) dephosphatation and nitrification are induced through the application of an anaerobic–aerobic cycle. This paper describes the first trials and experiments on the SBR and a period of 210 days during which the SBR was connected to the acidogenic and methanogenic reactors. It was shown that nitrification of ammonia took place in the SBR reactor, during the aerobic phase. Furthermore, denitrification and VFA production were achieved together in the acidogenic reactor, when the efflux of nitrates from the SBR reactor was added to the first reactor influx. The proposed process was fed with a synthetic industrial wastewater, the composition of which was: total organic carbon (TOC)=2200 mg dm⁻³, total Kjeldahl nitrogen (TKN)=86 mg dm⁻³, phosphorus under phosphate form (P-PO₄)=20 mg dm⁻³. In these conditions, removals of carbon, nitrogen and phosphorus were 98%, 78% and 95% respectively. The results show that the combination of the two-step anaerobic digestion reactor and an SBR reactor is effective for simultaneous carbon, nitrogen and phosphorus removal. Reactor arrangements enabled zones of bacterial populations to exist. Complete denitrification occurred in the acidogenic reactor and hence the anaerobic activity was not reduced or inhibited by the presence of nitrate, thus allowing high TOC removal. Stable phosphorus release and phosphorus uptake took place in the SBR after coupling of the three reactors. A fast-settling compact sludge was generated in the SBR with the operational conditions applied, thus giving good separation of supernatant fluid. The benefits from this process are the saving of (i) an external carbon source for denitrification and phosphorus removal, (ii) a reactor for the denitrification step. © 1998 Society of Chemical Industry     

序批式生物膜法对城市污水的脱氮效果

采用序批式生物膜对广州地区城市污水进行生物脱氮实验，研究表明：氨氮的去除率都在86％以上，出水浓度基本都小于4mg／L，而且大部分都在1mg／L；厌氧，反硝化经过60min左右后，硝酸盐浓度基本在0．08mg/L以下。温度对硝化和反硝化的影响较大。     

PN/A颗粒污泥-固相反硝化组合工艺的菌群功能解析

为解决部分亚硝化-厌氧氨氧化（PN/A）反应存在的硝酸盐残留问题,将PN/A颗粒污泥与固相反硝化（SPD）系统相耦合,用于高氨氮废水的连续处理。在逐级提高颗粒污泥自养脱氮效能的基础上,系统考察了石英砂、聚丁二酸丁二醇酯（PBS）和羟基丁酸戊酸共聚酯（PHBV）三种填料的SPD效能。结果表明,在高水力选择压下,PHBV的反硝化性能最佳,使PN/A-SPD组合工艺的总氮去除率超过了93%,远高于石英砂（83.6%）和PBS（85.8%）的水平。通过高通量测序与功能基因注释可知,固态碳源的溶出水平是影响生物膜菌群多样性的关键因素。其中,在PHBV表面占据主导的水解菌Clostridium-sensu-stricto-7与Comamonadaceae等反硝化菌形成了稳定的协作关系,在有效洗脱自养脱氮功能菌的同时,显著提升了菌群参与多元素循环的功能潜力。上述发现对于系统优化PN/A-SPD组合工艺,推动其工程化应用具有重要的指导意义。     

短程反硝化耦合厌氧氨氧化工艺及其应用前景研究进展

短程反硝化以其碳源消耗量、废污泥产量、温室气体排量极低及无需曝气等优势，被认为是最具研究潜势的厌氧氨氧化底物供给技术，成为近年来研究热点。本文首先介绍了短程反硝化工艺原理；其次从污泥源、反应时间、碳源类型、碳源量及pH等5个方面总结了影响短程反硝化工艺启动因素；随后综述了短程反硝化耦合厌氧氨氧化工艺的重要研究进展，同时指出了耦合工艺实验研究与工程应用的不足，并提出了解决实验与工程应用缺陷的方案；最后展望了耦合工艺处理城市污水和工业硝酸盐废水的可行性及应用前景，认为全面分析工业硝酸盐废水化学组分与基于分子生物学水平的宏基因组学测序、元转录组学技术是未来耦合工艺同步处理城市污水和工业硝酸盐废水的研究重点。     

COD/NO3--N对厌氧同时反硝化产甲烷的影响

采用间歇试验,以葡萄糖为碳源,加入不同量硝酸盐的人工配水进行不同m(COD)/m(NO3--N)下厌氧同时反硝化产甲烷研究。当m(COD)/m(NO3--N)≥7时,发生厌氧同时反硝化产甲烷反应;而m(COD)/m(NO3--N)=3或5时,反硝化不完全,未发生产甲烷过程。进一步通过与单独产甲烷体系对照,发现反硝化过程对产甲烷过程存在抑制。随着m(COD)/m(NO3--N)的增大,体系对NO3--N的去除率越高,直到100%。且发现同时反硝化产甲烷体系中,优先利用丙酸,乙酸积累,而后被利用。     

固相反硝化在水污染治理中的研究进展

水环境中硝酸盐污染是普遍存在的问题。固相反硝化（SPD）技术由于其相对于水基反硝化在水修复中的显著优势而受到越来越多的关注。本文对SPD在水修复中的应用提出了新的看法,介绍了SPD中氮转化的过程和机理,如直接反硝化、异化硝酸盐还原成铵和厌氧氨氧化;讨论了碳底物在SPD中转化的主要过程;研究了SPD的主要局限性,包括碳源可用性低,NO₂^-和N₂O积累,溶解有机碳释放和NH₄⁺的生产,并总结了相关的限制因素;此外,还介绍了一些新的措施来减轻这些限制,如应用可生物降解的聚合物底物和异养自养反硝化HAD过程;最后讨论了同时去除硝酸盐和一些典型污染物以扩大SPD应用的方法。本综述试图提高人们对废水处理或水修复工程中反硝化过程的理解。     

印染废水厌氧水解过程挥发性脂肪酸的产生及影响因素

针对印染废水普遍存在的B/C较低、脱氮优质碳源不足等问题,研究了水力停留时间（HRT）及温度对印染废水厌氧水解过程中挥发性脂肪酸产生量及组成成分的影响。结果表明对于染色废水,最佳厌氧HRT为15 h,VFAs浓度可达到472.1 mg/L,乙酸浓度占VFAs浓度的86.5%,其中相对于低温,中温厌氧更易于VFAs的产生,但温度的改变对于VFAs的组分影响较小。对于前处理废水,最佳厌氧HRT为60 h,出水VFAs浓度可达到692.4 mg/L。合理浓度的VFAs产生可以为后续反硝化单元提供优质的碳源,为印染废水总氮的削减奠定基础。     

Water denitrification by a hybrid process combining a new bioreactor and conventional electrodialysis

A feasibility study of an innovated denitrification process is achieved in this present work. It consists of a combination of the electrodialysis (ED) and the Column of Immobilized Biomass on Granular Activated Carbon – CIBGAC. In order to perform the electrodialysis process, the influence of various parameters such as current intensity, chloride, and sulphate concentrations were estimated. Therefore, an optimum efficiency of the denitrification for an applied current intensity value of 50 mA was obtained. The competition between the chloride and nitrate ions was encountered using the electrodialysis process inducing a slow electromigration of the nitrates. In contrary, the presence of sulphate ions had no influence on the electrodialysis during the denitrification. On the other hand, the biological denitrification of brines by electrodialysis was carried out. A clear decrease of pH was observed from 7.5 to 6.2 and the monitoring of the nitrate and nitrite ions through the bio-compartment affirmed the efficiency of this process. The successful establishment of the hybrid denitrification process was realized. Indeed, the treated water in dilute compartment was in conformity in terms of nitrates concentration and even more the concentrations of different ions are below the amounts recommended by the World Health Organization (WHO). TOHOH he brine solution after biological treatment agrees with WHO standards in terms of nitrate and nitrite ions.