污水硝化过程中N2O逸出控制的理论与实践

在污水生物脱氮工艺中,硝化过程是由自养硝化菌和异养硝化菌共同完成的.2类细菌的N2O生成机理及逸出量与系统中溶解氧的高低密切相关.了解硝化系统中的典型菌种自养菌Nitrosomonas europaea和异养菌Alcaligenesfaecalis生成N2O的机理是控制硝化过程中N2O逸出的理论基础,通过筛选优势菌种构建同步硝化-反硝化作用则是控制N2O逸出的新途径.     

贫营养异养硝化细菌的分离鉴定及硝化性能研究

从水库底泥中分离出1株贫营养异养硝化细菌,命名为菌株Y11。经菌株生理特性研究和16SrDNA测序,鉴定出菌株Y11属于假单胞菌属细菌(Pseudomonas sp.)。考察了温度、pH及C/N对菌株Y11的硝化性能影响,结果表明,菌株Y11进行硝化作用的最适温度为30℃,最适pH为中性,最适C/N为6.0,在该条件下进行4d的硝化反应,菌株Y11对氨氮去除率可达91.42%。     

一株高效异养硝化-好氧反硝化菌的分离鉴定及脱氮性能

从经驯化的污泥中筛选出一株异养硝化-好氧反硝化细菌，编号为TN-05，通过形态学特征观察，生理生化特征试验和核酸序列分析鉴定其为门多萨假单胞菌（pseudomonasmendocina）。同时对其进行脱氮性能研究，结果表明，TN-05具有较好的异养硝化能力，菌株在培养至48h时对总氮和氨氮去除率均能达95％以上。通过反硝化能力验证实验发现，菌株对NO3-N和N0f—N也分别具有较好的去除效率。将菌株应用于人工合成废水中，发现对废水中氨氮优先利用并能在24h时使去除率接近100％，对硝态氮和亚硝态氮也具有一定的去除效率。因此，菌株TN-05是一株同时具备异养硝化和好氧反硝化能力的高效菌株。     

一株耐盐好氧反硝化细菌的分离鉴定及其脱氮特性

从处理高盐废水的生物接触氧化工艺成熟活性污泥中分离得到一株耐盐好氧反硝化细菌F10.根据形态学特征、生理生化以及16S rRNA基因序列测定分析,初步判定该菌株为盐单胞菌属(Halomonas sp.).菌株能在盐度为3%~7%的培养基中良好的生长及脱氮,最适盐度为3%(以Na Cl计),最适碳源为乙酸钠,最适p H为7~8,最适温度为30℃.该菌株能利用NO-3-N进行反硝化作用,在盐度为3%的反硝化培养基中24 h内对NO-3-N的去除率达到92.6%,36 h基本完全去除。该菌株在3%盐度下表现出良好的异养硝化-好氧反硝化性能,初始硝态氮浓度在270 mg/L时,菌株的脱氮率可达90%以上,氨氮的去除率可达75%以上,脱氮过程中无NO-2-N积累,可实现同步硝化反硝化,具有一定的工程应用价值。     

异养硝化-好氧反硝化菌ADN-42的脱氮特性

从大连海域典型繁茂膜海绵(Hymeniacidon perleve)中筛选出1株耐盐异养硝化-好氧反硝化菌,通过形态观察、生理生化实验和16S rRNA基因序列分析,确定其为假单胞菌属(Pseudomonas),命名为ADN-42。其异养硝化-好氧反硝化条件为氯化铵为氮源,柠檬酸三钠为碳源,温度30℃,C/N值为12,摇床转速150 r/min,NH+4-N初始浓度约300 mg/L,盐度为40 g/L Na Cl,在此条件下菌株84 h时NH+4-N去除率为75.4%,无硝态氮产生,亚硝态氮最大积累量为8.3 mg/L;将菌株投加到NH+4-N和NO-2-N混合体系中,混合系统比仅以NH+4-N为氮源的体系的NH+4-N去除速率提高了12.7%;研究结果表明Pseudomonas sp.ADN-42可能是一株有着良好应用前景的高效耐盐异养硝化-好氧反硝化菌。     

异养硝化-好氧反硝化菌YZ-12的脱氮性能及其对养殖废水的处理效果

为获得高效脱氮菌,从南昌县一中型养猪厂曝气池筛选出一株异养硝化-好氧反硝化菌株YZ-12,经过16S rRNA基因序列分析,鉴定其为Klebsiella oxytoca;随后检测了该菌株的硝化和反硝化能力.结果 表明,在NH4-N质量浓度为100 mg·L-1的硝化培养基和NO3-N质量浓度为400 mg·L-1的反硝...     

蜡状芽孢杆菌WXZ-8的异养硝化/好氧反硝化性能研究

通过聚合酶链式反应(PCR)扩增、16S rDNA测序并结合同源性分析,鉴别出菌株WXZ-8为蜡状芽孢杆菌(Bacillus ce-reus).对菌株WXZ-8进行异养硝化/好氧反硝化性能测定,并通过正交实验进行培养条件的优选,选取的因素为COD/N、温度、转速和pH.结果表明,对菌株WXZ-8影响最大的因素是转速,其次为COD/N;在最优条件(即温度=30℃、COD/N=25、pH=9.0、转速=180 r/min)下,菌株WXZ-8的氨氮去除率最高达到96.06%.在最优条件下,提高初始氨氮质量浓度为211.52、429.16、897.29mg/L时.菌株WXZ-8在前48 h的氨氮去除速度均达到最大,分别为119.04、94.76,142.21 mg/(L·d),其氨氮去除率最高分别为94.41%、73.43%、51.08%.菌株WXZ-8具有良好的异养硝化/好氧反硝化性能.     

改性生物炭固定异养硝化菌对水中低浓度氨氮的去除

为探究改性生物炭固定异养硝化菌对水中低质量浓度氨氮(约10 mg/L)的去除效果,从污水处理厂污泥中筛选一株异养硝化菌,分别以未改性稻壳生物炭(BC)、NaOH和H2O2改性BC为载体,用吸附法制备生物炭基微生物固定化体(分别记为BC+N3、NaOH-BC+N3和H2O2-BC+N3),开展生物炭和生物炭基微生物固定化...     

不同分子量聚乳酸的异养反硝化脱氮性能及脱氮反应机制

聚乳酸(PLA)是一种发展潜力巨大的反硝化固体碳源。为探究不同分子量PLA反硝化脱氮路径及机制,以不同分子量PLA为固体碳源研究了PLA的静态释碳性能和反硝化脱氮效果,考察了反硝化出水溶解性有机质(DOM)组分和微生物群落结构。结果表明：PLA释碳稳定,在清水和脱氮反应器中出水COD均能稳定在20 mg·L^-1;PLA分子量越低,脱氮效果越好,5 000 g·mol^-1分子量PLA的NO₃^--N去除率和反硝化速率达到100%和1.29 mg·L^-1·h^-1。PLA脱氮路径有2条：一是反硝化功能菌群利用水解微生物分解PLA释放的小分子碳源作为电子供体进行异养反硝化作用;一是微生物利用溶解性微生物代谢产物等有机物进行反硝化脱氮。该研究结果可为PLA固体碳源在反硝化脱氮工艺中的高效应用提供参考。     

高温好氧反硝化菌的分离鉴定及脱氮特性

从太原市某污水处理厂SBR活性污泥中分离纯化得到一株高温(50℃)好氧反硝化菌,命名为XF3。通过生理生化特性鉴定及16S rDNA序列分析,初步鉴定为波茨坦短芽孢杆菌。通过单因子实验考察碳源、C/N、pH及接种量对该菌株的生长情况与反硝化性能的影响。结果表明,菌株XF3最适碳源为琥珀酸钠,最佳C/N为12∶1,最佳pH为7,最适接种量10%(体积分数)。同时该菌株具有良好的异养硝化能力,48 h可以将73 mg/L氨氮几乎全部降解。     

利用数学模拟方法分析硝化MBR系统中SMP转换过程

为深入了解膜生物反应器(MBR)中微生物代谢产物(SMP)的生成降解以及利用情况,研究了以NH4Cl为惟一能源物质的硝化MBR反应器中SMP浓度以及分子量(MW)变化情况,并运用活性污泥模型3(ASM3)准确地计算出微生物利用底物相关的溶解性产物(UAP)和微生物死亡相关的溶解性产物(BAP)的量分别是多少,最终证明硝化系统中产生的SMP可作为能源物质被异养菌进一步利用,而且相较于BAP而言UAP更易于被生物降解,得出结论 BAP是SMP中的主要污染成分。     

利用数学模拟方法分析硝化MBR系统中SMP转换过程

为深入了解膜生物反应器（MBR）中微生物代谢产物（SMP）的生成降解以及利用情况，研究了以NH4Cl为惟一能源物质的硝化MBR反应器中SMP浓度以及分子量（MW）变化情况，并运用活性污泥模型3（ASM3）准确地计算出微生物利用底物相关的溶解性产物（UAP）和微生物死亡相关的溶解性产物（BAP）的量分别是多少，最终证明硝化系统中产生的SMP可作为能源物质被异养菌进一步利用，而且相较于BAP而言UAP更易于被生物降解，得出结论BAP是SMP中的主要污染成分。     

Recycled and virgin plastic carriers in hybrid reactors for wastewater treatment.

The reduction of organic and nitrogen pollution of wastewater was investigated in two hybrid reactors and compared with the reduction obtained by using a conventional activated sludge reactor (ASR) run as a control. Both HR-1 and HR-2 were activated sludge systems where a low-density carrier, P1 (polyethylene) for HR-1 and P2 (recycled plastics) for HR-2, was added. Firstly, the three reactors were operated at 10 days Suspended Solid Retention Time (SRT(SS)), leading to a complete nitrification. Secondly, the SRT(SS) for each reactor was lowered to 3 days. Nitrification was lost for the ASR but remained complete for HR's. Respirometric techniques were used to measure fixed or suspended biomass activities for heterotrophic and autotrophic biomass. More than 90% of the autotrophic activity was found on the supports whatever the SRT(SS) used. The results may underline the role of the carrier geometry or surface characteristics on the autotrophic/heterotrophic microorganism distribution.     

Unraveling the source of nitric oxide emission during nitrification.

Nitric oxide production was measured during nitrification in a laboratory-scale bioreactor, operated at conditions relevant to municipal nitrifying wastewater treatment plants. This study aims to determine which type of microorganism and which metabolic pathway is responsible for nitric oxide emission during nitrification. Simulation studies were used to identify which pathway is the main source of nitric oxide emission, based on the following three hypothetical pathways for nitric oxide emission: (a) nitrification, (b) denitrification by ammonia-oxidizing bacteria with ammonium as electron donor, and (c) heterotrophic denitrification. The results of the study suggest that, in a nitrifying reactor treating wastewater containing solely ammonium and nutrients, denitrification by ammonia-oxidizing bacteria is the main nitric-oxide-producing pathway. During the experiments, 0.025% of the treated ammonium is emitted as nitric oxide, independent of the aeration rate imposed. Nitrite presence and oxygen limitation were found to increase the nitric oxide emission.     

Response of the bacteria and fungi of two soils to the sulfonylurea herbicide cinosulfuron.

Changes in aerobic bacteria and autotrophic nitrifier numbers, and in respiration and nitrification in two soils treated with cinosulfuron at 42 (field rate) and 4200 microg/kg were studied after 1 and 4 weeks of incubation under laboratory conditions. Only nitrification at 1 week was slightly inhibited by the cinosulfuron treatment, even at the field rate. In vitro toxicity tests carried out in agar media on representative aerobic bacteria, fungi and Azotobacter strains isolated from the two soils, as well as on nine collection soil bacteria, showed that only a very high cinosulfuron concentration (100 mg/l) can have negative effects on the growth of a limited number of soil heterotrophic microorganisms, under conditions similar to those of soil environment. The absence of three branched-chain amino acids increased bacterial sensitivity, thus showing the importance of the chemical conditions and suggesting acetolactate synthase enzyme blockage as the toxicity mechanism. It is concluded that cinosulfuron has a negative effect on only a few aspects of the microbial community in soil ecosystems, even at concentrations higher that those currently in use.     

生物活性炭填料反应器处理含盐水体的硝化性能

以颗粒活性炭为填料,采用盐度梯度两步驯化法构建含盐水体生物滤器硝化功能,研究了生物滤器稳定后水力停留时间(hydraulic retention time,HRT)、进水氨氮负荷和CODMn/N等对反应器硝化性能的影响。结果表明,25～27℃,盐度30的含盐水体生物滤器硝化功能构建需73 d,其中淡水生物滤器硝化功能构建需28 d,淡水驯化为盐度15的生物滤器需19 d,盐度15驯化为盐度30的生物滤器需26 d;实验条件下生物活性炭填料反应器中生物量达到146～742.1 nmolP/g-BAC;调节进水氨氮浓度2 mg/L左右时,最佳HRT为1 h,氨氮去除率达到84.98%,相应的氨氧化菌和硝酸菌氧吸收速率(oxygen uptake rate,OUR)分别为2.091和1.948 mg O2/(g-BAC.h);HRT为1 h时,随着进水氨氮负荷的加大,氨氮去除率逐渐降低,当进水氨氮负荷由0.12增加到0.48 g-N/(kg-BAC.d)时,氨氮去除率由84.98%降低到41.68%,同时氨氧化菌OUR由2.091降低到0.625 mg O2/(g-BAC.h);随着CODMn/N的升高,氨氮去除率下降,CODMn/N从1～8时,氨氮去除率由84.98%降低到53.64%,CODMn去除率却逐渐增加,由40.86%增加到93.59%,异养菌OUR随着CODMn/N升高呈上升趋势,最大达到0.914 mg O2/(g-BAC.h)。     

Investigation of triclosan fate and toxicity in continuous-flow activated sludge systems

The purpose of this research was to study the fate and toxicity of triclosan (TCS) in activated sludge systems and to investigate the role of biodegradation and sorption on its removal. Two continuous-flow activated sludge systems were used; one system was used as a control, while the other received TCS concentrations equal to 0.5 and 2mgl(-1). At the end of the experiment, 1mgl(-1) TCS was added in the control system to investigate TCS behaviour and effects on non-acclimatized biomass. For all concentrations tested, more than 90% of the added TCS was removed during the activated sludge process. Determination of TCS in the dissolved and particulate phase and calculation of its mass flux revealed that TCS was mainly biodegraded. Activated sludge ability to biodegrade TCS depended on biomass acclimatization and resulted in a mean biodegradation of 97%. Experiments with batch and continuous-flow systems revealed that TCS is rapidly sorbed on the suspended solids and afterwards, direct biodegradation of sorbed TCS is performed. Regarding TCS effects on activated sludge process, addition of 0.5mgl(-1) TCS on non-acclimatized biomass initially deteriorated ammonia removal and nitrification capacity. After acclimatization of biomass, nitrification was fully recovered and further increase of TCS to 2mgl(-1) did not affect the performance of activated sludge system. The effect of TCS on organic substrate removal was minor for concentrations up to 2mgl(-1), indicating that heterotrophic microorganisms are less sensitive to TCS than nitrifiers.