PN/A双菌层系统的构建及其脱氮性能

分别采用SBR反应器和MBR反应器驯化培养亚硝化污泥和厌氧氨氧化(anaerobic ammonia oxidation,ANAMMOX)污泥,并通过微生物包埋技术将两类污泥分别包埋,构建亚硝化-厌氧氨氧化(partial nitrification-ANAMMOX,PN/A)双菌层系统.短期实验证明该系统中亚硝化菌(ammonia oxidizing bacteria,AOB)和ANAMMOX菌在不同阶段分别起主导作用,维持系统的酸碱平衡,并实现NH+4-N的高效去除(98.8%).长期实验表明,在溶解氧受限时,PN/A双菌层系统能够有效提高系统对溶解氧的利用效率,并增强系统的稳定性和脱氮效能.在溶解氧为1.0 mg·L~(-1),进水NH+4-N质量浓度分别为200 mg·L~(-1)和400 mg·L~(-1)时,对照组脱氮效率仅为58.1%和61.4%,而PN/A双菌层系统脱氮效率均稳定在80%左右;溶解氧为3.0mg·L~(-1),进水NH+4-N质量浓度为400 mg·L~(-1)时,PN/A双菌层系统总氮去除率达87.9%,总氮积累负荷(NLR)为0.4kg·(m3·d)-1,总氮去除负荷(NRR)为12.8 mg·(g·h)-1.     

高含氟的光伏废水反硝化可行性及经济性分析

在多晶硅废水处理过程中,为了减少先除氟后脱氮工艺中酸碱的投加量.本实验运行反硝化反应器研究了先脱氮后除氟工艺中先脱氮的可行性.结果表明,废水中F-浓度对反硝化存在一定的影响.当F-浓度控制在750 mg·L~(-1)左右,反硝化污泥脱氮速率无明显影响,当F-浓度继续增加时,反硝化污泥的脱氮速率逐步降低.在处理含F-(浓度控制在800 mg·L~(-1))多晶硅清洗废水时,反硝化污泥的脱氮性能无明显影响,经过93 d的运行,总氮出水稳定在50 mg·L~(-1)以内,总氮去除率达到90%以上,去除速率达到5 kg·(m~3·d)~(-1).经计算,与传统先除氟后脱氮工艺相比,可节省大约70%的碱投加量和100%的酸投加量,极大地降低废水处理成本.     

硫自养反硝化处理高含氟光伏废水可行性

为了研究硫自养反硝化处理高含氟光伏废水的可行性,室温(20~25℃)下,采用驯化后的硫自养反硝化生物膜反应器,探究了不同进水F-浓度对硫自养反硝化脱氮效能的影响.结果表明,当进水F-浓度为0~700 mg·L~(-1)时,随着F-浓度的提升,反应器的脱氮效能逐渐提升,且当F-浓度为700 mg·L~(-1)时,可获最大TN去除速率1.0 kg·(m3·d)-1.当进水F-浓度在700~900 mg·L~(-1)时,经短期驯化,TN去除速率可稳定在0.81~0.87 kg·(m~3·d)~(-1).当进水F-浓度提升至900 mg·L~(-1)以上时,反应器的TN去除速率随进水F-浓度的提升而下降,最低至0.4~0.5 kg·(m~3·d)~(-1).以光伏废水为研究对象,在进水F-浓度为800 mg·L~(-1)左右,进水NO_3~--N浓度为390~420 mg·L~(-1),HRT为8.8 h的条件下,经50 d运行后,获得稳定的脱氮效能,TN去除速率为1.1 kg·(m~3·d)~(-1),出水TN为15~25 mg·L~(-1),达到污水接管排放标准.采用传统反硝化工艺和硫自养反硝化工艺脱氮处理光伏废水的成本分别为2.468元·t~(-1)和2.072 8元·t~(-1),硫自养反硝化工艺更节约脱氮处理成本.     

纳米零价铁对升流式颗粒污泥床反硝化性能的影响

为探究连续流条件下,纳米零价铁(nZVI)对反硝化颗粒污泥(DGS)性能的影响,本文利用升流式污泥床(USB),系统考察了反应器脱氮效能、污泥形态和反硝化特性随进水nZVI浓度的变化规律.结果表明,当nZVI5 mg·L~(-1)时,反应器脱氮效能与对照期(nZVI=0 mg·L~(-1))相差很小,DGS活性略微增大.当nZVI浓度在5~10 mg·L~(-1)时,DGS对nZVI的生物抑制作用表现出一定适应性,污泥浓度和颗粒粒径仍保持增长趋势,但泥相中总铁含量明显增大,DGS活性开始降低.当nZVI浓度增至30 mg·L~(-1)时,反应器对COD和NO-3-N的去除率分别降至对照期的23.3%和20.3%.DGS因吸附大量nZVI而呈黑色,颗粒粒径减小,污泥表面短杆菌等微生物密度明显降低.停止投加nZVI后,污泥浓度与DGS活性的持续上升,使得反应器脱氮效能在20 d内基本恢复至对照期的水平.异养菌在颗粒表面的快速增殖是实现上述目标的主要原因.     

饥饿对硫自养反硝化反应器生物群落结构的影响

采用颗粒硫磺/白云石和黄铁矿/白云石自养反硝化反应器处理二沉尾水,探究饥饿忍耐对反应器去除效果、微生物群落变化的影响及其性能恢复时间.结果表明,在12~14℃的低温条件下,经过30 d的不进水饥饿忍耐后,颗粒硫磺/白云石和黄铁矿/白云石反应器出水NO_3~--N浓度分别从1.78 mg·L~(-1)、11.32 mg·L~(-1)增加到27.87 mg·L~(-1)、26.56 mg·L~(-1).颗粒硫磺/白云石和黄铁矿/白云石自养反硝化反应器分别在重启后的第5 d和11 d使得NO_3~--N去除性能恢复至饥饿前的水平,并且在低温条件下保持了良好的脱氮效果.MiSeq高通量测序结果表明,2个反应器的细菌群落的丰度和多样性饥饿期均低于恢复期,且优势菌门均为Proteobacteria,主要的纲类为β-Proteobacteria.硫磺/白云石反应器中鉴别出Thiobacillus菌属为主要反硝化类群.     

反硝化-短程硝化-厌氧氨氧化工艺处理晚期垃圾渗滤液的脱氮除碳性能

本研究在一体式分区反应器中接种成熟的厌氧氨氧化污泥和亚硝化污泥,通过与反硝化反应器串联,研究了前置反硝化与短程硝化-厌氧氨氧化串联工艺处理晚期垃圾渗滤液的脱氮除碳性能.结果表明,未串联反硝化之前,短程硝化-厌氧氨氧化反应器在进水氨氮浓度为600 mg·L~(-1),COD浓度483 mg·L~(-1)时,总氮去除速率(NRR)可达1.88 kg·(m3·d)-1,总氮去除率(NRE)可达90.3%;而在进水COD浓度483 mg·L~(-1),即C/N0.8时,短程硝化-厌氧氨氧化反应器的NRR下降至1.50 kg·(m3·d)-1.通过前置反硝化反应器可以迅速缓解有机物对厌氧氨氧化的不利影响;反硝化与短程硝化-厌氧氨氧化串联反应器在进水NH+4-N浓度为1 100 mg·L~(-1),COD浓度1 150 mg·L~(-1)时,仍可稳定高效运行,整体NRR可达1.37kg·(m3·d)-1,厌氧区NRRana高达15.6 kg·(m3·d)-1,平均NRE可达98.6%,在仅利用原水中有机碳源的情况下实现了垃圾渗滤液的高效深度脱氮.此工艺晚期处理垃圾渗滤液可去除大部分易生物降解有机物.     

磷酸盐对CANON工艺的脱氮特性研究

为考察全程自养脱氮(CANON)处理高浓度含氮磷废水的可能性,以人工配制高氨氮废水为进水,研究了磷酸盐对连续流CANON工艺的脱氮性能的影响.结果表明:CANON反应器控制p H在7.60~7.80,HRT为16.5 h和温度(30±1)℃的条件下,当磷酸盐浓度为30 mg·L~(-1)时,反应器的脱氮性能达到最高,NH+4-N平均去除率为98.3%,TN的平均去除率85.3%,NRR为1.1 kg·m~(-3)·d-1.磷酸盐浓度大于30 mg·L~(-1)时,反应器内的微生物浓度逐渐降低,总氮去除效率逐渐降低.在整个磷酸盐试验期间,磷酸盐对短程硝化无明显影响,而对ANAMMOX反应影响较大.     

低温SNAD颗粒污泥工艺启动方式

为研究启动方式对同步短程硝化、厌氧氨氧化耦合反硝化(SNAD)颗粒污泥工艺的影响,低温(12.7~18.3℃)条件下,R1和R2反应器分别通过先启动全程自养脱氮(CANON)工艺和先启动厌氧氨氧化耦合反硝化(SAD)工艺的方式逐步启动SNAD颗粒污泥工艺.结果表明,R1反应器启动成功后,氨氮几乎完全去除,总氮去除率达到86.7%.低氨氮浓度运行时,出水总氮去除率下降至75.3%,出水总氮浓度在10 mg·L~(-1)左右,NOB存在过量增殖现象,出水总氮浓度超过北京市水污染物排放标准一级A规定.R2反应器启动成功后,出水几乎不含氨氮,总氮去除率在89.1%左右,略高于R1反应器.低氨氮浓度运行时,出水氨氮浓度小于1.0 mg·L~(-1),出水总氮浓度小于6 mg·L~(-1),出水氨氮和总氮浓度满足地标一级A标准.先启动SAD工艺可以在启动初期通过厌氧运行将NOB逐渐淘汰出系统内,维持了系统的稳定性,为后续曝气启动SNAD工艺提供了良好的基础,维持了反应器的稳定运行,实现出水总氮长期排放达标.     

基于CANON工艺的新型HABR反应器生物脱氮性能研究

采用新型复合式折流板反应器(HABR)启动及运行全程自养脱氮(CANON)工艺.通过缩短水力停留时间(HRT)的方式提高进水总氮负荷启动反应器,反应器运行成功后,考察反应器沿程氮素、电导率、p H值及MLSS的变化规律,并对反应器内微生物种群形态结构及空间分布进行分析.结果表明,当进水NH_4~+-N平均浓度为40 mg·L~(-1)时,经过89 d的连续运行,新型HABR反应器实现了快速启动,并能稳定运行至187 d,稳定运行期出水NH_4~+-N和TN浓度分别稳定在2 mg·L~(-1)和10 mg·L~(-1)以下,去除率分别达到96%和83%以上,NRR达到0.15 kg·(m~3·d)~(-1).稳定运行阶段,NH_4~+-N与TN浓度在反应器沿程逐渐降低,NO-2-N和NO-3-N的生成量一直维持在较低浓度.第1个单元格脱氮效率最高,通过SEM和FISH分析表明,在第1个单元格中存在丰富的功能菌种亚硝化菌(AOB)和厌氧氨氧化菌(An AOB).     

低浓度氨氮废水单级自养脱氮EGSB反应器的快速启动

将单级自养脱氮生物膜污泥作为种泥接种于膨胀颗粒污泥床反应器中,并对该反应器进行启动.在温度为(30±2)℃,p H值为7.8~8.2,DO为0.2~1.1 mg·L~(-1),上升流速为2.0~4.0 m·h~(-1)的条件下,进行了低浓度氨氮(60~100 mg·L~(-1))废水的单级自养脱氮工艺快速启动研究.结果表明,经过83 d的运行,反应器历经适应期、提高期和稳定期后,稳定运行阶段NH_4~+-N、TN去除率分别达到99.4%和80.7%.通过控制回流比和提高进水氨氮负荷维持了稳定的低DO状态,有效抑制了硝化细菌的生长,而部分亚硝化反应和厌氧氨氧化反应为主导反应并能保持高效、稳定的脱氮效果,成功实现了在膨胀颗粒污泥床反应器中单级自养脱氮过程的启动.颗粒污泥平均粒径从174μm增大到296μm.扫描电镜显示颗粒污泥表面光滑,微生物以球菌、短杆菌为主.FISH结果显示亚硝化细菌分布在颗粒污泥表面,厌氧氨氧化菌分布在颗粒污泥内部.反应器中构建了稳定的自养脱氮颗粒污泥系统.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.