固相自养-异养反硝化脱氮同步去除微污染物

针对固相反硝化体系,以聚己内酯复合花生壳(PCL/PS)的固体碳源为基底,耦合以S和Fe O主导的自养反硝化,构建新型多功能碳源,考察其对典型微污染物(Cr(Ⅵ)、Cl O₄^-、BPA、NPX)与硝酸盐的同步降解效能,探究自养异养共存的反硝化体系内微生物群落特征及微观作用机制.结果表明,PCL/PS异养反硝化体系具有更好的反硝化脱氮和同步去除Cr(Ⅵ)、BPA性能,对NO₃^--N、Cr(Ⅵ)的去除率分别为94%、92%,对NO₃^--N、BPA的去除率均可达99%以上;PCL/PS同时耦合Fe O和S的体系反硝化脱氮同步去除Cl O₄^-、NPX性能良好且稳定,在反硝化率均维持90%的基础上,对NO₃^--N、Cl O₄^-的去除率分别达90%、96%,对NO₃^--N、NPX的去除率分别达9...     

改性Cu-Pd双金属电极电化学还原硝酸盐性能研究

为揭示高盐废水中电催化还原硝酸盐氮的能力,采用阴极电沉积法成功制备了NF/CNTs/Cu-Pd双金属复合电极.通过SEM-EDS、XRD和XPS表征,证实CuPd纳米颗粒成功沉积在泡沫镍(NF)底板上.研究了电流密度、初始pH值、初始硝酸盐浓度和Cl^-浓度等因素对模拟水中NO₃^--N、TN的去除能力的影响,并用实际高盐废水验证了其可行性.结果表明:没有Cl^-存在情况下,NF/CNTs/Cu-Pd可有效去除NO₃^--N,但TN去除能力一般,NO₃^--N主要转化为NH₄⁺-N.有Cl^-存在作用下,NO₃^--N、TN得到有效去除.反应最佳条件为:电流密度30mA/cm²,初始pH值7,初始浓度50mg/L,氯离子浓度2.0g/L,此时NO₃^--N...     

薯渣缓释碳源强化反硝化滤池生物脱氮效果

为解决城市污水深度处理碳源不足导致脱氮效果不佳的问题,该文制备了具有缓慢释碳功能的薯渣固体缓释碳源SCPR。释碳试验与强化反硝化生物滤池(DNBF)脱氮试验表明,SCPR最大有机物释放量为129.87 mg/(L·g),碳源释放过程满足二级动力学,在水力负荷为0.1 m³/(m²·h)、SCPR与陶粒配比为1∶6、进水NO₃^--N平均浓度为50.09 mg/L时,DNBF中NO₃^--N、NO₂^--N与TN去除率分别为75.53%、86.21%与74.98%,出水 COD平均浓度为 25.24 mg/L,SCPR作用下DNBF反硝化反应级数介于零级与一级之间。SCPR具有良好的释碳与强化DNBF脱氮效果的能力,可作为污水深度脱氮处理的碳源。     

厌氧氨氧化耦合反硝化底物竞争抑制特性

通过连续流实验和批式实验研究了有机物和NO₂^--N对厌氧氨氧化菌和反硝化菌耦合脱氮特性的影响.在连续流实验中,保证底物NO₂^--N充足,研究了葡萄糖有机物对厌氧氨氧化颗粒污泥反应器脱氮性能的影响.当进水葡萄糖有机物的COD浓度为100mg/L时,颗粒污泥具有良好的厌氧氨氧化耦合反硝化脱氮活性,当COD浓度为200mg/L时,颗粒污泥的厌氧氨氧化耦合反硝化脱氮活性较差.当进水COD浓度分别为100,200mg/L时,反应器中颗粒污泥的厌氧氨氧化NH₄⁺-N去除活性分别为0.096,0.071kg NH₄⁺-N/（kgVSS-d）,厌氧氨氧化NO₂^--N去除活性分别为0.153,0.092kg NO₂^--N/（kgVSS-d）,反硝化NO₂^--N去除活性分别为0.111,0.212kg NO₂^--N/（kgVSS-d）.在批式实验中,研究了碳源种类和COD/NO₂^--N比对厌氧氨氧化耦合反硝化颗粒污泥脱氮性能的影响.控制COD/NO₂^--N比为1~4,以葡萄糖为碳源时,厌氧氨氧化菌在亚硝态的竞争过程中占据优势;以乙酸钠为碳源时,控制COD/NO₂^--N比为1~4,厌氧氨氧化菌在亚硝态的竞争过程中处于劣势.     

缓释碳源填充管式生物反应装置强化脱氮性能及其微生物分布特征

为研究缓释碳源填充管式生物反应装置(TBD)对不同氮组分生活污水的脱氮性能及机理,考察中试规模的TBD在3种不同溶解氧(DO)、氨氮(NH₄⁺-N)及硝氮(NO₃^--N)浓度工况下的实际运行效果,同时监测TBD沿程的DO浓度、碳氮比(C/N)、碳源等环境因子变化情况,并在运行期末对TBD的管内基质进行16S rRNA多样性高通量测序。结果表明：3种工况条件下TBD对污水中NH₄⁺-N、NO₃^--N和总氮(TN)的去除率均达90%以上,TBD具有良好的脱氮性能;缓释碳源有助于TBD沿程C/N的增加,且TBD出水CODCr始终低于GB 3838—2002《地表水环境质量标准》Ⅴ类水质标准限值,表明TBD在强化脱氮的同时不会产生有机质过量排放问题。此外,TBD中DO浓度沿程递减,形成了好氧-缺氧沿程分布的特征,且该特征促进了好氧反硝化-缺氧反硝化菌属在TBD的沿程分布。     

好氧反硝化菌LJ-1的脱氮及自聚集性研究

兼具成膜与高效脱氮好氧反硝菌株的获得,可以减少功能菌流失并维持高效脱氮。该研究通过富集、分离筛选获得一株好氧反硝化菌株LJ-1。通过形态学观察和16S rRNA基因序列分析,确定该菌株为施氏假单胞菌(Pseudomonas stutzeri)。对该菌株的脱氮特性和影响因素进行研究,结果表明,该菌株在以NH₄⁺-N、NO₃^--N和NO₂^--N为单一氮源时(100 mg/L),氮去除速率分别高达90.99%,96.53%和99.79%。反硝化脱氮最适生长条件测试分析表明,菌株的最佳碳源为葡萄糖,最适C/N为10,最适pH为9。菌株的自聚集和疏水性指数分别高达66%和59%,呈现高效的自聚集成膜特性。富含蛋白质类和多糖类物质的胞外聚合物成分与菌株的自聚集特性呈显著正相关。菌株LJ-1的获得有望实现高效除氮功能菌在污水处理系统中的长期固定,具有潜在的应用价值。     

一株Acinetobacter johnsonii的部分反硝化特性及动力学研究

从实验室A²/O小试设备中分离纯化出一株具有高亚硝酸盐氮（NO₂^--N）积累率的反硝化菌株ZY04,经过16SrDNA鉴定和基因比对后,初步鉴定为Acinetobacter johnsonii.使用Logistic模型可以很理想地拟合菌株ZY04的生长特性曲线,得到生长方程常数a=0.6588,b=24.08,k=0.2413.在维持初始基质中硝酸盐氮（NO₃^--N）浓度为100mg/L的条件下,改变碳源乙酸钠的浓度,使碳氮比（TOC/TN）为3.5,4.5,5.5,6.5,研究菌株ZY04部分反硝化性能,发现该菌株在不同碳氮比条件下均能够保持95%以上的NO₃^--N降解率,在碳氮比为3.5和4.5时,17h后NO₂^--N积累率达到70%以上;在碳氮比为5.5和6.5时,NO₂^--N积累率在更快的11h后达到85%以上,碳氮比为5.5时达到最高NO₂^--N积累率91%.使用Aiba,Edwards和Andrews模型对菌株的基质抑制动力学进行拟合,结果表明,3种模型均可以很好的拟合NO₃^--N和乙酸钠对菌株的单基质抑制动力学,在双基质抑制的9种组合中,有6种模型成功拟合了NO₃^--N和乙酸钠对菌株的双基质抑制动力学,得到了相关半饱和参数和基质抑制参数,相关系数（R²）可以达到98%.     

氮氧同位素示踪湿沉降NO3-来源及氧化途径

为探明焦作市大气湿沉降中硝态氮的污染水平,识别其来源及其形成过程,于2020年1月-2021年12月采集了焦作市大气湿沉降样品41个,测定并分析了TN、NH₄⁺-N、NO₃^--N浓度以及δ¹⁵N-NO₃^-、δ¹⁸O-NO₃^-值.结果表明：(1)TN、NH₄⁺-N、NO₃^--N浓度范围分别为2.52～13.27、0.11～1.70、1.64～8.31 mg/L,焦作市湿沉降中氮的主要存在形态为NO₃^--N,占比为52.11%～83.92%.(2)δ¹⁸O-NO₃^-、δ¹⁵N-NO₃^-值的范围分别为54.9‰～93...     

部分反硝化耦合厌氧氨氧化脱氮性能研究

在稳定运行的包埋厌氧氨氧化反应器的基础上,经过94d的启动成功耦合部分反硝化,部分反硝化NO₂^--N积累率高达63.5%,与此同时NO₃^--N去除率稳定为98.4%.确定了耦合反应最佳COD/NO₃^--N比值范围为2.3~2.7.将pH值提升至8.0,8.5后发现,耦合性能下降,这与之前很多报道的结果不同.在耦合反应器的基础上添加PCL（聚己内酯）固体碳源进一步成功耦合全程反硝化,使得厌氧氨氧化所产生的NO₃^--N能够得到全部去除,TN去除率也由原来的79.4%提升至88.3%,同时发现大量反硝化生物膜附着生长于PCL颗粒上.     

厌氧氨氧化工艺处理含海水污水的亚硝态氮抑制及反应动力学

采用ASBR厌氧氨氧化反应器,在全海水条件下,通过固定进水NH₄⁺-N 110mg/L,逐渐提高进水NO₂^--N的方式研究了NO₂^--N对厌氧氨氧化脱氮的影响及抑制动力学和脱氮过程动力学.结果表明:进水NO₂^--N浓度达到170mg/L时,厌氧氨氧化反应开始受到明显抑制, NH₄⁺-N的去除率下降8.41%;修正的Logistic过程动力学研究结果显示,进水NO₂^--N低于151.49mg/L会促进厌氧氨氧化反应的进行,进水NO₂^--N高于170mg/L时开始抑制厌氧氨氧化反应的进行;Luong模型适合描述全海水条件下高浓度NO₂^--N对厌氧氨氧化脱氮效能的抑制动力学.Luong模型得到的最大基质转化速率(NRR_max)为0.53kg N/(m³·d),出水NO₂^--N半饱和常数(K_S)为0.10mg/L,净生长停止的出水NO₂^--N浓度(S_m)为338.22mg/L,Luong动力学常数(n)为0.41,相关系数为0.97801.     

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.     

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.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.