微涡流絮凝在矿井废水处理中的应用

微涡流絮凝作为矿井废水处理的预处理工艺,对去除悬浮物有很高的效率。通过某矿区废水处理工程的运行实践表明,进水悬浮物浓度在1400²200mg·L-1时,微涡流絮凝对悬浮物去除的效率保持在94%以上,为后续污水处理回用提供了可靠的保证。项目运行一年多来,该设备运行稳定。     

复合生物絮凝剂CBF-1的制备及其絮凝特性

采用机械混合的方法,将微生物絮凝剂MBF8与植物胶粉羧甲基改性絮凝剂CG-A复合制备了新型高效复合生物絮凝剂CBF-1.采用FT-IR、zeta(ξ)电位、透射电镜分析,确定了CBF-1的特征官能团、电荷性及分子胶束形态等物化性质;采用烧杯絮凝实验,探究了CBF-1的絮凝特性.结果表明,制备CBF-1的最佳CG-A∶MBF8质量复合比为4∶6;CBF-1为含少量沉淀物的淡黄色液体(不溶物0.013%),有效成分为0.5%,pH6.1,相对粘度1.72;有效成分0.1%时等电点约pH1.5;主要特征官能团有羟基、羧基、氨基、酰胺基及磷酸基.采用PAC(3mg·L-1)+CBF-1(1.0～8.0mg·L-1)复配絮凝,适用的pH为6.0～10.0,离子强度为0.5～5.0mmol·L-1;对浊度100NTU的高岭土悬浊液,在最佳条件PAC(3.0mg·L-1)+CBF-1(1.0～2.0mg·L-1),pH8.0,离子强度3.0mmol·L-1下,浊度去除率>92%,残余铝<75μg·L-1;对浊度6～300NTU的水,浊度去除率为61%～98%.     

含特殊悬浮物矿井水正交混凝试验研究

针对煤矿在特定时期排出的以微细岩石粉为主的特殊悬浮物矿井水水质,设计了L25(56)正交混凝试验,考察混凝过程中各因素对出水浊度的影响程度及最优化条件.结果表明,在各因素水平取值范围内,各因素对出水浊度的影响显著性次序为:絮凝剂投加量＞絮凝剂种类＞PAM投加量＞絮凝转速＞絮凝时间＞PAM投加间隔时间;混凝的最优化条件:选择PAFC作为絮凝剂,PAFC投加量为250 mg·L-1,PAM投加量为0.50 mg· L-1,PAM投加间隔时间为120 s,絮凝转速和时间分别为190 r·min-1快速搅拌2 min、70 r·min-1中速搅拌10min、40 r·min-1慢速搅拌13 min.     

改性壳聚糖絮凝剂处理印染废水的研究

研究了用壳聚糖与丙烯酰胺接枝共聚物做为絮凝剂对印染废水的絮凝处理,并与壳聚糖进行了絮凝效果比较,结果表明,其絮凝效果明显好于壳聚糖,在pH值为5～8范围内,PAC和接枝共聚物浓度分别为400mg·L-1和100mg.L-1时,其对印染废水的色度和COD去除率分别为最好,达到95.92%和76%。     

生物絮凝剂产生菌的分离鉴定及其在饮用水除浊上的作用

从活性污泥中筛选分离到一株高效生物絮凝荆产生菌F1,鉴定为克雷伯氏菌属(Klebsiella sp.).对其所产生物絮凝剂MBF1进行初步提取,考察了MBF1对长江原水浊度的去除效果.结果表明,在对长江原水处理中絮凝荆MBF1用量为40mg·L-1时,长江原水浊度和CODCr从处理前的56.2NTU和42.67mg·L-1下降到0.6NTU和13.47mg·L-1,去除率可达到99.0%和68.4%,处理后水的两指标达到饮用水标准.同时,比较了生物絮凝剂MBF1与聚合氯化铝、聚丙烯酰胺等化学絮凝剂对长江原水浊度的处理效果,结果发现MBF1具有用量更少(40mg·L-1),适应性广(pH 1～10,温度0～45℃条件下都有较好处理效果,且对搅拌程序无特殊要求)及处理效果好的特点.动物急毒性试验表明,该絮凝剂无急毒性反应,在给水处理中具有良好的应用前景.     

臭氧氧化-混凝深度处理印染废水试验研究

通过研究反应时间、pH值、H2O2投加量、PAC投加量、不同工艺顺序对处理印染废水结果的影响,表明臭氧氧化效果随处理时间增加而增强,但增强幅度越来越小;随着pH值、H2O2初始投加量的增加,先增大后减小。30%H2O2初始投加量为0.4mL·L-1,pH为10,臭氧投加速率5.96mg·min-1·L-1,时间为30min,再加入30mg·L-1的PAC,调节pH为8搅拌絮凝,静止30min后,印染废水的CODcr和色度去除率分别为60%和96%,UV254为0.082,去除效果明显。     

珠江三角洲典型集约化猪场废水污染特征及风险评价

根据2009年3月~2011年11月废水水质调查监测数据,运用《畜禽场环境质量评价准则》中单项污染指数、综合污染指数等方法,研究珠江三角洲典型集约化猪场厌氧发酵处理过程中各工艺阶段废水污染特征,并对其潜在生态风险进行综合评价.监测结果表明,所有监测值中,除pH和重金属外,其它污染因子含量普遍超过排放及农田灌溉水质标准,猪粪水中主要污染因子为粪大肠菌群(FC)、总磷(TP)、化学需氧量(COD)和生化需氧量(BOD),其平均质量浓度分别为1.98×109个·L-1、158.61 mg·L-1、5 608.68 mg·L-1和1 984.34 mg·L-1,猪场沼液中主要污染因子为粪大肠菌群、总磷、氨氮(NH+4-N)和悬浮物(SS),其平均质量浓度分别为8.10×106个·L-1、81.76 mg·L-1、476.24 mg·L-1和464.58 mg·L-1.生态风险评价表明,高值区主要出现在固液分离后的高浓度废水,其分布呈现从分离后废水>冲栏废水>沼液递减的趋势特征,其综合污染指数分别为11.41、6.91、5.27,均达到重度污染级.因此,分离前后猪场废水属高浓度、高风险废水,绝对不可直接排放和农田灌溉,经厌氧处理后的猪场沼液中粪大肠菌群、总磷、氨氮和悬浮物是潜在的强生态风险元素,在长期直接排放或农田灌溉过程中仍存在一定的生态风险,有进一步深度处理的必要性.     

聚合氯化铝与聚磷硫酸铁絮凝除藻比较研究

针对武汉市莲花湖湖水,采用聚合氯化铝(PAC)和聚磷硫酸铁(PPFS)进行絮凝实验,比较了两种无机絮凝剂的絮凝效果及原水处理前后藻类群落变化。主要结论如下:①PPFS与PAC的最佳投加量分别为1.5mg/L、2.0mg/L;②PPFS在去除藻类细胞、浊度和色度方面均优于PAC,当PPFS投加过量时,因水体中Fe3+过量分布,使水样色度去除率下降;③PPFS絮凝处理微囊藻为主体的水华原水时,其效果比PAC更好。本文研究后表明:PPFS是一种新型高效絮凝剂,其絮凝性能明显优于PAC,当水体以微型藻类为主时,可使用PPFS以替代PAC,能提高絮凝效果。     

混合碳源制备生物絮凝剂的絮凝效能及产量预测模型

为实现混合底物的高效定向转化,以产絮菌根癌农杆菌(Agrobactrium tumefaciens)F2为研究对象,考察不同单一碳源及不同初始浓度对菌体生长、絮凝效能及絮凝剂产量的变化规律,采用BP算法构建絮凝效能及产量预测神经网络.产絮菌F2利用葡萄糖时的絮凝效能和产量分别为88.98%和2.20 g·L-1,过低的初始浓度将影响产量,不低于7.5 g·L-1为佳.以D-(+)-葡萄糖、D-半乳糖和D-甘露糖3种单糖为混合碳源,构建网络结构为3-5-2的产絮效能及絮凝剂产量预测模型,对两个输出层的预测误差范围均在4%以内,预测葡萄糖、半乳糖、甘露糖浓度的最优解为6.59 g·L-1、1.32 g·L-1、3.57 g·L-1,经验证混合碳源发酵产絮可使絮凝效能和产量比单一葡萄糖发酵时分别提高6.87%和26.82%,本文为产絮菌F2利用含糖有机质废液发酵产絮凝剂提供数据参考.     

二乙烯三胺接枝螯合絮凝剂的制备及其除汞性能

以聚丙烯酰胺（PAM）、甲醛、二乙烯三胺(DETA)为原料,按照Mannich反应机理制备部分胺化接枝型螯合絮凝剂(CFA),并对其去除水中汞的性能进行了研究.同时,实验考察了螯合絮凝剂合成及从含汞废水中除汞的最佳条件.结果表明,基于在聚丙烯酰胺分子长链上引入具有螯合作用的基团,所得的螯合絮凝剂既具有捕捉Hg2+的螯合作用又具有絮凝作用,对含汞8.1mg·L-1的模拟废水,按0.020%的投加量(絮凝剂与废水质量比),在搅拌速度80~100r·min-1、搅拌时间15min、沉降时间10min的条件下,进行絮凝沉淀处理后,可去除99.5%的汞,除汞效果明显,处理后的水可达到国家排放标准.因此,螯合絮凝剂可用于低浓度含汞废水的处理.同时,该螯合絮凝剂具有合成工艺简单、除汞快速、操作简便等特点,可望成为一种新型、低成本含汞废水处理材料.     

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.