复菌生物絮凝剂在纸箱废水处理中的实验研究

文章将微生物絮凝剂产生单菌M-3和M-2共同培养,获取生物絮凝剂,进行提取生物絮凝剂粗品,处理某纸箱厂废水。对生物絮凝剂投加量、Ca2＋离子浓度、pH值的影响条件进行较系统的研究,绘制出单一因素对生物絮凝剂处理效果影响的曲线,确定生物絮凝剂处理纸箱厂废水的最适条件,进行正交实验。实验表明复合型微生物絮凝剂对纸箱厂废水有较好的处理效果。单菌微生物絮凝剂絮凝率在92%以上,COD去除率接近55%,氨氮去除率也达到89%。复合型生物絮凝剂在更少的药剂下能获得比单菌絮凝剂更好的处理效果。絮凝率可达93%,COD去除率达到74%,氨氮去除率达到90%。     

化学生物絮凝工艺污染物去除试验研究

化学生物絮凝污水处理工艺是一种新的一级强化处理工艺。该工艺在传统的化学混凝的基础上将沉淀池内的污泥回流至化学生物絮凝池,利用化学混凝和污泥吸附的协同作用去除污水中的污染物。中试试验结果表明,聚合硫酸铝铁絮凝剂投加量为70mg/L,PAM投加量为0.5m g/L时,COD、TP和SS去除率分别为61.8%、74.5%和74.6%。化学生物絮凝池内污泥富集了未反应的絮凝剂,这部分絮凝剂对污水中TP具有很好的去除作用。化学生物絮凝池内污染物的沿程分析显示,回流污泥与污水充分接触可促进TP的进一步去除。     

化学生物絮凝工艺处理城市污水比较研究

本文比较了化学生物絮凝工艺和化学絮凝工艺对城市污水的处理效果。试验结果为化学生物絮凝工艺的COD、TP、SS去除率为70％、74％、88％，化学絮凝工艺分别高出12％、12％、3％；污泥产量为4kg／d，相对化学絮凝工艺而言要少10％～15％。从而得出，化学生物絮凝工艺比化学絮凝工艺更适合处理城市污水。     

生物絮凝剂在纸箱废水处理中的实验研究

文章将微生物絮凝剂产生单菌M－3和M－2共同培养,获取生物絮凝剂,进行提取生物絮凝剂粗品,处理某纸箱厂废水。对生物絮凝剂投加量、Ca^2＋离子浓度、pH值的影响条件进行较系统的研究,绘制出单一因素对生物絮凝剂处理效果影响的曲线,确定生物絮凝剂处理纸箱厂废水的最适条件,进行正交实验。实验表明单菌微生物絮凝剂絮凝率在92％以上,COD去除率接近55％,氨氮去除率也达到89％。     

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.     

生物絮凝剂(普鲁兰)处理渗滤液的试验研究

通过试验对生物絮凝剂(普鲁兰)和其它絮凝剂处理渗滤液的效果进行了比较、分析,对絮凝机理进行了探讨。对普鲁兰与硫酸铝复合处理渗滤液进行了试验研究,试验表明:普鲁兰与硫酸铝复合在处理渗滤液方面有着较好的应用前景。其COD去除率80%,浊度去除率95%以上。     

化学絮凝法处理实验室废水的研究

用8种无机絮凝剂对实验室废水的絮凝效果进行了比较。以碱式氯化铝和硫酸亚铁并用为絮凝剂,对废水的絮凝沉淀处理进行了工艺条件试验。在最佳工艺条件下,进行了小型试验。结果表明,用化学絮凝法处理实验室废水,对COD_■、BOD_5、有机物和重金属离子等的去除,具有显著效果。     

化学絮凝法和微电解法预处理酯化废水研究

研究了化学絮凝法和微电解法预处理酯化废水的工艺条件。首先考察了原水p H值、絮凝剂投加量及絮凝剂与阳离子聚丙烯酰胺复配对化学絮凝效果的影响;然后考察了p H、停留时间、填料量、曝气时间对微电解效果的影响。试验结果表明:化学絮凝在原水p H值为7.5、PFS+CPAM(360 mg/L+60 mg/L)时对酯化废水处理效果最好,COD去除率为17.23%;微电解法在最佳工艺条件(p H为2,反应时间为2 h,填料量为30%,曝气时间为5 min)下对酯化废水COD去除率达到30%以上,且在不调酸不曝气的情况下也可获得良好处理效果,COD去除率达20%以上,故酯化废水的预处理中采用微电解法。     

化学生物絮凝工艺污泥回流对污染物的絮凝效果研究

采用化学生物絮凝(CBF)工艺处理上海市城市污水,通过停止加药试验、不同污泥回流比模拟试验、污泥胞外聚合物组分及含量的分析测定,研究分析污泥回流对污染物去除效果的影响.结果表明,CBF的回流污泥具有较强的污染物去除能力,其携带的化学药剂可以增强系统抗磷酸盐冲击负荷能力,停止PAFC药剂投加期间,其COD去除率基本维持在50%以上, PO3-4、TP去除率呈现逐渐缓慢下降的趋势.化学药剂投加是CBF实现良好泥水分离效果的重要因素.CEPT工艺剩余污泥VSS中的EPS含量仅为17.24 mg/g,而CBF工艺VSS中的EPS含量高达145.89 mg/g,其微生物活性较高,生物絮凝能力较强.化学强化一级工艺(CEPT)剩余污泥中药剂的絮凝性能较差,其对TP和COD的去除能力随污泥回流比提高而显著降低,而由于存在生物絮凝作用,CBF系统的污泥具有较强的絮凝性能.化学生物絮凝工艺是一种化学与生物协同作用的污水强化一级处理工艺.     

化学生物絮凝工艺的反应机理初探

考察了化学生物絮凝工艺中的Zeta电位、颗粒物粒度分布和溶解性有机物的分子质量分级,并分别与化学强化一级工艺和初沉池进行了对比.研究表明,相同药剂投加量下,化学生物絮凝工艺和化学强化一级工艺的出水Zeta电位值基本相等,化学生物絮凝工艺的回流污泥所携带的化学药剂几乎不影响反应池内颗粒物的稳定状态,其中的生物作用是该工艺对污染物的絮凝效果优于化学强化一级工艺的关键因素.在化学生物絮凝工艺中,投加药剂仅对粒径>10 μm颗粒物和分子质量>6 ku溶解性有机物有较好的去除效果,而生物絮凝作用不但可以促进对大粒径颗粒物和大分子质量溶解性有机物的去除,而且对小粒径颗粒物和小分子质量溶解性有机物也有较好的去除,其出水中粒径>3 μm的颗粒物被完全去除,分子质量为2～6 ku 的溶解性有机物的去除率也高达42.5%.     

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.     

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.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

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.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

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.