絮凝剂产生菌对淀粉废水的处理效果

利用具有絮凝作用较高的两株假单胞菌属产絮菌(Pseudomonas)对马铃薯淀粉废水进行絮凝处理,考察了絮凝剂投加量、废水p H值、温度等因素对絮凝效果的影响。在淀粉废水处于自然p H值5.8时,絮凝剂投加量分别为4%和2%,少量助剂Mg2+的作用下,温度均为15℃,处理时间分别为20和40 min时,这2株产絮菌对淀粉废水的絮凝处理可达到最佳效果。     

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。     

PFMS多核絮凝剂净化海水效果及影响因素

制备镁铁复合絮凝剂(PMFS),研究其对近岸海水的处理效果,考察了PMFS在絮凝过程聚集状态以及投加量、p H等因素对污染物去除效果的影响。结果表明:PMFS絮凝过程是多种机制共同起作用的动态变化过程,形成絮体沉降性能良好;PMFS絮凝性能略优于聚合硫酸铁(PFS);浊度、溶解性有机碳(DOC)去除率和总磷(TP)去除率分别达到96%、45%和92%;p H对海水的浊度去除影响较小,但酸性条件下更利于DOC和TP的去除。     

聚合氯化铝中Alb形态去除腐殖酸的效果及机制研究

Alb形态[Al12AlO4(OH)247+]是聚合氯化铝(polyaluminiurn chloride,PAC)水解-聚合作用中形成的一种粒度小、所带正电荷多、聚集程度高及分子量大的多核羟基配合物.本试验采用乙醇.丙酮混合沉淀法分离PAC溶液中各种铝形态,提纯出Alb形态(Alb絮凝剂).研究投加量、pH及无机离子对Alb絮凝剂处理腐殖酸模拟水样絮凝效果的影响,并利用光散射颗粒分析仪(PDA2000)测定Alb絮凝剂对腐殖酸絮凝过程中絮体的形成与增长过程的动态变化,结合絮体的Zeta电位,对Alb絮凝剂的絮凝机制进行了初步探讨.结果表明,当投加量为4.3～6.3 ms/L、pH值为3.0～6.0时,Alb絮凝剂处理腐殖酸模拟水样达到最佳絮凝效果;NH4+、SiO32-、H2PO4-的存在明显抑制其絮凝性能.絮凝动力学过程和絮体Zeta电位表明,Alb絮凝剂在水处理中主要是通过电中和作用和吸附网捕卷扫作用共同起絮凝作用的.     

聚合氯化铁对浊度和腐殖酸的絮凝特性研究

采用聚合氯化铁(PFC)絮凝剂在不同pH条件下处理高岭土悬浮液和腐殖酸溶液, 测试了絮凝过程中的Zeta电位、浊度和腐殖酸的去除率变化.结果表明:pH=4时, PFC投加量最小, 剩余浊度最大,投加范围最窄;pH=7时次之;pH=10时由于Fe(Ⅲ)离子的正电荷减弱, 电中和能力不强, 而且同时产生Fe(OH)₃(s)的吸附作用使得剩余浊度最低, 投加范围最宽, 但投加量很大;在酸性条件下腐殖酸与Fe(Ⅲ)离子最容易发生络合反应;腐殖酸的存在并没有影响PFC的絮凝效果.     

化学絮凝剂预处理马铃薯淀粉废水的比较研究

马铃薯淀粉废水产生的季节性使得常规生物处理应用起来存在很大困难,采用絮凝剂对废水进行预处理可减轻后续处理负担。文章使用常规化学絮凝剂AlCl3、Fe2(SO4)3、PAM以及有机和无机之间的相互复配对马铃薯淀粉废水进行絮凝预处理,研究了投药量、废水pH值、助凝剂CaCl2投加量以及沉降时间等因素对絮凝效果的影响,确定了各絮凝剂处理废水的较佳絮凝条件,并在较佳条件下处理废水,通过综合比较处理效率、处理成本、絮凝条件难易程度等方面,确定了马铃薯淀粉废水的较佳絮凝剂为AlCl3+PAM,其具有废水处理效果好(COD去除率为41.08%,浊度去除率为95.06%,色度去除率为90.63%)、投药量少(2mLAlCl3+0.3mLPAM)、助凝剂投加量少(1mLCaCl)2、较佳pH在废水初始pH范围内、处理成本低(11.05元/t废水)、产生污泥量少(649g/t废水)等优点。     

从造纸污泥中提取木质素处理酿造废液的研究

从造纸污泥中提取木质素,并将其作为絮凝剂应用于酿造废液的处理,着重研究了影响絮凝效果的因素及处理条件。研究表明,木质素絮凝剂的用量、温度和pH等因素对絮凝效果有一定影响。在pH4,废液温度25℃,木质素投加量150mg/L的条件下,酿造废液的COD和浊度去除率分别可达53.42%和92.82%。     

壳聚糖接枝三元共聚阳离子絮凝剂对高岭土悬浊液的絮凝特性

采用烧杯混凝实验研究了壳聚糖(CTS)、CTS与丙烯酰胺和丙烯酸乙酯季铵盐三元接枝共聚阳离子絮凝剂(CAS)对高岭土悬浊液的絮凝特性.结果表明,CAS具有比CTS絮凝效果好、用量少、pH值适用范围广等优点.CAS絮凝效能受胶体颗粒性质的影响小,对自来水和蒸馏水配置的高岭土悬浊液均具有较好的絮凝效能.中性条件下,CAS的最佳投加量仅为CTS的1/10.在pH值2.0-11.0范围内,CAA对浊度的去除率在95%左右.CAS投加量与原水浊度的关系为:投加量低于0.5nag·L-1时,絮凝效果随原水浊度的升高降低;投加量大于0.5 mg·L-1,浊度去除率随原水浊度的增大而提高;投加量超过1.0 mg·L-1后,对浊度(10～160 NTU)的悬浊;液浊度去除率均在85%以上.悬浮颗粒聚集状态的变化分析、颗粒ξ电位测定、絮体粒径分布测定及其形态结构的观察结果表明,电性中和、吸附架桥是CAS的主要絮凝作用机理,絮凝过程是多种机制共同起作用的动态变化过程.     

基于Zeta电位的硅藻土复配剂强化混凝研究

采用硅藻土与传统无机絮凝剂复配处理模拟生活污水,考察硅藻土复配剂强化混凝过程中絮体Zeta电位的变化,以及浊度和COD的去除情况,研究絮体Zeta电位与强化混凝效果的关系。实验结果表明,絮体的Zeta电位与复配剂的强化混凝效果密切相关,可用于反映硅藻土复配剂的混凝处理效果。研究发现,氯化铝复配剂强化混凝时絮体Zeta电位在加药后迅速上升,25min后趋于稳定;絮体Zeta电位在pH值等于7时接近等电点,此时浊度与COD去除率最高,分别达到99.05%和45.77%;用硅藻土复配剂强化混凝时Zeta电位的控制值为-9.0～0mV之间,不同无机絮凝剂与硅藻土复配混凝时获得较好混凝效果的Zeta电位控制值略有差异。     

PAFC/CTS/红粘土复合絮凝剂对天然胶乳废水的处理

采用聚合氯化铝铁(PAFC)与壳聚糖(CTS)、红粘土复合,制备三元复合絮凝剂,并对胶乳废水进行处理。分别考察了絮凝剂各组分配比、絮凝剂投加量、絮凝搅拌强度对天然胶乳废水的浊度去除率和COD去除率的影响。研究结果表明,当以300 r/min搅拌2min,80¹00 r/min搅拌5 min,15100 r/min搅拌5 min,15²5 r/min搅拌10 min,聚合氯化铝铁/壳聚糖复合絮凝剂组分质量比为PAFC:CTS=1:0.16,投加量为6 mL/L,红粘土投加量0.09 g/L时,静置沉降10 min时对废水浊度去除率和24 h COD去除率分别达98%和80%以上。比单独使用PAFC絮凝剂减少了约一半的投料量。此外,通过扫描电镜观察絮体形貌,初步探讨了絮凝机理,可能是在絮凝体系中引入壳聚糖后,不仅能够保持PAFC絮凝过程中的电中和性能,还能发挥壳聚糖大分子链的吸附架桥性能,从而大大提高复合絮凝剂的絮凝能力。     

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.     

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.     

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.     

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.     

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.     

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.     

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

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