中国城市污水厂污泥处置现状研究

针对中国城市污水厂污泥处置现状问题,概述了国内外常规污泥处置目标和常规污泥处置方式,主要包括填埋处理的方式、污泥焚烧的方法、污泥土地利用的措施,并对目前在中国的适用情况进行了探讨.目前常用的几种常规污泥处置方法各有利弊,也在不断的发展,对于中国各城市来说不可能仅局限于一种处置方法,应结合每个城市的具体情况且还需与城市整体发展趋势相适应.只有这样才能处理好中国城市污水厂污泥处置.保证人民生活在蓝天碧水的环境之中.     

污泥处置与利用研究

为进一步保护生态环境,安全有效、科学合理地处置污泥,提出了污泥处置目标:定化,无害化,减量化,资源化.列举了几种主要的处置方法:污泥浓缩,污泥脱水干燥,污泥厌氧消化,堆肥化.提出污泥利用途径:制肥料,土地利用,制活性炭,焚烧,以实现污泥资源综合利用,避免二次污染,做好城镇环境治理工作.     

城市污泥土地利用近期发展趋势及其原因研究

现阶段中国的城市污泥处置目前仍以填埋为主,污染隐患较大,污泥土地利用资源化进展缓慢.本文分析了国际上污泥土地利用的现状,以及近年来中国土地利用发展缓慢的原因,经过梳理,污泥土地利用受限在于农业行业的诉求未得到充分体现,相关政策和法规的制定中"博弈"现象严重.最后提出应借鉴和充分参考欧美等国家对城市污泥土地利用的科学、合理和积极的态度.     

延安市河庄坪污水厂污泥资源化利用可行性分析

文中通过对比各种目前常用的污泥处置方法,分析了通过卫生填埋法、焚烧法、土地利用等方法进行延安市河庄坪污水厂污泥处置的可行性,同时结合延安市河庄坪污水厂污泥的实际情况,认为目前土地利用可以做为河庄坪污水厂污泥处置的合理方法.     

生活污水处理厂污泥处置技术研究

针对生活污水处理厂污泥处置技术,介绍了国内外污泥的处理现状,提出了传统的污泥处置技术,主要是海洋倾倒,污泥消化技术法,污泥堆肥技术法,污泥的土地利用和污泥的有效利用法,给出林地利用与绿化利用随着污泥量的增长,污泥的处置越来越来受到人们的关注。介绍了国内外污泥处理现状和传统污泥处理处置方法,分析了污泥稳定和资源化处置技术及应用进展,提出了污泥堆肥和堆肥后污泥的土地利用是符合中国国情的污泥处置与资源化利用途径。     

上海城市污水厂污泥处置现状研究

近年来,大量的污水处理厂不断建成投入运行,随之而来的城市污泥产量越来越大,对污泥的处理问题显得非常紧迫.城市污水厂污泥处置的技术路线和发展方向,要以无害化、减量化、资源化为处理目标.常规污泥处置目标和常规污泥处置方式,主要包括填埋处理的方式、污泥焚烧的方法、污泥土地利用的措施.同时对上海城市污水厂污泥处置现状及存在的问题进行了研究,指出污泥干化后进行与生活垃圾协同焚烧处理是污泥最终处置较好的出路.     

污泥土地利用的风险评价探讨

污泥土地利用是一种比较经济的处置方式,目前已为大多数国家所接受.如何根据我国的具体情况分析污泥土地利用过程带来的风险并制定相应的政策法规,是我国污泥合理、科学地进行土地利用的前提.美国历时11年对污泥中23种重点污染物进行了系统的风险评价,并建立了一套较为完整的风险评价方法.本文主要介绍美国环保局(EPA)如何通过风险评价的方法制定土壤中污染物的浓度,并对这些方法应用于我国应注意的问题进行了讨论.     

基于熵值法的城镇污水处理厂污泥处置方案选择研究

随着城镇污水处理厂数量不断增加,污泥问题越来越严重,污泥处置不当会造成严重的二次环境污染.论文首先对污泥处置技术及其投资运行成本进行简要分析;然后建立城镇污水处理厂污泥处置评估技术指标体系,以天津市为例,采用熵值法计算各评估技术指标的权重,对土地利用、填埋、焚烧及建材利用4种污泥处置方案进行了综合评价,结合天津市的实际情况,结果表明以土地利用为最佳处置方案.     

生活污泥处置和管理探析

为实现生活污泥的妥善处置,降低处置成本,促进城市发展,分析了生活污泥的成分及性质,指出了影响生活污泥处置的因素,包括污水处理厂自身因素和生活污泥处置单位因素.提出了生活污泥处置和管理措施:应合理选择生活污泥处置工艺,对其进行无害化处理,有效解决生活污水.污泥产生单位应发挥主体作用,建立健全生活污泥管理责任制.要重视生活...     

国外城市污泥处理处置方式研究及对我国的启示

介绍国内外常用的污泥处置技术和方法,通过与其他国家的对比,结合我国国情总结出:现阶段我国污泥处置技术应以污泥土地利用为主,在土地利用过程中应加强对污泥中重金属、有机污染物和病原体等污染物的控制。     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

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.