高速公路服务区废水处理工程实例

以湖北宜昌某高速公路服务区废水处理工程为例,分析了高速公路服务区废水水质特点及废水处理工艺、主要建(构)筑物设计参数、运行状况及投资运行费用。针对废水水量变化大、有机污染物浓度高、含氮、磷、油类、病原微生物等特点,综合考虑选择"水解酸化+A/O+消毒"处理工艺。实践运行表明,该系统出水效果稳定,污水经过处理达到《污水综合排放标准》(GB8978—1996)一级标准后排放。     

回流污泥石灰混凝法处理印染废水

印染厂排放的废水,色度、COD含量均较高,水质、水量变化复杂。常用的废水处理方法,或基建投资大,占地面积大,控制、操作复杂;或处理成本高、又可能造成二次污染,因此,对于乡镇企业和中、小型污水处理厂,降低运行费用、提高出水水质,是印染废水处理的关键。本文选择石灰与其回流污泥作为混凝剂,对印染废水进行模拟处理和实际运行的研究。结果表明,具有较好的脱色率和COD去除率,且运行费用低于其它常用方法。一、模拟试验 (一)试验方法水样取自某工厂的印染废水。其主要污染     

荆州市印染废水集中处理工程改造方案研究

通过对荆州市中环水业有限公司一期和二期印染废水处理工程差异的比较,在调查园区废水水质水量变化的基础上,对比了两期废水处理工程的工艺及处理效果,为二期工程的高效运行提供有价值参考.同时,通过对不同处理单元的设计规模、设计要求及运行参数等的综合分析,结合实际运行过程水质水量的调查,以COD、NH3-N、色度和悬浮物为主要评价参数,分析了工艺特点及处理效果,确定了各处理单元的最佳运行条件和对不同污染组分的去除特征,优化了各处理单元的运行条件和参数.     

印染废水处理技术研究综述

印染废水是一种水质水量变化大、有机物含量高、可生化性差、COD高、色度高的难降解废水。介绍了各种印染废水处理的方法:物理化学法、化学法及生物技术法,分析了各类技术方法的机制、处理效果及其优缺点。根据印染废水的水质特点,通过对不同处理方法进行组合,辅以微生物高效强化技术,是今后印染废水处理的发展方向。     

果蔬罐头生产废水治理工程设计研究

采用接触氧化-SBR工艺对果蔬罐头生产废水进行治理,其工艺抗冲击负荷能力强,抗污泥膨胀性能较好,对水质水量变化的适应性强。本文对该公司废水来源及水质、废水处理工艺流程及其特点、主要构筑物及其设备参数、工程运行效果做出了详细的分析和讲解。试验研究表明,工艺运行稳定、出水水质较好,能够满足《污水综合排放标准》(GB 8978-1996)中的一级排放要求。     

处理难降解抗生素废水的新成果——水解酸化-膜生物反应器工艺工业化技术

抗生素生产废水一般包括发酵废水(提取废水)、洗涤废水、酸碱废水、冷却水等，具有综合废水污染浓度高、成份复杂、有机物浓度高、含有大量难生化降解的物质及其生化抑制物、可生化性较差等特点．且水质、水量随时间的变化规律很难控制，影响废水处理设施的正常运行和处理效果。目前所采用的抗生素废水处理方法投资大，处理效率较低，难以稳定达标。     

印染废水处理工艺的改造实践

由于原有的废水处理系统的处理效果不能达到应有的处理目标。废水的色度、COD_(cr)、BOD_5、硫化物仍然经常出现超标现象。所以必须对原有的废水处理系统进行改进。通过实验室小试,确定新的絮凝剂和最佳操作条件,同时对接触氧化池的填料更换,提高废水中污染物的去除效率,使出水水质达到行业排放一级标准。该工艺具有运行费用低、处理效果稳定等特点,尤其适合中小型印染厂废水治理。     

汽车涂装废水处理系统的优化

通过对重庆某汽车制造厂涂装车间原废水处理工艺运行状况的调查 ,分析出该废水处理运行中存在的主要问题是 :废水水量与水质很不稳定 ;相同的处理方法加大了对不同废水的处理难度 ;设备腐蚀较为严重。改造后的处理工艺 ,对不同的废水先进行不同的物化处理 ,然后进入SBR反应器进一步进行生化处理 ,并且在设备的预制时就采取了一系列的防腐措施 ,很好地解决了原处理工艺中存在的问题。     

某饮料企业污水处理设施运行效果分析

对杭州某饮料企业废水处理设施运行效果进行了跟踪分析。分析表明对于该废水处理设施,其出水COD浓度和废水处理水量存在相关关系。当废水处理水量和进水COD浓度在一定范围时,设施可在最佳运行状态;处理量达到75%设计废水处理量下,应合理安排生产,控制进水COD值低于1 900 mg/L,才可保证出水水质达标排放。     

用活性污泥及气浮技术处理印染废水

本文介绍了沈阳第二印染厂废水的特性及采用活性污地及气浮技术处理印染生产废水的工程实例，工程设计规模３１００ｍ＾３／ｄ，经过九年多的运行实践表明，该工艺对处理印染废水具有投资省，抗冲击性能强，不易受水质、水量变化的影响，处理效果稳定，运行费用低等优点，排放水能达到辽宁省地方排放标准。     

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.     

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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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.     

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.     

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.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.     

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.     

Seed selections for crystallization of calcium phosphate for phosphorus recovery

Seed induces and promotes the crystallization of calcium phosphate, and acts as carrier of the recovered phosphorus （P）. In order to select suitable seed for P recovery from wastewater, three seeds including Apatite （AP）, Juraperle （JP） and phosphate-modified Juraperle （M-JP） were tested and compared. Batch and fixed-bed column experiments of seeded crystallization of calcium phosphate were undertaken by using synthetic wastewater with 10 mg/L P phosphate. It shows that AP has bad enduring property in the crystallization process, while JP has better performance for multiple uses, and M-JP is a hopeful seed for P recovery by crystallization of calcium phosphate.