利用共基质代谢提高活性污泥法处理焦化废水COD的效率

焦化废水中含有大量的有机污染物,通过实验发现,采用常规活性污泥法处理,进水COD为2000mg／L左右时,出水COD在350—700mg／L之间,COD的去除率仅为60％-70％,难以达到国家排放标准。根据共代谢机理,向焦化废水生化处理系统中投加共代谢初级基质,促进难降解有机物被微生物降解,从而使COD的去除率提高到75％～85％。     

水解酸化-接触氧化在处理石油化工废水中的应用

采用水解酸化+接触氧化工艺处理镇江新区某石油化工厂废水。设计总处理水量120m3/d,其中原浓废水20m3/d,出水回流100m3/d;设计进水水质:高浓度有机废水CODCr9000mg/L以上,pH5～9,混合后废水CODCr约1500mg/L,pH6～8;设计出水水质:CODCr≤130mg/L,pH6～9。实际出水CODCr为123.29mg/L;CODCr平均去除率为92.04%,处理后出水可达标排放。     

水解酸化-反硝化-硝化组合工艺处理土霉素废水的效果

采用水解酸化 反硝化 硝化的组合工艺对土霉素废水进行实验室规模连续处理 ,水解酸化和反硝化均采用上向流污泥床 ,硝化采用2个使用不同填料的生物膜反应器 ,稳定运行 70d .当进水COD和NH₄⁺-N浓度分别为2200～3000mg/L和400～460mg/L时 ,该系统在总水力停留时间为56h的条件下 ,稳定实现80%以上的COD和TN去除率 .生物处理出水经48mg/L聚合硫酸铁(以铁计)处理后COD降至293mg/L,实现了废水的达标排放.     

水解酸化/生物膜法SBR处理印染废水实验研究

针对印染废水污染物浓度高、种类多、色度高、可生化降解性差等特点,对印染废水采用水解酸化/生物膜法SBR进行处理,结果表明,该处理工艺处理效果较好,出水COD、色度、BOD5、NH3-N浓度分别为60~100 mg/L、50~70倍、20~24 mg/L、5~10 mg/L,平均去除率分别达到92.1%、86.5%、95%、90%。     

含有机氟工业废水处理工艺的研究

采用预处理-水解酸化-生物接触氧化相结合的处理工艺处理含氟代有机化合物废水。研究结果表明,水解酸化可将含氟废水的BOD5/CODCr比由0.258提高到0.396;在一定浓度范围内通过物化预处理及生化处理可以脱除氟代有机化合物中的氟原子,使该有机物成为可供微生物利用的基质。含氟废水经该工艺处理后,出水中BOD5为7.5mg/L,CODCr为75mg/L,氨氮未检出,总磷小于1mg/L,氟离子浓度为8.6mg/L。     

造纸法烟草薄片生产废水的处理

利用厌氧反应器技术+高效絮凝处理造纸法烟草薄片生产废水,CODCr可从6000mg/L降到2000mg/L以下,再用去除率高达90%的SBR序批式反应器技术进行深度处理,废水经处理可达标排放(CODCr≤100mg/L)。     

高浓度食品添加剂废水中试研究

根据食品添加剂废水水质变化大,成分复杂特点,提出了"水解酸化—接触氧化—臭氧催化氧化—曝气生物滤池(BAF)"的组合工艺。废水COD从进水2000～7000mg/L降到100mg/L以下,最低为33mg/L,排放水质达到国家排放标准。水解酸化系统使废水平均COD从5290mg/L降到2323mg/L,并使大颗粒难降解分子部分转化为小颗粒可降解分子,为后续的接触氧化系统处理提供良好的条件,接触氧化出水平均COD为268mg/L。接触氧化出水含较多难生物降解有机物,经O3氧化预处理后在COD下降45%的情况下其BOD5/COD由0.3升为0.44,更易于生化降解。废水经曝气生物滤池平均出水COD为66mg/L。中试研究表明,水解酸化系统和臭氧催化氧化(负载MnO2的陶粒为催化剂)-曝气生物滤池深度处理系统是该工艺处理高浓度废水稳定达标的关键。     

可发性聚苯乙烯废水处理工程的设计与运行

介绍了采用中和混凝 水解酸化 生物接触氧化 化学除磷工艺对可发性聚苯乙烯 (EPS)废水的处理工艺。在废水中的CODCr、TP、SS、NH3 N分别为 194 0mg L、112mg L、5 92mg L、2 3 6mg L的条件下 ,废水经过处理后 ,出水CODCr、TP、SS、NH3 N分别为 70mg L、0 38mg L、2 6mg L、0 32mg L ,均可达到《污水综合排放标准》中的一级标准 ,废水中CODCr、TP、SS、NH3 N的平均去除率分别为 96 4 %、99 3%、95 6 %、98 6 %。     

芬顿技术在造纸中段废水处理中的应用

介绍了造纸中段废水深度处理工艺。结合工程实例,在原有"气浮+曝气+稳定"的处理工艺后增加进水系统、芬顿系统、砂滤系统,处理后出水CODcr≤90 mg/L,BOD5≤50 mg/L,SS≤50 mg/L。经核算,吨水运行费用约为1.29元。     

水解酸化——生物接触氧化工艺在调味品生产废水治理工程中的应用

将水解酸化—生物接触氧化处理工艺应用于调味品生产废水治理中，运行结果表明，在进水CODcr：1000—2000mg／L，BOD5：500—1000mg/L，氨氮：40—100mg/L时，处理后出水水质可达到GB978—96中二级标准。该处理工艺运行管理简便，剩余污泥量少，不产生污泥膨胀，在处理高浓度调味品废水时达到了预期效果。     

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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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.     

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.     

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.     

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.     

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.