嗪草酮农药生产环合废水物化处理工艺研究

采用絮凝-树脂吸附组合工艺对嗪草酮农药生产环合废水进行物化预处理.实验确定的最佳工艺条件为:(1)絮凝-絮凝剂为10%硫酸铝溶液(W/W),投加量为8%(V/V),废水pH为6～9,快速搅拌1 min(150～180 r/min),慢速搅拌15 min(80～100 r/min);(2)树脂吸附-双柱串联吸附:上柱液p...     

Fenton氧化和絮凝作用对干法腈纶聚合废水中有机物的去除

采用Fenton法预处理干法腈纶聚合废水,考察H2O2投加量、Fe2+投加量及pH对Fenton反应过程中氧化和絮凝作用去除废水有机物的影响。结果表明,在H2O2投加量为90 mmolL,Fe2+投加量为30 mmolL,初始pH为3.0的条件下,反应120 min后调节pH至6.0进行絮凝,废水中TOC总去除率可达55.6%,Fenton氧化和絮凝作用可实现较好的有机物去除效果。Fenton氧化后将pH调至8.0,有利于絮体的沉降,在实际应用中更加合理。三维荧光光谱(EEM)和荧光区域积分(FRI)发现,Fenton反应能够去除废水中大部分类蛋白易降解有机物,氧化作用对废水中类富里酸有机物的去除作用较小,该类物质主要通过絮凝作用去除。     

絮凝法预处理酵母废水研究

酵母废水是一种高浓度有机废水,针对酵母废水处理工艺现状及存在问题,结合酵母废水COD浓度高、色度高、可生化性差的特点,提出在对酵母废水进行生化处理前进行絮凝沉淀预处理工艺,研究了工艺的运行参数。结果表明:絮凝剂选择氯化铁,投加量为8g/L,pH值为7.5,搅拌速度及时间为300r/min1min,80r/min20min,沉降时间为30min时COD去除率在35%左右;絮凝出水BOD5/COD值明显提高,从0.28上升为0.44,有效地提高酵母废水的生化性,有利于生物处理。     

微电解在中药煎制废水预处理中的应用

微电解工艺应用于中药煎制废水的预处理中,通过电化学、氧化还原、高吸附絮凝等协同作用,可实现对废水中高浓度有机物的去除、降低毒性、脱色、改善可生化性等目的,具有处理效果好、成本低、工程可操作性强、低碳环保等优点,是目前处理中药煎制类废水的一种较为理想的预处理工艺。     

吸附-絮凝法处理亚甲基蓝模拟废水研究

采用吸附-絮凝法处理亚甲基蓝模拟废水,以稻壳为吸附剂,优化了吸附的最佳条件,筛选了絮凝剂,并探讨了吸附-絮凝法处理亚甲基蓝模拟废水时,NX-A7阴离子絮凝剂加入时间对亚甲基蓝去除效果的影响。试验结果表明:稻壳用量为0.8 g,亚甲基蓝模拟废水浓度为100 mg/L,反应温度25℃,振荡速度为200 r/min条件下,吸附处理100 min时加入NX-A7阴离子絮凝剂,继续处理20min,亚甲基蓝去除率可达94.7%。用吸附-絮凝法处理高浓度亚甲基蓝模拟废水时,亚甲基蓝去除率大于单吸附和单絮凝之和,可以达到"1+12"的效果。     

絮凝-Fenton试剂法处理煤加压气化废水实验研究

采用絮凝-Fenton试剂法对煤加压气化废水进行预处理,确定了最佳处理条件,絮凝时,pH=6,每100mL废水中加Fe2(SO4)3(10%)0.4mL,加CaO2.5g,搅拌时间为30min,静置3h;Fenton试剂催化氧化处理絮凝反应后的废水时,H2O2的加入量为18g/L,[Fe2+]=1.8g/L,pH值为絮凝出水的值,温度为常温,搅拌时间为1.5h,反应后静置3h。实验表明,经该方法处理后,废水的COD从3722.26mg/L降至598.87mg/L,去除率达83.91%,并且BOD5、氨氮、挥发酚和色度都有很大的去除,去除率分别为78.70%、50.37%、72.71%和99.90%,BOD5与COD的比值由0.34提高到0.45,有效的提高了废水的可生化性。     

中小型造纸厂废水处理技术研究

根据中小型造纸厂废水的特点，采用腈纶丝吸附和蛋白石页岩过滤方法处理该废水。腈纶丝可以有效吸附去除废水中的悬浮物，蛋白石页岩对废水中的有机物有很好的处理效果。本处理工艺对废水中SS的去除率为86.8～99.5%,COD去除率可以达到40%以上。     

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。     

糠醛废水制备醋酸钙镁工艺中活性炭最佳吸附条件的试验研究

为了提高糠醛废水中和法生产醋酸钙镁(CMA)的纯度,采用活性炭对含CMA约30%的浓缩液进行预处理,结果表明活性炭吸附的最佳工艺条件为:活性炭使用量占液体质量的10%,加入少量硅藻土为助滤剂,温度为60℃,充分混合吸附30 min,反复过滤6次CMA含量可达29.19%.     

维生素B_1制药废水的铁炭微电解-混凝预处理工艺

针对维生素B1制药废水高有机物浓度、高悬浮物、色度高、难降解的特点,采用铁炭微电解-混凝工艺对其进行预处理,效果良好。铁炭微电解-混凝工艺的最佳运行条件为:进水pH值为4,铁炭比为1∶1,曝气量为0.2m3/h的情况下停留时间80min。出水CODCr浓度平均为1600mg/L,去除率约为79%,色度去除率为85%,出水达到了(GB8978-1996)二级排放标准。     

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.     

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.     

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.