焦炭和废铁屑微电解预处理垃圾渗滤液的研究

研究表明,废铁屑和焦炭微电解是预处理垃圾渗滤液的一种有效方法,可去除垃圾渗滤液COD、色度和腐殖酸等污染物质,改善其可生化性、降低负荷,为后续生化处理创造良好的条件.通过静态正交实验确定废铁屑和焦炭最佳投加体积比为1∶3;最佳反应pH值为4;动态实验中,反应时间为1 h时,COD和色度去除率分别高达68%和91%;BOD/COD从0.3提高到0.5左右.     

人工神经网络在强化一级处理系统过程模拟与优化中的应用

针对化学强化一级处理系统（CEPT）处理废水时影响因素多，难以进行适当的控制和处理效果的预测等问题，建立起基于BP人工神经网络的CEPT法处理猪场稳定塘废水预测模型，并应用该模型对烧杯试验进行了模拟。结果表明，预测值和实测值吻合较好，模型对COD、总磷、浊度去除率预测的平均相对误差分别为7．5％、4．8％和4．9％。通过对pH值和絮凝剂投药量等可控参数进行优化计算，得到CEPT系统的最佳操作条件和最合理操作条件。该模型的建立为CEPT法处理废水工艺系统实现自动化控制提供了一条简便实用的途径。     

扬水曝气技术在水源水质改善中的应用

扬水曝气技术是新开发的水质改善技术,用于混合上下水层、控制藻类生长、增加水体溶解氧、抑制底泥污染物释放.将该技术应用于某水源地,其提水效率达到同类设备--同温层曝气器的两倍;控制了水体表层的藻类数量,抑制了藻类的生长,将藻类叶绿素a含量降低了13.96%.扬水曝气技术的适用条件:用于控制藻类生长时,水深应不小于10 m;用于抑制底泥污染物释放时,水体应存在溶解氧小于1～2 mg/L的厌氧条件.     

Catalytic dechlorination kinetics of p-dichlorobenzene over Pd/Fe catalysts

p-Dichlorobenzene (p-DCB) was dechlorinated using Pd/Fe bimetallic catalytic reductants synthesized by chemical deposition. Batch experiments demonstrated that the Pd/Fe bimetallic particles could effectively dechlorinate p-DCB, p-DCB and its intermediate chlorobenzene were removed completely at a Pd loading of 0.02% (weight ratio of Pd to Fe) and Pd/Fe power to solution ratio about 4g 75 ml-1 in 90 min. Dechlorination was affected by various factors such as the reaction temperature, pH, Pd loading percentage over Fe and the introduction of Pd/Fe catalysts et al. Chlorobenzene represents partially stable dechlorinated intermediates in the generation of benzene and part of p-DCB was dechlorinated to benzene indirectly on the surface of Pd/Fe. The dechlorination of p-DCB took place on the surface of the Pd/Fe bimetallic particles in a pseudo-first-order reaction, the activation energy of the dechlorination reaction was determined to be 80.0 kJ mol-1 at the temperature range of 287-313 K.     

GIS在环境保护中的应用现状与发展

结合国内外地理信息系统(GIS)在环境保护研究工作中的介入情况，阐述了GIS在环境保护领域的应用现状，并探讨了GIS在此领域应用的未来发展趋势。     

Lead contamination in tea garden soils and factors affecting its bioavailability

The consumption of heavy metals is detrimental to human health and most countries restrict the concentration of metals such as lead (Pb) in food and beverages. Recent tests have detected high Pb concentrations in certain commercial brands of tea leaves and this finding has raised concerns for both producers and consumers. To investigate what factors may be contributing to the increase in Pb accumulation in the tea leaves we collected tea leaves and soils from tea producing areas and analyzed them for Pb concentration, pH and organic matter content. The result showed the Pb concentration of 47% investigated tea leaves samples was beyond 2 mg kg(-1), the permissible levels given by China. The total Pb concentration in the surface and subsurface soil layers averaged 36.4 and 32.2 mg kg(-1), respectively which fall below of the 60 mg kg(-1) limit provided for organic tea gardens in China. The pH of the tea garden soils was severely acidic with the lowest pH of 3.37. Soils under older tea gardens tended to have a lower pH and a higher Pb bioavailability which was defined as the amount of lead extracted by CaCl2 solution than those under younger tea gardens. We found that the concentration of bioavailable Pb and the percentage of bioavailable Pb (bioavailable Pb relative to total Pb concentration) were positively correlated with soil H+ activity and soil organic matter content, and the organic matter accumulation contribute more effects on Pb bioavailability in these two factors. We conclude that soil acidification and organic matter accumulation could contribute to increasing Pb bioavailability in soil and that these could increase Pb uptake and accumulation in the tea leaves.     

Photocatalysis enhancement by electric field: TiO2 thin film for degradation of dye X-3B

According to the theory of photocatalysis, the efficiency of photocatalysis decreases mostly due to the recombination of photo-generated electron-hole pairs. An electric field across a photocatalyst can promote the separation of photo-generated electrons and holes and prevent them from recombination so as to enhance the efficiency of photocatalysis. And the synergetic decomposition efficiency of photocatalysis and an electric field is greater than that of the simple combine of their single efficiency. The performance of photocatalysis enhanced by electric field (PEEF) and operating conditions such as the direction of the electric field, the voltages between the two electrodes, the material of the electrodes, which may affect the efficiency of PEEF, were investigated in this paper. The results indicate that the system of PEEF abides the established theory of photocatalysis.     

Performance of three-phase three-dimensional electrode reactor for the reduction of COD in simulated wastewater-containing phenol

The removal of chemical oxygen demand (COD) from wastewater-containing phenol was investigated using three-phase three-dimensional electrode reactor. Special attention was paid to experimentally probe the performance of the reactor in COD removal in the process of repeated batch runs. The experimental results showed that the reactor could remove COD from phenol-containing wastewater much more efficiently than both granulated activated carbon (GAC) adsorption bed and conventional three-dimensional electrode. For 200th batch run, the three-phase three-dimensional electrode reactor with an airflow of 5 l min(-1) and a cell voltage of 30 V could remove 1350 ppm COD from the wastewater in 30 min while conventional three-dimensional electrode reactor with a same cell voltage and GAC adsorption bed with a same airflow only could remove 610 and 1000 ppm, respectively, at the same reaction duration. Although it was found that COD removal decreased with increasing repeated batch runs in our experimental range, due to adsorption saturation of GAC and electrode passivation, the extent of decrease for the three-phase three-dimensional electrode is much less than those for conventional three-dimensional electrodes and GAC adsorption beds. The passivated reactor could be partly re-activated by electrolysis in the presence of MnO2.     

Biodegradation mechanisms and kinetics of azo dye 4BS by a microbial consortium

A microbial consortium consisting of a white-rot fungus 8-4* and a Pseudomonas 1-10 was isolated from wastewater treatment facilities of a local dyeing house by enrichment, using azo dye Direct Fast Scarlet 4BS as the sole source of carbon and energy, which had a high capacity for rapid decolorization of 4BS. To elucidate the decolorization mechanisms, decolorization of 4BS was compared between individual strains and the microbial consortium under different treatment processes. The microbial consortium showed a significant improvement on dye decolorization rates under either static or shaking culture, which might be attributed to the synergetic reaction of single strains. From the curve of COD values and the UV-visible spectra of 4BS solutions before and after decolorization cultivation with the microbial consortium, it was found that 4BS could be mineralized completely, and the results had been used for presuming the degrading pathway of 4BS. This study also examined the kinetics of 4BS decolorization by immobilized microbial consortium. The results demonstrated that the optimal decolorization activity was observed in pH range between four and 9, temperature range between 20 and 40 degrees C and the maximal specific decolorization rate occurred at 1,000 mg l(-1) of 4BS. The proliferation and distribution of microbial consortium were also microscopically observed, which further confirmed the decolorization mechanisms of 4BS.     

调理剂对CAF污泥浓缩工艺影响的试验研究

涡凹气浮（CAF）已广泛应用于工业废水和城市污水的预处理中.由于污泥本身的特性原因,CAF在污泥处理中尚没有应用.通过试验投加污泥调理剂改变污泥的特性,以达到将CAF工艺用于浓缩活性污泥的目的.试验表明,CAF工艺浓缩低浓度剩余活性污泥效果很好,但正确选择污泥调理剂的投加点和投加量对CAF污泥浓缩工艺至关重要.