壳聚糖复合絮凝剂处理造纸废水的实验研究

研究并考察了壳聚糖复合絮凝剂对造纸污水中COD和SS的絮凝效果,结果表明,当复合絮凝剂的配方和处理条件为：聚合硫酸铁（PFS）60 mg/L聚丙烯酰胺（PAM）2 mg/L壳聚糖（CTS）0.4 mg/L,pH为7.5时,其絮凝效果最佳,此时它对水中COD与SS的去除率分别达到57.4%和97.6%, 与传统絮凝剂PAC/PAM相比,COD与SS的去除率分别提高了10.1%和5.2%,药剂成本下降了21.1%,具有明显的经济效益与环境效益。     

微波无极紫外光催化-内电解协同降解活性艳红X-3B

采用微波无极紫外光源,以活性炭作为光催化剂TiO2的载体,与外加铁屑构成内电解反应,处理活性艳红X-3B模拟废水.实验结果表明,微波无极紫外光催化-内电解法对活性艳红X-3B的降解速率是微波无极紫外光催化和微波-内电解法单独作用时降解速率之和的2倍.在活性艳红X-3B模拟废水初始pH为7、空气曝气量为0.50 L/min、铁屑加入量为5 g/L、反应温度为40～45℃的最佳条件下,微波无极紫外光催化-内电解法的活性艳红X-3B模拟废水色度去除率达100%,TOC和可吸附有机卤化物的去除率分别为69.5%和81.8%.     

复合式吸收器采样还原一体化冷原子吸收法测定大气中的汞

目的研制一种高效率采集大气中汞的吸收器.方法利用一种集大泡式与玻砂板式吸收器为一体的复合式吸收器采样,并使采样还原一体化冷原子吸收法测定大气中汞.结果平均吸收率为96%,变异系数在4%～12%之间.结论复合式吸收器采样吸收效率高,适合于大气中微量汞的测定.     

Occurrence and distribution of polycyclic aromatic carbons in sludges from wastewater treatment plants in Guangdong, China

In this study, the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in six sludge samples collected from Guangdong Province, China. Concentrations of PAHs varying from 2,534.1 to 6,926.6 μg kg^???1 (dry sludge) were observed in three municipal wastewater treatment plants with phenanthrene (Phe), fluoranthene, and pyrene being the main compounds. In addition, 682.6 μg kg^???1 PAHs were detected in one sludge sample from a food processing plant, with fluorene, Phe, and chrysene being the main components. No PAHs were detected in sludge samples obtained from two cosmetic plants. The levels and distributional characteristics of PAHs, polychlorinated biphenyls (PCBs), and polycyclic musks (PMs) from the samples were also compared. The results of this comparison indicated that petrochemical refineries and road traffic played important roles in the PAH loads in sludge, while PMs primarily originated from domestic wastewater and industrial wastewater from cosmetic plants. Finally, the presence of 98.8 μg kg^???1 PCBs in sludge suggested diffusional emission sources from electrical components containing PCBs.     

Effective removal of coordinated copper from wastewater using a new dithiocarbamate-type supramolecular heavy metal precipitant

A new dithiocarbamate-type heavy metal precipitant, sodium 1,3,5-hexahydrotriazinedithiocarbamate (HTDC), was prepared and used to remove coordinated copper from wastewater. In the reported dithiocarbamate-type precipitants, HTDC possesses the highest percentage of the effective functional groups. It could effectively precipitate copper to less than 0.5 mg l⁻¹ from both synthetic and actual industrial wastewater containing CuEDTA in the range of pH 3–9. UV–vis spectral investigation and elemental analysis suggested that the precipitate was a kind of coordination supramolecular compound, [Cu₃(HTDC)₂]_n. The toxicity characteristic leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) indicated that the supramolecular precipitate was non-hazardous and stable in weak acid and alkaline conditions. Tests of an anion exchange resin D231 provided a clue to simultaneously remove excess HTDC and residual CuEDTA in practical process of wastewater treatment.     

The concentrations and distribution of polycyclic musks in a typical cosmetic plant

Polycyclic musks [cashmeran (DPMI), celestolide (ADBI), phantolide (AHMI), traseolide (ATII), tonalide (AHTN) and galaxolide (HHCB)] in the air, wastewater, sludge samples of a typical cosmetic plant were analyzed. DPMI, ADBI, HHCB and AHTN were found in all samples, and ATII was not found in any sample. HHCB and AHTN were the major components in all samples. The polycyclic musk concentrations were very high in the air of the cosmetic plant, and polycyclic musks were mostly contained in the gas phase at the percentage of 86.35-97.70%. Average polycyclic musk concentrations in effluent were high, and ranged from 0.62 to 32.06 microgl-1. The removal efficiency during the active sludge wastewater treatment was also high, resulting from the adsorption of those compounds into the sludge. So the polycyclic musk concentrations were very high in the primary sludge and second sludge, and ranged from 1.78 to 92.45 mgkg-1 (dry), and from 2.87 to 65.67 mgkg-1 (dry), respectively. Results suggested that the sludge needed to be further treated to make polycyclic musks less influence to the environment.     

Aerobic degradation of bisphenol A by Achromobacter xylosoxidans strain B-16 isolated from compost leachate of municipal solid waste

A novel bacterium designated strain B-16 was isolated from the compost leachate of the municipal solid waste (MSW) in a laboratory reactor. This strain was identified as a gram-negative bacterium, Achromobacter xylosoxidans that could grow on bisphenol A (BPA, a representative endocrine disruptor) as a sole carbon source under aerobic condition. BPA-degrading characteristics of strain B-16 were investigated in liquid cultures. The results show that BPA degradation was influenced by several factors (e.g. inoculum size, substrate concentration, temperature and pH, etc). The half-lives, optimum temperature and pH were found to be 0.58-3.1d, 35 degrees C and 7.0, respectively. BPA-degrading activity and cell growth were inhibited at high substrate concentration. Metabolic intermediates detected during the degradation process were identified as p-hydroxybenzaldehyde, p-hydroxybenzoic acid and p-hydroquinone, respectively. Metabolic pathway of BPA degradation was proposed in this study.     

Influence of the DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen transformation and leaching in multi-layer soil columns

The application of nitrogen fertilizers leads to various ecological problems such as nitrate leaching. The use of nitrification inhibitors as nitrate leaching retardants is a proposal that has been suggested for inclusion in regulations in many countries. In this study, using a multi-layer soil column device, the influence of new nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) was studied for understanding the nitrogen vertical transformation and lowering the nitrate leaching at different soil profile depths. The results indicated that, within 60 d of experiment, the regular urea added 1.0% DMPP can effectively inhibit the ammonium oxidation in the soil, and improve the ammonium concentration in soil solution over the 20cm depths of soil profile, while decline the concentrations of nitrate and nitrite. No obvious difference was found on ammonium concentrations in soil solution collected from deep profile under 20cm depths between regular urea and the urea added 1.0% DMPP. There was also no significant difference for the nitrate, ammonium and nitrite concentrations in the soil solution under 40cm depths of soil profile with the increasing nitrogen application level, among the treatments of urea added 1.0% DMPP within 60 d. It is proposed that DMPP could be used as an effective nitrification inhibitor in some region to control ammonium oxidation and decline the ion-nitrogen leaching, minimizing the shallow groundwater pollution risk and being beneficial for the ecological environment.