四川某中小城镇污水处理厂进水水质统计分析

生活污水水质对处理工艺的选择、设计参数的选取以及稳定运行十分重要。运用SPSS软件,对四川某中小城镇污水处理厂为期一年的进水指标(水量、COD、氨氮、总磷、pH、SS)进行方差和相关性分析。方差分析结果显示进水量、氨氮和SS在月份和季节之间存在显著性差异,而总磷和pH仅在月份之间存在显著差异,COD在季度和月份之间无显著性差异;指标相关性分析表明,进水量和氨氮之间呈负相关,氨氮和总磷、COD和总磷之间呈正相关,且相关性显著。在此分析的基础上对污水处理厂设计、工艺选择及运行管理提出了一些建议。     

Individual and combined toxic effects of cypermethrin and chlorpyrifos on earthworm

Toxicities were assessed for a pyrethroid (cypermethrin) and an organophosphate insecticide (chlorpyrifos) individually and in combination. A series of tests were conducted on di erent responses (acute, chronic, behavioral) of earthworms of species Eisenia fetida andrei in the ecological risk assessment of these pesticides. The results showed that the toxicity of the mixture of cypermethrin and chlorpyrifos was significantly higher than either of these pesticides individually, especially on the earthworm’s chronic responses. At a concentration of 5 mg/kg, the mixture caused significant reductions on the growth and reproduction rates of earthworms, but did not cause any significant e ect when the individual was tested. The increase in toxicity of the pesticide mixture means that the use of toxicity data obtained exclusively from single-pesticide experiments may underestimate the ecological risk of pesticides that actually present in the field.     

Mobilities and leachabilities of heavy metals in sludge with humus soil

Chemical forms of Zn, Ni, Cu, and Pb in municipal sewage sludge were investigated by adding humus soil to sludge and by performing sequential extraction procedures. In the final sludge mixtures, Zn and Ni were mainly found in Fe/Mn oxide-bound (F3) and organic matter/sulfide-bound (F4) forms. For Zn, exchangeable (F1), carbonate-bound (F2), and F3 forms were transformed to F4 and residual forms (F5). For Ni, F1 and F2 forms were transformed to F1, F2, and F3 forms. Both Cu and Pb were strongly associated with the stable forms F4 and F5. For Cu, F2 and F3 forms were major contributors, while for Pb, F3 and F4 forms were major contributors to F5. Humus soil dosage and pH conditions in the sludge were strongly correlated with the forms of heavy metals. Five forms were used to evaluate metal mobilities in the initial and final sludge mixtures. The mobilities of the four heavy metals studied decreased after 28 days. The metal mobilities in the final sludge mixtures were ranked in the following order: Ni > Zn > Cu = Pb. Leaching tests showed that the mobilities of Zn and Ni in lower pH conditions (pH 4) were higher than those in higher pH conditions (pH 8).     

Potential particulate pollution derived from UV-induced degradation of odorous dimethyl sulfide

UV-induced degradation of odorous dimethyl sulfide (DMS) was carried out in a static White cell chamber with UV irradiation. The combination of in situ Fourier transform infrared (FT-IR) spectrometer, gas chromatograph-mass spectrometer (GC-MS), wide-range particle spectrometer (WPS) technique, filter sampling and ion chromatographic (IC) analysis was used to monitor the gaseous and potential particulate products. During 240 min of UV irradiation, the degradation e ciency of DMS attained 20.9%, and partially oxidized sulfur-containing gaseous products, such as sulfur dioxide (SO2), carbonyl sulfide (OCS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2) and dimethyl disulfide (DMDS) were identified by in situ FT-IR and GC-MS analysis, respectively. Accompanying with the oxidation of DMS, suspended particles were directly detected to be formed by WPS techniques. These particles were measured mainly in the size range of accumulation mode, and increased their count median diameter throughout the whole removal process. IC analysis of the filter samples revealed that methanesulfonic acid (MSA), sulfuric acid (H2SO4) and other unidentified chemicals accounted for the major non-refractory compositions of these particles. Based on products analysis and possible intermediates formed, the degradation pathways of DMS were proposed as the combination of the O(1D)- and the OH- initiated oxidation mechanisms. A plausible formation mechanism of the suspended particles was also analyzed. It is concluded that UV-induced degradation of odorous DMS is potentially a source of particulate pollutants in the atmosphere.     

Preparation and coagulation efficiency of polyaluminium ferric silicate chloride composite coagulant from wastewater of high-purity graphite production

The aim of the present work was to produce a polyaluminium ferric silicate chloride (PAFSiC) coagulant from acidic and alkaline wastewater of purifying graphite by roasting, and subsequently to evaluate coagulation efficiency of the reagent by treating surface water from the Yellow River as well as municipal wastewater in comparison with the conventional coagulant polyaluminium chloride (PAC). The PAFSiC coagulant was prepared by co-polymerization. The effects of (Al+Fe)/Si molar ratio, OH/(Al+Fe) molar ratio (i.e., value), coagulant dosage and pH value of test suspension on the coagulation behavior of FAFSiC and the stability of the PAFSiC were also examined. Results showed that PAFSiC performed more efficiently than PAC in removing turbidity, chemical oxygen demand (COD), and total phosphate (TP). The PAFSiC with a value of 2.0 and (Al+Fe)/Si ratio of 5 (PAFSiC 2.0/5) showed excellent coagulation effect for both turbidity and COD, while PAFSiC 1.0/5 was the best for TP. The optimum coagulation pH range of PAFSiC 2.0/5 was 5.0–9.0, slightly wider than that of PAC (6.0–8.0). The process can be easily incorporated into high-purity graphite production plants, thereby reducing wastewater pollution and producing a valuable coagulant.     

Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period

Considerable variations may exist in CH4 emissions from the Three Gorges Reservoir.     

基于REOF方法的辽宁气候舒适度区域特征分析

基于辽宁省50个气象站1964-2008年的气象资料,采用适应东北地区的人体舒适度计算公式及分级标准,得出辽宁省近45年历年人体各舒适度级别日数,使用旋转经验正交分解法(REOF),对辽宁省气候舒适度进行区域划分,并分析了各区域气候舒适度的空间分布特征和变化趋势.结果表明:(1)根据前4个旋转倚载向量场高载荷区分布,将...     

淀山湖入湖水质净化的生态工程实践研究

作为上海境内最大的天然淡水湖泊以及黄浦江上游重要的水源保护地,淀山湖的水质状况对上海市饮用水水源安全起着举足轻重的作用。文章运用生物治理与工程措施相结合的手段,在淀山湖大朱厍港实施了净化人湖水质的生态工程试验。研究表明工程示范区域存在风浪大、水位较深、水流较急等特点,是水生植被尤其是沉水植物恢复的重要限制因素。通过选择...     

西辽河流域沙土的氨氮解吸行为研究

采用小型回填式土柱淋溶实验方法研究了西辽河流域沙土的氨氮解吸行为。结果表明,西辽河流域沙土的氨氮解吸行为符合Langmuir和Freundlich解吸等温式;沙土氨氮解吸比率Dr在0.44～0.99之间,平均为0.75,解吸迟滞性指数TⅡ在0.05～0.65之间,平均为0.29,沙土对氨氮的解吸迟滞性较强,解吸可逆性较弱。被吸附的氨氮解吸淋失的环境风险较小;沙土氨氮解吸比率Dr与土壤有机质含量、粘粒含量和粗粘粒含量呈极显著负相关,影响程度顺序为:有机质含量>粗粘粒含量>粘粒含量;解吸分配系数k和解吸迟滞性指数与土壤有机质含量分别呈极显著和显著正相关,与粘粒含量和粗粘粒含量没有相关性;草地、农田和林地结构由于土壤有机质和团聚体含量较高,氨氮解吸迟滞性较强,氨氮流失的环境风险较小,沙荒地结构氨氮流失的环境风险较大。