有机化合物KOC片段常数估算模型的误差与稳健性分析

分析了估算有机化合物吸着系数的片段常数模型的误差,并用４种不同方法检验了估算有机化合物吸纱数的片段常数模型的稳健性。重复随机抽取单一合物,逐一抽取估算值与实测值差别较大的个别化合物,重复随机抽取５０个化合物以及逐一抽取特定化合物类别。     

Interaction between Cu2+ and different types of surface-modified nanoscale zero-valent iron during their transport in porous media

This study investigated the interaction between Cu²⁺ and nano zero-valent iron (NZVI) coated with three types of stabilizers (i.e., polyacrylic acid [PAA], Tween-20 and starch) by examining the Cu²⁺ uptake, colloidal stability and mobility of surface-modified NZVI (SM-NZVI) in the presence of Cu²⁺. The uptake of Cu²⁺ by SM-NZVI and the colloidal stability of the Cu-bearing SM-NZVI were examined in batch tests. The results showed that NZVI coated with different modifiers exhibited different affinities for Cu²⁺, which resulted in varying colloidal stability of different SM-NZVI in the presence of Cu²⁺. The presence of Cu²⁺ exerted a slight influence on the aggregation and settling of NZVI modified with PAA or Tween-20. However, the presence of Cu²⁺ caused significant aggregation and sedimentation of starch-modified NZVI, which is due to Cu²⁺ complexation with the starch molecules coated on the surface of the particles. Column experiments were conducted to investigate the co-transport of Cu²⁺ in association with SM-NZVI in water-saturated quartz sand. It was presumed that a physical straining mechanism accounted for the retention of Cu-bearing SM-NZVI in the porous media. Moreover, the enhanced aggregation of SM-NZVI in the presence of Cu²⁺ may be contributing to this straining effect.     

一组高效稳定纤维素分解菌复合系MC1的筛选及功能

从4种堆肥样品中分别筛选出纤维素分解能力较强的4组混合菌,再以酸碱反应互补的原则重新优化组合并驯化成1组纤维素分解能力非常强而稳定的纤维素分解菌复合系MC1.100mL培养物在50℃静止培养72h,分别可分解0.48g滤纸、0.49g脱脂棉、0.19g麦秆和0.08g锯末.分解滤纸时,第24h CMC糖化力最高,为122.3U·mL^-在初始pH4～10的不同培养基上接种,均能把pH调到中性,最后稳定在8.0～8.5之间.在连续投放滤纸情况下纤维素分解能力稳定保持20d以上,其发酵液的pH在有滤纸时稳定在6.0～6.5之间,没有滤纸时稳定在8.0～8.5之间.     

曝气强度对同时硝化反硝化（SND）脱氮过程中N2O排放的影响

为了控制污水脱氮中N2O排放,在不同曝气强度下研究了好氧硝化段同时硝化反硝化（SND）系统的N2O排放特性,并采用PCR—DGGE技术分析微生物群落特征。结果发现,随着曝气强度的增强,系统总氮去除率下降,但脱氮中N2O—N所占比例则上升,实验中从低到高3个曝气强度下,总氮去除率分别为80．01％、65．28％和58．62％,脱氮中N2O—N所占的比例为1．89％、7．84％和9．20％。PCR—DGGE分析显示,和低曝气强度下相比中、高曝气强度下系统微生物群落发生明显变化,但中曝气强度和高曝气强度下系统微生物群落表现出较高相似性。这表明,不同曝气强度下系统N2O排放受到氮素转化和微生物群落变化的影响。适宜曝气强度不仅提高总氮去除率,还可有效控制N2O排放。     

论企业环境监督员资质管理制度的建立

企业环境监督员资质管理制度是推动企业履行环境责任的重要手段,是建立和完善现代企业环境管理制度的重要环节,是提高环境执法有效性的重要保障。同时建立企业环境监督员资质管理制度将促进我国环境专业人才的培养与发展。因此,应将其纳入法制管理轨道,充分发挥其作用。     

Effect of substrate feeding frequencies on the methane production and microbial communities of laboratory-scale anaerobic digestion reactors

Even though full-scale digesters have been designed based on laboratory-scale tests, the substrate feeding modes of laboratory-scale tests might be different from those of full-scale digesters. The effect of substrate feeding frequencies on the performance and microbial community of laboratory-scale anaerobic digestion reactors was investigated. Feeding frequencies of twice a day, once a day, and every two days were tested in three 2-L reactors with an organic loading rate of 0.5 g-glucose/L/day under mesophilic condition. According to the results of this study, all the reactors showed similar methane production rates and SCOD removal efficiencies after sufficient time of acclimation, but frequently feeding promoted more stable digestion. Although there was no significant difference in microbial diversities from pyrosequencing analyses, the changes of archaeal community composition were observed. The decrease in feeding frequency appeared to cause shifts from acetoclastic methanogens affiliated with Methanosaeta to H₂-utilizing methanogens. The increase of Methanosaeta at a frequently feeding might contribute to the stability of reactor operation. Since this study uses glucose as the substrate, there is still possibility of different results for more complex substrates, such as sludge, food waste, etc.     

基于mcrA基因分析污泥干化芦苇床中产甲烷菌的多样性

基于mcrA基因探讨污泥干化芦苇床稳定污泥过程中的产甲烷菌多样性,利用PCR-DGGE技术分析不同时期、不同干化床污泥中产甲烷菌群落变化。DGGE图谱聚类分析发现,同一时期不同干化床污泥中产甲烷菌群落相似度较高;而同一干化床、不同时期污泥中的产甲烷菌群落有显著的差异。结果表明,污泥干化芦苇床中产甲烷菌的优势种属主要随芦苇生长时期和污泥稳定化时间的延长而改变。基于序列和系统发育树分析,干化床污泥样品中主要的产甲烷优势菌属是甲烷杆菌属(Methanobacterium),甲烷微菌属(Methanomicrobium),表明有通气结构的芦苇床更能有效抑制产甲烷菌的生长,进而有利于减少甲烷的排放。     

完善环境仲裁制度的几点建议

本文在简要总结分析我国试行环境仲裁制度的实践及其存在的主要问题的同时,根据《仲裁法》的有关规定,提出了建立适合我国国情的环境仲裁制度的几点建议。     

Stabilization of mercury-containing wastes using sulfide

This paper summarizes the findings of our studies on mercury stabilization using sulfide. Primary stabilization variables such as stabilization pH and sulfide/mercury molar ratio were tested. Mercury stabilization effectiveness was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) and the constant pH leaching tests. The influence of interfering ions on mercury immobilization was also tested. The experimental results indicate that the sulfide-induced treatment technology is an effective way to minimize mercury leaching. It was found that the most effective mercury stabilization occurs at pH 6 combined with a sulfide/mercury molar ratio of 1. The combined use of increased dosage of sulfide and ferrous ions ([S]/[Hg]=2 and [Fe]/[Hg]=3 at pH=6) can significantly reduce interferences by chloride and/or phosphate during sulfide-induced mercury immobilization. The sulfide-treated waste stabilization efficiency reached 98%, even with exposure of the wastes to high pH leachants.     

湘境国道4项目危险品运输风险环境影响分析方法研究

根据具体范例，分析了公路项目危险品运输风险环境影响评价的分析方法，其研究成果对开展同类项目危险品运输风险环评有重要的参考价值。