地下渗滤系统处理农村生活污水的研究

在天津武清区一村落构建了2个并行的地下渗滤系统,考察了其对农村生活污水的处理效果。该系统水力负荷为10 cm/d,处理能力为50 t/d。填充介质选用土壤、陶粒、炉渣和两种自然有机质,按5∶2∶2∶1的比例配置的人工土层。结果表明地下渗滤系统对污水中各种主要污染因子均有一定的去除效果,在进水COD和C/N较低的不利条件下,COD、总磷、氨氮、总氮、悬浮物均得到有效去除,出水中各项污染指标平均浓度均达到《城镇污水处理厂污染物排放标准》中的一级A标准;具体到不同的污染指标,添加了不同有机质的2个并行系统的处理效果也有所不同。总体上看,地下渗滤系统作为农村生活污水的处理设施有很好的应用前景。     

天然矿物复合陶瓷材料制备及对印染废水脱色的研究

印染废水是水污染的重要来源之一,是目前较难处理与急需处理的工业废水。天然矿物材料通过吸附、光催化降解等作用可有效去除印染废水中的染料分子。为了开发新型环境矿物材料,采用白云石、菱镁矿等天然矿物作为原材料经粉碎、配料、造粒、烧结、水洗合成天然矿物复合陶瓷材料,用于印染废水的脱色。对酸性黑10B和直接混纺蓝D-3GL2种不同性质的染料废水进行了定量脱色研究。研究表明,当材料投加量为8 g/L,处理时间12 h,pH2~8,对2种废水均有95%以上的去除率;经800℃煅烧15 min的工艺进行再生活化,实现了陶瓷材料的循环使用。此方法制得的天然矿物复合陶瓷材料微孔结构明显,机械强度高,散失率低,解决了粉末材料在废水脱色过程中存在的固液难以分离的问题。     

废纸造纸废水结垢原因及防治对策研究

针对无锡某废纸造纸企业产生的污水经厌氧-好氧-化学混凝处理后,出水在放流池产生结垢现状,对各段污水中主要离子浓度进行跟踪分析,并对结垢的组分、结垢原因、机理和防治结垢对策进行了探讨。结果表明:垢样的主要成分为CaCO3;污水中含有较高浓度的钙离子和碳酸氢根离子是导致结垢的主要原因,较高的水温、pH值、流速、流动状态、池壁的粗糙程度以及PAC的投加对结垢也有一定的影响;最佳防治对策为使用Ca(OH)2+PAM代替PAC+PAM混凝,保证COD达标排放同时,也解决了出水结垢问题。     

农村分散型的生活污水处理工程实例

介绍了农村小城镇分散型的生活污水处理经验,即采用隔油沉淀、水解酸化、接触氧化法的处理工艺;污水处理设施采用埋地式土壤覆盖型;最终废水出水的各项水质指标均达到《城镇污水处理厂污染物排放标准》（GB18918—2002）中的一级B类标准。     

江苏省农业面源污染与经济增长关系的实证

运用基于VAR模型的脉冲响应函数和方差分解的方法,考察了江苏省1990-2007年农业面源污染与经济增长的动态演进关系。研究结果表明:①经济增长是影响江苏省农业面源污染的重要原因,农业面源污染的环境库兹涅茨曲线规律在一定程度上得到验证;②农业面源污染对江苏省经济增长的影响不明显,且具有一定滞后效应;③方差分解结果显示人均GDP是解释农业面源预测方差的重要变量,而农业面源污染对经济增长的预测方差贡献度则相对较小。因此,我们要充分关注江苏省经济快速增长对农业环境质量恶化所带来的负面影响。同时,为了充分体现农业面源污染对江苏省经济增长的反作用,其关键前提是必须要对农业面源污染所导致的负外部效应进行清晰的界定,以及建立一个有效、完善的农业资源配置、污染权的市场交易机制,以充分发挥资源约束和环境恶化对涉农微观经济主体投资、生产和消费行为的影响,进而对经济增长形成反作用。     

New Development in Study of the Faustmann Optimal Forest Harvesting

Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model in...     

喀斯特生态治理区可持续发展能力评价——以贵州毕节鸭池、遵义龙坪、沿河淇滩示范区为例

为检验喀斯特生态治理区的治理效果,以贵州省毕节鸭池、遵义龙坪、沿河淇滩3个示范区为例,从资源承载力、环境支持力、人口发展与支持能力、经济发展能力、社会发展能力5个方面,选择45个单项指标,建立评价指标体系,采用“纵横向”拉开档次动态综合评价法,评价3个示范区2005、2007年的可持续发展能力。结果显示：空间上看,龙坪示范区的可持续发展能力最好,鸭池示范区次之,淇滩示范区最差;时间上对比,龙坪示范区和淇滩示范区的发展能力2007年比2005年有所提高,〖JP2〗鸭池示范区稍有退步。根据各示范区的主要人 地矛盾,提出控制人口、优化配置水土资源、加大林牧产业比重等对策,以提高其可持续发展能力,并为同类地区的可持续发展提供借鉴。     

An improved method to study the impact of pesticide sprays on small song birds

Abstract

Four test groups of small songbirds (Zebra Finch, Poephila guttata) were sprayed in a chamber with varying concentrations of fenitrothion. Exposure levels were assessed by monitoring air concentrations, deposits of the active ingredient (AI) on glass plates and droplets/cm² on Kromekote® cards. All indices of exposure were linearly correlated and the mean AI deposit on glass plates for the four groups tested were equivalent to 38, 51, 139 and 255 g/ha or 14%, 18%, 50% and 91% of the highest permissible emitted rate for broadscale forest spraying in Canada. Significant depression in body weights and brain acetylcholinesterase levels were noted only for the highest exposure group. Fenitrothion residues in blood were detectable only at the highest exposure level, and in liver at the two higher levels. Carcass and feather residues were much higher than those in blood and liver, and were detectable at all exposure levels but the residues did not increase linearly with exposure. For one of the spray groups, we were able to compute an equivalent acute oral dose based on matching acetylcholinesterase inhibition.     

Characterization of an efficient catalytic and organic solvent-tolerant azoreductase toward methyl red from Shewanella oneidensis MR-1

The acyl carrier protein (ACP) phosphodiesterase gene (SO 4396) of Shewanella oneidensis MR-1 which was analyzed to have azoreductase activity was heterologously expressed in Escherichia coli. The ACP phosphodiesterase was found to reach maximum enzyme velocity 220.59 U/mg, named azoreductase in this study. The azoreductase had highest specific activity (153.16 U/mg) at pH 6.5, which showed a preference for nicotinamide adenine dinucleotide (NADH) as electron donor. The phylogenetic tree analysis indicated that the azoreductase had preference for NADH and dependence for flavin mononucleotide (FMN). However, the azoreductase from S. oneidensis MR-1 still had high enzyme activity in the absence of FMN. The Mg²⁺ had a positive influence on the enzyme activity with 25 mM concentration, whereas Cr³⁺, Cd²⁺ usually had significantly negative effect on enzyme activity. The purified azoreductase retained nearly 100 % activity after incubating in 30 % dimethyl sulfoxide (DMSO), 30 % acetone, 30 % methanol, 20 % ethanol, 20 % isopropanol, and 10 % propanol.     

Distribution and temporal trend of polybrominated diphenyl ethers in one Shanghai municipal landfill, China

The scarcity of information on polybrominated diphenyl ethers’ (PBDEs) flow in landfill restricts the life cycle analysis of PBDEs. In this study, eight PBDE congeners (BDEs 28, 47, 99, 100, 153, 154, 183, and 209) in topsoil, vegetation leaves, leachate, and municipal aged refuse collected from Shanghai Laogang Municipal Landfill (SLML) were investigated. The present study revealed elevated PBDE concentrations in topsoil and proved PBDE leakage from SLML and vegetation uptake. BDE-209 was the predominant congener, and this could be due to massive usage of deca-BDE mixture in Shanghai. ΣPBDE concentrations in leachates treated by reed wetland and A²/O process fell in the low end of the worldwide range. ΣPBDE concentrations in aged refuse samples rose from under 50 ng/g dw in 1989 to the range of 5,150–5,718 ng/g dw in 2002. PBDE concentrations increase in aged refuse samples throughout the 1990s into the 2000s paralleled municipal solid waste output from 1991 to 2002 in Shanghai. Exponential increase in BDE-209 concentration in aged refuse suggested the increasing market demands for deca-BDE mixture after 1990 in China. Notably, the inventory of PBDEs in SLML was 28.7 MT, and the doubling time of BDE-209 in aged refuse was calculated to be 1.6 year. SLML can be considered as a source of PBDE and one main recipient of PBDE as well, receiving inputs predominantly from the PBDE-containing waste. Priority should be given to formulate regulation on PBDEs and sorting work before landfill disposal.