城市土地生态适宜性分区划分研究

在新型城镇化与生态文明建设背景下,城市发展迫切需要合理布局以实现城市土地的节约集约利用,降低城市化过程中因建设用地肆意蔓延所导致的土地资源浪费与生态环境破坏影响。以常州市武进区为例,采用地形地貌、生态环境、交通设施、建设密度4类因子建立景观过程阻力赋值体系,结合GIS空间分析技术,以垂直生态过程的多因素多因子综合判别得到的生态保护用地扩张和城镇用地扩张阻力基面为基础,再以描述水平生态过程的最小累积阻力模型计算两种扩张过程的最小累积阻力值,并依据二者的最小累积阻力差值表面,从空间上将武进区划分为4个等级的城市土地生态适宜性分区,分别为优先建设区118.39 km²、适宜建设区233.60 km²、生态缓冲区777.91 km²、生态控制区115.90 km²,明确指出了各分区的空间布局,提出了相应的发展建议,以期为武进区未来城市发展提供科学合理的空间布局参考。同时考虑了垂直生态过程和水平生态过程,一定程度上弥补了传统方法只从景观单元垂直过程研究的不足之处,为生态适宜性分区划分的方法研究提供了有益的尝试和补充。     

Laboratory-scale study of the suppression of PCDD/F emission during coal and MSW co-incineration

The experimental test of co-incinerating Chinese raw municipal solid waste （MSW） and coal in a laboratory-scale tubular reactor was first reported in present study, and the emission of normal gas components and the effects of the S/Cl molar ratio or coal mixing percentages on polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDDs/Fs） emission were investigated and discussed. The results indicated that OCDD was the only PCDD homologues since others like TCDD-HpCDD was hardly detected, while as the categories of PCDF homologues were comparatively much more general. The amount of PCDD was much larger than that of PCDF in all operating conditions. Since ZPCDF/∑PCDD〈〈1, the dominant role of the precursor formation was proven in our experimental conductions. With increasing the coal addition to MSW （from 0 to 16%）, PCDD and PCDF were reduced considerably. Coal and MSW may suppress the PCDD/F emissions efficiently （over 95%） during the MSW incineration process. The PCDD/F suppression results of the present study could be helpful guidance to the industrial application of Chinese MSW and auxiliary coal co-incineration processes. The PCDD/F stack emission data of two industrial incinerators using co-incineration technology in China seem to have a great positive reduction of PCDDs/Fs.     

臭氧高级氧化法处理化工废水的进展研究

单独臭氧氧化降解化工废水的效率较低,为提高降解效率,研究者们开发了O3/UV、O3/H2O2、O3催化氧化等组合工艺,不仅能够对难降解有机物进行降解,而且最终生成无害的氧气.关于O3/UV、O3/H2O2、O3催化氧化这三种臭氧高级氧化法处理化工废水的协同机理及一些研究进展取得了一定成效,分别阐述了研究者们对各方法一些应用研究,对臭氧高级氧化在化工废水处理领域的应用前景进行了概述.     

Effect of carbon source and nitrate concentration on denitrifying phosphorus removal by DPB sludge

Effect of added carbon source and nitrate concentration on the denitrifying phosphorus removal by DPB sludge was systematically studied using batch experiments, at the same time the variation of ORP was investigated.Results showed that the denitrifying and phosphorus uptake rate in anoxic phase increased with the high initial anaerobic carbon source addition. However once the initial COD concentration reached a certain level, which was in excess to the PHB saturation of poly-P bacteria, residual COD carried over to anoxic phase inhibited the subsequent denitrifying phosphorus uptake. Simultaneously, phosphate uptake continued until all nitrate was removed, following a slow endogenous release of phosphate. High nitrate concentration in anoxic phase increased the initial denitrffying phosphorus rate. Once the nitrate was exhausted, phosphate uptake changed to release. Moreover, the time of this turning point occurred later with the higher nitrate addition. On the other hand, through on-line monitoring the variation of the ORP with different initial COD concentration, it was found ORP could be used as a control parameter for phosphorus release, but it is impossible to utilize ORP for controlling the denitrificaion and anoxic phosphorus uptake operations.     

有机磷酸酯阻燃剂降解方法的研究进展

有机磷阻燃剂(OPFRs)已取代溴代阻燃剂广泛应用于各行业,并很容易通过挥发、磨损等方式进入各环境介质中.目前,已在水体、土壤等环境介质中检测到了 OPFRs的存在.本文总结了目前已有的OPFRs在环境中的降解方式,据其原理主要可分为化学法和生物法,化学法主要包含Fenton/类Fenton氧化法、紫外-双氧水法(UV...     

不同污水处理工艺中全氟和多氟烷基物质的来源、去除效率及生态风险

使用固相萃取-超高效液相色谱串联质谱法,测定广西3个污水处理厂（P1、P2、P3）中17种全氟和多氟烷基物质（PFASs）。结果显示,共检测出10种PFASs,检出率为33.3%～100%。进、出水中PFASs质量浓度分别为32.0～86.4和23.0～39.6 ng/L。全氟丁烷磺酸（PFBA）、全氟戊酸（PFPeA）和全氟辛酸（PFOA）是进、出水中的主要污染物。厌氧-缺氧-好氧（AAO）工艺对PFASs的去除率为49.0%;改良型序批反应器（MSBR）工艺对PFASs的去除率为72.2%,氧化沟工艺对PFASs的去除率为25.0%。P1和P3进水中的PFASs主要来源于生活污水,P2进水中的PFASs来源包括生活污水和工业废水。P1出水中的全氟十二烷酸（PFDoDA）对纳污河流的鱼类和水蚤构成高生态风险,对藻类构成中等生态风险,P2和P3出水对纳污河流构成的生态风险较低。     

金泽水库库区细菌群落构建过程与关键驱动因子分析

为探究微污染水生态系统中细菌群落对人为干扰响应所依赖的生态机制,基于生态零模型(ecological null model),应用拟合分析(fitting analysis)研究了环境因子与金泽水库来水及库区不同区域间细菌群落构建过程的关系.结果表明,细菌群落在系统发育上的聚类比预期要分散得多(SES.MNTD的单样本t检验95%置信下限为9.79).温度是影响群落系统发育的重要因子.随机性过程(stochastic processes)和确定性过程(deterministic processes)在不同样品细菌群落演替中的相对重要性呈明显的季节性特征.春、夏和秋季样品细菌群落演替由随机性过程主导,冬季则由随机性过程和确定性过程共同主导.NH~+_4-N是影响随机性过程和确定性过程相对重要性的主要环境因子.NH~+_4-N浓度为0.06～0.40 mg·L~(-1)时,由随机性过程主导;NH~+_4-N浓度为0.40～0.80 mg·L~(-1)时,则由随机性过程和确定性过程共同主导.分散限制(61.68%)和异质选择(26.65%)在研究区域中不同采样点之间细菌群落变化中起到重要作用.     

小流域农业面源氮污染时空特征及与土壤呼吸硝化关系分析

土壤呼吸与硝化特性是控制土壤生态系统中氮素转化和面源氮流失的关键因子,也是土壤氮循环的重要组成部分.选取位于巢湖北部的柘皋河流域作为案例研究区,应用BaPS技术测定林地和农田土壤呼吸、硝化和反硝化特性,运用SWAT模型分析农业面源氮污染输出的时空特征,并初步探讨土壤呼吸和硝化特性与农业面源氮污染的相互作用关系.结果表明,由于土地利用和施肥量的变化,1996~2012年间的年均和月均面源氮污染负荷明显大于1980~1995年间的模拟结果,不同月份的面源氮污染输出负荷均存在显著性差异,月均氮负荷受降雨量影响密切.1996~2012年流域面源总氮流失平均负荷为10.40 kg·hm-2,明显大于1980~1995年的8.10 kg·hm-2,方差分析表明两个时期面源总氮流失负荷的空间分布存在一定的差异.林地的呼吸速率远大于农田的呼吸速率.农田较高的总硝化速率和反硝化速率导致土壤氮库中的氮素减少,从而在一定程度上使得面源氮污染的输出负荷减小.农田土壤的总硝化速率大于反硝化速率,导致农田硝态氮的面源污染流失量增加,而有机氮的流失量有所减少.因此,土壤呼吸与硝化特性的研究有利于从土壤生物学角度深入分析土壤氮循环,对农业面源氮污染的防治具有重要的理论和现实意义.     

降水与氮沉降变化对草地关键氮过程的影响研究进展

研究降水格局变化和氮沉降增加对草地氮循环关键过程的影响,探索不同氮循环过程对未来全球气候变化的叠加效应和适应特征,为最终调节氮素转化过程,提高草地氮素利用效率并降低其生态环境负效应提供科学依据.本文综述了不同水分、氮素以及水氮耦合作用分别对植物氮库、土壤氮库的影响,同时分析了在这些条件变化下可能存在的微生物和酶活性变化的驱动机制.在此基础上探讨了水、氮变化对草地氮循环关键过程影响的不确定性以及目前研究中存在的主要问题.     

Combined UV-C/H2O2-VUV processes for the treatment of an actual slaughterhouse wastewater

In this study, a three-factor, three-level Box-Behnken design with response surface methodology were used to maximize the TOC removal and minimize the H₂O₂ residual in the effluent of the combined UV-C/H₂O₂-VUV system for the treatment of an actual slaughterhouse wastewater (SWW) collected from one of the meat processing plants in Ontario, Canada. The irradiation time and the initial concentrations of total organic carbon (TOC_o) and hydrogen peroxide (H₂O_2o) were the three predictors, as independent variables, studied in the design of experiments. The multiple response approach was used to obtain desirability response surfaces at the optimum factor settings. Subsequently, the optimum conditions to achieve the maximum percentage TOC removal of 46.19% and minimum H₂O₂ residual of 1.05% were TOC_o of 213 mg L^?1, H₂O_2o of 450 mg L^?1, and irradiation time of 9 min. The attained optimal operating conditions were validated with a complementary test. Consequently, the TOC removal of 45.68% and H₂O₂ residual of 1.03% were achieved experimentally, confirming the statistical model reliability. Three individual processes, VUV alone, VUV/H₂O₂, and UV-C/H₂O₂, were also evaluated to compare their performance for the treatment of the actual SWW using the optimum parameters obtained in combined UV-C/H₂O₂-VUV processes. Results confirmed that an adequate combination of the UV-C/H₂O₂-VUV processes is essential for an optimized TOC removal and H₂O₂ residual. Finally, respirometry analyses were also performed to evaluate the biodegradability of the SWW and the BOD removal efficiency of the combined UV-C/H₂O₂-VUV processes.