生活垃圾焚烧发电厂烟尘中重金属沉降对土壤环境影响分析

本文以一日处理生活垃圾2250t的生活垃圾焚烧发电厂为例,根据其重金属的排放量,预测重金属随大气扩散、迁移,最终通过自然降水和自然沉降进入土壤后,对土壤环境的影响。结果表明,项目建成后的20年内,大气评价范围内土壤中重金属的累计值满足《土壤环境质量建设用地土壤污染风险管控标准(试行)》 (GB36600-2018)表1中第二类用地筛选值要求。     

TiO2光催化氧化降解乳酸的工艺及机理研究

以TiO2为催化剂、紫外灯为光源对乳酸进行光催化降解实验,考察了乳酸初始浓度、TiO2用量、反应时间、曝气方式等因素对乳酸降解率的影响,并在此基础上应用正交实验对降解条件进行优化,同时对乳酸的降解机理进行了探索研究.实验结果表明:以300 W紫外汞灯为光源,在乳酸初始浓度为O.5 g/L、TiO2量为0.20 g/L、...     

以剩余污泥水解酸化液为外加碳源的污水生物脱氮

为解决低碳氮比污水生物脱氮过程反硝化碳源不足的问题，利用剩余污泥水解酸化液为外加碳源，通过具有曝气段与非曝气段的一体化曝气生物滤池（BAF），研究低碳氮比污水生物脱氮的性能与工艺条件。实验结果表明，预处理后的水解酸化液VFAs为3134．9～5251．4mg／L、ThODVFAs／COD为59．87％～91．85％，适合作为生物脱氮的外加碳源；水解酸化液的投配量、进水TN浓度对系统生物脱氮效果的影响较大，气水比、曝气段与非曝气段比例对系统的硝化和反硝化性能有重要的影响；在温度为25±1℃，水解酸化液COD平均为7555．1mg／L，进水TN、NH4-N和COD分别平均为43．88mg／L、39．04mg／L和56．8mg／L，碳源与污水投配的流量比为1：75的条件下，当BAF水力停留时间（HRT）为8h、曝气段与非曝气段比例为3：3、气水比为10：1、回流比为2：1时，NH4-N和TN的去除率分别超过98％和75％，出水COD平均为28．6mg／L。研究指出，剩余污泥水解酸化液经过预处理后可用作低碳氮比污水生物脱氮的外加碳源，有效地提高了反硝化效果，并不会造成二次污染，同时又可以实现剩余污泥的减量化和资源化。     

餐厨垃圾连续堆肥处理系统中试研究

餐厨垃圾是影响城市环境重要的污染源,其处理尤其是就地堆肥处理近年来受到重视.为了利用园林绿化基质作为餐厨垃圾堆肥的水分调节材料,按照1:1体积比进行连续堆肥,研究添加园林绿化基质对餐厨垃圾堆肥过程中理化指标的影响,为餐厨垃圾无害化处理提供科学依据和技术指导.结果表明,物料堆肥升温启动迅速,第3天就达到50℃,高温持续10 d以上,达到无害化要求；堆肥最终减容率达到53％以上,减量化效果明显；物料总氮和总磷含量呈升高趋势,总有机质含量降低,肥料营养元素含量在6％以上,符合有机肥国家标准(NY525-2002).总的来说,园林绿化基质作为调理剂与餐厨垃圾联合堆肥方法可行,减量化效果好,品质符合标准.     

土壤理化性质对Fe0还原硝基苯的影响

采用零价铁(Fe0)还原降解土壤中的硝基苯，考察土壤理化性质对还原效果的影响。结果显示，当2 g土壤中NB含量约为2.5 ×10-6mol/g，铁粉用量为50 mg，土壤含水量为75％时，控温25℃条件下反应1 h，硝基苯在松砂土和中壤土中的还原率分别可达到82.9％和91.1％。硝基苯在2种土壤中的还原率表现出中壤土...     

间歇曝气条件下短程硝化的实现及影响因素研究

研究间歇曝气条件下短程硝化的实现及温度、pH值和DO对实验效果的影响。以城市生活污水为研究对象，采用间歇曝气方式进行短程硝化实验，利用接种法培养驯化亚硝化细菌。实验研究结果表明，经过22 d的培养驯化，成功获得了亚硝化细菌，亚硝酸盐的积累率达到90％左右。在温度为25℃、pH为7.5、DO＜1 mg/L的条件下，亚硝酸...     

Investigations on the sorption of a toxaphene model congener, the B7-1450, on marine sediments

Sorption is a natural process that takes place in sediments or soils and changes the mobility and availability of hydrophobic organic compounds, such as toxaphene pesticide in the environment. The sorption of the 2-exo,3-endo,5-exo,8,9,10,10-heptachlorobornane (B7-1450), used as a model compound of the toxaphene heptachlorobornane congeners found in sediments, was investigated for the first time through a series of batch sorption experiments. The losses of B7-1450 due to adsorption onto glass walls and to evaporation occurring during analytical treatment steps were corrected. The study showed that these specific losses ranged from 2% to 3.5% for the glass walls adsorption and can be as high as 15% for the evaporation treatment. The sorption coefficients, K(d) and K(oc), of B7-1450 could be overestimated by >30%, particularly for low-concentration samples, if the losses were not corrected. Loss correction equations were established, validated and applied to determine sorption coefficients for the B7-1450 congener. The K(oc) values for B7-1450 determined over a gradient of concentrations ranged from 3.5x10(4) to 6.5x10(4)mlg(-1), revealing a strong affinity of B7-1450 for marine sediments.     

Toxicity profile of labile preservative bronopol in water: the role of more persistent and toxic transformation products

Transformation products usually differ in environmental behaviors and toxicological properties from the parent contaminants, and probably cause potential risks to the environment. Toxicity evolution of a labile preservative, bronopol, upon primary aquatic degradation processes was investigated. Bronopol rapidly hydrolyzed in natural waters, and primarily produced more stable 2-bromo-2-nitroethanol (BNE) and bromonitromethane (BNM). Light enhanced degradation of the targeted compounds with water site specific photoactivity. The bond order analysis theoretically revealed that the reversible retroaldol reactions were primary degradation routes for bronopol and BNE. Judging from toxicity assays and the relative pesticide toxicity index, these degradation products (i.e., BNE and BNM), more persistent and higher toxic than the parent, probably accumulated in natural waters and resulted in higher or prolonging adverse impacts. Therefore, these transformation products should be included into the assessment of ecological risks of non-persistent and low toxic chemicals such as the preservative bronopol.     

Polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants in air and seawater of the European Arctic

The spatial distribution of polybrominated diphenyl ethers (PBDEs) and several alternative non-PBDE, non-regulated brominated flame retardants (BFRs) in air and seawater and the air-seawater exchange was investigated in East Greenland Sea using high-volume air and water samples. Total PBDE concentrations (Ó₁₀PBDEs) ranged from 0.09 to 1.8 pg m⁻³ in the atmosphere and from 0.03 to 0.64 pg L⁻¹ in seawater. Two alternative BFRs, Hexabromobenzene (HBB) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE), showed similar concentrations and spatial trends as PBDEs. The air-seawater gas exchange was dominated by deposition with fluxes up to −492 and −1044 pg m⁻² day⁻¹ for BDE-47 and DPTE, respectively. This study shows the first occurrence of HBB, DPTE and other alternative flame retardants (e.g., pentabromotoluene (PBT)) in the Arctic atmosphere and seawater indicating that they have a similar long-range atmospheric transport potential (LRAT) as the banned PBDEs.