我国工业场地再利用的环境风险管理困境及对策

我国污染场地再利用的开发活动日渐增多,伴随场地的再利用对环境和人体健康造成不良影响的环境事件也愈加频繁。在土壤污染防治立法、相关的土壤环境质量标准与监管制度都欠缺的情况下,针对污染场地再利用环境风险管理的项目规划的失当、环境风险评估指标的缺失及监督管理制度不健全的障碍,应加强区域环评与单项建设项目环评的协调,落实场地监管主体、层级及各自的监管职责,形成环境损害赔偿机制,从而健全场地环境风险管理制度。     

Deodorization of pig manure using lignin peroxidase with different electron acceptors

Odor pollution is a big environmental problem caused by large-scale livestock production in China, and developing a practical way to reduce these odors is pressing. In this study, a combination of 0.2–1.0 U/mL lignin peroxidase (LiP) and one of three peroxides (H₂O₂, CaO₂, 2Na₃CO₃·3H₂O₂) was examined for its efficiency in reducing the release of eight chemicals (propionic acid, isobutyric acid, isocaproic acid, isovaleric acid, phenol, p-cresol, indole, and skatole), NH₃, H₂S, and odor intensity from pig manure. The results showed an approximately 90% reduction in p-cresol, 40–60% reduction in odor intensity, 16.5–40% reduction in indolic compounds, and 25–40% reduction in volatile fatty acids. Being the electron acceptors of LiP, 2Na₃CO₃·3H₂O₂ and CaO₂ performed better than H₂O₂ in reducing the concentration of eight chemicals, NH_3, H₂S, and odor intensity from pig manure. The effect of deodorization can last for up to 72 hr.

Implications: In China, one of the major environmental problems caused by confined feeding is odor pollution, which brings a major threat to the sustainability, profitability, and growth of the livestock industry. To couple the LiP with the electron acceptors, a low–cost, simple, and feasible method for odor removal was established in this study. Based on the study results, a practical treatment method was provided for odor pollution and supply the farm operators a more flexible time to dispose treated manure.     

Rebound effect and its decomposition – an analysis based on energy types in China

Rebound effect derived from energy efficiency improvement has been widely invested. However, most of studies focus on the rebound effect of the energy composite level and neither distinguish nor compare different energy types. We compare the differences in energy saving and energy rebound between primary and secondary energy sources, and further decompose the rebound effect into production rebound part and final demand component. To do so, we add a module for rebound into a comparative state China-CGE model. We design and test two simulation scenarios using the model. In Scenario 1, all production sectors’ energy efficiency of using primary energy increases by 5%. In Scenario 2, all production sectors’ energy efficiency of using secondary energy increases by 5%. The results show that Scenario 2 leads to more GDP growth and more energy saving. Our scenarios show rebound effects range between 9.6% and 27.9%, and in general are higher when energy efficiency of using primary energy sources is improved. Our decomposition analysis shows that improving energy efficiency in production sectors would stimulates energy use of final demand. Indeed, the consumption side has significant contribution to rebound in secondary energy use, especially in crude oil and gas. This study reveals that improving efficiency of using secondary energy is better than improving that of primary energy, both in terms of economic impact and energy rebound. And complementary policies that prevent energy services prices from falling too much can be adopted to reduce rebound. Controlling residential energy use could also be effective in reducing rebound, this has particular implication to economies in which residential energy consumption are far from saturation.     

Levels and distribution of Dechloranes in sediments of Lake Taihu,China

The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g^?1 dw and 0.051 to 2.10 ng g^?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake.     

火电灰渣场自然恢复下灰渣养分及重金属含量研究

对自然恢复下4类不同年代样地的灰渣养分含量及重金属含量进行研究,通过对比分析发现,有机质、全氮、全钾、全磷含量随着自然恢复时间的增加呈现递增的趋势,全磷含量在各恢复阶段与对照样地之间并不存在显著差异(P0.05)。pH随着恢复时间的增加呈现递减的趋势。对灰渣综合质量指数进行研究发现,自然恢复长期、中期、短期与自然恢复初期对比均有显著提高(P0.05),且随着自然恢复时间的增加灰渣综合质量指数逐渐提高。对灰渣场锌、铅、铜3种重金属研究后发现,在自然恢复下随着时间的增加,灰渣中重金属含量均呈现递减的趋势。     

印染RO浓水深度处理及回用

采用Fenton-石灰苏打法耦合工艺对某印染厂印染反渗透(RO)浓水进行深度处理。通过实验研究了不同H2O2和Fe2+投加量、p H和反应时间对废水COD去除率的影响,以及不同石灰和碳酸钠投加量对废水硬度的脱除效果,出水回用于染色工段进行染色实验。结果表明,在p H=3.0,Fe2+投加量为1.5 mmol/L,H2O2投加量为3.75 mmol/L,反应时间为45 min,石灰和碳酸钠投加量分别为450 mg/L和1 000 mg/L的条件下,出水COD和硬度的去除率可分别达到73.9%和85.0%,耦合工艺出水水质符合该厂回用染色水标准,且减少了盐的使用,可实现印染RO浓水回用。     

改性SCAC催化臭氧氧化去除布洛芬效能与反应活性位点研究

采用不同的表面改性方法(去矿化处理、氧化改性、碱改性和还原改性)对污泥基活性炭(SCAC)进行处理,分别获得了表面金属含量低、碱位低、碱性官能团含量高及Lewis碱含量高的4种改性SCAC(SCAC-D、SCAC-S、SCAC-OH和SCAC-N),对比考察了改性前后SCAC催化臭氧氧化去除布洛芬(IBP)的效能,并探讨了SCAC催化臭氧氧化反应的主要活性位点。结果表明,5种SCAC催化活性顺序为:SCAC-N>SCAC-OH>SCAC>SCAC-S>SCAC-D;金属组分减少会直接影响SCAC的催化活性,碱位减少对其催化活性的影响相对较弱,说明SCAC表面较为丰富的金属组分是其催化臭氧氧化反应的主要活性位点;增加SCAC表面碱位(Lewis碱和碱性官能团),减少表面酸性官能团有助于提高其催化活性。     

日本污水脱氮除磷深度处理工艺分析

为提高进入琵琶湖水体水质和有效恢复并保持琵琶湖流域水生态环境,日本滋贺县10家下水道污水处理厂全部采用脱氮除磷深度处理工艺。湖南中部净化中心目前规模为26.85万t/d,采用缺氧-好氧循环硝化/反硝化(AO)、厌氧-缺氧-好氧(AAO)和多段进水多级缺氧-好氧硝化/反硝化(SMAO)3种深度处理工艺。AAO工艺是国内城镇污水处理厂广泛采用的二级生化工艺,AO、SMAO工艺在国内还没有应用实例。AO、AAO工艺采用内循环硝化/反硝化反应脱氮,SMAO工艺采用无内循环的多段进水多级硝化/反硝化反应脱氮。AO、SMAO工艺采用化学方式除磷,PAC添加浓度约50mg/L。AAO工艺采用化学和生物组合方式除磷,PAC添加浓度降低到约30 mg/L。AO、AAO工艺出水BOD、CODMn、SS、TN和TP均值分别约为0.9 mg/L、5.2 mg/L、1 mg/L、6.5 mg/L和0.06 mg/L,相应的去除率约为99.5%、94.2%、99.5%、78.0%和98.1%。SMAO工艺出水TN约为2.5 mg/L,TN去除率提高到91.6%,其他指标和AO、AAO工艺基本相同。     

300MW燃煤锅炉机组超细颗粒聚并器的实验研究

为了解决燃煤锅炉烟气中超细颗粒难以脱除的问题,基于流体动力学原理设计了一种超细颗粒聚并器,并在300 MW燃煤锅炉机组电除尘器的前置烟道中进行了实验研究。结果表明,聚并器内部存在超细颗粒之间以及超细颗粒与大颗粒之间的相互聚集行为,从而使超细颗粒数量显著减少。例如,对于粒径在2.65和10.48μm以下的颗粒,其体积比例在聚并器出口分别减少了56.7%和62.3%,在电除尘器出口的粉尘浓度减少了26.34 mg/Nm3,这表明,基于流体动力学原理的聚并器对超细颗粒的聚并作用明显,具有良好的应用前景。