乙醇汽油对减少机动车污染排放的机理研究与分析

以93#国Ⅲ乙醇汽油(E10)、93#国Ⅲ普通汽油和93#国Ⅳ普通汽油为实验对象,对GB18352.3-2005中要求限定的CO、HC和NOx,以及颗粒物(PM)和CO2等主要污染物的排放进行了测量和对比研究,并对CO、HC、PM、NOx、CO2和苯系物等污染物的形成原因和减排机理进行了分析。和93#国Ⅲ普通汽油相比,93#国Ⅲ乙醇汽油(E10)排放的尾气中:CO降低了19.7%,HC降低了16.4%;和93#国Ⅳ普通汽油相比,93#国Ⅲ乙醇汽油(E10)排放的尾气中:CO降低了1.8%,HC降低了12.9%, CO2降低了2.4%。研究表明,乙醇汽油在减少CO、HC、NOx、颗粒物和苯系物等有毒物质排放方面具有显著功效,使用乙醇汽油可以减少环境污染物的排放,显著改善空气质量。     

水体浊度对马来眼子菜和菹草生长的影响

研究了不同浊度(30、60和90 NTU)水体中,马来眼子菜及菹草的生长发育状况,并用水下饱和脉冲叶绿素荧光仪(Diving-PAM)测定其叶片荧光参数指标。结果表明,不同的浊度对马来眼子菜的叶片数及株高无显著影响,而对菹草的叶片数及株高生长速率有一定的影响。30 d胁迫下,浊度组马来眼子菜的最大光化学量子产量(maximum quantum yield,Fv/Fm)、光化学淬灭系数(photochemical quenching,qP)、非光化学淬灭系数(non-photochemical quenching,qN)、相对光合电子传递速率(electron transport rate,ETR)与对照组差异不显著(p>0.05),表明马来眼子菜对浑浊水体有较强的耐受能力;实验结束时,高浊度组(90 NTU)中,菹草Fv/Fm、qP、qN、ETR与对照组达到极显著差异(p<0.01),其余浊度组也相应受到影响,说明菹草的光系统II(PSII)受到破坏。该研究的成果可为沉水植物恢复研究与实践提供技术支撑。     

MnO2/Al2O3吸附草甘膦及微波紫外耦合降解再生工艺

以掺混煅烧法制备MnO2/Al2O3,并对草甘膦进行吸附,将吸附态草甘膦置于微波紫外耦合系统中进行降解和再生。研究并给出了MnO2/Al2O3的最佳制备条件、最佳吸附条件和微波紫外耦合降解再生的最佳工艺参数。MnO2/Al2O3最佳制备条件为MnO2质量分数15%,煅烧温度500℃,煅烧时间2 h。在常温下,MnO2/Al2O3对草甘膦的最大吸附量为75 mg/g。微波紫外耦合系统最佳工艺参数为功率500 W,时间25 min,空气量0.06 m3/h。在此操作条件下,MnO2/Al2O3的再生率达到85%,并且可以多次再生利用,草甘膦最终降解产物为二氧化碳、氮氧化物、磷酸和水,矿化率为65%。     

生物酶生态修复重金属污染土壤

以多种重金属污染的土壤为材料,研究了酶对重金属的去除效果.在单因素实验基础上,采用响应面法对重金属去除的反应条件进行优化,结果表明,α-淀粉酶质量浓度0.2%、pH 3.5、反应时间12 h为最佳淋洗修复条件,Cd、Cr、Cu、Ni、Zn去除率分别为82.36%、75.02%、38.38%、34.69%和57.54%,去除率的大小顺序为Cd >Cr >Zn >Cu >Ni.酶作为土壤的组成部分,利用酶修复重金属污染的土壤,可以降低环境风险,具有较好应用前景.     

昆明市主城区热环境效应及影响因素分析

以昆明市主城区为研究对象,根据2000年、2010年和2020年3期Landsat TM/OLI遥感影像,反演3个时期的地表温度,采用标准差椭圆分析热环境效应的时空演变,并使用地理探测器探讨热环境效应的影响因素。结果表明：近20 年来,昆明市主城区热岛区集中分布在城镇建设密集区域,热环境方向主轴由东北—西南走向转为西北—东南走向;前期热环境重心向西北方向偏转了57.5°,偏移2.47 km,后期向西北方向偏转24.25°,偏移0.86 km;有极低温区向低温区、较低温区转变,较高温区与高温区向极高温区转变的态势,其中,官渡区的热环境效应增强趋势最显著;建筑用地和植被覆盖度对地表温度产生的影响力最大,建筑用地与高程交互作用时会增加对地表温度的影响力,水体与建筑用地或不透水面的交互作用减弱了水体对热环境效应的缓解作用。

     

不同生境来源硝化细菌群对氨氮的去除性能

硝化细菌是微生物脱氮的关键功能菌群之一,筛选优质硝化细菌对于强化微生物脱氮具有重要意义。将河流沉积物、土壤自然环境和市场售人为环境3种生境来源的硝化细菌功能进行比较研究,并利用分子生物学手段分析了硝化细菌群落结构。结果表明,沉积物生境中硝化细菌的活性以及耐氨氮、pH和盐度等环境因子的能力高于土壤和市售硝化细菌。利用MPN-PCR法和克隆文库分析法对各生境硝化细菌丰度及群落结构组成进行分析,发现沉积物生境中硝化螺旋菌(Nitrospira)生物量较高,促使该生境硝化细菌氨氮去除率较高。沉积物生境中硝化细菌的高耐氨氮和耐pH能力与群落中存在硝化杆菌(Nitrobacter)有关,而高耐盐性可能是由于该生境中存在耐盐或适度嗜盐特异基因型硝化细菌,运用Blast程序进行序列比对发现,这些特异基因型硝化细菌为不可培养微生物。     

Co-composting of green waste and food waste at low C/N ratio

In this study, co-composting of food waste and green waste at low initial carbon to nitrogen (C/N) ratios was investigated using an in-vessel lab-scale composting reactor. The central composite design (CCD) and response surface method (RSM) were applied to obtain the optimal operating conditions over a range of preselected moisture contents (45–75%) and C/N ratios (13.9–19.6). The results indicate that the optimal moisture content for co-composting of food waste and green waste is 60%, and the substrate at a C/N ratio of 19.6 can be decomposed effectively to reduce 33% of total volatile solids (TVS) in 12 days. The TVS reduction can be modeled by using a second-order equation with a good fit. In addition, the compost passes the standard germination index of white radish seed indicating that it can be used as soil amendment.     

Review of recycling performance indicators: A study on collection rate in Taiwan

The Taiwan Environmental Protection Administration (Taiwan EPA) launched a national Extended Producer Responsibility (EPR) system after integrating eight private recycling organizations in 1998. After that, the environmental performance of the EPR system brought a lot of attention to policy makers. Many studies show positive environmental effects of the EPR system in Taiwan. However, there are controversial questions remained, such as whether the performance indicators used are the right choice to estimate the environmental effects of the recycling policy? Can those estimated results really reflect the performance of the system?This paper would therefore like to more accurately evaluate the performance indicators of the EPR system based on data observed over the past decade in Taiwan. In the process of evaluating the performance indicators, we have found that the collection rates for durable goods are often ignored in countries that pursue a zero waste policy. This may affect the actual recycling outcome and resource direction targeted by producers. However, in order for the collection rate to be adopted as a policy indicator, how to estimate the amounts of retired or waste products during a period is critical. In this paper, we estimate the collection rate for electrical and electronic waste by using the survival analysis and ownership data analysis approaches. We also provide a comparison of both approaches and put forward suggestions for directions in the future in solid waste management.