Critical review for the quantification of leachate production: Evaluation example for the “Oum Azza” public landfill in Rabat city,Morocco

The estimation of leachate quantities produced in landfills is necessary to dimension the treatment plants allowing to reduce the polluting load of these effluents and consequently avoid their negative impacts on the environment. Different leachate quantification methods were used in this study to assess the leachate volume produced at the Oum Azza landfill. The water balance method give comparable estimations of leachate production to the Ouled Berjal landfill ratio. The first method showed average values between 487 and 495 m³/day for 2015, 2018, and 2019, and at the same time, the second method gave values between 470 and 477 m³/day for the same years. In contrast, the World Bank ratio showed high values that vary between 2260 and 2295 m³/day for 2015, 2018, and 2019. The on-site data and the statistical analysis showed us that the World Bank ratio is not adapted for the estimation of the leachates produced in Oum Azza landfill, while the water balance and the ratio of Ouled Berjal landfill allowed to give comparable results to reality.     

The formation of aerobic granular sludge for the treatment of real landfill leachate using a granular sequencing batch reactor at a constant volume

Leachate generated in a landfill may not be treated by conventional biological treatment due to its nature and complexity. The process of forming aerobic granules in batch sequencing reactors having features such as; reducing the settling process time and saving energy consumption and high decomposition rate have been noticed by researchers. In the present study, the structure of sequencing batch reactors (SBRs) was evaluated for the formation of granules, which were subsequently utilized for the treatment of landfill leachate. The experiment was initiated by using the GSBR, containing 1200 ml with different apparatuses, to develop granular sludge, and synthetic wastewater was added to reinforcement. The selected parameters for the operational hydraulic retention time (HRT) of the wastewater (6-h cycles) included feeding, idle, aeration, settling, and discharge. Furthermore, the controlled conditions were the dissolved oxygen (DO) range of 2–2.2 mg/L, temperature range of 20–23℃, and pH of 7.5–8.3. The chemical oxygen demand (COD), mixed liquor suspended solids (MLSS), and sludge volume index (SVI) daily were measured at the influent and effluent of GSBR reactor. The main properties of aerobic granular sludge were identified during the research procedures, and the remarkable settling and potent, high-density microbial structure of the granules were confirmed. The mean size of the formulated granules was estimated at 7.46 ± 1.8 mm, and the volume of the biomass also increased from approximately 1607 to 4137 mg/L through the granulation process. Moreover, 98% of the influent chemical oxygen demand (COD) could be removed by the formulated granular sludge, and the final-stage organic loading rate was estimated at 5.65 COD/m³/day. According to the results, GSBRs could be employed for the formulation of aerobic granular sludge for the treatment of landfill leachate.     

基于ALOHA软件的某化工厂选址合理性评估

为了研究化工厂选址的合理性,以山东省某化工厂为例,采用ALOHA(有害大气空中定位软件)模拟软件定量确定厂区内环氧乙烷毒气扩散事故的影响区域和敏感点毒气浓度,结合GoogleEarth地图对影响范围进行实地拟合。结果表明化工厂的环氧乙烷储罐泄漏后,毒气扩散到厂区范围之外,毒气浓度在50~500ppm之间的重伤区(ERPG-2)扩散距离可达1.7km,对周围居民的人身安全构成严重威胁;厂区应根据拟合结果重新规划工厂中环氧乙烷储罐的位置;ALOHA软件对化工厂选址评价提供了新的手段。     

我国污染场地土壤石油烃环境质量标准体系的现状与趋势

石油烃污染场地已经成为国内外重点关注的工业污染场地类型之一。国内基于人体健康风险的污染场地管理模式及分层次评估方法已经展现雏形,为风险管理者提供了基于人体健康的土壤石油烃风险筛选值和管制值,也为污染场地的防治与修复工作提供了决策支持。在前人研究的基础上,梳理了国内土壤环境质量标准体系的建立与发展历程,分析了石油烃类污染物检测方法的现状与未来发展趋势,并着重对比与分析了各标准制订的石油烃及其指示化合物的风险评估筛选值。目前面临的关键问题:①完善石油烃监测指标体系及分析方法是精准获得风险评估结果的前提。现有石油烃馏分指标划分较为宽泛,有必要参考国外先进标准体系,逐渐完善石油烃馏分指标划分及其配套的定量分析方法。②新颁布的国家建设用地土壤污染风险管控标准在前期场地调查中具有一定的普遍适用性,但是考虑到地域建筑物参数、人群暴露参数等的差异性,在后期场地调查中还需要因地制宜地制定适合污染场地的具体修复目标值,并针对关键性参数作定量化解析。     

土压平衡矩形顶管施工引起的地表沉降规律研究

为了分析与掌握矩形顶管施工引起的地表沉降变形规律，提出基于MIDAS-GTS有限元软件的分析方法，首先，通过工程实例验证MIDAS-GTS有限元软件在分析顶管施工引起地表沉降变形的有效性；其次，通过影响因素的敏感性分析确定不同影响因素作用下的地表沉降变形特性，这些影响因素主要包括开挖面支护压力、侧摩阻力、地层结构特性等；最后，通过地表沉降变形特性分析得出矩形顶管的适用范围。研究结果表明:基于MIDAS-GTS有限元软件的地表沉降规律分析方法和结果，可为矩形顶管施工过程提供相关参考和借鉴。     

Efficacy of created and restored nesting sites for the conservation of colonial Laridae in the South of France

By rapidly modifying key habitat components, habitat restoration is at risk of producing attractive cues for animals without providing habitats of sufficient quality. As such, individual fitness components, such as reproduction, could be reduced and restored habitats could become ecological traps. This risk notably appears by using artificial constructions in restoration projects, yet few studies have evaluated their efficacy in a robust way. We investigated this by analyzing 154 islets that were created or restored to improve the conservation status of 7 colonial Laridae species in the South of France. From 2007 to 2016, we compared occupancy dynamics and breeding parameters of these species between the restored sites and 846 unmanaged nesting sites. We also explored species’ preference for different nesting site characteristics and their respective effect on breeding parameters. Restored nesting sites were 2–9 times as attractive as unmanaged sites for all species except the Black-headed Gull (Chroicocephalus ridibundus). Colonization probability was up to 100 times higher in sites already used by other species the previous year and increased with distance to the shore until >0.2 when distance was over 250 m. Abandonment probability was 29–70% lower when breeding was successful the previous year in all species except the Sandwich Tern (Thalasseus sandvicensis). Productivity and breeding success probability were 2 times higher on managed sites. Distance from the shore was an important attractive characteristic of artificial nesting sites in all species. Other nesting site characteristics had species-specific effects on colonization, abandonment, and breeding success. Our results indicate that managed nesting sites are successful conservation tools for colonial Laridae in the Mediterranean and do not act as ecological traps. Our study showed that testing the ecological trap hypothesis is a robust way to evaluate the success of restoration projects of breeding habitats.     

石灰法在延吉市污水处理厂污泥半干化处置中的应用

城市污水处理厂污泥经过半干化处置,使污泥含水率下降到60％,以满足国家新的垃圾填埋场卫生填埋的要求,这是一个新课题。利用石灰法进行延吉市污水处理厂污泥半干化处置,能够以较小的投资及较低的运行费用实现污泥半干化,为实现城市污水处理厂污泥半干化处置探索出新途径。     

垃圾渗滤液处理工艺的应用及分析

垃圾渗滤液是一种高浓度的有机废水,如何对其进行有效处理是垃圾填埋场面临的一个难题。介绍了UASB厌氧处理工艺、氨吹脱工艺、光催化技术等垃圾渗滤液的处理工艺,并对比了不同工艺的处理效果。     

销毁日本遗弃在华化学武器危险废物填埋场的安全选址

危险废物填埋场的安全选址是销毁日本遗弃在华化学武器工作中的一项重要的技术工作。本文依据我国环境保护的法律法规及标准,并采用科学的方法对危险废物填埋场址的选择进行了论述和评价,即:首先通过分析场址选择的影响因素,制定出科学、合理、可行的场址选择技术方案;然后再按优劣顺序对拟选的5个填埋场进行科学评价;最后选出最优的填埋场。     

上海城市生活垃圾处置现状及发展方向

分析上海生活垃圾的特点和处理处置现状,对处理处置现状存在的问题进行了分析说明。分类收集要实行日常化,无害化处理水平有待提高,焚烧造成了严重的二次污染,要加强对渗滤液的处置,并且末端处置技术中填埋处置比例过高。同时提出了生活垃圾处置的技术路线和发展方向,要以无害化、减量化、资源化为处理目标。要求巩固和完善生活垃圾卫生填埋技术,谨慎发展生活垃圾焚烧技术,充分重视生活垃圾生化处理技术,多元并举走可持续发展之路。