Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs. • The succession of microbial community is an important factor affecting ARGs. • Horizontal transfer mechanism of ARGs during composting should be further studied. Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.     

Potential energy production from organic waste and its environmental and economic impacts at a tertiary institution in Palestine

Municipal solid waste (MSW) is one of the most well-known biomass resources that can be utilized to produce renewable energy. Numerous countries are plagued by the proliferation of waste, particularly organic waste that can be utilized for energy recovery. Palestine suffers from inefficient solid waste management, and only recently have a few projects focused on bioenergy production been implemented. Throughout the years, the city of Tulkarm experiences power outages which cause a challenge to the Palestine Technical University-Kadoorie campus in Tulkarm. Thus, the possibility of energy recovery from the organic portion in Palestine Technical University-Kadoorie was evaluated. The analysis of an economic impact included discussions of a number of economic aspects, including Levelized cost of energy, internal rate of return, present worth, annual worth, and payback period. On the other hand, a carbon dioxide savings analysis and gas emission were evaluated. The outcomes of the energy optimization demonstrated that the suggested system could supply the institution with an average of roughly 7 MWh of electrical energy. According to the economic study, this project offers 0.25 million dollars in present value, 0.144 million dollars in annual value, a 13 percent internal rate of return, a payback period of 6 years, and a levelized cost of energy of 0.11 dollars for each kWh generated. Additionally, the environmental assessment revealed that this system might reduce CO₂ emissions by around 8,343,778 tons. For effective waste management, energy recovery, and emission reduction, it is advised to implement anaerobic digestion technology.     

沈阳地区臭氧污染日时空变化特征及天气分型研究

利用2013—2019年沈阳地区11个国控监测站近地层臭氧(O_3)浓度监测数据和地面气象观测资料,分析了沈阳地区O_3污染日的O_3浓度时空分布规律,并对造成O_3污染日的天气系统进行了主观分型。结果表明:自2013年以来,以O_3为首要污染物的天数逐年增加,2017年达到研究期内的最高值,但2018—2019年略有下降。O_3浓度的日变化趋势呈现明显的单峰形,O_3-1 h在10:00—20:00明显高于其他时间段,最大浓度值出现在15:00,而在01:00—07:00则相对较低。从季节变化上看,沈阳地区O_3污染主要发生在6—7月,两个月的O_3污染日之和占全年O_3总污染日的比例高达51%。从O_3浓度空间分布上看,沈阳地区三环外监测站测得的O_3浓度明显高于三环内监测站,高浓度区域主要集中在东部和东北部,城市中心存在明显的低浓度区,南部和北部差别不大,但也明显高于城市中心。造成沈阳地区O_3污染的主要天气类型有4种:暖脊型、均压场型、高空槽型和副热带高压型。其中:暖脊型出现的频次最高,占总样本的49.1%;副热带高压型出现的次数最少,占总样本的7.7%。     

废旧硬质聚氨酯泡沫塑料的木质素改性及再生

采用含有二乙二醇(DEG)和乙醇胺(ETA)的双组分解交联剂降解废旧硬质聚氨酯泡沫塑料(PU硬泡),并利用降解得到的低聚物多元醇与木质素复合制备出性能增强的再生PU硬泡。通过对制备的再生PU硬泡的红外光谱、密度、吸水率、抗压强度、热稳定性、导热系数、热重曲线等进行分析测试,考察m(DEG)∶m(ETA)对再生PU硬泡性能的影响。实验结果表明:m(DEG)∶m(ETA)=1∶3时废旧PU硬泡的降解效果最好;木质素加入量为2.0%(w)时再生PU硬泡的密度低、抗压强度高、保温性能良好,达到国家标准《建筑绝热用硬质聚氨酯泡沫塑料》(GB/T 21558—2008)的品质要求。     

乡镇垃圾分类循环利用现状——以闽侯县上街镇为例

由于我国乡镇经济的迅速发展以及乡镇村民生活水平加速提高,乡镇的垃圾种类及数量趋向于城市。乡镇村民居住较为分散,垃圾分类、收集、循环利用相较于城市困难,因此推进乡镇垃圾分类循环利用迫在眉睫。本文从闽侯县上街镇展开调查,以乡镇垃圾分类、回收循环利用为关键词展开分析,并从上街镇垃圾分类循环利用模式存在的问题进行分析、总结和建议。     

北京市典型废弃物焚烧源2010—2017年二NFDA1英排放特征和减排效果分析

分析2010—2017年北京市三类典型废弃物焚烧源的废气二NFDA1英排放监测数据,计算排放因子和排放量,评估减排政策成效,并分析不同排放源达标排放时同类物分布特征异同和变化规律,探讨影响排放的重要因素。结果表明: 5家焚烧源平均排放浓度为 0.008～0.069 ng/m³(以TEQ计,下同),废气二NFDA1英排放因子为 0.027～1.7 μg/t,2016年向空气中排放的二NFDA1英量为 0.002 5～0.058 g；生活垃圾、危险废物和医疗废物焚烧源的低、高氯代同类物质量分数比的平均值分别为接近于 0.5、大于0.5和小于0.5,危险废物焚烧源的 ∑PCDFs、∑PCDDs质量分数比的平均值大于2； 123478-HxCDF和123678-HxCDF质量浓度接近且线性相关,具有相近的生成机理和去除效率； I-TEQ变化趋势与∑PCDFs质量分数的变化趋势基本一致,活性炭喷射和布袋除尘的去除效率是影响二NFDA1英排放的重要因素之一；危险废物焚烧源HWI1随运行时间增加排放浓度增加,而及时更换烟道管壁有助于消除“记忆效应”的不良影响。     

低中放废物处置FEPs清单的构建——以飞凤山处置场为例

识别所有影响其长期安全的有关因素,即特征(Features)、事件(Events)和过程(Processes)(FEPs),是放射性废物处置场安全全过程系统分析的关键过程之一。我国目前低中放固体废物处置环境影响评价中未开展FEPs识别和景象开发。拟以飞凤山处置场为例,选择自下而上方法的构建方法,对如何建立我国的低中放废物处置FEPs清单进行了探讨。并以最新发布的NEA国际FEPs清单(3.0版)中提出的基于外部因素和处置组成(废物包、处置场、岩石圈和生物圈)的分类方案为基础,结合飞凤山处置场的近地表处置及其环境特征,建立了该处置场的FEPs清单。     

基于共词分析的城市生活垃圾治理公共政策变迁量化分析

以1979—2020年我国中央政府颁发的411份城市生活垃圾治理政策文本作为研究对象,运用共词与聚类分析方法研究了我国不同时期城市生活垃圾治理公共政策焦点的演变规律。结果发现:纵观我国城市生活垃圾治理公共政策焦点的演变轨迹,在"技术路线"、"垃圾属性"、"管理手段"、"治理结构"和"保障机制"方面发生了显著的政策主题变迁,呈现出垃圾治理朝更加绿色、更加经济方向发展的趋势。未来,应从监管体系、资源评估、财政补贴、空间布局4个方面保障生活垃圾零污染、高价值资源化治理。     

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.     

Physico-chemical characterization of Residual Household Waste for energy recovery in insular territories: Case study of Reunion Island

Waste-to-energy is a promising approach to face the current challenge of waste overproduction in Reunion Island, a French territory. In this particular context of an isolated and tropical territory, it is essential to study the properties of potential feedstocks to choose the most appropriate conversion process. This article reports on the composition of Residual Household Waste from Reunion Island and its physico-chemical parameters. Twelve representative samples of Residual Household Waste were subjected to thermal and elemental analysis. The results showed that their composition had a significant influence on the physico-chemical properties, including calorific value. Residual Household Waste from the selective sorting (rich in wood, plastic, and sanitary textiles) as well as dry mixed RHW are the most interesting for energy recovery. Due to their high volatile matter and high carbon content, and their low moisture content, these types of waste have a high calorific value exceeding 18 MJ/kg. Furthermore, the RHW sample comply with the environmental and health criteria applied by French regulations concerning halogen and heavy metal. Thus, it seems that Residual Household Waste can be an alternative to conventional fuels used in incineration or pyro-gasification processes. However, the study also points the need for a pre-treatment process for these wastes. Indeed, it is necessary to sort them correctly in order to avoid the risks of pollution and important maintenance. And more importantly, drying beforehand is unavoidable to improve combustibility and obtain optimal energy conversion.