废旧线路板中贵金属湿法浸出技术研究进展

废旧线路板(WPCB)的数量逐年增长,妥善处理废旧线路板不仅体现其回收利用价值,并且具有可观的环境效益.湿法处理废旧线路板工艺成熟,具有流程短、效率高的优点.本文综述了废旧线路板中贵金属(主要以金为例)浸出方法的研究状况,并从效率、环境影响、成本等方面对不同方法进行了比较.分析表明,硫脲法和碘化法浸出效率高、环境影响小、成本可控,是较优的浸出方法.合理、有效地处置废旧线路板,减少处置过程中的环境污染并高效回收贵金属,需要考虑不同方面的因素,多种浸出与富集回收方法共同使用,以达到最佳贵金属回收效果.     

铝电解槽废旧阴极炭块的处理

实验研究了铝电解工业的废渣——废旧阴极炭块的浮选处理。考查了浮选条件,以及不同捕收剂的浮选结果。     

废旧轮胎回收利用行业循环经济评价指标体系

废旧轮胎是具有高再生价值的产品类废弃物,具备环境污染潜在性和资源性的双重性质。充分回收利用废旧轮胎既能缓解橡胶资源紧缺,又能解决废旧轮胎的环境污染问题。在调研的基础上,分析了我国废旧轮胎回收利用体系;初步构建了废旧轮胎回收利用行业循环经济评价指标体系,阐明了评价指标的含义,确定了评价的方法,并针对行业统计工作提出建议。     

硫杆菌浸出废旧MH/Ni电池中重金属研究

生物淋滤法具有对环境友好、反应温和、运行成本低等优点,近年来主要用于回收难浸提矿石中有用金属及城市污泥有毒重金属脱除。应用氧化硫硫杆菌和氧化亚铁硫杆菌对废旧MH/Ni电池电极材料中重金属进行了生物淋滤处理可行性及工艺技术研究,考查了初始pH值、电极材料投加量、温度及底物单质硫添加量对金属Ni、Co浸出率的影响。试验结果表明:硫杆菌可以浸出电极材料中的重金属Ni和Co,初始pH值及温度对生物淋滤过程金属Ni、Co浸出率影响显著。在初始pH值1.0、电极材料质量分数为1.0%、温度30℃、底物单质硫质量浓度为4.0g·L-1条件下,经过20d生物淋滤,废旧MH/Ni电池中金属Ni和Co浸出率分别为95.7%和72.4%。     

居民农产品消费系统氮磷流动环境影响分析

居民农产品消费中的氮磷流动造成的环境问题突出,基于生命周期评价方法,以居民农产品消费系统(包括作物初加工、畜禽屠宰加工、农村居民农产品消费和城镇居民农产品消费等过程)为研究系统边界,构建了居民农产品消费氮磷环境影响分析模型,并以安徽省为例,分析了2015年安徽省居民农产品消费系统氮磷流动造成的资源消耗、酸化、富营养化和全球变暖等环境影响,同时比较了不同子过程中氮磷物质流动对各类环境影响的贡献。结果表明:在农产品加工过程中,小麦对磷资源消耗量最大,猪对富营养化的贡献最大,分别达到43. 05%和41. 48%;另外,城镇居民和农村居民的谷物消费造成的磷资源消耗较高,分别达到51. 09%和65. 22%,农村居民粪便对环境的富营养化和酸化贡献率最大,分别达91. 05%和99. 49%,而农村固废对环境的全球变暖贡献率最大,达77. 76%。提高加工工艺,合理地改善饮食结构,加强对农村生活粪便、生活污水以及生活固废的处理是减轻居民农产品消费过程中氮磷环境影响的有效途径。     

废弃日用品塑料中多溴联苯醚浸出特征及地下水健康风险

选择典型废弃日用品塑料,对特征处置场景下其PBDEs的浸出特征及健康风险进行了评价.结果表明,日用品塑料在硫酸/硝酸、醋酸和腐殖酸溶液中达到溶出平衡时,∑21PBDEs释放量分别为20.00、63.65、125.60μg·kg-1,均以BDE209为主.进入生活垃圾填埋场的释放量高于堆存和简易填埋过程,在最不利条件下距填埋场下游500 m处地下水中PBDEs最大浓度为39.67μg·L-1,居民饮用地下水产生的非致癌风险指数为2.11×10-1,其中十溴代物(BDE209)的非致癌风险指数为1.85×10-1,均小于美国标准中非致癌的可接受风险水平(1.0),表明废旧日用品塑料可进入生活垃圾填埋场处置.     

世界双遗产地武夷山风景名胜区居民旅游感知分析

旅游地居民的感知和态度被认为是评价旅游发展状况最直接的因素。为充分了解武夷山文化和自然遗产地内当地居民对旅游开发的感知情况,进而为管理决策提供依据,通过问卷调查与访谈方式调查了武夷山双遗产地核心旅游区武夷山风景名胜区内居民对旅游开发的感知及其发展需求,运用因子分析和方差分析方法分析了居民对旅游开发影响的感知及其与人口社会特征的关系。结果表明,建立的指标体系能从基础建设、环境体验、经济观念、收入就业、原始文化、美誉传承和商机分配7个维度(公因子)揭示当地居民对旅游开发的感知状况。居民普遍认为旅游已成为当地经济支柱产业,旅游开发改变居民经济意识的同时,居民观念也更加积极与开放;居民已对文化习俗的改变有所认知。但居民旅游参与程度相对较低,受到外来人口对自身旅游收益分配的冲击,承受着因环境和居住体验改变导致的负面影响。人口特征不同的居民对经济观念的感知差异程度最突出,对原生文化与基础建设的感知差异次之,对收入就业、商机分配的感知差异较小,对环境体验、美誉传承的感知无差异。性别、年龄和家庭年收入不同的居民对7个公因子感知均无显著差异;文化程度、职业、家庭规模、家庭年旅游收入和家庭旅游收入比例不同的居民对公因子的感知均有不同程度差异。不同村庄居民对基础建设、经济观念、收入就业和商机分配感知有显著差异(P0.05);政策制定应关注各村庄居民对基础建设、经济观念、收入就业和商机分配感知等方面的不同需求。     

上海市轨道交通明珠线对沿线不同人群噪声影响调查

采用现场监测和公众参与相结合的方法调查和评价了上海市轨道交通明珠线对沿线居民、学校师生和商办楼办公人员的噪声影响。评价结果表明:明珠线列车运行噪声对沿线居民影响较大,对沿线办公楼和学校的影响相对较轻,且居民在采取噪声防护措施方面相对较为困难。居民对噪声损害赔偿的要求比办公人员和学校师生强烈。     

藏东南察隅河流域不同海拔居民对气候变化的感知

在藏东南察隅河流域选取海拔分别为3 313.5、2 891.1和2 476.4 m的3个村庄,对268位居民进行问卷调查,研究不同海拔居民对气候变化的感知状况,并对居民的感知状况与海拔进行相关性分析。结果表明,海拔为3 313.5、2 891.1和2 476.4 m的村庄中,分别有91.7%、88.9%和97.7%的居民认为当地气候发生了变化,其中又有91.7%、95.5%和97.7%的居民认为气候变化明显。不同海拔居民对温度的感知强烈,分别有75.0%、100%和48.3%的居民认为夏季变暖,41.7%、100%和49.4%的居民认为冬季变冷,但大部分居民对湿度的感知不强烈。随着海拔降低,认为以前气候比现在好的居民比例增大(分别为50.0%、56.5%和61.4%),认为冰川面积增加(分别为8.3%、13.6%和45.5%)、河流水量增加(分别为46.7%、56.0%和79.1%)、农作物病虫害增加(分别为33.3%、58.3%和72.7%)的居民比例增大,认为以前气候比现在好的居民比例与海拔呈显著负相关(P0.05)。分别有75.0%、74.1%和72.7%的居民认为气候变化对生产生活造成了影响。在感知气候变化的途径中,自身经历是最主要的途径(分别为83.3%、100%和90.9%)。当地政府应当进行相应的宣传指导,帮助当地居民适应气候变化带来的不利影响。     

煤焦油炼钢和降低环境污染的研究

煤焦油是煤气生产的副产品,对煤焦油的处理和使用,有人主张用作原料,提取其中的一些芳香族化合物;有人认为在我国能源现状上用其来代替重油做为燃料,经济合理。调查国内一些较大的煤气站除个别将煤焦油制取沥青外,大多数工厂廉价售给职工和居民做为生活燃料。由于居民炉灶炉膛小,烟囱低,燃烧不完全,室内室外黑烟弥漫,严重污染环境,并危及职工和居民的身体健康。随着国民经济的发展,煤气用量     

电子废物管理体系研究

分析了欧盟、日本、美国等国家的电子废物管理体系主要特点,并介绍我国电子废物管理现状和主要措施,在此基础上归纳总结了当前电子废物管理存在的主要问题并提出相关建议。     

Tetrabromobisphenol A recovery from computer housing plastic by a new solvothermal process

Brominated flame retardants contained in electrical and electronic waste plastic are toxic to both humans and the environment. Most disposal technologies for brominated flame retardants are environmentally unfriendly. Here, a novel solvothermal process was designed to recover tetrabromobisphenol A, a typical brominated flame retardant, from waste computer housing plastic. The plastic waste was treated by the solvothermal process followed by vacuum rotary evaporation. Results show a tetrabromobisphenol A recovery efficiency of 78.9 %, and a purity of 95.6 %. The stability of tetrabromobisphenol A during the solvothermal process was confirmed by nuclear magnetic resonance. Kinetics showed that diffusion across the polymer layer controlled recovery. We conclude that the novel solvothermal process is a promising green way to recover tetrabromobisphenol A from electrical and electronic waste plastic.     

Gastric bioaccessibility and human health risks associated with soil metal exposure via ingestion at an E-waste recycling site in Kumasi,Ghana

Environmental Geochemistry and Health - Over 1000 people make a living by processing electronic and electrical waste (E-waste) and scrap metals for the recovery of valuable metals and integrated...     

Take back and treatment of discarded electronics: a scientific update

This paper indicates that the performance of tack-back and treatment of electronic waste (e-waste) system can be improved substantially. This can be reached by better taking into account in a better way the big variety in material composition and potential toxicity of electrical and electronic products - from a technical, organizational and regulatory perspective. Realizing that there is no ‘one size fit for all’ and combining smart tailor made solutions with economic of sale will result in the best environmental gain/cost ratio. Several examples show how science and engineering have supported or will support this approach.     

PCBs,PCDDs and PCDFs in soil samples from uncontrolled burning of waste electrical material for metal reclamation

PCDDs, PCDFs and PCBs have been analysed in soil samples where waste electrical equipment has been burned directly on the ground in three locations of Burgos (Spain). High levels of PCDDs, PCDFs and PCBs were detected in the centre of combustion sites. The results show PCB levels between 0.824 and 1.240 μg/g, and PCDDs and PCDFs levels between 8.73–36.37 ng/g and 12.79–50.95 ng/g. The I‐TEF values between 2.96–9.15 for dioxins and furans indicate that these soils are heavily polluted and may represent a risk for human and animal health.     

Practices,attitudes and motives for domestic waste recycling

SUMMARY

Solid household waste management in Malaysia has reached a critical stage. Increasing population, urbanization and changing patterns of lifestyle have instigated the phenomenon. The 15 000 tonnes of garbage produced daily are thrown into 230 landfills nationwide, where 80% of them have only two years of life span left. Although recycling programmes were launched as early as 1990, only 5% of the wastes are recycled. The purpose of the present research was to ascertain the current management of household solid waste, attitude and motivational factors towards recycling. Data were collected using interview survey on 150 households in an urban residential area. The findings demonstrated that the respondents had very low awareness and knowledge regarding local domestic waste management. Separation of organic and non-organic wastes was rarely practised by 76% of the respondents. Most waste was thrown away, except for newspaper and aluminium cans which were regularly recycled, while furniture, and electrical items were reused by giving away or trading-in. The attitude of the respondents towards recycling was modest. Of the five motivational factors, intrinsic satisfaction and individual commitment were more important reasons for recycling than convenience, economic motivation and societal commitment. The results of the study indicated that, in order to overcome the solid waste crisis, the conscience of the individual needs to be raised through environmental awareness and concern, inculcation of sustainable consumption practices and education on waste management.     

浅谈堆肥设备

随着堆肥技术在不同固体废弃物处理中的广泛应用，与之相关的堆肥设备得到了极大的发展，堆肥设备包括物料处理、翻堆、反应器和除臭设备。家庭堆肥器和小容量反应器堆肥系统是堆肥设备新的发展趋势。     

Performance evaluation of waste electrical and electronic equipment disassembly layout configurations using simulation

Recycling of waste electrical and electronic equipment (WEEE) is crucially important since it handles hazardous waste according to ever tightening laws and regulations and it adds benefits to economy and sustainable environment. Disassembly is one of the most important processes performed during the recovery of WEEE. The overall goal of disassembly is to maximize the retrieval of various metals and plastics contained in WEEE in order to reduce their negative effects on human health and environmental sustainability and to increase economic gains. This study aims to evaluate alternative layout configurations for WEEE disassembly systems (WDS). In this context, various configurations were compared in terms of pre-defined performance criteria, such as the total number of disassembled WEEE and the total revenue from sales, using simulation models. The results of this study show that the performance of a WDS was significantly affected by output transfer systems along with the specialization of operators on certain types of WEEE.

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Biotransfer of persistent organic pollutants from a large site in China used for the disassembly of electronic and electrical waste

Samples of groundwater, river water, river sediment, paddy soil, rice seeds, hen eggs, fish, umbilical cord blood, and newborn meconium were collected from October 2002 to October 2003 near a large site in China used for the disassembly of obsolete transformers and other electronic or electrical waste. Six indicator PCB congeners, three non-ortho dioxin-like PCB congeners, and six organochlorine pesticides were determined in the samples by GC with electron capture detector. The results demonstrated that the local environment and edible foods had been seriously polluted by toxic PCBs and organochlorine pesticides. The actual daily intakes (ADIs) of these pollutants were estimated for local residents living in the area. The intake data showed that the contents of PCBs in these local residents were substantial, as the ADI estimates greatly exceed the reference doses set by the World Health Organization and the United States Agency for Toxic Substances and Disease Registry. The presence of the indicator PCB congeners in the cord blood and the meconium samples, as well as significant correlations (r ² > 0.80, p < 0.05) between these levels, suggests a potential biotransfer of these indicators from mothers to their newborns. This preliminary study showed that obsolete transformers and other electronic or electrical waste can be an important source for the emission of persistent organic pollutants into the local environment, such as through leakage, evaporation, runoff, and leaching. Contamination from this source appears to have reached the level considered to be a serious threat to environmental and human health around the disassembly site.     

Repercussions of COVID-19 pandemic on solid waste generation and management strategies

• Implication of COVID-19 on medical waste and MSW generation is studied. • Challenges and effective strategy of solid waste generation is reviewed. • 2.9 million tons of COVID-19 related medical waste has been generated until Sep. 22. • The pandemic has postponed policies related to the reduction of plastic use. • Blockade resulted in a significant drop in waste generation in some regions. It has been over ten months since the beginning of the 2019 coronavirus disease (COVID-2019), and its impact on solid waste management, especially medical waste, is becoming clearer. This study systematically reviews the potential influences of the COVID-19 pandemic on medical waste, personal protection equipment waste and municipal solid waste (MSW), and discusses the corresponding measures and policies of solid waste management in typical countries. The results show that the generation of medical waste from the pandemic increased significantly, with 18%‒425% growth. It is estimated that the daily output of COVID-19 medical waste increased from 200 t/d on Feb. 22 to over 29000 t/d at the end of September 2020 throughout the world. The use of personal protective equipment will continue to grow in the long-term, while the blockade and isolation measures greatly reduced the volume of commercial waste, especially for tourist cities, and part of this waste was transferred to household waste. Residents’ attitudes and behavior toward food waste have changed due to the COVID-19 pandemic. In response to the pandemic, international organizations and several countries have issued new policies and guidelines and adjusted their management strategies for medical waste and MSW treatment. The pandemic has brought specific challenges to the disposal capacity of medical waste worldwide. It has also brought about the stagnation of policies related to the reduction of plastic products and waste recycling. This study will provide some useful information for managers and governmental officials on effective solid waste management during and after the COVID-19 pandemic.