Solid waste treatment and disposal: effects on public health and environmental safety

The safety and acceptability of many widely used solid waste management practices are of serious concern from the public health point of view. Such concern stems from both distrust of policies and solutions proposed by all tiers of government for the management of solid waste and a perception that many solid waste management facilities use poor operating procedures. Waste management practice that currently encompasses disposal, treatment, reduction, recycling, segregation and modification has developed over the past 150 years. Before that and in numerous more recent situations, all wastes produced were handled by their producers using simple disposal methods, including terrestrial dumping, dumping into both fresh and marine waters and uncontrolled burning. In spite of ever-increasing industrialisation and urbanisation, the dumping of solid waste, particularly in landfills, remains a prominent means of disposal and implied treatment. Major developments have occurred with respect to landfill technology and in the legislative control of the categories of wastes that can be subject to disposal by landfilling. Even so, many landfills remain primitive in their operation. Alternative treatment technologies for solid waste management include incineration with heat recovery and waste gas cleaning and accelerated composting, but both of these technologies are subject to criticism either by environmentalists on the grounds of possible hazardous emissions, failure to eliminate pathogenic agents or failure to immobilise heavy metals, or by landfill operators and contractors on the basis of waste management economics, while key questions concerning the effects of the various practices on public health and environmental safety remain unanswered. The probable and relative effects on both public health and environmental safety of tradition and modern landfill technologies will be evaluated with respect to proposed alternative treatment technologies.     

Webalert of waste management

Waste is unwanted or useless material. It is widely recognized that waste materials are valuable resources, whilst there is debate as to how this value is best realized. Re-use, recycling and energy recovery are being applied to regulated wastes. Yet, while recycling and re-use are increasing, the overall amounts of waste are still growing, and there is an increasing demand for primary resources and stress on eco-systems. In this webalert, we will focus on some important websites which provide readers with more informative resources related to waste management.     

青藏高原生态屏障区环境基本公共服务的非均衡性及其成因——基于青海村镇居民点的实证分析

环境基本公共服务是青藏高原生态屏障区生态环境治理及农牧民人居环境品质提升的关键环节,揭示其配置均衡状态及失效原因,对提升青藏高原环境基本公共服务均等化水平、降低生态屏障区内人类活动的生态环境胁迫风险具有重要意义。以青海省4315个村镇居民点为对象,选取生活垃圾处理、生活污水处理、卫生户厕改造3项特征指标,定量测度村镇环境基本公共服务配置非均衡性,运用有序多分类及二元逻辑斯蒂回归模型解析非均衡性的生成原因。结果显示：青海环境基本公共服务水平总体偏低,处于低和极低等级的村镇居民点占37.13%和37.84%;环境基本公共服务非均衡性受配置成本、人口社会、经济收入和基层管理因素的多重影响,自然地理的高寒性和交通区位的偏远性是生成非均衡性的重要因素;人口社会因素的规模报酬递增效应使非均衡性加剧,大分散、小聚居的农牧民定居点通常是服务配置的弱势区域,经济收入和基层管理因素分别是非均衡性加剧的内因和外因。建议在青藏高原生态屏障区实施递进式均衡配置模式及适应性管理,建立就地消纳与跨区处理结合的弹性生活垃圾处置体系,推广耐低温分散化污水处置模式和生态化处置技术体系,适应高寒环境的户厕改造技术研发和农牧...     

Livestock waste treatment systems for reducing environmental exposure to hazardous enteric pathogens: Some considerations

Intensive livestock production systems produce significant quantities of excreted material that must be managed to protect water, air, and crop quality. Many jurisdictions mandate how livestock wastes are managed to protect adjacent water quality from microbial and chemical contaminants that pose an environmental and human health challenge. Here, we consider innovative livestock waste treatment systems in the context of multi-barrier strategies for protecting water quality from agricultural contamination. Specifically, we consider some aspects of how enteric bacterial populations can evolve during manure storage, how their fate following land application of manure can vary according to manure composition, and finally the challenge of distinguishing enteric pathogens of agricultural provenance from those of other sources of fecal pollution at a policy-relevant watershed scale. The beneficial impacts of livestock waste treatment on risk to humans via exposure to manured land are illustrated using quantitative microbial risk assessment (QMRA) scenarios. Overall, innovative livestock treatment systems offer a crucially important strategy for making livestock wastes more benign before they are released into the broader environment.     

Composting of waste from palm oil mill: a sustainable waste management practice

Malaysia is blessed with abundant natural resources and bears a favorable climate for commercial cultivation of crops such as oil palm. In Malaysia the total plantation area of oil palm was 4,487,957 ha in 2008. It has been reported that in 2005 there was a total of 423 palm oil mills having production capacity of approximately 89 million tonnes of fresh fruit bunch (FFB) per year. Waste from the oil palm mill process include palm oil mill effluent (POME), generated mainly from oil extraction, washing and cleaning up processes. POME contains cellulosic material, fat, oil, and grease. Discharging untreated effluent into water streams may cause considerable environmental problems. The solid wastes generated are mainly decanter cake, empty fruit bunches, seed shells and fibre from the mesocarp. POME as well as the solid wastes may rapidly deteriorate the surrounding environment if not dealt with properly. Hence there is an urgent need for a sustainable waste management system to tackle these wastes. As these wastes are organic in origin, they are rich in plant nutrients. Composting of waste generated from palm oil mills can be good practice as it will be helpful in recycling useful plant nutrients. This review deals with various aspects of waste management practices in palm oil mills and the possibility of composting the wastes.     

Sustainable sanitation technology options for urban slums

Poor sanitation in urban slums results in increased prevalence of diseases and pollution of the environment. Excreta, grey water and solid wastes are the major contributors to the pollution load into the slum environment and pose a risk to public health. The high rates of urbanization and population growth, poor accessibility and lack of legal status in urban slums make it difficult to improve their level of sanitation. New approaches may help to achieve the sanitation target of the Millennium Development Goal (MDG) 7; ensuring environmental sustainability. This paper reviews the characteristics of waste streams and the potential treatment processes and technologies that can be adopted and applied in urban slums in a sustainable way. Resource recovery oriented technologies minimise health risks and negative environmental impacts. In particular, there has been increasing recognition of the potential of anaerobic co-digestion for treatment of excreta and organic solid waste for energy recovery as an alternative to composting. Soil and sand filters have also been found suitable for removal of organic matter, pathogens, nutrients and micro-pollutants from grey water.     

Household Wastes as Larval Habitats of Dengue Vectors: Comparison between Urban and Rural Areas of Kolkata,India

Porcelain and plastic materials constitute bulk of household wastes. Owing to resistibility and slow degradability that accounts for higher residence time, these materials qualify as potential hazardous wastes. Retention of water permits these wastes to form a congenial biotope for the breeding of different vector mosquitoes. Thus porcelain and plastic wastes pose a risk from public health viewpoint. This proposition was validated through the study on the porcelain and plastic household wastes as larval habitats of Dengue vectors (Aedes spp.) in rural and urban areas around Kolkata, India. The wastes were characterized in terms of larval productivity, seasonal variation and a comparison between urban and rural areas was made using data of two subsequent years. The number of wastes positive as larval habitats and their productivity of Aedes spp. varied among the types of household wastes with reference to months and location. Multivariate analysis revealed significant differences in the larval productivity of the household wastes based on the materials, season, and urban–rural context. Results of Discriminant Analysis indicated differences in abundance of Ae. aegypti and Ae. albopictus for the urban and rural areas. The porcelain and plastic wastes were more productive in urban areas compared to the rural areas, indicating a possible difference in the household waste generation. A link between household wastes with Aedes productivity is expected to increase the risk of dengue epidemics if waste generation is continued without appropriate measures to limit addition to the environment. Perhaps, alternative strategies and replacement of materials with low persistence time can reduce this problem of waste and mosquito production.     

Anaerobic waste digestion in Germany – Status and recent developments

Anaerobic treatment processes are especially suited for the utilization of wet organic wastes from agriculture and industry as well as for the organic part of source-separated household wastes. The anaerobic degradation is a very cost-effective method for treating biogenic wastes because the formed biogas can be used for heat and electricity production and the digester residues can be recycled to agriculture as a secondary fertilizer. The anaerobic technology will be used today also for the common treatment of wastes together with renewable energy crops in order to reduce the CO₂-emissions according the Kyoto protocol. Various process types are applied in Germany which differ in material, reaction conditions and in the form of the used reactor systems. The widespread introduction of anaerobic digestion in Germany has shown that biogenic organic wastes are a valuable source for energy and nutrients. Anaerobic waste treatment is done today in approx. 850 biogas plants on small farm scale as well as on large industrial scale with the best beneficial and economic outcome. Due to some new environmental protection acts which promote the recycling of wastes and their utilization for renewable energy formation it can be expected that several hundreds new biogas plants will be built per year in Germany. For using the synergetic effects of a combined fermentation of wastes and energy crops new process types must be developed in order to optimize the substrate combinations and the process conditions for maximum biodegradation.     

Carbon and life cycle implications of thermal recovery from the organic fractions of municipal waste

Purpose

The aim of this research was to determine the optimum way of recovering energy from the biodegradable fractions of municipal waste. A part-life cycle study was carried out on the following wastes: paper, food waste, garden waste, wood, non-recyclable mixed municipal waste and refuse-derived fuel. The energy recovery processes considered were incineration, gasification, combustion in dedicated plant, anaerobic digestion and combustion in a cement kiln.

Methods

The life cycle assessment (LCA) was carried out using WRATE, an LCA tool designed specifically for waste management studies. Additional information on waste composition, waste collection and the performance of the energy recovery processes was obtained from a number of UK-based sources. The results take account of the energy displaced by the waste to energy processes and also the benefits obtained by the associated recycling of digestates, metals and aggregates as appropriate.

Results and discussion

For all the waste types considered the maximum benefits in terms of climate change and non-renewable resource depletion would be achieved by using the waste in a cement kiln as a substitute fuel for coal. When considering the impacts in terms of human toxicity, aquatic ecotoxicity, acidification and eutrophication, direct combustion with energy recovery was the best option. The results were found to be highly sensitive to the efficiency of the energy recovery process and the conventional fuel displaced by the recovered energy.

Conclusions and recommendations

This study has demonstrated that LCA can be used to determine the benefits and burdens associated with recovering energy from municipal waste fractions. However, the findings were restricted by the lack of reliable data on the performance of waste gasification and anaerobic digestion systems and on the burdens arising from collecting the wastes. It is recommended that further work is carried out to address these data gaps.     

城市生活垃圾代谢的研究进展

城市代谢是导致城市发展、能量生产和废物排放的社会、经济和技术过程的总和。生活垃圾管理系统是一类典型的、具备社会、经济、自然要素的复杂系统,它不仅同管理体制、技术水平和居民素质有关,也贯穿生产、消费、流通、还原过程,更和水体、土壤、大气、生物、矿产等自然环境紧密联系。综述了近年来基于城市生态系统代谢思路,在生活垃圾碳、重金属、营养元素和能量的城市代谢等方面的研究进展,分析了未来该领域研究需重点关注的方向。生活垃圾在城市生态系统中的能量流动、物质循环、代谢效率等方面的研究,可为生活垃圾管理系统的评价、规划、工程、管理研究提供科学基础。     

Nuclear waste management activities in the pacific basin and regional cooperation on the nuclear fuel cycle

Abstract

Pacific Ocean and island sites have been used since World War II for nuclear activities, including effluent discharges from nuclear facilities, sea dumping of packaged radioactive wastes, and testing of nuclear explosives. In the future, the amounts of radioactive wastes deliberately released into the Pacific Ocean may increase in connection with planned commercial‐scale nuclear fuel reprocessing operations, recommencement of plutonium production for weapons purposes, and resumption of sea dumping of low‐level wastes. Proposed storage of spent nuclear fuel on Pacific island sites or disposal of high‐level wastes in the deep seabed of the Pacific could also expose the ocean to a risk of contamination by long‐lived radio‐nuclides. The consequences of all these activities should be assessed in practical terms—their likely effects on the living marine resources of the Pacific and the economic development of the societies benefited by them; in terms of the legal principles which govern activities such as marine radioactive waste disposal that could pollute the marine environment; and in relation to current and future organizational arrangements that could achieve political resolution of outstanding international nuclear energy issues. Despite the prospective dangers of marine nuclear activities, the use of relatively remote or extraterritorial marine locations including those in the Pacific basin for nuclear operations could provide a basis for international cooperation on management of the “back end”; of the nuclear fuel cycle, including storage and reprocessing of spent fuel and high‐level waste disposal. A broadly recognized international regime for the nuclear fuel cycle could be based on regional organization of such back‐end operations, provided local acceptance could be obtained.     

Marine disposal of radioactive wastes

In a general sense, the main attraction of the marine environment as a repository for the wastes generated by human activities lies in the degree of dispersion and dilution which is readily attainable. However, the capacity of the oceans to receive wastes without unacceptable consequences is clearly finite and this is even more true of localized marine environments such as estuaries, coastal waters and semi-enclosed seas. Radionuclides have always been present in the marine environment and marine organisms and humans consuming marine foodstuffs have always been exposed, to some degree, to radiation from this source. The hazard associated with ionizing radiations is dependent upon the absorption of energy from the radiation field within some biological entity. Thus any disposal of radioactive wastes into the marine environment has consequences, the acceptability of which must be assessed in terms of the possible resultant increase in radiation exposure of human and aquatic populations. In the United Kingdom the primary consideration has been and remains the safe-guarding of public health. The control procedures are therefore designed to minimize as far as practicable the degree of human exposure within the overall limits recommended as acceptable by the International Commission on Radiological Protection. There are several approaches through which control could be exercised and the strengths and weaknesses of each are considered. In this review the detailed application of the critical path technique to the control of the discharge into the north-east Irish Sea from the fuel reprocessing plant at Windscale is given as a practical example. It will be further demonstrated that when human exposure is controlled in this way no significant risk attaches to the increased radiation exposure experienced by populations of marine organisms in the area.     

能源重化工工业园环境系统动力学仿真与调控

以锦界工业园环境系统为对象,在系统结构分析基础上,构建其系统动力学模型,并确定生产性投资比例、科技投资比例、环保投资比例、污水处理投资率、废气处理投资率、固废处理投资率为调控参数进行仿真。结果表明,当生产性投资比例由0.14提高到0.16,科技投资比例由0.02提高到0.04,环保投资比例由0.04提高到0.08,污水处理投资率由0.4下调为0.36,废气处理投资率由0.2提高到0.34,固废处理投资率由0.4下调为0.3时,园区年均工业总产值增长率达到21%,环境相对污染度年均降幅为8.1%,人口年增长率为4.7%,系统达到相对最优状态。因此,锦界工业园在环境管理中应采取以下措施:一是合理的调整生产、科技和环保的投资比例,适当降低生产性投资比例,增加科技投资和环保投资比例;二是合理的调整污水、废气和固废处理的投资比例,加强三废处理的基础设施建设,为构建完整的三废回收和处理系统奠定基础。     

国外环境生物技术的发展和展望

环境生物技术在社会的发展中起着越来越重要的积极作用,相关产业也随之迅速发展起来,环境治理要依赖对生物,尤其是微生物及其生理,生化特性的了解和认识,从而可以对其生理,生化和遗传方面的性能加以利用。在这方面,分离解毒微生物及阐明毒物降解过程和机理仍是现在研究的焦点,与此同时,对遗传基因方面的研究和利用还有许多研究工作待进行,监测和跟踪微生物已进入到了分子水平,而传感监测方面已有一些可喜的成果正在向生产转化,生物修复作为消除污染的手段正治理中发挥巨大的作用,但环境保护的根本应是在于进行无污染产生的生产,也称之为绿色生产,未来的社会中,环境生物技术仍对将社会产生巨大的影响,对环境保护起到重要的作用,特别是在新型生物能源的开发和探索方面,本文同时也对世界不同地区在环境生物技术的发展及其特点进行了综述。     

Assessing the addition of mineral processing waste to green waste-derived compost: an agronomic, environmental and economic appraisal

The overall aim of this study was to evaluate the benefit of mixing two large volume wastes, namely mineral processing waste and source-segregated green waste compost, on the growth performance of plants targeted towards high (horticulture/agriculture) and low (amenity/restoration) value markets. The secondary aims were to evaluate the influence of mineral waste type on plant growth performance and to undertake a simple economic analysis of the use of mineral-compost mixtures in land restoration. Our results showed that in comparison to organic wastes, mineral wastes contained a low available nutrient content which reduces compost quality. This is supported by growth trials with tomato, wheat and grass which showed that, irrespective of mineral source, plants performed poorly in compost blended with mineral waste in comparison to those grown in green waste or peat-based compost alone. In terms of consumer confidence, unlike other wastes (e.g. biosolids and construction/demolition waste) the mineral quarry wastes can be expected to be free of potentially toxic elements, however, the production costs of compost-mineral waste mixtures and subsequent transport costs may limit its widespread use. In addition, handling of the material can be difficult under wet conditions and effective blending may require the purchase of specialist equipment. From our results, we conclude that mineral fines may prove useful for low quality, low value landscaping activities close to the source of production but are unsuited to high value markets.     

Use of Symbiosis Products from Integrated Pulp and Paper and Carbon Steel Mills: Legal Status and Environmental Burdens

This study assesses the policy/legal status of both multistream residues and potential secondary products (“symbiosis products”) and whether there could be environmental benefits associated with the utilization of residues from integrated pulp and paper and carbon steel mills as raw materials for such secondary products. Waste‐related European Union (EU) and Finnish policy and legal instruments were reviewed to identify potential constraints for, and suggested next steps in, the development of potential process industry residue‐based symbiosis products. The products were soil amendment pellets, low‐grade concrete, and mine filler. A global warming potential (GWP) assessment and an exergy analysis were applied to these potential symbiosis products. Some indicative GWP calculations of greenhouse gas emissions associating similar and/or analogous products based on virgin primary raw materials, more energy‐intensive processes, and the alternative treatment of these residues as wastes are also presented. This study addresses GWP, exergy, and legal aspects in a holistic manner to determine the potential environmental benefits of secondary products within the EU legal framework. The GWP assessment and exergy analysis indicate that the utilization of multistream residues causes very low environmental burdens in terms of GWP. The utilization option can have potential environmental benefits in terms of GWP through process replacement and avoided landfilling and waste treatment impacts, as well as potentially through emission reductions from product replacement if suitable and safe applications can be identified. Waste regulation does not define the legal requirements under which utilizing residues in such novel concepts as introduced in this study would be possible, nor how waste status could be removed and product‐based legislation be applied to the potential products instead.     

Integrating lifecycle assessment and urban metabolism at city level: Comparison between Spanish cities

Urban systems are important consumers of resources and producers of wastes derived from the lifestyles and daily needs of their citizens. The quantification of environmental impacts arising from urban metabolism (UM) plays a key role in the design of more sustainable cities and in the development of decision‐making strategies into more effective urban policies. This article combines UM and lifecycle assessment methodology to quantify mass and energy flows within the city limits and derived urban environmental pressures, thus prioritizing the environmental perspective of sustainability. This methodology is applied to the two very different Spanish cities of Bilbao and Seville. The results acquired in this study identify the consumption of construction materials, electricity, fossil fuels, and food and beverages as environmental hotspots. The results are primarily affected by differences in the climate (extreme conditions), which mainly affect the consumption of fossil fuels, and differences in purchasing power, which mainly influence the intake of foodstuffs. Further research should focus on data management and quality as well as on designing more efficient cities (e.g., through the introduction of more energy‐efficient buildings, sustainable building materials, and public transport) in order to create improvements in their environmental profiles.     

Solar-Driven Hydrogen Evolution from Value-Added Waste Treatment

Hydrogen is one of the most important energy alternatives to conventional fossil-based fuel. Solar energy based photocatalytic hydrogen evolution (PHE) is a salient approach to produce hydrogen fuel but its efficiency is generally limited by the sluggish and energy-unfavorable oxidation reaction. Meanwhile, waste treatment has become a worldwide problem and clean treatment is highly demanded to avoid the vast greenhouse emission currently. Inspiringly, PHE can be effectively coupled with the favorable photooxidation of many wastes, which kills two birds with one stone. In this review, the recent progress in PHE coupled with waste treatment is presented, where typical solid, liquid, and gas wastes have been briefly discussed. Focusing on the understanding of complicated reaction mechanism and the revelation of oxidation products, the cutting-edge techniques for photophysics and surface chemistry characterization have been analyzed, which are imperative to facilitate the following investigation. Finally, the developing trend and existing issues in current research are also discussed in detail so that a holistic blueprint of PHE coupled with waste treatment can be portrayed to accelerate their application in a realistic world.     

生物干燥处理城市垃圾技术的研究进展

生物干燥是对城市垃圾的一种预处理技术。它是利用生物反应放热来干燥城市垃圾,以改善其燃烧特性。经常用于在机械生物处理工厂干燥城市垃圾。生物干燥技术与堆肥工艺不同,它旨在干燥和保留垃圾基质中的生物质含量。在生物干燥反应器中主要干燥机制为空气对流蒸发,而物料的物理特性对干燥效果也有一定影响。反应器通风系统的类型的选择也是生物干燥的一个重要的影响因素。本文主要介绍了影响生物干燥过程的各项因素和研究进展。