Recycling — an environmentally friendly and income generating activity towards sustainable solid waste management. Case study — Dar es Salaam City, Tanzania

Traditionally solid waste management has evolved as mainly the removal of municipal wastes by hauling them out of the city boundaries and dumping them ‘there’. This is in conformity with the ‘out of sight out of mind’ philosophy. However, with the ever increasing tonnage of refuse due to the expansion of urban centers, which implies increased collection, transportation and disposal costs, recycling is currently accepted as a sustainable approach to solid waste management. This paper reports on the findings of a study, conducted in the city of Dar es Salaam between the years 1993 and 1995, on the scavenging activities and recycling trends of some selected items in Dar es Salaam. Apart from the discussions on existing solid waste generation rates (2000 tonnes/day), composition (60% being organic/or vegetable matter) and their management in Dar es Salaam, the paper also presents data obtained through a survey of Vingunguti dump site and other waste collection centers. It was established that there are currently about 600 solid waste scavengers in Dar es Salaam, approximately 109 of whom operate at Vingunguti dump site and others at 14 different collection centers. Many of them opted for scavenging due to unemployment. The study findings indicate that their average monthly income exceeded the official minimum wage (at the time of study) enabling them to support their families. This demonstrates the potential of recycling to generate gainful employment with implied lower crime rates among the unemployed. Recycling activities in the city were observed to be not only a critical source of raw materials for small-scale industries, in the absence of which they would cease to operate, but also a widely accepted environmentally friendly technology for solid waste management. Out of 294 tonnes of studied waste materials (paper, metal, plastic, glass and textiles) only 4 tonnes are recovered and recycled. The remaining 290 tonnes/day of recyclable material are left to pollute the environment or are collected and transported for final disposal and, therefore, unnecessarily contribute to the shortening of the life span of the dump site. Finally, the paper gives some recommendations for improved recycling activity so as to make it an important means of reducing the overall volume of waste materials to be transported and deposited in the dump site and at the same time provide a potential opportunity for employment for unskilled workers.     

Critical review of industrial and medical waste practices in Dar es Salaam City

Industrial and medical wastes constitute a larger part on what is known as ‘hazardous wastes’. The production of these wastes is and will continue to be an on going phenomenon as long as human civilization persists. The health impacts of direct and indirect exposure to hazardous wastes include carcinogenic effects, reproductive system damage, respiratory effects, central nervous system effects, and many others. Today, many developed countries have legal provisions with regard to proper management of hazardous wastes. Tanzania, like many developing countries, has little emphasis on the proper handling and disposal of hazardous wastes. There is a serious inadequacy in handling industrial and medical solid wastes in the Dar es Salaam City. Improper waste deposition is increasingly becoming a potential public health risk and an environmental burden. Due to poor control of waste, industrialists and hospital owners are not well checked on how they handle and dispose of the wastes they produce with the result that many hazardous wastes reach the Vingunguti dumpsite without notice. Data on waste generation in Dar es Salaam is also inadequate, making it difficult to plan an efficient solid waste system. Promotion of public awareness, legislation and regulations enforcement and establishment of a proper sanitary landfill are considered to be principal remedial measures to ensure sound environmental maintenance. This paper summarizes the findings of the study on the practices of industrial and medical waste management in Dar es Salaam. The author aims to express the inadequacy in hazardous waste management and suggests possible measures to be applied in order to rectify the situation.     

Recycling inorganic domestic solid wastes: results from a pilot study in Dar es Salaam City, Tanzania

Solid waste recycling and recovery approach can be a sustainable and effective waste management system in many growing cities of the least developed countries. In the course of achieving proper solid waste management, a lot of efforts in these countries have, however, been focused more on collection and disposal and ignored waste recycling which can result into income generation, employment creation and reduction of the waste quantities that will finally require disposal in the existing municipal landfills or disposal sites. This paper reports the findings of a study on solid waste recycling in a selected semi-planned settlement in Dar es Salaam City, Tanzania. The objective of the study was to describe the existing solid waste management in the study area with a view to identifying the waste generation rates, types of the wastes and determine the amount of waste from the settlement that can be recycled for the purpose of income generation and reduction of the total amount of waste to be disposed of. Findings from this study revealed that waste generation rate in the study area was 0.36 kg per person per day, and that out of the 14 600 kg of recyclable waste generated per year, 8030 kg or 55% can be recycled and generate a per capita income of Tsh 834 000 for waste recyclists which is more than twice the official minimum annual wage (Tsh 360 000) in Tanzania at the time of the study. The study also revealed that effective waste recycling in the study area would result in the reduction of the total waste that need to be transported for final disposal by 11%.     

Sustainable recycling model: A comparative analysis between India and Tanzania

Higher economic growth in developing countries has caused higher amounts of wastes. Local government authorities in these countries usually fail to provide adequate services to dispose the increasing amounts of waste, resulting in threats for both the population and environment health. There is therefore an urgent need for recycling as a form of waste management in order to stop the devastating effects of solid waste in developing countries. Using a qualitative method of analysis, this study presents a model to measure and rank the sustainability of recycling programs in India and Tanzania. The model consists of six main constructs including “production, economic, governmental, social, technological, and international factors”. The results showed that India outperforms Tanzania in sustainable recycling programs: per capita waste generated per day in Delhi is higher than in Dar es Salaam; the government of India focuses more on developing recycling plans and techniques as compared to the government of Tanzania where the country is not actively involved in the recycling process; and the solid waste management planning in India is being performed better than Tanzania.     

The governance of waste management in urban Tanzania: towards a community based approach

Solid waste management in urban areas in Tanzania is examined from a governance point of view. Capitalising on the case of the Dar es Salaam City Council, governance is seen in terms of central–local government relationship and the relationship between local government and international, national, and community institutions and stakeholders. Major impediments to waste management in urban Tanzania include corruption, poor relations between the politicians and the general population, politics of privatisation, and political apathy. Lack of resources is seen as the least important of all the impediments. An evaluation of the governance of waste management with respect to public participation, privatisation, citizen-rights, accountability and transparency and financial efficiency is discussed. Management of solid wastes in Dar es Salaam and other urban centres in Tanzania should shift from command-and-control approaches to systems of partnerships between the public authorities and the various stakeholders on the urban scene. A community-based solid waste management approach is suggested for wider adoption. The strategic approach to this non-conventional method should be carried out through four steps: elaboration, trial, evaluation and extension to other neighbourhoods.     

Overview of non-hazardous solid waste in the small island state of Mauritius

In Mauritius, solid waste disposal has been a cause for concern since the 1980s. Currently, there is no segregation of waste and some 1200 tonnes of solid waste are generated daily by the 1.24 million inhabitants of the island. As processes such as recycling and composting are still in their infancy stage, most of the waste generated have to be disposed of at the sole landfill. The solid waste management practices of 1980s and early 1990s are no longer compatible with the changing composition and quantity of wastes now generated. As a result, there is an urgency to review the whole waste management system and come forward with sustainable solutions.This paper presents an overview of the disposal of non-hazardous solid waste in Mauritius and provides recommendations for improving the current disposal system.     

Analysis of Scavengers’ Activities and Recycling in Some Cities of Nigeria

The state of solid waste recycling by scavengers in Onitsha, a heavily commercial city in Anambra State, and some other urban areas such as Nsukka, Enugu, and Port Harcourt was analyzed. Data were obtained through interviews of scavengers who deal with recyclables. Although the activities of scavengers are sub-optimal, they can have a great impact on Nigerian economy with respect to resource conservation, creation of job opportunities, and reduction of the magnitude of waste disposal problems. A cost analysis is presented to compare the different forms of recycling utilized by municipal solid waste management. It is shown that a well-planned recycling program with recycling and composting would result in 18.6% savings in waste management costs and 57.7% in landfill avoidance costs. However, if the compost materials are not recycled, the corresponding savings in cost become 8.6% and 28.6%, respectively. The option with the lowest cost involves encouraging individual households to separate at the source their recyclables, which are bought by scavengers. This results in 78.0% savings in waste management cost and 79.5% landfill avoidance cost. A low-cost approach aimed at the integration of scavenging activities into conventional solid waste management is presented.     

碳达峰碳中和目标下固体废物治理的法律因应

我国在联合国大会上提出了“2030年碳达峰2060年碳中和”的目标。为达成此目标,固体废物治理领域也需要积极作出响应。固体废物治理体系的核心是固体废物的处置。不同的固体废物处置方式有着不同的碳排放结果,填埋或焚烧方式处置所排放的温室气体量都远大于循环利用的方式。应以固体废物领域碳排放统一核算制度为基石,从推进政策实施和立法修改等的多个层面上去因应。立法面向上,《固体废物污染环境防治法》《清洁生产促进法》《循环经济促进法》乃至编纂中的“环境法典”都应当围绕减碳模式的固体废物处置方式改进和制定相关法律规范;制度建设面向上,以固体废物碳排放强制核算法律制度建设为主,通过碳排放强制核算制度规范相关主体及其权利义务关系并深度挖掘固体废物处置的碳减排潜力。     

Recycling in the USA : Vision and reality

In 1978 the US Environmental Protection Agency contracted Mathtech Incorporated to identify the impediments to recycling and evaluate their economic effects. The facilities studied represented a cross-section of recycling technologies, ownership types, geographical locations, and recovered products. It was discovered that none of the facilities was economical in the sense of providing the least-cost mode of disposal for municipal solid waste, and all of them suffered net losses in recent operations. Indications were that financial performance would improve slightly. A major deterrent to economical operations was the availability of lower-cost disposal by landfill.     

Botswana's environmental policy on recycling

Recycling operations have become one of the primary strategies for waste management, worldwide. Especially, recycling operations are viewed as among the most effective techniques for reducing the amount of municipal solid waste disposed at landfill sites. Botswana's environmental policy on recycling stipulates, among others, that all waste management authorities should provide information on the classification and quantities of controlled waste targeted for recycling. This paper, therefore, examines the extent to which recycling operations in Botswana have either been conducted in compliance with or in violation of some major environmental requirements as enunciated on statutory guidelines. Compatibility between environmental policies on recycling and actual practice is evaluated focusing on two companies (Dumatau trading and Botswana Tissue) involved in recycling operation. Data from the two companies is complemented by one collected from the Gaborone landfill site. Finally, this study discusses on the role played by various stakeholders in policy formulation and implementation with particular emphasis being placed on a select number of non-governmental organisations (NGO).     

城市生活垃圾填埋场甲烷气资源的产量估算及其利用

本文论述了填埋场甲烷气体的产生过程及影响因素，介绍了三种产气量估算方法及其主要特点、适用范围，并指出运用数学模型对产气量作出预测，为垃圾填埋场气体收集与处理系统的设计提供可靠的依据。同时，论述了甲烷气体的减排和综合利用措施。     

The effect of recycling price uncertainty on municipal waste management choices

This paper analyzes the effect of price uncertainty and irreversible investment on the decision of municipalities to switch from landfill waste disposal to recycling by developing a model to predict recycling adoption behavior and applying it to empirical data. It is shown that uncertainty regarding the price of recycled materials may induce a risk neutral municipality to prefer landfill disposal, even when recycling is less expensive. A model is developed to describe the switching process and estimate its parameters using empirical data from 79 municipalities in Israel. The model is then used to predict municipalities' recycling adoption decisions under various assumptions regarding price uncertainty. The results support the hypothesis that price uncertainty is a major obstacle for recycling. Finally, several options for price stabilization are sketched and it is argued that these policies may be effective in establishing viable recycling markets.     

The impact of the European landfill directive on waste management in the United Kingdom

The European Union Landfill Directive calls on member states to reduce the amount of biodegradable municipal solid waste disposed of to landfill. In addition, national waste strategies will require the constituent parts of the United Kingdom to achieve increased household waste recycling and recovery rates. Both these measures will require the development of the infrastructure to support national high-intensity recycling and composting schemes and the construction of at least 35 new municipal waste to energy incinerators. Before plans can be developed for meeting the targets several areas relating to municipal solid waste need to be clarified. Depending on the definition of municipal solid waste, its composition and likely future growth rates the number of incinerators required could be up to 170.     

A generic comparison of the airborne risks to human health from landfill and incinerator disposal of municipal solid waste

A comparison of the potential risks to human health from municipal solid waste (MSW) incineration and landfill on a generic basis is attempted. For this purpose a 'worst case' approach is adopted and a number of assumptions regarding the size and activities of each waste disposal method are made. The airborne pollutants measured for an incinerator are different from those for a landfill with or without gas collection. However, based on the available information it appears that as far as airborne pollution is concerned, landfill sites without gas collection pose a potentially higher generic risk to human health than MSW incinerators performing to Environmental Agency (UK) standards. This analysis cannot be used to replace specific evaluations for a particular incinerator or a landfill site because local conditions can have a very large impact on the magnitude of risks involved.     

北京市垃圾填埋场地下水中砷、汞含量分析

生活垃圾的处置一直以填埋为主,垃圾填埋承载着巨大的环境压力,尤其是垃圾填埋产生的渗滤液会对地下水造成砷、汞污染。为了解北京市生活垃圾填埋场地下水砷、汞污染水平,在北京市5座生活垃圾填埋场布设采样点,采集36个地下水样品,采用氢化物发生-原子荧光法,分析了地下水砷、汞含量特征。结果表明,36个地下水样品砷浓度范围0.41~4.82μg/L,汞浓度范围0.024~0.121μg/L,北京市典型垃圾填埋场地下水样品不存在砷、汞污染问题。     

Overview of household solid waste recycling policy status and challenges in Malaysia

With the annual increase in waste generation and heavy reliance on landfilling as disposal, method in Malaysia, it is just a matter of time before significant problems of space limitations, health, and environmental issues hit the nation severely. This paper attempts to develop an overview on solid, waste recycling in Malaysia at the most basic level of a community or nation which is the household, unit. Households are the main primary source of municipal solid waste in Malaysia, consisting of, recyclable materials at most 70% to 80% of the total waste composition as found placed in the, landfills. Overview on the existing household solid waste recycling policy and program status in, Malaysia is relevant in enhancing solid waste management measure from recycling perspective. Despite the high potential and opportunities for solid waste recycling, wastes are still simply being, dumped in an open area of ground without any attempt for recovery and recycling. Comparing to, recycling rates of neighboring countries, Malaysia is falling back at merely 5% which proves how, uncommon recycling practice is. The government is committed to significantly improve the national's, solid waste management services especially in waste minimization. Fortunately the emphasis on, recycling as a sustainable waste management strategy has taken a shift in paradigm as wastes, separation and recycling are part of the major changes in the current policy implementation. With, issues and challenges in recycling practice that were highlighted in this context especially from the, aspects of information availability and other loopholes within solid waste management policies and, related recycling program within the community, the question on whether the goals in 2020 can be, met remains unsure of but there is a possibility for a successful implementation of sustainable solid, waste management particularly in recycling.     

Tribute chromite mining and environmental management on the northern Great Dyke of Zimbabwe

A combination of poor mining methods, waste storage and disposal systems, as well as the day-to-day activities associated with tribute and contract chromite mining are primarily responsible for environmental problems on the Zimbabwe Great Dyke. For instance, the unsystematic dumping of waste rocks in rivers blocks channels and results in flooding, which further sterilizes agricultural land and mineral resources. Erosion of these haphazardly located dumps causes siltation of water bodies and results in the dispersion of heavy metals in soils and watercourses. Vegetation growth on waste dumps is limited and constrained by the high pH levels from phytotoxic metals in soils, the lack of nutrients, poor moisture retention qualities of the mining waste and critical cation imbalances within dumps. This article attributes poor environmental management on the Dyke to poverty, a direct result of the nature of tribute agreements and output prices. Prices based on output targets are exploitative and undervalue labour and thus perpetuate poverty. By absolving claim holders from environmental liability, tribute agreements contribute directly to environmental problems. Thus, the incorporation of enforceable dual environmental responsibility requirements in contract mining agreements is needed to overcome this problem. This article recommends that, to break the poverty cycle, the primary cause of environmental mismanagement in the sector, miners need to be empowered through claim ownership and the enhancement of their capacity to negotiate prices with buyers of chrome.     

Landfill space consumption dynamics in the Lower Rio Grande Valley by grey integer programming-based games

The Lower Rio Grande Valley (LRGV) region in South Texas emerges as a warehouse and transportation center between Central America and the US with positive growth impacts due to the North American Free Trade Agreement (NAFTA). In 10 years time, a 39.8% population increase has resulted in a 25% boost in solid waste per capita disposal rate in the region. A landfill space shortage drives a need for landfill operators to understand their optimal management strategies in this highly-competitive market. Initially, a strategic plan for optimal solid waste pattern distribution minimizes net costs for cities. This is accomplished through a grey integer programming algorithm that encapsulates all uncertainty present in the solid waste system. Secondly, a series of grey integer submodels construct payoff matrices for a zero-sum two-person game. The ensuing game theoretic analysis is critical for evaluating optimal pricing strategies for tipping fees available to the most significant regional landfills (e.g. Browning-Ferris Industries (BFI) and City of Edinburg) as they compete over disposal contracts. The BFI landfill intrinsically benefits from its competitive pricing policy and central location to solid waste generators. The City of Edinburg landfill, on the other hand, wishes to secure its lucrative solid waste management revenue. It desires a gaming strategy backed by optimality that integrates ambiguity in solid waste generation, design capacity boundaries, and unitary shipping costs. Results show that a two-tiered analysis via grey integer programming-based games may pave the way for 'grey Nash equilibria' pricing tactics that will help the Edinburg landfill maintain its waste contracts.     

固体废物全过程管理中固体废物鉴别研究

对固体废物应进行全过程管理,固体废物鉴别是固体废物全过程管理的基础和关键,包括依据产生来源鉴别和过程鉴别两种方法,依据产生来源鉴别包括丧失原有利用价值的物质、在生产过程中产生的副产物、环境治理和污染控制过程中产生的物质、其他物质四类,在每一类中详细地列举了属于该产生来源的具体固体废物种类名称,便于理解和增强可操作性。过程鉴别包括在固体废物再生利用过程和处置过程中的固体废物鉴别两类,其中在再生利用过程的固体废物鉴别中明确指出了固体废物再生利用产物只有同时满足产品质量标准要求、国家污染控制标准要求以及有实际市场需求、固定用户等条件时,才不作为固体废物管理,在处置过程的固体废物鉴别中具体地列出了处置固体废物全过程中仍然作为固体废物管理的国际惯用处置方式。同时,给出了清晰的"原料—产品—固体废物—处置或产品"全过程中固体废物的产生节点和相应的固体废物类别图,为固体废物鉴别工作提供参考,使固体废物全过程管理有的放矢,有效防止固体废物对环境和人体健康造成的危害。     

Questioning the Waste Hierarchy: The Case of a Region with a Low Population Density

Discussions of municipal solid waste (MSW) management are influenced increasingly by the concept of the waste hierarchy which, broadly speaking, places landfill as the least acceptable option for dealing with MSW, followed by incineration, recycling, re-use and reduction at source. In this paper, we want to question the wisdom of applying the waste hierarchy in a region with a low population density. The hierarchy was first developed with reference to the high population density areas such as the core of the EU. However, in low population density areas the economics of the various approaches to MSW is likely to be quite different. As a result, the application of the hierarchy could place an undue economic burden on a region relative to the environmental benefits that might arise. We estimate the costs, both internal and external, of the various methods of dealing with MSW in an area with the appropriate population density, drawing on information from a wide variety of sources. We find that landfill is significantly cheaper than in high population density areas, even when account is taken of the associated externalities. In addition, it is generally cheaper than the alternative methods. As such, we conclude that landfill should not be shunned as a disposal method in low population density areas.