ABSTRACT
CHAPTER 2: SOLID WASTE MANAGEMENT IN THE CONTEXT OF SUSTAINABLE DEVELOPMENT: LITERATURE REVIEW
2.1 EVOLUTION OF WASTE MANAGEMENT THEORY AND SUSTAINABLE DEVELOPMENT CONCEPT SUSTAINABLE DEVELOPMENT CONCEPT
CHAPTER 2: SOLID WASTE MANAGEMENT IN THE CONTEXT OF
2.1.1 What is Solid Waste? 2
Snel defines solid waste (or refuse) as any material, apart from gaseous and liquid waste, which the holder discards, intends to discard or is required to be discarded (Snel, 1997). In addition, Liu
& Liptak (2000) define solid waste as all waste materials, excluding hazardous waste, liquid waste and atmospheric emissions. According to Witzsch (1990), "solid waste" was not defined in Lesotho's legal system. However, various pieces of legislation do make reference to what constitutes waste, viz "filth", "night soil", rubbish", "refuse" (Sanitary & refuse Regulations 1972).
Furthermore, it is stated that ''waste is any substance that may be prescribed as a waste or any matter, whether liquid, solid, or radioactive, which is discharged, emitted or disposed of in the environment in such a volume, composition or manner as to cause an alteration to the environment" (WHO, 1990, GOL, 2001).
Taking these definitions into account, then solid wastes should generally include street sweeping (including dead animals); pumped sludge from septic tanks and cesspits (but not waste water treatment plant sludge); refuse collected from residential establishments, commercial enterprises, and institutions; pharmaceutical and surgical wastes from medical clinics and hospitals; and refuse and processing wastes from industrial manufacturing facilities. Whilst this broad definition of solid waste is adopted for the purposes of this study, it is important to mention that waste can be used as a resource through recycling and reuse processes. The composition of solid waste varies from country to country, city to city and from culture to culture. Solid waste can contain putrescible organic matter (e.g. kitchen and market wastes and feacal matter); combustible organic matter (e.g., paper, textile and bone); plastics, metal, glass, oil and grease, and inserts (e.g. soil and ash).
2 Note, in this thesis, the term "municipal solid waste" refers primarily to residential solid waste, with some contribution from commercial, institutional and industrial sources. Hazardous wastes are generally managed outside the municipal solid waste stream. Exceptions are the household hazardous wastes and those hazardous wastes generated in very small quantities, which are often placed in the municipal solid waste stream by the generator. This thesis does not attempt to grapple with the pharmaceutical/medical waste.
Solid waste can contain pathogenic microorganisms (e.g. bacteria and parasites) and toxic chemicals (e.g pesticides, heavy metals, volatile organics and solvents) (World Bank, 1991).
Table 2.1 shows composition of waste by category for a typical developing country, in this case Lesotho. These figures represent expected maximum percentages of each type of waste in a given area (urban, peri-urban and rural); not exact proportions, hence are not expected to add to 100%.
Table 2.1 Distribution of household waste in a Typical Developing Country (%)
Main Waste Item Urban Peri-Urban Rural
Paper 52 51 31
Plastics 24 30 21
OrganicslFood Waste 15 2 21
Beverage cans 4 4 10
Glasslbottles 2 - 3
Other 2 14 14
Total 100 100 100
Source: Modified from Mhlanga & Gulilat 1997
2.1.2
Evolution of Waste Management TheoryIn the past, nature was considered as a perennial spring of survival, renewal which could easily neutralise human impacts (Polizou, 1992). From the days of primitive society, humans and animals have used the resources of the earth to support life and to dispose of wastes. In early times, the disposal of human and other wastes did not pose a significant problem, because the population was small and not concentrated. Furthermore, the amount ofland available for the assimilation of wastes was large (Tchobanoglous et a1.1977).
Problems regarding the disposal of wastes can be traced from the time when humans first began to congregate in tribes, villages and communities. The accumulation of waste became a consequence of communal life (UNEPIUNESCOIUNDP, 1995). Littering of food and other solid wastes in medieval towns led to the breeding ofrats and the outbreak ofthe plaque epidemic which killed half of the Europeans popUlation in the 14th century. The absence of waste disposal preachers caused many subsequent epidemics and high death tolls (Tchobanoglous et al. 1977). Public health was therefore the motivation for removing solid wastes from the human habitat. This approach changed radically during the past thirty years, when environmental pollution and its adverse
effects on mankind became even more apparent (Polizuo, 1992).
Furthermore, as society developed, pollution became one of the major environmental problems.
For example, the population increase and migration into cities have created serious environmental problems, including inadequate solid waste management and lack of minimal pollution control (Cotton et al.1999). Improper storage, collection or disposal of solid waste have an impact on public health as well as on ecosystems through the pollution ofland, water and air. Meanwhile, one of the branches of the environmental science, "solid waste management" grew out ofa need to address these problems. Undeniably, countries: industrialised and developing alike have to deal with similar waste disposal problems. Globally, there is growing importance attached to these issues. Given the importance attached to this issue throughout the world, it is the task of each society to ensure that waste disposal is carried out in such a way that it cannot damage the environment (Suess, 1985).
2.1.3 Solid Waste Management Systems/ Concept
In this Chapter, the term "solid waste management system" includes organized programmes and established central facilities for final disposal of waste, and for recycling, reuse, composting and incineration (Liu & Liptak, 2000). In this literature review, it is essential to describe the general concept of solid waste chain and in line with the defined solid waste. Waste management in the world has changed dramatically during the last 20 years. The impetus for this change was catalyzed by a number of unfortunate environmental disasters such as Love Creek Canal in Niagara Falls county in the USA, the Redhill- Surrey cyanide in the UK, and the dioxin fall-out contamination around Serveso in Italy (Lombard, 1993). Debate shifted to issues of waste utilization in the 1970s (Melosi, 1980).
The concept of solid waste management encompasses materials flow streams of waste from generation to ultimate disposal. 3 It comprises generation, storage, collection, transfer or
3 Waste generation encompasses those activities in which materials are identified as no longer being of value and are either thrown away or gathered together for disposal. (Pfeiffer, J. T. (1992). Solid Waste management engineering).
transportation, and disposal. Accordingly, solid waste management involves the full range of activities for these streams: from generation of used materials to disposal (Beede & Bloom, 1995;
Lardinois, 1996). On the other hand, resource recovery includes all activities of waste segregation, collection and processing, which are carried out taking into account economic viability of materials (Cointreau et al. 1984; Baud & Schenk, 1994; Beede & Bloom, 1995).
Diagram 2.1 illustrates the various stages of solid waste management chain .4
Flow Chart: Diagram 2.1 Solid Waste Management Chain
I
GENERATIONI
t
I
PRIMARY STORAGE1 I
I
PRIMARY COLLECTIONt
SECONDARY STORAGE
t I
SECONDARY COLLECTION (TRANSPORTATION)
!
DlSPOSAUfREATMENTIRES OURCE RECOVERY and
RECYCLING
Source: Modified from Cointreau, 1987
4.In most cases, it includes all the wastes arising from human and animal activities that are normally solid and are dIscarded. as us.el~~s or unwanted. It encompasses the heterogeneous mass of throwaways from residences and com~ercIaI actIvItIes as well as homogenous accumulations of a single industrial activity (Peavy et at. (1988).
EnVIronmental Engineering).
The picture of waste generation has changed dramatically in developed countries. In a typical scenario the amount of solid materials, consumption is reduced and the rate of recovery and re- use of waste materials are increased as illustrated in Diagram 2.2.
Diagram 2.2 Solid Waste Management System in Industrialised Countries
Raw materials
~,
-. Manufacturing
- - - - +
Residual debris~
- - - +
Residual waste materialProcessing an~ .- .. Secondary
recovery ",. 7 ' manufacturing
- ---
.
-
14'
II I 1
I
J
H II I I
I
L _ _ _
Consumer L II - I
I I
I I I
I
I
II
*
IL - - - ~ ___
Fi_nal_d_iS_PO_S_al_.Jr - - -J
Raw materials. products and recovered materials Waste ma1eriafs
Source: UNEPIUNESCOIUNDP, 1995
The solid waste management concept has slowly shaped an improved integrated solid waste management system, as indicated in Diagram 2.3.
2.1.4 Integrated Solid Waste Management (lS\VM) Concept
Integrated solid waste management has evolved over time. Several examples linked to this concept can be cited. In the 1660s, burial in cotton or linen was banned in Europe to allow more cloth for paper- making (World Resource Foundation, 1997). Similarly, the first combined incineration and electric scheme began operating in East London, UK in the early 18th century. In 1894, New York City introduced a "program of source separation of waste" after a long time of dumping waste into the Atlantic Ocean. This practice of separation at source allowed recovery of valuable materials from waste (Gandhy, 1994). The concept oflSWM did not occur only in the Western world, but in Africa as well. In the early 1900s, Zabbaleen in Egyptian was one of the first communities to integrate recovery and recycling of municipal waste (Baaijens, 1994).
The philosophy of a "Waste Management Hierarchy" (prevention/minimisation, materials recovery, incineration and landfillldisposal) has been adopted by most industrialized nations as a means for developing municipal solid waste management strategies (Sakai et al. 1996). Following the environmental movement of the late 1960s, which formally presented integrated solid waste management as a guiding principle for managing societies' refuse, municipalities began applying the concept. This trend coincided with a period of prosperity in the industrialized world.
Ironically, the ISWM concept was further enhanced by the recession period of the early 1980s, when municipalities in developed world had no choice but to adopt the new paradigm shift to integrated solid waste management, subsequently the concept was widely implemented. This philosophy of waste management hierarchy has further been enhanced by Beukering et al. (1996).
In his paper, he illustrates integrated nature of the system as a key element in the integrated solid waste management systems of all the industrialized countries (see Diagram 2.3). It is based on the principle, which proposes that waste should be handled by different methods according to its characteristics. For example, prevention of waste could be done by either reducing or re-using the waste. Diagram 2.3 illustrates the general philosophy of a waste management hierarchy.
Diagram 2.3 Waste Management Hierarchy