SOLID WASTE SEGREGATION AS A STRATEGY FOR IMPROVED WASTE MANAGEMENT

CHAPTER TWO

LITERATURE REVIEW

2.1What is Waste?

The concept of waste is tricky to define (Lardinois and Van de Klundert, 1995). The definition of post-consumption materials as resources in the wrong place at the wrong time incorporate the idea of 'wastes' being resources left over from initial consumption(Lardinois and Van de Klundert, 1995). There is a problem with this definition because not all wastes can properly be regarded as resources. Many hazardous and toxic materials cannot be safely recycled or reused. In any one society, there will always be materials that cannot be used as resources for various reasons. What is a waste is considered from the point of view of the waste generator soit is mainly a subjective matter. Waste is what the person responsible for discarding the material regards as waste(Lardinois Van de Klundert, 1995). General waste is any material for which a specific owner ceases to have use for it. It is also any unwanted or discarded material, in solid, liquid or gaseous form. A product, material or container is not considered waste until someone throws it away.

2.2Solid Waste

Solid waste is non-liquid waste arising from domestic, commercial, industrial, agricultural, mining and construction activities and from public services. Solid waste can also be defined as ―unwanted material disposedoff by man which can neither flow into streams nor escapes immediately into the atmosphere(Kulkari, 2008).

2.3Classification of Solid Waste

Solid waste can be classified in several ways and most classification of solid waste is based on the source from which it is generated(Hoornweg et al., 2008). Major sources of solid waste include;

i.Residential/Domestic Waste

This can be single or multifamily dwellings. Types of waste generated here are food wastes, paper, cardboard, plastics, textiles, leather, yard wastes, wood, glass, metals, ashes, special wastes (e.g., bulky items, consumer electronics, white goods, batteries, oil, tires, and (household hazardous wastes.) (Hoornweget al., 2008). ii.Industrial Waste

These are light and heavy waste from manufacturing, fabrication, construction sites, power and chemical plants, manufacturing processes such as (refineries, mineral extraction and processing. etc.). The types of waste generated here are housekeeping wastes, packaging, food wastes, construction and demolition materials, hazardous wastes, ashes, special wastes, industrial process wastes, scrap materials, off-specification products, slay, tailings etc. The manufacturing industry has a central role to play in the prevention and reduction of waste as the products they manufacture today become the wastes of tomorrow. Manufacturers can achieve this by:

• considering the impact of their products throughout its life at the design stage of the product.
• using manufacturing processes that minimize material and energy usage.
• eliminating or reducing where possible the use of substances or materials hazardous to health or the environment and
• manufacturing products in such a way that they last longer and may be recycled or reused at the end-of-life stage.

The European Union and government policy across Europe is increasingly driven by the need to influence manufacturing practices in an effort to decrease the environmental impact of products during their manufacture, use and end-of-life (Hoornweget al., 2008).

iii. Commercial Waste

These are wastes from stores, hotels, restaurants, markets, office buildings etc. The type and nature of waste generated from these premises are paper, cardboard, plastics, wood, food wastes, glass, metals, special wastes and hazardous wastes(Hoornweget al., 2008).

iv. Institutional Waste

These are waste from schools, hospitals, prisons, government centres and other public services. The types of waste generated is similar to those from commercial source. These include paper, cardboard, plastics, wood, food wastes, glass, metals, special wastes and hazardous wastes(Hoornweget al., 2008).

v.Construction and Demolition Waste

These wastes are from new construction sites, road repairs, renovation sites, demolition of buildings etc. The types of waste associated with these activities are wood, steel, concrete, dirt, glass, bags, polythene, plastic etc. Construction activity is seen as a key indicator of growth and prosperity in western countries. However, construction and demolition waste; instead of being a burden on society and environment, can become a resource to be recycled and reused within the construction industry. Construction and demolition waste have been identified as a priority waste stream by the European Union. This means that particular attention will be paid to policies and measures to ensure increased recycling of construction and demolition waste. Due to the very large volume of construction and demolition waste produced, it can use up valuable space in landfills. In addition, if not separated at source, it can contain small amounts of hazardous waste. However, it also has a high resource value and the technology for the separation and recovery of construction and demolition waste is well established, readily accessible and in general inexpensive. Most importantly, there is a reuse market for aggregates derived from construction and demolition waste in roads, drainage and other construction projects(Hoornweget al., 2008).

vi. Municipal Waste

Municipal waste source includeshousehold waste, construction and demolition debris, sanitation residue, and waste from streets. This garbage is generated mainly from residential and commercial complexes Street cleaning, landscaping, parks, beaches, other recreational areas, water and wastewater treatment plants, tree trimmings; sludge, paupers, disuse vehicles and heavy construction equipment‘s, abandoned building material and boats. Management ofmunicipal waste has traditionally been landfilled and this remains the predominant management option in most countries. However, some countries have taken significant steps away from landfill. Alternatives offered include incineration (increasingly with recovery of energy), composting and recycling of glass, paper, metal, plastics and other materials etc.Environmental relevance includes the potential impact associated with the landfilling of waste such as the production of leachate and landfill gas, odours, flies, vermin and the use of land (Patriti, 2006).

vii. Agricultural Waste

Agricultural Waste mostly comes from farm produce. Sources of Agricultural Waste are crops, orchards, vineyards, dairies, feedlots and farms. Waste types are spoiled food wastes, agricultural wastes, hazardous wastes (e.g. pesticides). There are a number of potential environmental impacts associated with agricultural waste if it is not properly managed not least of which is the run-off of nutrients to surface waters which can cause over-enrichment of the water bodies. Leaking and improper storage of agricultural waste can also pose a serious threat to the environment should the waste reach surface waters. In addition, farming activities can give rise to emissions of ammonia and methane which can cause acidification and contribute to greenhouse gas emissions. There are a number of methods used to treat agricultural waste. These include spreading the waste on land under strict conditions, anaerobic digestion and composting(Hoornweget al., 2008).

viii. Hazardous Waste

Wastes are classified as hazardous if they are reactive, toxic, corrosive or otherwise dangerous to living things the environment. Hazardous waste sources including households, industrial, hospitals, and most commercial areas. The main disposal route for hazardous waste is landfill, incineration and physical or chemical treatment. On the recovery side, a significant proportion of hazardous waste is recycled or burnt as fuel. Although hazardous waste generated is sometimes very small, it can present a potential risk to both human health and the environment. Hazardous waste is typically the subject of special legislation and requires special management arrangements to ensure that they are kept separate from and treated differently to non-hazardous waste (Patriti, 2006).

ix. Mining Waste

Mining waste arises from prospecting, extraction, treatment and storage of minerals. Mining and quarrying activities give rise to the single biggest waste stream at 29% of the total quantity of waste generated in European Economic Area countries. It has been shown that approximately 50% of the material extracted during extraction and mining activities in Europe becomes waste. It is made up of topsoil, overburden, waste rock and waste from the processing of the ore body (tailings) which may also include process water, process chemicals and portions of the remaining materials. The two major concerns in relation to mining waste are the large volumes that are produced as well as the potential for hazardous substances to be present in the waste stream. Large areas of land are used for depositing mining waste and this activity has the potential to cause environmental pollution if not properly controlled. A number of recent cases of uncontrolled releases of mining waste to surface waters (rivers and lakes) have highlighted the risks of poor mining waste management. In response, the European Union has proposed initiatives that are designed to improve mining waste management(EIONET, 2012).

x. Electrical and Electronic Waste

Waste electrical and electronic equipment (commonly called WEEE) has end of life products and comprises a range of electrical and electronic items such as refrigerators, IT and telecommunication equipment, freezers, electrical and electronic tools, washing machines, medical equipment, toasters, monitoring and control instruments, hairdryers, automatic dispensers, televisions, etc. Therefore, sources are all users of electrical and electronic equipment from householders to all kinds of commercial and industrial activities. WEEE is one of the fastest growing waste streams all over the world. Presently large proportion of WEEE is disposedoff into landfills or incineration plants, depending on local or national practices. In some countries and regions, products such as fridges and freezers are separately collected and sent to recycling plants for dismantling and recycling. WEEE has been identified as a priority waste stream by the European Commission due to its potentially hazardous nature, the consumption of resources in its manufacture and its expected growth rates. In response, the European Commission has prepared legislation in the form of the following two directives;

• A directive on waste electrical and electronic equipment (WEEE); and
• A directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment.
• A directive on the environmental impact of electrical and electronic equipment.

The directives propose that manufacturers will become responsible for taking back and recycling electrical and electronic equipment. This will in turn provide industry with incentives to design electrical and electronic equipment in an environmentally more efficient way, taking waste management issues into consideration(Hoornweget al., 2008).

xi. Biodegradable Municipal Waste

Biodegradable municipal waste (BMW) is waste from households and commercial activities that is capable of undergoing biological decomposition. Food waste such as corn, tubers, plantain peelings and cuttings, left over foods, garden waste, paper and cardboard are all classified as biodegradable municipal waste. Management options used to treat Biodegradable municipal waste, other than sanitary landfill include composting, mechanicalbiological pre-treatment recycling and incineration (with and without energy recovery). Potential impacts associated with landfilling of biodegradable municipal waste include the production of leachate and landfill gas, odours, flies and vermin(Coker et al., 2008).

xii. Packaging Waste

Packaging is defined as any material which is used to contain, protect, handle, deliver and present goods. Items like glass bottles, plastic containers, aluminium cans, food wrappers, timber pallets and drums are all classified as packaging. Packaging waste can arise from a wide range of sources including supermarkets, retail outlets, manufacturing industries, households, hotels, hospitals, restaurants and transport companies. A number of different methods are used to manage packaging waste, these included reuse, recycling (mechanical, chemical and feedstock), composting, thermal treatment and landfill.Packaging and packaging waste can have a number of impacts on the environment. Some of these impacts can be associated with the extraction of the raw materials used for manufacturing the packaging itself, impacts associated with the manufacturing processes, the collection of packaging waste and its subsequent treatment or disposal. In addition packaging may contain some critical substances e.g. polyvinyl chloride and heavy metals which may pose a risk to the environment(Hoornweget al., 2008).

xiii. End of Life Vehicle and Tyres (ELVs)

End-of-life vehicles are defined as cars that hold up to a maximum of eight passengers in addition to the driver and trucks and lorries that are used to carry goods up to a maximum mass of 3.5 tonnes. Thus their sources range from households to commercial and industrial uses. Cars are made up of numerous different materials. Approximately 75% of the weight of a car is made up of steel and aluminium, most of which is recycled. Other materials present include lead, mercury, cadmium and hexavalent chromium in addition to other dangerous substances including anti-freeze, brake fluid and oils that, if not properly managed, may cause significant environmental pollution. The remainder is composed of plastic which is recycled, incinerated or landfilled(Hoornweget al., 2008).

2.4Health Impacts of Improper Handling of Solid Waste

Modernization and progress has its share of disadvantages and one of the main aspects of concern is pollution of the earth – be it land, air or water. With increase in the global population and rising demand for food and services, there has been a rise in the amount of waste being generated daily by each household. This waste is ultimately thrown into municipal waste collection centres from where it is collected by the area municipalities to be further thrown into landfills and dumps. However, either due to resource crunch or inefficient infrastructure, not all of this waste gets collected and transported to the final dumpsites. If at this stage the management and disposal is improperly done, it can have serious impacts on health the surrounding environment. Waste that is not properly managed, especially excreta and other liquid and solid waste from households and the community, are a serious health hazard and lead to the spread of infectious diseases. Unattended waste lying around attracts flies, rats and other creatures that in turn spread disease. Normally it is the wet waste that decomposes and releases a bad odour. This leads to unhygienic conditions and thereby a rise in the health problems. The plague outbreak in Surat is a good example. Plastic waste is another cause for ill health. Thus excessive solid waste that is generated should be controlled by taking certain preventive measures. The group at risk from the unscientific disposal of solid waste include the population in areas where there is no proper waste disposal method, especially the pre-school children; waste workers and workers in facilities producing toxic and infectious material. Other high-risk groups include population living close to a waste dump and those whose water supply has become contaminated either due to waste dumping or leakage from landfill sites. Uncollected solid waste also increases risk of injury and infection(Hoornweget al., 2008).

2.4.1Organic Domestic Waste

Food residuals in many areas in are left to decompose in the environment,attracting flies, cockroaches, rodents and other vectors of public health importance. Apartfrom being an unsightly, they create foul odour due to their gradual decomposition. Thisposes a serious threat, since they ferment; creating conditions favourable to the survival and growth of microbial pathogens .Direct handling of solid waste can result in various types of infectious and chronic diseases with the waste workers and the rag pickers being the most vulnerable(Yuwono and Lammers, 2004).

2.4.2Exposure To Hazardous Waste

Thiscan affect human health; children being more vulnerable to these pollutants. In fact, direct exposure can lead to diseases through chemical exposure as the release of chemical waste into the environment leads to chemical poisoning. There‘sa connection between health and hazardous waste(Hoornweget al., 2008).

2.4.3Waste From Agriculture and Industries

Theycan also cause serious health risks. Otherthan this, co-disposal of industrial hazardous waste with municipal waste canexpose people to chemical and radioactive hazards. Uncollected solid waste can alsoobstruct storm water runoff resulting in the forming of stagnant water bodies thatbecome the breeding ground for disease. Waste dumped near a water source alsocauses contamination of the water body or the ground water source. The direct dumpingof untreated waste in rivers, seas and lakes results in the accumulation of toxic substances in the food chain through the plants and animals that feed on it directly or indirectly(Hoornweget al., 2008).

2.4.4Disposal of Hospital and other Medical Waste

Theserequire special attention since they can create major health hazards. Waste generated from hospitals, health care centres, medical laboratories, and research centres such as discarded syringe needles, bandages, swabs, plasters, and other types of infectious waste are often disposedoff with the regular non-infectious waste(UNEP, 1996).

2.4.5Waste Treatment and Disposal Sites

These sitescan also create health hazards for the neighbourhood. Improperly operated incineration plants cause air pollution and improperly managed and designed landfills attract all types of insects and rodents that spread disease. Ideally these sites should be located at a safe distance from all human settlement. Landfill sites should be well lined and walled to ensure that there is no leakage into the nearby ground water sources(UNEP, 1996).

2.4.6Recycling

Waste recyclingtoo carries health risks if proper precautions are not taken. Workers working with waste containing chemical and metals may experience toxic exposure.Disposal of health-care wastes require special attention since it can create major health hazards, such as Hepatitis B and C, through wounds caused by discarded syringes. Rag pickers and others, who are involved in scavenging in the waste dumps for items that can be recycled may sustain injuries and come into direct contact with these infectious items(UNEP, 1996).

2.4.7Occupational Hazards Associated with Waste Handling

i. Infections

Skin and blood infections resulting from direct contact with waste, and from infected wounds. Eye and respiratory infections resulting from exposure to infected dust, especially during landfill operations. Several diseases results from the bites of animals feeding on the waste. Intestinal infections are also transmitted by flies feeding on the waste(Patriti, 2006). ii.Chronic diseases

Incineration operators are at risk of chronic respiratory diseases, including cancers resulting from exposure to dust and hazardous compounds(UNEP, 1996).

iii. Accidents

Bone and muscle disorders resulting as a result of handling of heavy containers infecting wounds resulting from contact with sharp objects Poisoning and chemical burns resulting from contact with small amounts of hazardous chemical waste mixed with general waste. Burns and other injuries resulting from occupational accidents at waste disposal sites or from methane gas explosion at landfill sites(UNEP, 1996). Therefore, from the above public health implication of Solid waste its proper management can never be over emphasized and should be handled with caution and in line with best practices of safety and hygienic standards.

2.5 Solid Waste Management

Waste management is the practice of the gradual removal of waste substances or materials in an environment with the ultimate aim of eliminating those substances or materials that have the potential to cause harm to people and the environment. Solid waste management therefore, is the planned systematic administration of activities that provide for the collection, source separation, storage, transportation, transfer, processing, treatment and disposal of solid waste.

Figure2.1; Schematic diagram of Solid waste management(Sridhar, 2013).

2.6 Objectives of Waste Management

The objectives of waste management are designed to promote aesthetics, land-use, health, prevent pollution of air and water, generate income for economic growth; create awareness for proper solid waste management for municipal, corporate, and individual. Solid waste management is a complex process because it involves many technologies and disciplines. These include technologies associated with the generation (source reduction); on-site handling and storage; collection; transfer and transportation; processing and disposal of solid wastes. All of these processes have to be carried out within existing legal, social and environmental guidelines that protect the public health and the environment in a safe, hygienic and economically acceptable manner. In other to achieve these solid waste management must take an integrated approach (Sridhar, 2013).

2.7 The Waste Management Hierarchy

Waste management activities are often planned and arranged in a hierarchical manner to reflect their desirability:

1. The first priority is waste avoidance, which is, not producing the waste in the first place.
2. If the waste must be produced, then the quantities should be minimized.
3. Once that has been achieved, the next priority is to maximize recovery, reuse and recycling of suitable waste materials.
4. Taken together, these three options are often called waste prevention, although strictly speaking, only the first two are prevention whereas the third is already an end-of pipe solution.
5. Once the possibilities for waste prevention have been exhausted, the next priority is to reduce the volume of residual wastes being passed on for final disposal, extracting resources in the form of products and/or energy in the process.

Most important of the hierarchy, is waste management education, which ensure strict adherence to other options (Sridhar, 2013).

Figure 2.2; Hierarchy of waste segregation (Sridhar, 2013).

2.8Waste Segregation

Segregation or Separation at source refers to the practice of setting aside post-consumer materials and household goods so that they do not enter mixed waste streams. The purposes of waste segregation are recycling, reuse, improved waste management suchthat different processes- composting, recycling or incineration can be applied to different kinds of waste, create incentives, improve the aesthetics of the environment, promote public health etc. The concept was coined in affluent societies during the 1980s in contradistinction to the recovery of resources for recycling from mixed post-consumer waste in plants called materials recovery facilities (MRFs). It is an important step in the 'hierarchy' of solid waste management practices.

Goods and materials usually diverted from domestic waste streams by source separation include:

• Reusable items (such as clothes and accessories, utensils and appliances, containers, books and magazines)
• Materials which are usually regarded by the primary consumer as wastes (newspapers, scrap paper, cardboard and boxboard, broken, irreparable plastic items such as buckets and basins, food and drink cans and containers);
• Organic matter (such as food wastes, organic residues and garden wastes);
• Toxic and hazardous wastes that are dangerous in landfills (such as biomedical items and pressurized cans) (Lardinous and Furedy, 2012).

Occupational safety can only be maintained if the risks from the materials are defined, identifiable and the resulting counter measures are taken. By this, the risk of injury and incidents can be minimized in a cost effective way. Recycling can only be carried out if recyclable materials are separated from the hazardous waste (contaminated materials are excluded from any recycling activity and must be treated as mixed hazardous waste). To guarantee a high quality of the recycling materials it must be collected in at source. Mixed waste will decrease the possible income. The separate handling, treatment and disposal of different kinds of hazardous and non-hazardous waste in different ways will drastically reduce costs. Only the different kind of hazardous waste will be treated and disposedoff in a costly way instead of the entire waste stream in a hospital. Segregation is the key to any effective waste management! Without effective segregation system, the complete waste stream must be considered as hazardous (CETH, 2002).