Impact of Municipal Solid Waste

1.5.1. On Human Health, Animals and Aquatic life

There is a heightened risk to health and environment due to insufficient treatment and management of solid wastes. Generally, workers in this field are exposed to direct and potentially fatal health concerns (World Bank, 2012). As a result, these people need to be protected from direct contact with waste. Waste treatment in hospitals and clinics is another important source of risk. (El-Fadel et al., 1997)

With the incorporation of the MSW involving industrial uncontrolled hazardous wastes, high risks to human health may occur. The concentration of heavy metals in the food chain creates tangible

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risks to human health (El-Fadel et al., 1997). When these wastes and leachates are discharged into open dumping sites of MSW or drainage/ sewerage system, they end up creating a vicious cycle; making the recurrence of problems such as follows (Bingemer and Crutzen, 1987):

1. Chemical poisoning through inhalation 2. Cancer

3. Congenital malformations 4. Neurological disease 5. Nausea and vomiting

6. Eating fish with high levels of mercury

7. Plastic found in oceans ingested by fish and birds 8. High algae population in rivers and sea.

9. Degraded water and soil quality

1.5.2. Impact of Solid Waste on Environment

Waste decomposition is the main source of environmental pollution and the developing countries experience this problem more frequently. Despite the high level of advancements in terms of environmental standards, few current landfills within these countries meet these environmental standards. This problem is, partly, due to rapid urbanization and development (World Bank, 2012). Organic waste decomposition produces many gases collectively known as greenhouse gases (GHGs). However, the gas released by the degradable waste (mainly methane, CH4) is the primary cause of environmental concern. Normally, the proportion of methane under anaerobic condition in the landfill is 50 percent of the total gases (World Bank, 2012). However, in a high-moisture content landfill, methane proportion may increase beyond 50 percent (World Bank, 2012). The problem with GHGs is their contribution to the rapid climate change, in general, and global warming, in specific.

1.5.3. Green House Gases (GHG) Emissions

When solid waste (SW) is disposed in dumping sites and landfills, most of the organic material will be degraded, ranging in a wide span of less than one year to 100 years or more (Frøiland- Jensen and Pipatti, 2002). Most of the degradation processes will be bio-degradation involving bacterial activity. This biodegradation process will be either aerobic or anaerobic, which is

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predicated on the conditions of the site where the solid waste is disposed (Frøiland-Jensen and Pipatti, 2002).

The main degradation products of biodegradable materials are carbon dioxide (CO2), water and heat for the aerobic process and methane (CH4) and CO2 (or the GHGs) for the anaerobic process (Bogner and Matthews, 2003; USEPA, 2016). A greenhouse gas can be defined as “...a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range” (IPCC, 2017). The anaerobic route is known to be a major cause of the greenhouse effect. The main greenhouse gases in earth's atmosphere can be summarized as following (IPCC, 2009):

1. Water Vapour (H2O) 2. Carbon Dioxide (CO2) 3. Methane (CH4)

4. Nitrous Oxide (N2O) 5. Ozone (O3)

Universally, most MSW is discarded in non-regulated and ill-designed landfills, which generate landfill gas (LFG). LFG is produced when organic material decays anaerobically, consisting of 40percent to 60percent carbon dioxide (CO2), 45percent to 60percent methane (CH4) gas, and 2percent to 9percent other gases which are frequently emitted into the atmosphere (Metz et al., 2007). According to estimates from the IPCC, the methane emission from landfills accounts for 3–19percent of the anthropogenic causes globally and is known to be a huge contributor to global warming after agricultural activity and losses from fossil fuel distribution, respectively (Metz et al., 2007).

It has been postulated that, in the absence of the anthropogenically generated GHGs, the average temperature of earth's surface would be about 15 Celsius degree, as opposed to the current average of 14 Celsius degree (Karl and Trenberth, 2003). Methane, generated from MSW is 23 times more harmful than the same volume of carbon dioxide (IPCC, 2009). One of the key places for methane generation is landfills, which leak harmful GHGs to the atmosphere that then contribute to global warming. Currently, landfilling is the commonly used method to dispose off MSW in developing and industrial countries (Mor et al., 2006).

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Since the effects of methane are not confined to a local place and end up crossing boundaries, which merits serious consideration. For instance, the CH4 produced and released into the atmosphere contributes to global warming, and its emission needs to be estimated and reported (Bogner and Matthews, 2003). One of the main reasons for the significant climate change is global warming. Global warming can be defined as “…. a gradual increase in the average temperature of the earth's atmosphere and its oceans, a change that is believed to be permanently changing the Earth's climate” (Gillis, 2015).

Today, global warming is, scientifically, better understood as a result of dedicated efforts of scientists all over the world. Despite a plethora of information on this topic, global warming remains a controversial issue. According to the IPCC, researchers are more than 95percent confident that global warming is mainly initiated by increasing concentrations of GHGs and other human industrial or anthropogenic activities (IPCC, 2013).

Moreover, methane is replete with high energy value, which makes it economically viable to be recovered and utilized (Ljungberg et al., 2009). For this reason, a good amount of methane produced in landfills can be trapped and used as a renewable energy source to produce electricity. The concentration of methane in the atmosphere is growing globally 0.6-0.8percent per year (Galle et al., 2001). The USEPA has estimated that the world-wide methane release from landfills was 30-70 million tonnes in the year 2000 (Themelis et al., 2007).

1.5.4. Impact of Waste Dumping

When waste is not managed carefully, it has negative effects on human health, especially for those living in close proximity to disposal sites. Waste, when not disposed of properly, has also a range of environmental impacts on air, water, and land; for example, a decay of organic waste contributes 5 percent to greenhouse gases globally. Waste is a significant economic drain, especially on city budgets: frequently, 50percent of a city’s budget is spent on waste management. In addition, the inefficient use of scarce resources is reflected in materials discarded and abandoned as waste represents a substantial economic and environmental cost. Methane emitted from landfills accounts for 12 percent of total global methane emissions (World Bank cited in USEPA, 2012). Landfills account for nearly half of the methane emissions attributed to the municipal waste sector in 2010 (IPCC 2007). The level of methane emission from landfills varies by country, depending

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on waste composition, climatic conditions (ambient temperature, precipitation) and waste disposal practices.

The U.S. Environmental Protection Agency (USEPA) projects worldwide methane emissions from landfills to touch 800 million metric tonnes by 2020. Other than CH4, gasses emitted by landfills can pose health risks to surrounding communities that are directly exposed to the site. Moreover, certain landfills produce leachate—a potentially polluting liquid that contains dissolved substances from water percolating through the landfill. This leachate may then enter the surrounding environment, threatening underground aquifers and other water supplies, causing a major health risk to both surrounding ecosystems and the human population (Hochman et al., 2015).

In social parlance, waste has a disproportionate impact on the poor and marginalized in cities, towns, and villages. Waste pickers earning a meagre income on the fringes of the waste management industry, particularly women, are frequently among those who experience most difficulty making a viable place for themselves in local economies.

Nevertheless, waste also represents a widely untapped opportunity. Proper waste management presents an opportunity to not only avoid the detrimental impacts associated with waste, but also to recover resources, realize environmental, economic and social benefits besides embarking on the journey to a sustainable future (AlAnsari, 2012; AlSabbagh, 2012).