Solid waste management Waste A waste is unwanted or useless material. AS seen earlier, there are three forms of wastes, ie; • solid waste • liquid waste • gaseous waste Solid waste is the unwanted or useless solid materials generated from combined residential, industrial and commercial activities in a given area. Solid waste management(SWM) Solid waste management: is the collecting, treating, and disposing of solid material that is discarded because it has served its purpose. Objectives of SWM Minimize waste generation. Maximize the collection efficiency of waste. Reduce the volume of waste requiring disposal and maximize the economic value of waste. Develop and adopt environmentally sound treatment and disposal methods . KEY COMPONENTS OF SWM Generation Storage Collection Transportation Disposal Key components of SWM • GENERATION Generation is the stage at which materials become valueless to the owner and since they have no use for them the wish to get rid of them • STORAGE Is the system for keeping materials after they have been discarded and prior to collection and final disposal. Storage facilities include; • Small containers e.g. plastic bins. • Large containers e.g communal bins . • Shallow pits • Communal depots ,walled or fenced areas Continuation COLLECTION Is how wastes are collected for transportation to final disposal sites. TRANSPORTATION This is when solid waste is transported to final disposal site . Transportation methods include; • Human powered e.g. wheelbarrow used in small sites like markets . • Motorized ,used when distance to final disposal site is great or when volume of waste transported is high. DISPOSAL Removing and destroying or storing damaged, used or other unwanted industri al products and substances. Disposal includes burning, burial at landfill sites or at sea, and recycling. They are categorized into two; • Offsite disposal • Onsite disposal ONSITE DISPOSAL • This is carried out within a small environment with relatively small volumes of waste OFFSITE DISPOSAL This is carried out when there are large volumes of waste generated. Offsite disposal options include ; • Recycling and reuse; here useful materials such as glass, paper, plastics, wood and metal are recovered from the waste stream so they may be incorporated in the fabrication of new products. • Landfilling; here waste is placed in large excavation in the ground which is backfilled with excavated soil each day waste is tipped . • Incineration; this method includes burning of combustible waste offsite and wastes are ignited within pits and covered with soil once incinerated . its the best option when there is limited space for burial or landfill. • Composting ; is a way of harnessing the natural process of decomposition of organic waste to speed up there decay . HIERARCHY OF WASTE MINIMIZATION HIERACHY EXPLANATION Waste prevention This means avoiding the potential for waste generation in the first place . Waste prevention is considered the most important action in the waste hierarchy; however it often receives minimal priority in terms of resource allocation and effort. Waste avoidance is critical to decoupling waste generation from economic growth. Within waste prevention there exists a raft of mechanisms that can deliver climate benefit, such as cleaner production, extended producer responsibility, sustainable consumption and production, etc. Various mechanisms have been developed and applied to prevent waste arising, with most relying on concerted efforts to educate waste generators. The table below provides examples of several waste prevention programmes. Table 1: Waste prevention initiatives Waste minimization (reduce) is the process and the policy of reducing the amount of waste produced by a person or a society.it has advantages like ; • Reduced volume of waste for disposal • Reduced costs of collection and disposal • Reduced environmental and health impacts • Reduced costs through more efficient use of resources Reuse To reuse is to use an item more than once. This includes conventional reuse where the item is used again for the same function, and new-life reuse where it is used for a different function. Recycling involving the utilization of discarded material to produce another product of the same grade or lower. Effects of solid wastes to the environment • • • • Waste breaks down in landfills to form methane, a potent greenhouse gas. Change in climate and destruction of ozone layer due to waste biodegradable. Littering; due to waste pollutions, illegal dumping . Leaching; is a process by which solid waste enter soil and ground water and contaminating them. Impacts of waste on health • • • • • Chemical poisoning through chemical inhalation. Uncollected waste can obstruct the storm water runoff resulting in flood, Low birth weight, Cancer, Congenital malformations and Neurological disease. Nausea and vomiting Increase in hospitalization of diabetic residents living near hazard waste sites. Mercury toxicity from eating fish with high levels of mercury Effects of waste on animals and aquatics life • Increase in mercury level in fish due to disposal of mercury in the rivers. • Plastic found in oceans ingested by birds. • Resulted in high algal population in rivers and sea. • Degrades water and soil quality . Table 2: Waste management options Climate • Climate is the weather conditions prevailing in an area in general or over a long period. • Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions. Causes of climate change • Human causes: burning of fossil fuels and the conversion of land for forestry and agriculture(deforestation), Industrial Revolution. • Natural causes: Water vapor increases as the Earth's atmosphere warms, but so does the possibility of clouds and precipitation. Carbon dioxide (CO2), respiration and volcano eruptions and through • Greenhouse gases fall under natural and human causes examples CO2,methane, nitrous oxide and Chlorofluorocarbons (CFCs) Effects of climatic change • Climate change is amplified in the polar regions. The earth’s north and south extremities are crucial for regulating our planet’s climate and are particularly vulnerable to the impacts of global warming, which has global consequences. • Oceans are vital ‘carbon sinks’, meaning that they absorb huge amounts of carbon dioxide, preventing it from reaching the upper atmosphere. Increased water temperatures and higher carbon dioxide concentrations than normal, which make oceans more acidic, are already having an impact on oceans. Effects of climatic change • In tropical forests such as the Amazon, where there’s abundant biodiversity, even modest levels of climate change can cause high levels of extinction. • Climate change is having serious impacts on the world’s water systems through more flooding and droughts. Warmer air can hold a higher water content, which makes rainfall patterns more extreme. • Many of the world’s threatened species live in areas that are severely affected by climate change. And climate change is happening too quickly for many species to adapt. Relationship between climatic change and waste management There are two kind of relationships between climatic change and solid waste management which are; • How climatic change affects solid waste management • How waste management affects climatic change The table below shows how climatic changes affect the different options of solid waste management Effects of climate change on the waste sector 1. Increased sea level Several countries and territories are low lying with very small land size and many of the dumpsites are located in swampy areas or in coastal areas. Rising sea levels due to the warming climate will lead to increased flooding and erosion of coastal dumpsites causing increased pollution of coastal waters. 2. Changing weather patterns Rainfall patterns are changing and there is increased likelihood of extreme events such as cyclones. Such events have the potential to cause damage to infrastructure and property, giving rise to disaster waste which must be managed. More severe weather events may increase the risk of marine pollution. 3. Changing technology Measures for mitigating climate change effects include a shift towards renewable sources of energy generation such as solar and hydro. In the longer term, this shift will eventually result in obsolete petrol-based, energy generation technology that will require disposal. Moreover, renewable energy technologies will eventually give rise to new waste streams such as from damaged parts. Waste management effects on climatic change Organic wastes: • Waste generated everyday in the contains readily biodegradable organic matter such as kitchen waste, garden waste and paper, which on average accounts for about 58% of the total weight of waste generated. • When organic waste decomposes, carbon dioxide and methane gas is created. Methane is created when there is no air present while carbon dioxide is the natural product when anything rots in air. • Both carbon dioxide and methane are greenhouse gases, which contribute to global warming and climate change. Inorganic wastes • Inorganic waste does not contribute directly to greenhouse gas emissions, unless it is incinerated. However it does represent greenhouse gases emitted previously during the manufacturing process. • All manufactured goods use natural resources such as water, fuel, metal, timber in their production and this results in the emission of greenhouse gases, particularly carbon dioxide and other pollutants. • Thus, rubbish sent to a dumpsite or landfill represents a significant amount of greenhouse gases already emitted to the atmosphere and have contributed to climate change.
