Solid Waste Management in Nigeria Problem and Prospect for 2023 and beyond
Most human activities generates waste (Brunner and Rechberger, 2014). Despite that, the production of wastes remains a major source of concern as it has always been since pre historic period (Chandler et al, 1997). In recent times, the rate and quantity of waste generation have been on the increase. As the volume of wastes increases, so also does the variety of the waste increases (Vergara and Tchobanoglous, 2012).
Unlike the pre historic period where wastes were merely a source of nuisance that needed to be disposed of Proper management was not a major issue as the population was small and a vast amount of land was available to the population at that time. In those days, the environment easily absorbed the volume of waste produced without any form of degradation (Tchobanoglous et al, 1993).
A substantial increase in volume of wastes generation began in the sixteenth century when people began to move from rural areas to cities as a result of industrial revolution (Wilson, 2007). This migration of people to cities led to population explosion that in turn led to a surge in the volume and variety in composition of wastes generated in cities. It was then that materials such as metals and glass began to appear in large quantities in municipal waste stream (Williams, 2005).
The large population of people in cities and communities gave rise to indiscriminate littering and open dumps. These dumps in turn formed breeding grounds for rats and other vermin, posing significant risks to public health. The unhealthy waste management practices resulted in several outbreaks of epidemics with high death tolls (Tchobanoglous et al, 1993). Consequently, in the nineteenth century public officials began to dispose waste in a controlled manner in other to safe guard public health (Tchobanoglous et al, 1993).
Most developed countries passed through a period when they were developing environmentally. Today, however, most of these countries have effectively addressed much of the health and environmental pollution issues associated with wastes generation. In contrast, the increasing rate of urbanisation and developments in emerging countries is now leading to a repeat of the same historical problems that developed countries have had to address in the past (Wilson, 2007).
An important question in modern day wastes management is what exactly is a waste? Waste is the useless by product of human activities which physically contains the same substance that are available in the useful product (White et al, 1995). Wastes have also been defined as any product or material which is useless to the producer (Basu, 2009). Dijkema et al, (2000) pointed out that, wastes are materials that people would want to dispose of even when payments are required for their disposal. Although, waste is an essential product of human activities,it is also the result of inefficient production processes whose continuous generation is a loss of vital resources
THE CONCEPT OF SOLID WASTE MANAGEMENT
Solid-waste management, the collecting, treating, and disposing of solid material that is discarded because it has served its purpose or is no longer useful. Improper disposal of municipal solid waste can create unsanitary conditions, and these conditions in turn can lead to pollution of the environment and to outbreaks of vector-borne disease that is, diseases spread by rodents and insects. The tasks of solid-waste management present complex technical challenges. They also pose a wide variety of administrative, economic, and social problems that must be managed and solved.
MERITS AND DEMERITS EACH OF THE FOLLOWING METHODS OF SOLID WASTE MANAGEMENT
MERITS AND DEMERITS OF HOG FEED
Merits Of Hog Feed
- Most economical method where land is available.
- Minimum public health problem because flies, rats and other pests are unable to breed in the covered waste.
- Minimum fire hazards.
- Can receive all types of waste, eliminating the necessity of separation of waste into degradable and non-biodegradable.
- Hog feed sites can be used for the development of parks, playground, golf courses etc.
Demerits Of Hog Feed
- Unavailability of suitable land especially near the crowded area.
- Proper operation and skilled manpower are needed for daily operation.
- Danger of surface and ground water pollution if site aren’t properly selected and designed.
- Sealing materials used do not remain effective permanently
- Leakage of gases may cause odor problems.
- Sanitary Landfill: This is the most popular solid waste disposal method used today. Garbage is basically spread out in thin layers, compressed and covered with soil or plastic foam.
Modern landfills are designed in such a way that the bottom of the landfill is covered with an impervious liner, which is usually made of several layers of thick plastic and sand. This liner protects the groundwater from being contaminated because of leaching or percolation. When the landfill is full, it is covered with layers of sand, clay, topsoil and gravel to prevent seepage of water.
ADVANTAGES OF SANITARY LANDFILL
- There are many advantages of sanitary landfills. The main advantage is that burying can produce energy and can be obtained by the conversion of landfill gas.
- The waste products of sanitary landfills can be used as direct fuel for combustion or indirectly they can be processed into another fuel.
- Sanitary landfill is a specific location for waste deposition that can be monitored.
- On completion of the sanitary landfill it can be reclaimed and it can be used as parks or farming land.
- In properly designed sanitary landfills the waste can be processed and all recyclable materials can be used before closing.
- Organic material can also be separated from a properly designed sanitary landfill which can be used for compost or production of natural gas.
- The sanitary landfills that are properly managed can capture the natural gas or methane that is produced by the underground decomposing material.
DISADVANTAGES OF SANITARY LANDFILL
- Landfills that are poorly designed or operated share more problems that are faced at the uncontrolled dumping areas.
- The areas surrounding the landfills become heavily polluted.
- Landfill can pollute air, water and also the soil.
- In a poorly developed landfill it is difficult to keep the dangerous chemicals from leaching out into the surrounding area.
- Dangerous chemicals can seep into the ground water system.
- Many insects and rodents are attracted to landfills and can result in dangerous diseases.
- It can cause diseases and illness in the communities living around the landfill.
ADVANTAGES OF RECYCLING
- Reduced Energy Consumption: This first benefit is what catapults recycling into the discussion of green energy. As humans, our demand for energy is ever-increasing. This continues to be the case as more countries are being modernized and introduced to the wonderful world of technology. Recycling plays its part in the green energy debate by reducing the amount of energy required to manufacture certain products. This reduces greenhouse gas emissions generated by the manufacturing process and lowers global energy consumption.
- Decreased Pollution: Coke bottles, soda cans, and those plastic ring holders. What do all of them have in common? They’re categorized as industrial waste, which is the primary source of pollution to our planet in today’s world. By recycling, you drastically reduce the amount of industrial waste. Instead of those soda cans going into a landfill to clutter the Earth, they’re taken back to the manufacturer to be broken down and reused.
- Considered Very Environmentally Friendly: The Amazon rain forest continues to be bulldozed over in record amounts. Why? To make more of our precious paper products. Recycling is an act that can heavily impact the deforestation problem on Earth. Recycled paper products mean less trees that need to be cut down and processed. This alone is one of the major reasons pro-recyclers feel so empowered chucking their used materials into that blue bin. Every time you do it, you’re potentially saving a tree from being cut down.
- Slows the Rate of Resource Depletion: Sooner or later, the Earth is going to run out of raw materials. It might not be for a long while, but the concern is still there. By recycling, you limit the need to mine and use those raw materials to make new products. Instead, your recycled material is used.
- Fights Global Warming: Global warming continues to be a heated debate topic across the planet. We’ve already mentioned earlier one way that recycling reduces greenhouse gas emissions. The other way is by reducing the amount of waste that’s burned when it’s time to clear some space. Burning piles of waste leads to toxic emissions, which accelerates the rate at which our planet is warming up. By recycling, less material becomes waste that needs to be burned, and it’s instead used in ways that are much more beneficial to the environment.
Disadvantage of Recycling
- High upfront capital costs: Recycling is not always cost-effective. Building up a new waste recycling unit takes up a lot of capital. The accompanying costs include buying different kinds of utility vehicles, upgrading the recycling unit, waste, chemical disposal and schooling the locals by initiating useful programs and seminars.
- Recycling sites are always unhygienic, unsafe and unsightly: Go to any waste recycling site, and you will almost always stumble upon unhygienic, unhealthy and unsightly conditions.
- A location, where every manner of waste is piled, provides a nice ground for the formation of debris and the spread of infectious diseases. The harmful chemicals from these wastes can also be dangerous. On top of causing massive pollution, the whole recycling process poses health risks for dedicated individuals responsible for recycling these waste products. Also, if such waste products come into contact with water, it results in the formation of leach ate that ends up polluting water bodies, not to mention drinking water.
- Products from recycled waste may not be durable: The quality of products manufactured from recycled waste may not be at par regarding quality. These kinds of products are almost always made of trashed waste material collected from mountains of other waste materials that have been overly utilized and fragile. This makes products of recycled waste less durable and low-priced. Also, there is no assurance that high-quality products will be obtained from waste recycling if input raw material is of an inferior nature. Some items earmarked for recycling are ultimately subjected to combustion or landfill dumping due to substandard quality.
- Recycling might not be inexpensive: Sometimes, recycling waste may not be less costly as most people think. At times, a need arises to establish another waste recycling unit for processing. This will only drive up the costs related to setting up the new unit or upgrading the processing facility, collection of waste materials, acquiring different utility vehicles, educating residents by organizing seminars and other programs etc.
- More energy consumption and pollution: Recycling tons of garbage will require waste to be transported, sorted, cleaned and processed in separate factories, all of which need energy and may result in by-products that can pollute soil, air or water. Even vehicles that are employed to pick up recyclable products will also increase air pollution by releasing toxins that are all airborne.
- Result in pollutants: When waste materials break down, pollutants, such as chemical stews, harm the environment. Toxins and impurities from the original material, such as lead paint or spray cans, could pass through the recycling into the recycled product. It could take years to realize that the items we have been using are contaminated. For example, recycled steel used in buildings in Taiwan has caused gamma radiation poisoning for the past 12 years.
- Advantages Of Deep Sea Dumping
- It helps in reducing the potentially hazardous effects on the local biota even if some secondary plumes develop along during the downward flow
- It helps to reduces water pollution
- It saves as habitat to some organism in the water
- It helps to control the ocean wave and reduced water speed
- It improve environmental performance, perhaps only chemically treated tailings (e.g., desulfurized) should be disposed into the ocean
Disadvantages Of Deep Sea Dumping
- Burial and smothering of benthic fauna
- Remobilization of tailings and release of contaminants
- Water column impacts of secondary tailings plumes which peel off from the main density current
- Impacts on the deep oceans are largely unknown
- No possibility of tailings re-uses
- Restricted to mines located close to coasts
- Cost of pre-mining environmental investigations and their duration
- Potential contamination of marine food webs which may affect coastal communities.
ADVANTAGES OF OPEN BURNING
- Decreases Quantity of Waste: Incinerators can decrease the quantity of waste by 95% and reduce the solid quantity of the original waste by 80-85% depending on the components that were in solid waste. Therefore incineration reduces the dependency on landfills. Hence, even though incinerators do not completely get rid of dumping ground, they definitely decrease the quantity of land needed. For nations that are small in size and with a shortage of land like Japan, this is noteworthy since landfills take up large amounts of land required for other productive uses.
- Efficient Waste Management: Incineration plays a vital role in making waste management easier and more efficient. Incineration can burn up to 90% of the total waste generated and sometimes even more. However, landfills only allow organic decomposition without making much difference, and non-organic waste keeps accumulating.
- Production of Heat and Power: Incineration plants generate energy from waste that can be used to generate electricity or heat. During the 1950s, energy costs increased considerably. So a lot of countries incorporated the heat and energy produced from waste incinerators for the generation of power by using steam turbines. It can be used to power the needs of people living nearby. On average, a single facility can burn up to 300 million tons of garbage every year, converting it into power and, at the same time, reducing the load on coal-fired power plants, which of course, are a disaster for the environment.
- Reduction of Pollution: Research has shown that solid waste incinerators are less likely to pollute the environment than landfills. One particular study done during a 1994 lawsuit in the US showed that a waste incinerator location was more environment-friendly compared to a landfill. The research discovered that the landfill was releasing higher quantities of greenhouse gases, nitrogen oxides, dioxin, hydrocarbons, and non-methane organic compounds.
- Incinerators Have Filters For Trapping Pollutants: The main problem concerning the incineration of solid waste was the release of hazardous compounds, particularly dioxin. Nonetheless, up to date incinerator plants use filters to trap hazardous gases and particulate dioxin. The current incineration plants operate within the required pollution limits recommended by the Environmental Protection Agency and international protocols.
- Saves on Transportation of Waste: Incineration plants can be near cities or towns. This is advantageous since it means waste does not have to be driven for long distances for dumping. It significantly reduces the cost of transport; the money can then be spent on the wellbeing of the community and sustaining the growth of a city or district. Additionally, it reduces the harmful gases released by vehicles during transportation, thus drastically reducing the overall carbon footprint.
Disadvantages of Waste open burning
- Pollutes the Environment: Incinerators produce smoke during the burning process. The smoke produced includes acid gases, carcinogen dioxin, particulates, heavy metals, and nitrogen oxide. These gases are poisonous to the environment. Research has shown that dioxin produced in the plant is a cancer forming chemical.
- Damaging Public Health: According to (CAP, 2013) research, the communities where incinerators plants are built, its long term effects come in the form of health hazards such as cancer, birth defects, reproductive dysfunction, neurological problems and other health effects that are known to occur at very low exposures to many of the metals, and pollutants released by incineration facilities.The respiratory problems, increased cancer rates, reproductive abnormalities and other health effects are common in areas where incinerator plants are built.
- The Possibility of Long-term Problems: Incineration does not encourage recycling and waste reduction. This is not a calculated strategy for any society. The point of focus should be on reducing waste and recycling most of it. Merely burning most of the waste without recycling some of it will only cause environmental damage because it may encourage more waste production.
- Ash Waste Can Potentially Harm People and the Environment; Even though the ash that remains from the process can be comparatively small in quantity, it contains several poisons and heavy metals which require further treatment. If not disposed of correctly, it can cause serious harm to the public and the environment.
MERIT and Demerit of Plasma arc Gasification
The main advantages of plasma torch technologies for waste treatment are:
- Preventing hazardous waste from reaching landfills[
- Some processes are designed to recover fly ash, bottom ash, and most other particulates, for 95% or better diversion from landfills, and no harmful emissions of toxic waste
- Potential production of vitrified slag which could be used as construction material[
- Processing of biomass waste into combustible syngas for electric power and thermal energy
- Production of value-added products (metals) from slag[
- Safe means to destroy both medical and many other hazardous wastes.
- Gasification with starved combustion and rapid quenching of syngas from elevated temperatures can avoid the production of dioxins and furans that are common to incinerators
- Air emissions can be cleaner than landfills and similar to that of incinerators.
Main disadvantages of plasma torch technologies for waste treatment are:
- Large initial investment costs relative to that of alternatives, including landfill and incineration.
- Operational costs are high relative to that of incineration.
- Little or even negative net energy production.
- Wet feed stock results in less syngas production and higher energy consumption.
- Frequent maintenance and limited plant availability.
ADVANTAGES OF BIOLOGICAL DECOMPOSITION
- It is a net energy-producing process which produces renewable energy in the form of biogas.
- It sanitizes the feedstock/ waste which is put through it, as long as the temperature is held above a required temperature for a pre-defined time period (pasteurized).
- It reduces odour below unprocessed waste odour levels. an example of this is the comparison between manure spreading and the same material spread after anaerobic digestion when it is known as “digestate”.
- It is much less likely to cause environmental pollution than spreading untreated organic waste on land.
- Provides for efficient resource recovery, and conservation of non‑renewable energy sources.
- Lower sludge mass generation when used as a primary water treatment method compared to an aerobic system applied to the same contaminant concentration and flow.
- The effect of the fertilizer is’ longer lasting than for untreated organic waste.
Disadvantages of Biological Decomposition
- When carried out at a commercial scale on farms and at wastewater treatment works (WwTWs) it requires a high level of investment in large tanks and other process vessels.
- If run inefficiently AD can cause an odour nuisance.
- Does not convert as large a proportion of the carbon in the biomass to biogas as can be achieved using gasification.
- It takes longer to start‑up the process due to the slow growth rate of the methane-producing organisms as compared to aerobic systems.
- In some applications have higher buffer chemical dosing requirements for pH control to keep the pH for AD within the range of 6.5–8.
- Nutrients removal is not as efficient as in aerobic treatment if is used as a water treatment process. Invariably a post treatment process will be necessary before any discharge to a watercourse. For such discharges, a secondary process stage will be needed such as membrane filtration, or even further aerobic treatment, in order to meet the river, ditch, or stream discharge consent requirements and protect the aqueous environment.
Most of the developing countries are not able to provide proper facilities for collection and disposal of communal solid waste to whole population. In Rawalpindi city, solid waste is being dumped openly along roadsides. Like other cities of Pakistan, in Rawalpindi, diverse solid waste management systems are in practice. Open dumps are responsible for the blockage of drains, breeding of flies and spread of epidemic diseases.
Due to lack of proper equipment and funding, the present solid waste management system is insufficient for Rawalpindi city. Remote areas of the city are mostly ignored and the collection efficiency is very low. Hospital and other hazardous waste materials are being treated as ordinary waste. Considering the overall negative impacts associated with open dumping and open burning, these practices must be strongly discharged.
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