8.9 Solid Waste Disposal

Waste

Waste disposal and management is a major issue facing society today. The amount of waste generated and disposed of annually continues to increase, with industries generating over 7.6 billion tons of industrial solid waste each year and it is estimated that over 40 million tons of this waste is hazardous. Nuclear and medical wastes are also increasing in quantity every year. Developed nations generate more waste per capita than developing nations, with the United States generating the most waste per capita of any country.

Landfilling has traditionally been the main method of waste disposal, but it is becoming less desirable and feasible due to declining landfill capacity, stricter environmental regulations, and public opposition. As a result, alternative waste management methods such as recycling, composting and incineration are being considered. However, it is important to note that not all waste is the same, and different materials require different methods of disposal.

In natural systems, everything flows in a natural cycle of use and reuse. However, solid waste is a human concept and refers to materials that are deemed useless or worthless. It is important to reduce the amount of waste produced and recycle valuable resources contained in the waste in order to maintain a livable and sustainable environment.

Sources of Solid Waste

There are several sources of solid waste, including:

1. Residential: This includes waste generated by households, such as food scraps, paper, plastics, and other household items.
2. Commercial: This includes waste generated by businesses, such as packaging materials, office paper, and other business-related items.
3. Industrial: This includes waste generated by factories and industrial processes, such as chemicals, machinery parts, and manufacturing by-products.
4. Construction and Demolition: This includes waste generated by the construction and demolition of buildings, such as wood, bricks, and other construction materials.
5. Agricultural: This includes waste generated by farming operations, such as crop residue, livestock manure, and other agricultural by-products.
6. Medical: This includes waste generated by hospitals and other healthcare facilities, such as medical equipment, sharps, and other hazardous materials.
7. Municipal: This includes waste generated by municipal services, such as street sweeping, park maintenance, and other public services.
8. Electronic: This includes waste generated by electronic devices, such as computers, smartphones, and other electronic equipment. All sources of solid waste have an impact on the environment and human health, and proper management and disposal of waste is crucial to minimize negative impacts.

Types of Solid Waste

Solid waste can be classified into two main categories: non-municipal and municipal solid waste.

Non-municipal solid waste is the discarded solid material from industry, agriculture, mining, and oil and gas production, and it makes up almost 99 percent of all the waste in the United States. Some common examples of non-municipal waste include construction materials, waste-water sludge, ash, scrubber sludge, and pesticide containers.

Municipal solid waste, on the other hand, is made up of discarded solid materials from residences, businesses, and city buildings. It makes up a small percentage of waste in the United States, only a little more than one percent of the total. Municipal solid waste consists of materials from plastics to food scraps, with paper being the most common waste product, accounting for about 40 percent of the total. Other common components include yard waste, plastics, metals, wood, glass, and food waste. The composition of municipal waste can vary depending on the region and the season.

Hazardous waste is a subset of solid waste that can be detrimental to human health and the environment. It is defined as materials that are toxic, carcinogenic, mutagenic, teratogenic, highly flammable, corrosive, or explosive. Hazardous waste is subject to strict regulations in the United States, but there are some materials that are excluded from these regulations such as hazardous household and small business waste, and mining waste.

Waste Disposal

Solid waste can be disposed of in several ways, including landfilling, ocean dumping, and incineration.

Landfilling is the most common method of disposal, where solid waste is either dumped in a hole or canyon area or a giant mound, and then covered with clay or plastic to prevent redistribution by animals or the wind. Sanitary landfills have layers of clay, sand, and plastic to prevent contamination of local aquifers, and a methane collection system to collect the gas produced by the decomposition of the waste. Secure landfills are designed to handle hazardous wastes and have thicker plastic and clay liners to prevent contamination.

Ocean dumping was a popular method of disposal for coastal communities, but it is now banned in the United States due to pollution problems it created.

Incineration is another method of disposal, where waste is burned at high temperatures to reduce its volume. This method significantly reduces the volume of solid waste but can release air pollutants.

In addition, there are other alternative methods such as recycling, composting, and waste-to-energy conversion. However, each method has its own advantages and disadvantages, and the most suitable method depends on the type and composition of the waste and the local regulations and infrastructure.

Mass Burn Incinerators

Mass burn incinerators are facilities that are used to burn municipal solid waste (MSW) at high temperatures. They are designed to reduce the volume of waste by up to 85 percent. This is done by burning the waste at temperatures of over 1000 degrees Celsius. The ash that remains after the burning process is much more compact than unburned solid waste.

Mass burn incinerators are considered to be one of the most efficient ways to reduce the volume of MSW. However, they also have some disadvantages. For example, they produce pollutants, such as particulate matter, dioxins, and heavy metals, which can harm human health and the environment. Additionally, they require a significant amount of energy to operate, and the ash produced must be disposed of in landfills.

In the US, about 15 percent of the municipal solid waste is incinerated, however, this method has been decreasing in popularity, primarily due to the environmental concerns and the associated costs of operating these facilities.

Effects of Improper Waste Disposal

Improper waste disposal and unauthorized releases can have serious negative effects on the environment and human health. When waste is not disposed of properly, it can lead to pollution of air, water, and soil, and can harm wildlife and ecosystems.

For example, used rubber tires can become breeding grounds for mosquitoes that can spread disease when they are not disposed of properly. Similarly, when waste is dumped into the ocean, it can lead to large floating islands of trash that can harm marine life and damage ecosystems. Wildlife can become entangled in the waste or ingest it, which can lead to injury or death.

Past practices of improper waste disposal have led to numerous contaminated sites where soils and groundwater have been contaminated, posing a risk to public safety. The EPA has identified over 1,400 sites that require immediate cleanup under the Superfund program National Priority List (NPL). Additionally, the Department of Defense maintains 19,000 sites, many of which have been extensively contaminated from a variety of uses and disposal practices.

Accidental spills of hazardous wastes and nuclear materials due to human activities or natural disasters can also cause enormous environmental damage. For example, the 1986 Chernobyl disaster in Ukraine and the 2011 Tohoku earthquake and tsunami in Fukushima, Japan, resulted in severe environmental damage and long-term health effects for the local population.

It is important to continue to enforce regulations and develop new strategies to ensure proper waste disposal and minimize negative impacts on the environment and human health.

Examples of Improper Waste Disposal Around the World

Some specific examples of where improper waste disposal has occurred include:

1. Love Canal, New York: In the 1950s, a chemical company disposed of hazardous waste in a canal in Niagara Falls, New York. The waste was not properly contained, and eventually leached into the surrounding soil and groundwater. As a result, residents in the area were exposed to a range of toxic chemicals, leading to a variety of health problems.
2. Bhopal, India: In 1984, a gas leak at a chemical plant in Bhopal, India, released a toxic cloud of methyl isocyanate gas, killing thousands of people and injuring hundreds of thousands more. The disaster was caused by a lack of safety measures at the plant, as well as poor waste management practices.
3. Gulf of Mexico oil spill: In 2010, an oil spill in the Gulf of Mexico resulted from a blowout at an offshore drilling rig. The spill released millions of barrels of oil into the ocean, causing widespread environmental damage to the Gulf's ecosystems and wildlife.
4. Hanford Nuclear Reservation, Washington: In the 1940s and 1950s, the US government produced plutonium at the Hanford Nuclear Reservation in Washington state. The nuclear waste was not properly stored and it contaminated the land and water and still poses a risk for the nearby communities and the environment
5. Landfills in developing countries: many developing countries lack proper waste management infrastructure, leading to the proliferation of unregulated, overcrowded landfills. These landfills often do not have proper liners or leachate collection systems, leading to contamination of soil and groundwater.