Waste disposal is either placing waste in water or onto land. Waste is taken to facilities where the waste is permanently contained and can prevent the release of pollutants into the environment. When disposing of solid waste, often is placed on land in a landfill. Liquid waste is disposed of in injection wells that bury the refuse deep underground. These wells are closely monitored to prevent the leakage of harmful pollutants into the drinking water.
America alone generates nearly 208 million tons of solid waste per year and it is only expected to increase. Each person actually generates about 4.3 pounds of waste per day. Even though we have developed many different ways to dispose of refuse, there is still no absolutely safe way to remove and store trash.
History of Waste Disposal
The disposal of waste wasn’t always so carefully monitored. In the 18th century in England and France, people with carts were paid to carry the trash out of town and dispose of it. Benjamin Franklin spurred the first municipal cleaning system in Philadelphia in 1757, making the dumping of trash in open pits a routine action. However, since then our trash has become more complicated and can’t simply be placed in a hole in the ground. We have many different types of trash and they must be disposed of properly to prevent contaminating the environment.
Types of Waste
There are many different types of waste and it is classified according to their physical, chemical, and biological characteristics. One of the major ways it is classified is by consistency; whether it is solid or liquid waste. To classify as a solid waste the material must contain less than 70% water. This classification often encompasses materials such as; household garbage, industrial waste, mining waste, and some oilfield wastes. Liquid wastes must be less than 1% solid and are often from wastewater. Wastewater often contains high levels of dissolved salts and metals. Sludge is the final consistency classification; being somewhere between a liquid and a solid. Sludge often contains between 3 and 25% solids and the rest of it is made up of water-dissolved materials.
The Federal government classifies waste into 3 categories; non-hazardous, hazardous, and Special wastes. Non-hazardous waste does not pose any immediate threat to health or the environment. This category includes household refuse. Hazardous wastes can either be ignitable/reactive or leachable. This means that hazardous waste is either flammable or has the potential to leach toxic chemicals. Special wastes have very specific guidelines to regulate them. Examples of Special Waste would be radioactive waste and medical waste.
How do we dispose of it?
There are a variety of ways that we dispose of trash and waste. Landfill use is the most common and can account for more than 90% of the country’s municipal waste. However, landfills have been proven to contaminate drinking water in some regions. Landfills are the most cost-effective way of disposing of; collection and transport represent 75% of the total cost involved. In modern landfills, the garbage is spread thin in compacted layers and then covered by fresh earth. Landfills minimize pollution by lining the hole, contouring the fill, compacting and planting the top cover layer, diverting drainage, and choosing sites that are not often affected by flooding or high groundwater levels. Clay is the best type of soil for a landfill because it is less permeable than other types of soil. Some materials that are disposed of in landfills can be solidified into solid materials like cement, fly ash, asphalt, or organic polymers.
Garbage is also disposed of using incinerators. This method is more costly but safer than a landfill. Modern incinerators can destroy nearly 99.9% of organic waste material. Many thermal processes recover energy from the solid waste that is incinerated. Pyrolysis, the process of chemical breakdown can produce a plethora of gasses and inert ash. Incinerators that burn garbage have been known to contaminate the air, soil, and water. Many communities near incinerators object to them for fear of possible harmful emissions.
Hazardous waste is also pumped into deep wells inside the earth. This is called waste injection. Many people are strongly opposed to this because it has caused explosions and even earthquakes in the past.
Organic materials that contain little or no heavy metals can be detoxified biologically. This is often done by composting and land farming; where waste materials are spread over a large area of land so that microbes can easily work to decompose them. However, hazardous wastes must be detoxified before they leach into the groundwater causing water contamination.
Recycling solid waste is not a new idea. In prehistoric times, metal tools were often melted down and recast. These days, recyclable materials are removed from municipal waste by shredding, magnetic separation of metals, screening, and washing. Composting involves the preparation of waste and breaking down the organic matter using aerobic microorganisms. This has led many municipalities and garbage collection agencies to require their customers to separate recyclable items from other types of household waste.
Another type of waste is livestock waste. It is created by large livestock companies. These generate more than 30 times the waste that humans do. Yearly, livestock waste accounts for 1.375 billion tons of refuse. The Environmental Products and Technologies Corporation has developed a system to reduce the amount of livestock waste. With their Closed Loop Waste Management System they can turn animal waste into commercial quantities of pathogen-free, nutrient-dense, soil-building materials.
The Future of Waste
Currently, the best way to reduce the amount of waste that must be disposed of is to prevent its creation. Consumers must protest against the production of needless waste and push the movement for using and producing recycled products. These strategies to reduce waste may cost us more upfront but we will pay a lesser price in the end. Reducing waste can add extra years in which we can live on this planet healthfully.