Technology in Waste Disposal

Humans produce untold millions of tons of solid waste around the world each year, which leads to a very pressing problem: What to do with so much trash? Until recently, few methods for properly disposing waste existed, with only a few addressing the pollution they can generate. Luckily, advances in technology have opened the doors for more environmentally friendly, alternative waste treatment techniques that at the same time can serve as energy sources.

Traditional Methods

• By far, the most common way to dispose of solid waste is to dump it into a hole in the ground and cover it. The landfill method actually involves a more complex process in which compartments are sealed to prevent the escape of polluting liquid or gases, according to Waste Online, an UK-based information website. Newer systems capture and remove gases and liquids produced by the rotting waste. Another treatment method burns waste with the use of incinerators. Despite the negative stigma concerning health effects, the technology in this field has advanced in over the past 50 years, and many times, the energy released from the process is used to generate electricity. Other long-used methods include recycling and composting.

Anaerobic Digestion

• Turning to newer, alternative methods of waste disposal, we start with the anaerobic digestion process, also known as methane recovery. When placed in a landfill, most biodegradable waste breaks down into methane, a potent greenhouse gas, according to the Waste Treatment Technology Network. However, methane can also be used as fuel to produce electricity. Anaerobic means "absence of oxygen," and in this instance it refers to anaerobic bacteria that digest this organic material in the absence of oxygen. Through this process, the waste breaks down into a biogas made up of about 60% methane and 40% carbon dioxide, as well as other byproducts. The biogas can then be burned to generate electricity.

Plasma Arc Waste Disposal

• This method uses a plasma torch that works by shooting an electric current across inert gas. This ionizes the gas, meaning it changes the number of charged particles in the gas, which makes it extremely hot. Temperatures even surpass those on the Sun's surface, according to a Slate article. At such temperatures, waste gets subjected to more than just incineration; instead, it gets broken down instantly into two main components: syngas, made up mostly of hydrogen and carbon monoxide, and a slag-like substance. Both substances are cleaned up to remove harmful contaminants and then put to use. Syngas can burn and produce electricity, while the slag can be used to pave roads.

Gasification

• Gasification plants use carbon primarily, or any carbon-based feedstock or waste, according to the Department of Energy. During the gasification process, the waste is exposed to steam and controlled amounts of oxygen under high temperatures and pressures. This breaks the waste into its basic chemical constituents and produces a gas containing hydrogen, oxygen and methane that can then be used to generate electricity. Gasification is touted as a viable alternative to incineration in waste treatment.

Other alternatives

• Pyrolysis constitutes just another method of energy from waste, with the difference that the process has a total lack of oxygen. Other methods focus on the recycling aspect, specifically on the sorting and separation of different kinds of waste. Magnets can extract metals while paper can be taken off by weight and other screening methods. However, the separation of different kinds of plastic poses a challenge. Mechanical biological treatment plants aim to make this process more efficient by a variety of methods that separate dry solid waste from wet and organic waste. The plants then employ one of the previously mentioned methods to turn bio-waste, while sending off the sorted solid waste off to recycling or landfills.