With both waste management and sustainable energy being widely discussed topics currently, the leap to the idea that waste could be converted to energy is almost natural. The technology does exist, and although it is not widely available, it can still be used even in the residential scale as a cost-effective method of waste management. ‘Waste-to-Energy’ or ‘Energy-from-Waste’ is the generation of electric or heat energy through the treatment of waste or processing the waste into a fuel. The technology is not yet sufficiently developed for this technique to be a primary method of energy generation, but it is efficient when considered a method of waste management which can generate energy as a by-product. Converting to energy is also only feasible for waste matter that is comprised of or can be converted into hydrocarbons, and more specifically, hydrocarbons which, when combusted gives a net positive quantity of energy. This makes most biodegradable and plastic waste viable candidates for conversion to energy but not industrial waste, heavy metals, or other inorganic chemicals.
Waste from Energy has been a popular hobbyist endeavour at the household level for the past few years. While large scale energy production is still difficult, most biodegradable waste produced in a household i.e., kitchen waste is an ideal candidate for energy production as they are composed of hydrocarbons and undergo biological decay and release methane which is a flammable gas. The execution of the process is also relatively affordable and can result in substantial savings, especially if you use gas to cook. The waste is packed into a container with water and sealed, with an outlet for gas. When the process is underway, the system will output methane gas which can be safety used to fuel a stove. The liquid effluent may also be used as fertiliser in a hydroponics system for growing plants. Permanent enclosures for the waste can be made with concrete but there are commercially available plastic containers, or an everyday skip bin, purchased from organisations such as 6m skip bin hire Geelong, can be used with some modifications.
The most common waste-to-energy implementation is the incineration of waste that contains hydrocarbons. It should be noted that incineration as a method of generating energy works only if the energy released by the hydrocarbons is greater than the energy consumed to incinerate the waste. This usually results in an electric efficiency of around 15%-30%, with the rest of the energy being emitted as heat. This can be increased to over 80% by directly using the heat generated in the incineration process. (a process known as cogeneration)
However, incineration of waste can be harmful if done improperly as it releases other compounds in the waste directly to the atmosphere. Examples for such gases are the oxides of sulphur and nitrogen which cause acid rains, and carbon monoxide and carbon dioxide which are greenhouse gases, deteriorate the ozone layer and cause general pollution of air. It is also said to discourage recycling although this point is subject to debate, with countries that recycle the most also engaging in incineration.