METHODS OF WASTE MANAGEMENT

METHODS

Historically, people disposed of their household garbage by burying or burning, but these methods became impractical, resulting in developments of other methods such as:-

(i) Landfill

It is a common practice in most countries and historically known as one of the oldest form of waste management. Landfills are not only used to bury disposed waster but also act as a temporary storage, consolidation and transfer, or processing of waste material. For non hazardous waste landfills, three techniques are applied by which waste are:-

Ø Confined to as small an area as possible

Ø Compressed to reduce their volume

Ø Covered with layers of soil (daily)

A by product of this method is gas, mostly composed of methane and carbon dioxide; which resulted from the breakdown of organic waste anaerobically. This gas can create odour problems, kill vegetation, and is a greenhouse gas.

ii) Incineration

This is a disposal method in which solid waste are converted into residue and gaseous products. Incineration and other high temperature waste treatment systems are sometimes described as thermal treatment. Incinerators convert waste materials into heat, gas, steam and ash. Incineration however remains a controversial method of waste disposal, due to issues such as emission of gaseous pollutants. According to Wikipedia; incineration emits flue gas to the atmosphere which may contain significant amounts of particulate matter, heavy metals, dioxins, furans, sulphur dioxide and hydrochloric acid.

In a study carried out in 1994, Delaware Solid Waste Authority discovered, for the same amount of produced energy, incineration plants emitted fewer particles, hydrocarbons and less SO₂, HCl, CO and NO_x than coal-fired power plants, but more than natural gas-fired power plants. According to Germany's Ministry of the Environment, waste incinerators reduce the amount of some of the atmospheric pollutants by substituting power produced by coal-fired plants with power from waste-fired plants.

(iii)

Recycling (History)

The earliest record of recycling activities could be traced as far back as during the time of Plato in 400BC. During periods where natural resources were scarce, archaeological studies of ancient waste dumps shows less household waste, implying that more waste was being recycle in the absence of new raw materials. Recycling of household waste appears to have become more commonly practised since early 1990’s. Household wastes such as glass, paper, plastic, metal, textiles and even electronics are recyclable. However, reuse of biodegradable waste such as food or garden waste does not count as recycling.