More than 100 million tonnes of waste is produced in the UK every year. The waste needs to be disposed of in the right way to ensure that the damage caused to the environment is as minimal as possible.
There are a number of steps that need to be taken starting from the household and other origins of waste such as restaurants and offices etc. to the last stage of waste disposal for effective waste clearance Edinburgh.
Unless waste is segregated at the source, it is difficult to manage waste efficiently. For this reason households are asked to put waste into three bins; one each for recyclable waste, kitchen and garden waste, and non-recyclable waste.
The most common disposal methods in the UK are anaerobic digestion, incineration, and landfill, along with the use of other disposal methods.
Each year approximately 57 percent of all controlled waste produced in the UK by households, commercial and industrial institutions ends up in landfill sites. Along with waste from quarrying and mining, and some amount of waste from sewage sludge which is also sent to landfill.
For industrial purposes, the valuable minerals that are found in the UK are mined extensively. Large holes are produced in the ground as a result of extraction of these minerals. These holes need to be filled in and landscaped. A convenient solution to address this need is to use these sites for the burial of waste. As ideal underlying geology can be found in many places in the UK, turning these holes into landfills is a cost-effective disposal option. In the year 1994, there were nearly 4000 landfill sites in the UK.
In many parts of the USA and Europe, a large number of landfill sites can be found. However, in some countries it is difficult to find significant amounts of suitable land which can be used for the purpose of landfilling. Therefore, the practice of landfilling is not so common in these countries. For instance, incineration is the preferred method of waste disposal in Japan as its geology is not particularly suited for the purpose of landfilling.
For very low quantities of waste, dumping it into a site and forgetting it may not be very harmful. But such a practice becomes unsustainable if large amounts of waste are being produced and needs to be disposed of. As this generation is responsible for the condition in which our planet will be passed on to subsequent generations, it is important that we use a method of waste disposal which inflicts least possible damage upon the planet.
The two main types of landfill sites which ar used for waste disposal are:
In Japan, North America and Europe, containment landfills are the predominant type of landfill sites which are used. When the waste degrades, the escaping gases or liquids need to be treated or managed. In some countries such as France and the USA, entombment, which is a special type of containment, is used wherein the waste is kept dry and the generation of leachate is minimised.
Attenuate and Disperse Landfills
This method of waste disposal relies on uncontrolled generation of leachate into the environment. The permeation is gradual and it happens through the surrounding geological strata and groundwater. This process is known as attenuation. The process is slow enough to dilute any contaminants which may be present in the leachate, eventually making them safe.
A landfill site which has been filled to its capacity must be capped, covered and landscaped so that it can blend in with the surrounding natural environment.
The second largest method of disposing of waste, which is practiced in most countries, is incineration. In the UK alone, incineration disposes of nearly 7.5 percent of industrial waste, 5 percent of household waste and 2 percent of industrial waste. A large amount of energy is released when waste is burned. This release of energy is utilised by modern incinerators to generate electricity and thereby prevents wastage of energy.
There are several types of incineration plants which can be found in the UK, which range from mass-burn, large scale, and clinical waste incinerators to municipal waste incinerators.
In the decade from the year 1990 to the year 2000, clinical waste incinerators were employed by many hospitals. However, according to the Environmental Protection Act of 1990, the emissions resulting from the burning of hazardous hospital waste posed a serious threat to the environment.
New regulations were enforced which many hospitals failed to meet and they were therefore forced to discontinue the use of incinerators. Currently, one large incinerator is shared by hospitals to dispose of their medical waste. Similar problems were experienced by large-scale municipal waste incinerators, as they too failed to meet the standards set by the EC legislation.
Most of the incinerators were forced to shut down, barring four which were allowed to continue to operate as they were fitted with gas clean-up systems. These systems cost a great deal of money which is the reason why most incinerators were not equipped with them.
Mass Burn Incinerators or other types of incinerators are the two categories into which incinerators are classified. Municipal solid waste is disposed of using mass burn incinerators in most countries around the world. Other types of incinerators are used to dispose of other types of waste such as clinical waste.
The decomposition of waste through anaerobic digestion takes place in a way which is quite similar to that of the landfill method, except that it uses an enclosed chamber for the same. The environment created in the chamber is such that there is no oxygen. This environment is suitable for bacteria which uses the oxygen which is chemically combined with the waste. Molecules are broken down by this bacteria to form methane which is a gaseous by-product along with small quantities of solid residue.
Enormous effort has been taken to reduce the amounts of waste being generated in recent years and it is evident from waste statistics that these efforts have been largely successful so far. However it is important to stress that efforts must continue to ensure that the safe disposal of waste continues to be a priority in preventing environmental problems.