Even if the public bins are provided they may be far away from houses or they are not emptied for a number of days compelling the users to throw the refuse around or near the bins which is also a nuisance. The refuse from the public bins is carried to distant places for disposal in open vehicles on the main roads which causes a lot of air pollution. The refuse must be carried in covered vehicles to places of disposal and not in open vehicles. Now a day’s trucks fitted with mechanical devices for tilting the public dust bins directly into the truck for quick and speedy removal of refuse are used in big cities. In advance countries now a day instead of conventional dust bins paper sacks or polythene sacks are used.
Household refuse is stored in the sack and the sack itself is removed with its contents by the conservancy staff for disposal/destruction at a far off place from the habitation and a new sack is kept in its place. This method of refuse collection is becoming very popular in India and is being used specially in hospitals. Disposal of refuse depends on the circumstances prevailing in the area e.g. availability of land, distance from the collection point, number of persons and vehicles available.
The refuse after collection must be disposed of in such a way that it does not create any nuisance. Following methods are used for disposal of refuse: (i) Dumping (ii) Controlled tipping (iii) Burial (iv) Compositing (v) Burning
Dumping is the simplest and easiest method of disposal of dry refuse. Low lying areas away from habitation are selected and dry refuse is dumped over there. When the area is filled it is leveled and covered with earth. image source: clearimpression.files.
wordpress.comDumping serves two purposes, first low lying areas are filled, and secondly the levelled land may be used for agricultural purposes or otherwise. But indiscriminate dumping is a nuisance to the public since during summer and rainy season it emits very offensive gases. It acts as a breeding place for flies, attracts rodents, pigs and stray catties who scatter the refuse adding further nuisance to the public. The air and ground water also gets polluted.
(ii) Controlled Tipping:
This is the best method of disposal of refuse. In this method trenches or pits of 3 feet depth but not in any case more than 6 feet in depth are dug in an open land away from the habitation. The refuse is put in the trench and covered with earth daily. When the trench is nearly full it is completely covered with earth and the trench is allowed to remain as such for a period of about 6 months. During this period certain chemical and bacteriological changes will take place and heat is produced which will convert the refuse into manure. At the end of six months when the refuse is fully decomposed, the pits are dug open and the manure is removed which is used in fields and pits are reused.
The earth which is put daily as a layer over the refuse prevents the escape of gases and spread of refuse by air. Moreover flies, insects etc. will not be attracted. When the low lying area is filled by disposal of refuse either by dumping or by controlled tipping method that must not be used for construction of buildings at least for 10 years. This land may be used for agricultural purposes.
Burial is another method of disposal of dry refuse when the requirement of refuse disposal is for short period of time as in camps. In this method a trench is-dug and refuse is dumped in it and covered with earth daily. When the trench is full it is completely covered with earth and another trench is dug for further use.
Compositing is the process of converting organic matter into manure with the help of bacterial action. This method is used in some cities and towns where refuse is disposed of along with human excreta (night soil). In this method trenches or pits of 3 feet depth are dug.
Refuse and human excreta are put in the trenches in alternate layers in the proportion of 6? and 2? thickness of refuse and night soil respectively. The uppermost layer should always be of refuse. When the trenches are full they are covered with earth.
After this they are left as such for about 6 months for compositing. As a result of chemical and bacterial action intense heat is produced inside the compost pits. The temperature rises to about 60 C.
At this temperature the pathogenic and other micro-organisms are killed and pits gradually cool down. After 4-6 months the decomposition is complete and manure is formed which is used for agricultural purposes. The pits are reused. This method of disposal of refuse and human excreta is also known as ‘Hot fermentation process’.
Mechanical Compositing: This is an advanced method of refuse disposal. In this method the water insoluble or large size substances such as rags, metal, glass, stones, bones etc. are sorted out from the refuse, and then it is ground in a machine to reduce the size of particles. This ground refuse is then mixed with sewage containing night soil, mixed well mechanically and then incubated. In this process the chemical and bacteriological decomposition takes place and entire period of compositing is complete in 4-6 weeks. The compost so formed is used as manure. Such composting plants are used in big cities.
Burning is one of the best methods of disposing of the refuse where sufficient land for pits is not available for dumping etc.
This process is also known as incineration and the equipment used for this purpose is called incinerator. Burning is more suitable for disposing of the hospital refuse which is generally more infectious than street refuse because of the presence of various types of discharges, blood and dead tissues of patients. The burning is carried out in an incinerator. If refuse contains pieces of glass, metal, sand etc.
then they may create problems in burning which will have to be sorted out. Although burning is a good method of disposal of refuse but it has certain drawbacks: (i) There is direct loss of manure. (ii) It is an expensive method.
(iii) An incinerator is required. (iv) During rainy reason this process may not be very effective due to excess content of moisture in the refuse which may not burn properly. Refuse disposal is a very important part of environmental hygiene and public health. It is the duty of the government to make arrangements for the proper disposal of refuse. The public should be educated through different Medias regarding the advantages of proper refuse disposal. The public must give full co-operation in this cause.
Even if we have the most sophisticated machinery for collection and disposal of refuse, and the public does not co-operate then the whole system will fail therefore involvement of the public is very important.