Let's be wise in solid waste management
Solid waste generation in huge amount is key feature of modern industrial and urban economic system where increasing the production is a prime goal. Waste management is the mechanism of collection, transport, processing, recycling or disposal of waste materials and is generally undertaken to reduce their effect on health, aesthetics or amenity. Waste management practices differ for developed and developing nations, for urban and rural areas, and for residential and industrial generators. Management for non-hazardous residential and institutional waste in metropolitan areas is usually the responsibility of local government authorities, while management for non-hazardous commercial and industrial waste is usually the responsibility of the generator. Collection and transportation: Waste collection methods vary widely between different countries and regions. Some areas, especially in less developed countries, do not have a formal waste-collection system. In Australia most urban domestic households have a 240-litre (63.4 U.S. gallons) bin that is emptied weekly from the curb using side- or rear-loading compactor trucks. In Europe and a few other places around the world, a few communities use a proprietary collection system known as Envac, which conveys refuse via underground conduits using a vacuum system. In Canadian urban centres curbside collection is the most common method of disposal, whereby the city collects waste and/or recyclables and/or organics on a scheduled basis. In rural areas people often dispose of their waste by hauling it to a transfer station. Waste collected is then transported to a regional landfill. Disposal methods
Waste management methods vary widely between areas for many reasons, including type of waste material, nearby land uses, and the area available. An analysis of existing methods of disposal processing waste materials is attempted here. Landfill: Disposing of waste in a landfill involves burying the waste and this remains a common practice in most countries. Historically, landfills were often established in disused quarries, mining voids or burrow pits. A properly-designed and well-managed landfill can be a hygienic and relatively inexpensive method of disposing of waste materials. Older, poorly-designed or poorly-managed landfills can create a number of adverse environmental impacts such as wind-blown litter, attraction of vermin, and generation of liquid leachate. Another common byproduct of landfills is gas (mostly methane and carbon dioxide), which is produced as organic waste breaks down anaerobically. This gas can create odor problems, kill surface vegetation, and is a greenhouse one. Design characteristics of a modern landfill include methods to contain leachate such as clay or plastic lining material. Deposited waste is normally compacted to increase its density and stability, and covered to prevent vermin (such as mice or rats). Many landfills also have landfill gas extraction systems installed. Gas is pumped out of the landfill using perforated pipes and flared off or burnt in a gas engine to generate electricity. Many local authorities, especially in rural areas, have found it difficult to establish new landfills due to opposition from owners of adjacent land. As a result, solid waste in these areas must be transported further for disposal or managed by other methods. This fact, as well as growing concern about the environmental impacts of excessive waste generation, has given rise to efforts to minimize the amount of waste sent to landfill in many areas. These efforts include taxing or levying the waste sent to landfill, recycling waste products, converting waste to energy, and designing products that use less material and thus generate less waste. Incineration: Incineration is a disposal method that involves combustion of waste material. 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 is carried out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid and gaseous waste. It is recognised as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Although it remains a controversial method of waste disposal in many places due to issues such as emission of gaseous pollutants, modern combustion technologies such as the RCBC (rotary cascading bed combustor) allows efficient energy production with emissions well within regulatory standards. Incineration is common in countries such as Japan where land is scarcer, as these facilities generally do not require as much area as landfills. Recycling: The popular meaning of 'recycling' in most developed countries refers to the widespread collection and reuse of everyday waste materials such as empty beverage containers. These are collected and sorted into common types so that the raw materials from which the items are made can be reprocessed into new products. Material for recycling may be collected separately from general waste using dedicated bins and collection vehicles, or sorted directly from mixed waste streams. The most common consumer products recycled include aluminium beverage cans, steel food and aerosol cans, HDPE and PET bottles, glass bottles and jars, paperboard cartons, newspapers, magazines, and cardboard, types of plastic (PVC, LDPE, PP, and PS etc. However, recycling of complex products (such as computers and electronic equipment) is difficult, due to the additional dismantling and separation required. Biological processing: Waste materials that are organic in nature, such as plant material, food scraps, and paper products, can be recycled using biological composting and digestion processes to decompose the organic matter. The resulting organic material is then recycled as mulch or compost for agricultural or landscaping purposes. In addition, gas from the process (such as methane) can be captured and used for generating electricity. The intention of biological processing in waste management is to control and accelerate the natural process of decomposition of organic matter. There is a large variety of composting and digestion methods and technologies varying in complexity from simple home compost heaps, to industrial-scale enclosed-vessel digestion of mixed domestic waste. Methods of biological decomposition are also differentiated as being aerobic or anaerobic. Conclusion: Waste management system includes waste collection, processing and disposal mechanism. Various mechanisms are applied for collection, segregation, processing and disposal. For environment friendly disposal various components of waste should be carefully segregated. Different parts of solid waste have their own physical, chemical and biological properties. They separately demand distinctive disposal . It will not be wise to burn the waste that can be composted to produce environment friendly biofertilizer and biogas through anaerobic decomposition in a digester. Again you should not burry the substance you can burn to extract energy and utilize the ash as raw material for certain industry.
For all latest news, follow The Daily Star's Google News channel.
Comments