Waste management covers all types of waste, whether solid, liquid or gaseous, each with its specific sector. Ways of managing waste differ depending on whether one is in a developed or developing, in a city or in a rural area, which is dealing with an individual, industrial or commercial. Management of non- hazardous waste for individuals or institutions in urban areas is usually the responsibility of local authorities, while waste management in commerce and industry under their own responsibility.
Principles of waste management
Several principles guide the management of waste whose use varies in different countries or regions.
The principle of responsibility (which may include the polluter pays). For example, for radioactive waste, the Russian nuclear industry got its regulators the "pay and forget" principle allowing an operator (eg, via its subsidiary Rosenergoatom Rosatom, to "liberate the responsibility of management waste through a cash payment, in France, owners of waste retain ownership and therefore responsibility, even when they have been stored"
The hierarchy of strategies (three R's):
The hierarchy of strategies has repeatedly appearance changed over the last ten years, but the underlying concept has remained the cornerstone of most waste management strategies: maximum use of materials and generate minimal waste. Some experts who waste management have recently added a "fourth R": "Re- thinking", which implies that the current system has weaknesses and a perfectly efficient system would require a totally different look or worn on waste. Some "rethought" solutions are sometimes unintuitive. We can take for example a case in the textile industry to reduce the amount of paper used for the bosses, he was advised to cut from larger sheets, so you can use falls for cutting small pieces boss. Thus, there is a reduction in the overall residue. This type of solution is of course not limited to the textile industry.
The source reduction requires efforts to reduce toxic waste and other by modifying industrial production. Methods of source reduction involve changes in manufacturing processes, inputs of raw materials and product composition. Sometimes the principle of "prevention of pollution" actually indicates the implementation of a policy of source reduction.
Another method of reducing waste at the source is to increase incentives for recycling. Several cities in the United States have implemented tax whose amount depends on the amount of waste deposited (Pay what you throw: Pay As You Throw - PAYT) which have proved effective in reducing the volume of municipal waste. The effectiveness of policies to reduce at source measure the importance of reducing waste. Another approach, more controversial, is to consider reducing the use of toxic substances. The focus here is to reduce the use of toxic substances, even though the trend is upward. This approach, which is the precautionary principle is put forward, met strong opposition from the chemical industry. They accuse this approach stigmatizing chemicals. Some U.S. states, such as Massachusetts, New Jersey and Oregon have implemented policies to reduce toxic waste.
A relatively recent idea is to treat waste as a resource to be exploited rather than as waste which must be disposed. Methods to produce new resources from waste are many and varied: for example we can extract raw materials waste and recycle or burn to produce electricity. These methods are booming, thanks to the contribution of new technologies.
This process is called waste- material recovery, recycling or if reusable materials and energy recovery are recovered if one gets instead of energy. Treat the waste as raw materials become increasingly common, particularly in urban areas where space to open new landfills is scarce. Public opinion is changing the position to seriously considering that, in the long term, we can not just get rid of waste as raw materials are only available in limited quantity.
In some developing countries the recovery of waste is already happening: people hand sort the mountains of waste to recover materials that can be sold on the market recovery. These unrecognized workers called waste collectors are the hidden part of this business but play an important role in reducing the workload of municipal waste management. Increasing their contribution to the preservation of the environment is recognized and we try to integrate the formal system of waste management, which is a useful part, but also it helps to reduce urban poverty. However, the high cost in human lives of these activities: disease, accidents and expectancy reduced with toxic substances or contaminated life would not be tolerated in a developed country.
Waste management techniques
Traditionally, urban waste management, industrial and commercial was to retrieve and store them. Once collected, various treatments may be applied thereto. The purpose of these treatments may reduce their danger, enhance its material (metals, for example) by recycling, produce energy, or reduce their volume, in order to more readily available.
Recovery methods vary greatly between countries and regions, and it is impossible to describe them all. In Australia, most urban households have a 240 liter bin is emptied every week by local authorities. Many areas, especially in the least developed countries do not have formal waste collection system. In Canadian cities, sorting is the most common method of waste recovery and/or recycling and organic waste a set schedule. In some rural areas, people bring their garbage in collection sites. Waste thus collected is then transported to a regional landfill.
Storage methods also vary widely as well. In Australia, the solid waste is currently stored in landfills, because the country is large and the population density low. In contrast, in Japan, it is more common to incinerate waste because the country is small and the population dense.
Incineration is the process of destruction of a material by burning. Incineration is often called "energy from waste" or "waste to energy" necessary precision these names are misleading since there are other ways to recover energy from waste without directly burn (see fermentation, pyrolysis and gasification). It is known to be a convenient way to get rid of contaminated medical waste such as organic waste. Many organizations today use the exposure of waste at high temperatures for heat treating (this also includes gasification and pyrolysis). This technique includes metal recovery and energy of solid waste as appropriate disposal of solid residues (slag) and reducing the volume of waste.
Incineration is a proven and popular clarification needed in Europe and in developing countries, although it is subject to controversy for several reasons technique. Controversies usually involve environmental and health problems associated with incinerators that have worked in the past, before the application of existing standards.
Firstly, this method of waste disposal has limited recovery rates. Incineration destroys the natural resources contained in waste and does not recover 100 % of their calorific value. The energy recovered from the cooling of the flue gases in a boiler. The recovered heat can be used directly or in turn drive a turbine to generate electricity. Incineration is however identified in France in 2002 as the second source of renewable energy for electricity production (after water) and heat production (after biomass).
Second, the solid waste incineration produces a certain amount of air pollutants (dioxins and furans, heavy metals, acid gases, dust), the emission limit values are set by regulation. During the 1990s, advances in the control of discharges and new government regulations have led to a massive reduction in the amount of various pollutants, including dioxins and furans. The European Union and the Agency for Environmental Protection of the United States (EPA) took the decision to establish strict standards for waste incineration.
Incineration also produces a large amount of solid residues (slag) that must be disposed of in landfill or be treated if a valuation technique is proposed road. In the 1980s, storage of bottom ash, which at that time were also mixed with ashes, was a major environmental problem. In the mid- 1990s, experiments were carried out in France to treat and develop slag (extraction of ferrous metals and aluminum, screening, grinding, crushing, maturation outdoors to promote carbonation reactions and oxidation). The positive results of monitoring of experimental platforms using slag under roads led to the development of this sector.
The platform of NGOs Environmental Alliance has called for the world March 15, 2007 a moratorium on incineration. It notes "the very long delay (from France) in waste management compared to its European neighbors : only 19 % of household waste is recycled or composted (against 55% in Germany and 70% in Flanders) then 38% is landfilled and 43 % is incinerated. "His view is that" incineration is an outdated technique that poses health and environmental problems, which is not conducive to reducing our waste, leaving aside the public and democratic debate." Composting and fermentation
Waste composting barn.
Organic waste, such as plants, food scraps or paper, are increasingly valued compost and/or biogas. These wastes are deposited in a compost bin or a digester to control the biological process of decomposition of organic matter and neutralize pathogens.
The practice varies from simple composting compost pile plant in the case of an automated home composting in the case of industrial process platform. This is an aerobic biological process (in the presence of oxygen). Under the action of bacteria and soil organisms, biowaste is converted into compost for use in agriculture and gardening. Anaerobic digestion is itself an anaerobic process. The degradation of organic matter by bacteria in the absence of oxygen, to produce biogas which can then be used to produce electricity, heat, fuel, or be directly injected into the network.
Sample Policy composting
Green bin policy ("green bin") for the recovery of organic waste used in Toronto, Ontario (Canada) and surrounding cities such as Markham, allows reducing the amount of waste sent to Michigan in the United States of America. It is a new pan system of waste management in three axes which was set up in Toronto and is a further step to achieve the goal of 70% reduction of the amount of waste that is currently being landfill. Green bin policy allows organic waste were sent to landfill are recycled into compost and nutrient rich soil amendment for. Waste involved in the green bin program are food scraps, soiled paper and sanitary napkins. Currently Markham, like other municipalities in the Greater Toronto Area, send all their waste to Michigan at a cost of $ 22 Canadian per tonne.
Green bin policy is currently being studied by other cities in the province of Ontario as a way to avoid sending waste to landfill. Including Toronto and Ottawa are almost ready to adopt a similar policy.
Edmonton, Alberta, Canada adopted the compost on a large scale to manage its municipal waste. Its compost plant is the largest of its kind in the world and represents 35% of the total capacity of compost Canada. The cocomposteur itself to a size of 38,690 square meters, equivalent to eight football fields. It was designed to treat 200,000 tons of solid waste per year and 22,500 dry tonnes of biosolids, while transforming the 80,000 tons of compost annually .