29-08-2014, 12:10 PM
Solid waste management
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ABSTRACT
As long as humans have been living in settled communities, solid waste, or garbage, has been an issue, and modern societies generate far more solid waste than early humans ever did.Daily life in industrialized nations can generate several pounds (kilograms) of solid waste per consumer, not only directly in the home, but indirectly in factories that manufacture goods purchased by consumers
Due to increase in population, the Indian environment has undergone rapid changes. Uncontrolled growth of population is tremendous for which an innovative disposal technique is essential. The composition of municipal solid waste typically in India has about 40-45% organics and about 40% construction waste. The organic waste needs to be segregated and composted at site. This will solve 40% of the problem. Plastic, paper, glass and metal should be recycled and not wasted in landfills.
Solid waste management is a system for handling all of this garbage, and includes municipal waste collection, recycling programs, dumps, and incinerators.Solid waste is the unwanted or useless solid materials generated from combined residential, industrial and commercial activities in a given area.
Management of solid waste reduces or eliminates adverse impacts on the environment and human health and supports economic development and improved quality of life.A number of processes are involved in effectively managing waste These include monitoring, collection, transport, processing, recycling and disposal.
This paper deals with the solid waste and various aspects of removal and disposal of the solid wastes.
1. INTRODUCTION OF SOLID WASTE MANAGEMENT.
Besides liquid wastes or sewage, solid wastes are also produced in large quantity in cities and towns.
The solid wastes are practically in dry state and hence these are also known as dry refuse.
The removal and disposal of solid wastes is also necessary to maintain a clean environment.
1.1 Reduce, Reuse, Recycle
Methods of waste reduction, waste reuse and recycling are the preferred options when managing waste.
Reduce, reuse and recycle, the three R’s for waste management, are effective measures that serve as alternatives to disposing waste in landfills.
Today, we have several options available for handling the solid waste that we produce.
we need to remain focused on reducing the amount of waste we produce.
We also need to consider the types of waste we are producing and whether or not these waste materials are hazardous and their long-term impact on the environment.
By recycling, we can conserve natural resources and energy.
Recycled materials can be processed and made into new products, so it's not only important to recycle, but to also purchase goods with recycled content.
By reducing, reusing and recycling you can help to protect our water,air,land,energy and cultural resources.
1.2 DEFINATION OF SOLID WASTE
The definition of solid waste is any unwanted or discarded material that is not a liquid or a gas.It can include organic waste, paper, metals, glass, cloth, brick and rock, yard waste and wood.
3. Waste management
Waste management is the collection, transport, processing or disposal, managing and monitoring of waste materials.
The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment or aesthetics.
Waste management is a distinct practice from resource recovery which focuses on delaying the rate of consumption of natural resources.
All waste materials, whether they are solid, liquid, gaseous or radioactive fall within the remit of waste management.
Waste management practices can differ for developed and developing nations, for urban and rural areas, and for residential and industrial producers.
5.2 Incineration
Incineration is a disposal method in which solid organic wastes are subjected to combustion so as to convert them into residue and gaseous products.
This method is useful for disposal of residue of both solid waste management and solid residue from waste water management.
This process reduces the volumes of solid waste to 20 to 30 percent of the original volume.
Incineration and other high temperature waste treatment systems are sometimes described as "thermal treatment".
Incinerators convert waste materials into heat, gas, steam and ash.
It is used to dispose of solid, liquid and gaseous waste.
It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste).
Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous pollutants.
Incineration is common in countries such as Japan where land is more scarce, as these facilities generally do not require as much area as landfills.
Waste-to-energy (WtE) or energy-from-waste (EfW) are broad terms for facilities that burn waste in a furnace or boiler to generate heat, steam or electricity.
Combustion in an incinerator is not always perfect and there have been concerns about pollutants in gaseous emissions from incinerator stacks
1. Ash and clinker are by products of this method.
2. This is mostly hygienic in nature.
3. Clinker which can be used in road construction work.
4. No odour , nuisance
5.3 Composting
Composting is the controlled aerobic decomposition of organic matter by the action of micro organisms.
There are a number of composting techniques being used today.
At the simplest level, the process of composting simply requires making a heap of wetted organic matter (leaves, "green" food waste) and waiting for the materials to break down into humus after a period of weeks or months.
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At the simplest level, the process of composting simply requires making a heap of wetted organic matter (leaves, "green" food waste) and waiting for the materials to break down intohumus after a period of weeks or months. Worms and fungi further break up the material.
Compost can be rich in nitrogen..It is used in gardens, landscaping, horticulture, andagriculture.
The compost itself is beneficial for the land in many ways, including as a soil conditioner, a fertilizer, addition of vital humus or humic acids, and as a natural pesticide for soil.
Due to composting the volume of solid waste is very much reduced, and the resulting matter can be safely handled since becomes free from pathogens.
The process is controlled by making the environmental conditions optimum for the waste decomposers to thrive.
The rate of compost formation is controlled by the composition and constituents of the materials i.e. their Carbon/Nitrogen (C/N) ratio, the temperature, the moisture content and the amount of air.
The C/N ratio is very important for the process to be efficient.
The micro organisms require carbon as an energy source and nitrogen for the synthesis of some proteins.
If the correct C/N ration is not achieved, then application of the compost with either a high or low C/N ratio can have adverse effects on both the soil and the plants.
A high C/N ratio can be corrected by dehydrated mud and a low ratio corrected by adding cellulose.
Moisture content greatly influences the composting process.
A high temperature is desirable for the elimination of pathogenic organisms.
However, if temperatures are too high, above 75oC then the organisms necessary to complete the composting process are destroyed
Composting by Trenching :
1. The trench is excavated in length 6m ,0.6 to 1m height and 1 to 2m width at an amount of 60% moisture.
2. Here on the top layer 10cm thick layer of good earth is spread so that flies do not get access to the refuse and also the refuse does not get blown off by wind.
3. In 2 or 3 days biological action starts to destroy organic matter in refuse.
4. The refuse get stabilized in about 4 to 6 months period, and gets changed into brown coloured odourless powdery form known as humus, which has high manure value because of its nitrogen content.
5. The stabilized mass is removed from trenches, sieved through 12.5 mm sieve to exclude coarse inert materials like stones, bricks bats, etc., the sieved material is then sold as manure.
Open window composting
The trench is excavated in length 6m ,0.6 to 1m height and 1 to 2m width at an amount of 60% moisture.
The covering of pile is done by cow dung, cattle urine etc, which organisms are necessary for fermentation.
Due to this heat starts developing and it is turned cooling and aeration to avoid anaerobic reactions set up.
The process may take about 4-6 weeks for completion and the compost is ready to use.
Design consideration for composting (aerobic) process
Particle size
For optimum results the particle size in the range of 25-75 mm.
Seeding
Composting time can be reduced by adding partially decomposed compost (1-5%) or sewage sludge.
Moisture content
It should be in the range of 50-60% during composting process.
Temperature
The optimum temperature for biological stabilization is between 45-55° C.
Carbon nitrogen ratio
6. SOLID WASTE IN INDIA
1. 7.2 million tonnes of hazardous waste
2. One Sq km of additional landfill area every-year
3. Rs 1600 crore for treatment & disposal of these wastes
4. In addition to this industries discharge about 150 million tonnes of high volume low hazard waste every year, which is mostly dumped on open low lying land areas.
6.1 WASTE COLLECTION IN INDIA
1. Primarily by the city municipality
-No gradation of waste product eg bio- degradable, glasses, polybags, paper
shreds etc
-Dumps these wastes to the city outskirts
1. Local raddiwala / kabadiwala (Rag pickers)
-Collecting small iron pieces by magnets
-Collecting glass bottles
-Collecting paper for recycling
1. In developing countries it is now common for local municipalities to spend as much 50% of their recurrent budget on solid waste management, but 30-60% of all urban solid waste is still uncollected and over 50% of the population is still un-served.
8. CONCLUSION
1. It is not possible for proper waste management without co-operation one and all citizens.
2. We need not required to do any big task only we have to segregate waste into dry and wet and handover them to garbage collector separately.
3. Government can also introduce some schemes like two separate waste vehicles for waste collection, one for dry waste and other for wet waste.
4. Remember to reduce generating waste and segregate the waste systematically.
5. Segregation of waste is not a new thing but it is ignored by most.
6. Together we work and manage waste properly.