Solid Waste Engineering: Landfills - Term Paper Example

Running Head: Landfills Landfills of Landfills Landfills are sites for waste material disposal. This is achieved by burying waste materials. They are the oldest and most common form of waste treatment and disposal systems in the world. Landfills consist of internal waste disposal sites and sites used by producers. They are also used for temporary storage, consolidation, and transfer and processing of waste materials. Landfills are also filled with soil and rocks to be used for specific purposes. A landfill must be constructed using a staged approach. There are specific requirements for the construction of a landfill. A landfill must be easily accessible for transport by road. The land value is also considered during the construction of a landfill. Government requirements must be met. The community location is also another important factor in the design of a landfill (Tchobanoglous, 1993). Usually a landfill is built on a pit with existing holes being filled in the ground. A canyon is also a good place for building a landfill. The waste is piled above the ground using a mound. Geological stability is an important factor in the design of a landfill. Water table and location of rivers can also create stable landfills. The landform is compared with the restoration profile to calculate the capacity of the landfill. The amount of daily cover and density of wastes are factors that base the capacity. Other factors considered are the thickness of capping and construction of drainage layers. Intermediate cover and construction of lining layers is also important for the capacity of a landfill. Soil and water are protected using liner and collection systems. Protection is further achieved by storm water control, leachate management and landfill gas management. The costs for the design of a landfill are conducted by feasibility studies and site investigations. There are small areas for confining wastes in non hazardous waste landfills. Wastes are compacted to reduce their volume and covered with layers of soil (Tchobanoglous, 1993). A single cell is filled in the area for the landfill. Contamination by leachates migrating through the geological formation is prevented by a rubberized landfill liner that is exposed on the left. Waste collection vehicles are present at a weigh bridge. The load is inspected for wastes that are not in accord with the landfill's waste acceptance criteria. The load is unloaded at the existing road network. Dozers are used to spread and compact the waste. The wheel cleaning facility allows the waste collection vehicles to pass through. The daily waste tonnage is calculated and listed in databases during the weighing process. Many landfills have railroad containers. This allows landfills to be located at remote sites. Solid covers the waste in the landfill. There are alternative waste cover materials which can be sprayed on foam products. Temporary blankets, chipped wood and bio solids can also be used as daily cover. A daily cell is the space occupied by compacted waste and cover material. Waste compaction plays a vital role in extending the life of the landfill. Waste densities are affected by waste layer thickness and number of passes. Landfills have been developed using land re-use strategies. There are some adverse impacts of landfills. They can be fatal accidents and infrastructure damage. They can also cause pollution, contamination of ground water and harboring of disease vectors. Vehicles accessing a landfill can also generate environmental noise and dust. The best way to tackle these issues is during the planning stage. Access routes and landfill geometrics are beneficial in mitigating these issues. Daily cover protocols can be helpful in combating vector control (Tchobanoglous, 1993). A secure landfill is a carefully engineered depression in the ground. The aim is to prevent any hydraulic connection between the wastes and the surrounding environment. A bottom liner, leachate collection system, cover and hydro geologic setting are the four essential elements of a secure landfill. Each of these elements is critical for the design of a secure landfill. The natural hydro geologic setting should prevent the wastes from escaping and the rocks must be waterproof. A landfill can allow waste products to stay inside it for a very long time. Oxygen and moisture are in small quantities inside a landfill. Trash does not break down easily in landfills. They are not designed to break trash. They are used to bury landfill. Monitoring and maintaining the landfill is essential once it is closed. The area of land necessary is the first step in the selection of a landfill. The underlying soil and bedrock are analyzed for their composition. Surface water over the site is checked for its flow. Historical places are good sites for the construction of landfills. Trash consists of organic material which can be broken down by bacteria in a landfill. Using oxygen microorganisms break down the organic materials. The remaining components are degraded by anaerobic microorganisms. Landfills contain microorganisms which contribute to the breakdown of refuse. The gases formed are called landfill gas (Vesiland, 2002). Temperature usually determines the rate of degradation of refuse. Other factors which are responsible are the composition of the refuse and toxic compounds. Water passes through the landfill and absorbs organic compounds from the refuse. Some compounds are suspended and precipitated into the leachate. Some of the organic components are converted into landfill gas. These gases leave the landfill by passive diffusion or extracted by a gas collection system. Landfill sitting is initiated by estimating the volume of landfill space required for the community. These are made by considering the population and predicted growth. The site should have capacity to accept waste for up to thirty years. It must also be economically feasible. There must be space for offices and leachate treatment. Recycling facilities can also be established on the area. Landfills cannot be established near airports, floodplains, wetlands or earthquake zones. The landfill must be accessible for the community it serves. Any long distance would create a financial burden for the community (Vesiland, 2002). Because a landfill is constructed as the final disposal site for refuse generated by a community or communities, for economic reasons it is preferable that the landfill be readily accessible to the community or communities that it serves. If a landfill is sited at a great distance, the expense of hauling refuse to the landfill becomes a major consideration and a financial burden. An application is usually forwarded to the local building authorities for the construction of a landfill. Once approval is granted than construction of the landfill, offices, leachate treatment and recycling facilities can be initiated. A landfill site is prepared by grading the surrounding land. This is done to reduce the water runoff into the landfill. Access roads and fences are constructed to secure the area. They are constructed in sections. The base is graded to allow the collection of water. Sides are sloped and a liner system is installed. The liner prevents leachate from leaving the landfill. Perforated collection pipes are within the liner system to remove leachate. Waste is collected in layers within the landfill. Heavy machinery is used to compact the waste to ensure that it can be disposed of in the landfill. Soil or plastics are used to cover the waste. This covers restricts the amount of rodents, odors and insects on the site. It also minimizes the amount of rain water. Landfills reduce degradation and production of leachate. This reduces the danger to the environment (Vesiland, 2002). Gas collection tubes collect the landfill gas. They can be added until the landfill allows the permitted height. Landfills are monitored. The chemical composition of leachate is analyzed. The amount of leachate present is maintained to minimize the threat of leaks. A collection system pumps leachate if there is too much leachate. It is treated to prevent any danger to the environment. Ground water is regularly monitored so that the liner and leachate systems are functioning properly. Wells are installed around the landfill. They can detect compounds in the ground water. This may indicate a leak. A monitoring system ensures that gas collection systems can capture the landfill gas generated in the landfill. Rainwater must be prevented from draining into the landfill. This can be achieved by routing rain water to sedimentation ponds. Similarly hazardous wastes must be disposed of properly. A separate facility is usually constructed to allow the separation and disposal of hazardous wastes. Public access to the landfill must be restricted and traffic must be controlled on the landfill. Safety equipment must be provided to the landfill personnel (Vesiland, 2002). A landfill is closed by final cap that minimizes the amount of water that can enter the landfill. This cap has a gas collection system. Landfill gas is piped to a flare to be burned or used to produce electricity. An uppermost layer of soil allows revegetation of the site. A landfill must be monitored and cared for at least thirty years. The leachate on the liner is controlled after the closing of the landfill. Ground water is monitored to prevent any leaks. Grass is mowed to prevent cap layers being punctured by tree roots. Periodic inspections must be conducted to ensure that the system is in good conditions. Landfills being designed and managed today have reduced the environmental hazards associated with older technologies. Engineering safeguards have allowed the successful reclamation of closed landfills for community use. They have converted into golf courses, recreational areas, and residential, industrial and commercial areas (EPA, 1994). Landfills can also be mined and potentially valuable products can be recovered. Recyclable materials, minerals, soil and landfill space can be recovered by mining. There are also operating schemes for new and existing landfills. Landfills are also filled with soil and rocks to be used for specific purposes. A staged approach is required for the construction of a landfill. There are specific requirements for the construction of a landfill. A landfill must be easily accessible for transport by road. The landfills designed today have improved the level of environmental protection. Modern landfills no longer pose serious risks to the environment. As long as society produces solid wastes, the use of landfills will remain. Facilities and methods of dealing with waste products in landfills continue to be improved. The importance of landfills is expected to continue as new technologies are designed which can minimize the affects on the environment. Landfills are some of the oldest and most common waste disposal systems in the world. Solid covers the waste in the landfill. There are alternative waste cover materials which can be sprayed on foam products. Temporary blankets, chipped wood and bio solids can also be used as daily cover. A daily cell is the space occupied by compacted waste and cover material. Waste compaction plays a vital role in extending the life of the landfill. Waste densities are affected by waste layer thickness and number of passes. References Tchobanoglous, G., 1993. Integrated Solid Waste Management: Engineering Principles and Management Issues. McGraw-Hill, Boston, Mass. U.S. Environmental Protection Agency. 1994. Design, Operation, and Closure of Municipal Solid Waste Landfills. Vesilind, P. A., 2002. Solid Waste Engineering. Brooks/Cole, Pacific Grove, Calif. Read More