Presentation on theme: "Solid Waste Management Department of Geology and Environment science at Islamic University of Gaza (IUG) - represent- -March 2007- Presented by Prof. Dr."— Presentation transcript:
Solid Waste Management Department of Geology and Environment science at Islamic University of Gaza (IUG) - represent- -March 2007- Presented by Prof. Dr. Samir Afifi
2/64 4- Landfills 4.1 Introduction The ultimate storehouse of a city's MSW In some cases, landfill is the only MSWM option available Effective operation depends on planning, administration, and management of MSWM system. (Institutional, policy, regulations)
3/64 4- Landfills 4.2 Planning Key considerations in landfill planning Required capacity Not In My Back Yard (NIMBY) Hydro-geology Cost Post-closure land use
4/64 4- Landfills Required capacity: Capacity refers area and volume required over the useful life It depends on the generation rate, rate of population growth, density and waste compacted at landfill and maximum in-place elevation.
5/64 4- Landfills Not In My Back Yard (NIMBY): NIMBY refers to community opposition to the sitting and operation of MSW facilities close to their neighborhood. Residents concerns include: Health and environmental risks; Negative impact on aesthetics in the area; Lowering of property values; Increased traffic, noise and dust; and …
6/64 4- Landfills Hydro-geology: Include water table, hydrological conductivity of the soil, surface water, precipitation and others; ideally, landfill should be sited in an area:
7/64 4- Landfills Continue Hydro-geology: Low hydrological conductivity with low water table Landfills should not be sited in wetlands, to avoid contamination ecologically sensitive areas. Landfills should not be sited in floodplains, to minimize the risk of waste washout during flooding.
8/64 4- Landfills Costs: The costs may be broken into: Capital costs which often determine the type of facility that can be constructed. Operating costs of the facility
9/64 4- Landfills Planned post-closure use: Post-closure use will have an impact on how the land is developed during use as a landfill. Planned heavy building construction require the use of high density compaction equipment Recreational uses planned, as golf courses or parks, site must be graded with vegetation replanted on closed areas of the operating facility.
10/64 4- Landfills 4.3 Classification Three general categories: 1.Open dumps 2.Controlled dumps 3.Sanitary landfills
14/64 4- Landfills Open dumps and the need to upgrade them Due to the low initial costs of open dumps, and lack of expertise and equipment, these sites are common in developing countries. Significant risks to human health and the environment,
15/64 4- Landfills Continue Open dumps and the need to upgrade them Remediating cost can easily exceed their total lifetime capital and operating costs. Contaminated groundwater may never be returned to usable condition
16/64 4- Landfills Continue Open dumps and the need to upgrade them Open dumps attract birds that feed on the wastes, which can make serious disease vectors than flies or rodents. High need to upgrade open dumps and construct new controlled landfills in developing countries.
18/64 4- Landfills Sound practices for MSW landfills Leachate management and environmental impact minimization Gas management and risk reduction Secure access and maintenance of gate records Compaction and daily cover
19/64 4- Landfills Continue Sound practices for MSW landfills Documented operating procedures, and worker training and safety programs Establishment and maintenance of good community relations Closure and post-closure planning
20/64 4- Landfills Sitting Sitting can be one of the most difficult processes in the landfill process. The main considerations are: Capacity Public involvement in the sitting process Hydro-geology/cover material Access Proximity to airports
21/64 4- Landfills Capacity: Available land area to minimize costs associated with design, permitting, sitting, and closure and post-closure requirements, Ideally capacity for 10 - 20 years of operation in case of sanitary landfills.
22/64 4- Landfills Public Involvement: The planner must be prepared to involve potentially affected communities in the sitting process.
23/64 4- Landfills Hydro Geology: It is desirable to take advantage of the geology of a site (types of soil and rock)
24/64 4- Landfills Sitting guidelines related to hydro-geology Do not site landfills: in wetlands or in an area with a high water table; in floodplains; in areas that are close to drinking water supplies; or Along geological faults or areas which experience frequent seismic activity.
25/64 4- Landfills Continue Sitting guidelines related to hydro-geology Do site landfills: above clay soils; above igneous rock; and where cover material is available nearby.
26/64 4- Landfills Cover material. The compacted MSW must be covered by 15-30 centimeters of soil at the end of each day's operations. The availability of cover material is also an important consideration in the sitting decision.
27/64 4- Landfills Access: The ideal location would therefore be sufficiently far from the city to allow for future population growth, but close enough to be reasonably accessible. The roads that provide access to a landfill must be adequate to handle the types and quantity of vehicles that will be used.
28/64 4- Landfills Proximity to Airports: A landfill should not be sited closer than two kilometers from the nearest airport. Birds converging at the landfill may pose a problem for aircraft
29/64 4- Landfills Other Considerations: Sloping area will facilitate leachate collection.
30/64 4- Landfills Landfills should not be sited: in very windy areas, near existing gas, sewer, water, or electrical lines, near residential areas, churches, schools, etc.
31/64 4- Landfills An environmental risk assessment (EnRA) should be made once the final site is selected. EnRA should detail the risks to ground and surface water from the facility, the risks from gaseous emissions, the impact of vermin, traffic, litter, and noise on the area and the potential for recovery of the land after post- closure period.
33/64 4- Landfills In the case upgrading open dump in to a controlled dump or sanitary landfill, planner applies the above procedure to the areas for proposed expansion of the existing site.
34/64 4- Landfills Items for consideration at the design stage Capacity Public/private ownership/operation Monitoring and control of leachate Monitoring and control of landfill gas Access and tipping area Pre-processing and waste picker policy Operations and safety manuals Closure and post-closure plans Community relations program
35/64 4- Landfills Capacity Controlled Dump: In case of planned capacity may not be protected by zoning and land use restriction, the landfill planner must use the designated site strategically to minimize the risk of future incursion by municipal development and maximize the total area available over the lifetime (acquisition of property surrounding site)
36/64 4- Landfills Continue capacity Sanitary landfill: Capacity is granted by regulatory permits on an incremental basis. So, planner develops it in two- to five-year increments once the overall site meets the required zoning and land use requirements.
37/64 4- Landfills Public/private ownership and operation In most developing countries landfills are owned and operated by local governments. Where expertise is available in the private sector, municipal planners should explore the option of privatizing landfill operations on a contractual basis. This option should be weighed carefully in bases of cost recovery and the payment of fees.
38/64 4- Landfills Monitoring and control of leachate: Leachate management is a key factor in safe landfill design and operation. The natural decomposition of MSW and rain infiltration into the site causes potentially toxic contaminants. The wetter the climate is the greater potential risks of ground- and surface water contamination. The geology of a site can exacerbate or reduce amount of leachate.
39/64 4- Landfills Continue Monitoring and control of leachate: Household hazardous waste (e.g., paint products, garden pesticides, automotive products, batteries) and hazardous wastes from commercial and industrial generators can release organic chemical and heavy metals contaminants in leachate.
40/64 4- Landfills Continue Monitoring and control of leachate: Natural or synthetic materials are used to line the bottom and sides of landfills to protect ground and surface water. Two feet or more of compacted clay, thin sheets of plastic made from a variety of synthetic materials and others used in lining landfills. Natural and synthetic liners can crack, if improperly installed, or can lose strength over time.
41/64 4- Landfills Continue Monitoring and control of leachate: More than one liner or a mix of natural and synthetic liners, called a composite liner, is a recommended alternative. To minimize production of leachate, covering material should be applied after each day of MSW is spread.
43/64 4- Landfills Leachate collection and treatment: Leachate collection systems are installed above the liner and consist of a perforated piping system which collects and carries the leachate to a storage tank. Periodically, leachate removed from the storage tank and treated or disposed of. Most common leachate management methods are: discharge to wastewater treatment plant, on-site treatment and recirculation back into the landfill.
44/64 4- Landfills Leachate recirculation over waste in landfills showed an increase the quantity (by factor of 10) and quality of methane gas for recovery as well as possibly reduces the concentration of contaminants in leachate and enhances the settling of the waste.
45/64 4- Landfills Leachate reinjection may be appropriate for areas with low rainfall. This technology could be more cost-effective than other treatment systems.
46/64 4- Landfills possible drawbacks of leachate recirculation include clogging of leachate collection systems, increasing release of leachate to the environment and increasing odor problems. After weighing these advantages and disadvantages, federal regulators in the US decided to allow leachate recirculation only at landfills that have a composite liner and a leachate collection system that meets specified performance requirements.
47/64 4- Landfills At controlled dumps monitoring operations may involve the scheduled withdrawal of samples to test for indicator contaminants such as bacteria, heavy metal ions, and toxic organic acids.
48/64 4- Landfills Monitoring operations at sanitary landfills may involve computerized statistical sampling and automatic reporting of results at the regulatory agency. Such systems are costly and require skilled personnel.
49/64 4- Landfills Monitoring and control of landfill gas Gas management is required at sanitary landfills. At controlled dumps, it should be monitoring to determine if dangerous amounts of gas are being released. A low-cost design (passive collection system) to handle landfill gas consists of covered vertical perforated pipes, using natural pressure of gas to collect and vent or flare it at surface. More costly active collection systems utilize covered network of pipes and pumping to trap it. Gas is processed and used for process heat or electricity. This collection system is risky and expensive.
50/64 4- Landfills Continue Monitoring and control of landfill gas Gas management is required at sanitary landfills. At controlled dumps, it should be monitoring to determine if dangerous amounts of gas are being released. A low-cost design (passive collection system) to handle landfill gas consists of covered vertical perforated pipes, using natural pressure of gas to collect and vent or flare it at surface. More costly active collection systems utilize covered network of pipes and pumping to trap it. Gas is processed and used for process heat or electricity. This collection system is risky and expensive.
51/64 4- Landfills Necessary conditions for economic capturing of landfill gas Sufficient methane is generated; Capital is available for processing the gas; There is local demand for natural gas or a means to transport it elsewhere; and The market price for natural gas is relatively high.
52/64 4- Landfills In many situations, not all of the conditions stated above are fulfilled, and landfill gas recovery is not economical.
53/64 4- Landfills These are two enclosed methane flares at a Landfill.
54/64 4- Landfills A county technician checking on a gas collection well
55/64 4- Landfills An example of the electrical generation equipment in one of the Michigan Cogeneration System Plants. These engines burn only landfill gas as a fuel and operate 24 hours a day. Each engine produces 750 kw of electricity
56/64 4- Landfills A methane "flare" is used for burning landfill gas.
57/64 4- Landfills Access and tipping area Fencing should be designed to restrict unauthorized access to the landfill and to keep out animals. A staffed gate should be the point of entry to the facility for vehicles and any waste pickers. Gate should be equipped with scales for the weighing of vehicles as they enter and exit the facility. They provide critical information for planning purposes and for operational management of collection vehicles.
58/64 4- Landfills Tipping area should be at the working cell. This requires the design of access roads to these locations within the site.
59/64 4- Landfills Pre-processing and waste picker policy Landfill is the least efficient alternative for materials recovery operations. Where composting is attractive at the landfill and/or waste picking activity is permitted, sorting of the waste should occur close to the gate or tipping area rather than at the working cell. Such activities reduce the volume of material to be landfilled and extend the life of the facility. Waste picking policy should be established during the design phase of the facility
60/64 4- Landfills Operations and safety manuals Manuals should be prepared during the design phase of the landfill. This permits their content to be specifically adapted to the processes for which the facility is designed. Clear operating procedures and well-trained workers are vital to safe and effective landfill operations.
61/64 4- Landfills Closure/post-closure plans Essential closure and post-closure elements are: Plans for the sealing and application of final cover (including vegetation) Plans for long-term leachate and gas management system monitoring;
62/64 4- Landfills Continue Closure/post-closure plans Plans for long-term ground and surface water monitoring; Financial assurance guarantees to the local or state government; and Land use restrictions for the site
63/64 4- Landfills In the case of controlled dumps in most developing countries, closure and post-closure plans are not prepared. However, ongoing monitoring and control of the facility after its useful life is an unavoidable for periods that may exceed 30 years after their closure.
64/64 4- Landfills Community relations The designer should establish a program for ongoing dialog with community. This should be based on transparency in landfill operations and procedures to addressing community concerns. Some facilities offer give-backs to their host community.