TABLE 4-2-7D Site Closure Checklist Preplanning Identify final site topographic plan. Prepare site drainage plan. Specify source of cover material. Prepare vegetative cover and landscaping plan. Identify closing sequence for phase operations. Specify engineering procedures for the development of onsite structures. Annotate base maps showing landfill area, time period, and source for further details. Six Months Before Closure Review closure plan for completeness. Schedule closing date. Prepare final timetable for closure procedures. Notify appropriate regulatory agency. Notify site users by letter if they are municipalities or contract haulers, and by published announcement if private dumping is allowed. At Closure Erect fences or appropriate structures to limit access. Post signs indicating site closure and alternative disposal sites. Three Months After Closure Complete needed drainage control features or structures. Complete, as required, gas collection or venting system, leachate Use of Impermeable Liners to Control Movement of Gas and Leachate 4.2.7.26 The long-term maintenance of a closed landfill site will be a function of the ultimate site use. Many current landfills have gas and leachate collection systems that will require continuous attention after closure. Groundwater monitoring devices may also be incorporated into the design to check the performance of the leachate control system. Other site features that will require a degree of attention on a continuing basis are drainage control structures and erosion control features. 4.2.7.27 Methane gas control systems may be either active or passive. Passive systems allow the gas to escape to the atmosphere by natural means. The blower and pumps in the active system require periodic maintenance. In addition, the withdrawal pipes and collection lines may need condensate removed and repairs of damage caused by differential settling. 4.2.7.28 Leachate collection systems installed at landfills will require continuous attention once the landfill is closed. The leachate collection system must be maintained to ensure effective operation. This work may include annual leachate collection pipe cleaning, collection tank cleaning, and inspection and pump cleaning and repairs. Collected leachate needs to be disposed of in the appropriate manner. Failure to withdraw leachate could allow it to seep out of the side of the landfill and possibly contaminate groundwater. Records shall be maintained that show the quantity of leachate removed. The leachate quantity will vary with the season of the year and shall be carefully monitored, possibly with automated signaling devices to ensure that it is being properly removed. The duration over which this must be practiced is somewhat uncertain. Regulations require that many landfills have a groundwater monitoring system incorporated into their design. The purpose of these wells is to evaluate the performance and design of the facilities provided for leachate control. 4.2.7.29 Drainage control problems can result in accelerated erosion of a particular area within the landfill. Differential settling of drainage control structures can limit their usefulness and may result in failure to direct storm water properly off the site. Serious erosion problems can result from improper drainage control. 4.2.7.30 The site closure plan should consider that sites larger than 10 acres be prepared for the DoD forestry program if no more productive use is planned. Production of species with shallow root systems, such as Virginia pines or cedar, for Christmas trees may be a viable alternative. 4.2.7.31 The criteria for Solid Waste Disposal Facilities are currently undergoing revision by the EPA. The proposed (1988) revisions are included in Appendix A-1. 4.2.8 Volume Reduction 4.2.8.1 Reducing the volume of solid waste has the potential for cost savings when land costs are high or space is unavailable, or transfer and long-distance hauling are necessary. Several processes are available for consideration. Ail are expensive and shall be justified only when significant cost savings can be achieved in the disposal process. Table 4-2-8A summarizes advantages of common waste processing techniques. Resource recovery is discussed in Section 4.3. Incineration is the topic of Section 4.4. 4.2.8.2 Mechanical volume reduction by compaction is widely practiced. Shredding is less common because component wear (cost) is high. Table 4-2-8B lists several types of commercially available compaction equipment. Table 4-2-8C gives important design factors to consider in the selection of compaction equipment. 4.3 RESOURCE RECOVERY AND RECYCLING 4.3.1 Resource Conservation. Resource conservation is defined as the reduction of the amounts of solid waste that are generated, reduction of overall resources consumed, and utilization of recovered resources. DoD policy is that solid and other waste materials will be reduced at the source whenever possible. 4.3.2 Reuse/Recycling. Reuse is defined as the use of a waste material or product more than once without any change in form. For example, a softdrink bottle is reused when it is returned to a bottling company and refilled. Recycling is the process by which reclaimed resources are transformed into new products in such a manner that the original products may lose their original forms. A market analysis is essential before instituting recycling programs. The material must be in a form that the market will accept (i.e., clean, segregated, etc.). For example, an aluminum can is recycled when it is returned to the smelter, melted, and reformed into sheet aluminum to be manufactured into a new can or another completely different product. The Vertical Remarks Vertical compaction ram; may be mechanically or hydraulically operated; usually hand-fed; wastes compacted into corrugated box containers or paper or plastic bags; used in medium- and high-rise apartments. Ram mechanisa used to compact wastes into paper or plastic bags on rotating platform, platform rotates as containers are filled; used in medium- and high-rise apartments. Compactor can be chute-fed; either vertical or horizontal rams; single or continuous multibags; single bags must be replaced and continuous bags must be tied off and replaced; used in mediumand high-rise apartments. Small compactors used in individual residences and apartment units; wastes compacted into special paper bags; after wastes are dropped through a panel door into bag and door is closed, they are sprayed for odor control; button is pushed to activate compaction mechanism. Compactor with vertical or horizontal ram; waste compressed into steel container; compressed wastes are manually tied and removed; used in low-, medium-, and high-rise apartments, commercial and industrial facilities. Collection vehicles equipped with compaction mechanisms Transport trailer, usually enclosed, equipped with self-contained compaction mechanism Disposal site Movable wheeled or tracked equipment Specially designed equipment to achieve maximum compaction of wastes. Stationary/track-mounted High-pressure movable stationary compactors used for volume reduction at disposal sites. |