The environment and human health of Kuwait, a developing arid country, is in jeopardy due to improper waste disposal management. Hazardous and liquid wastes are frequently commingled with municipal solid waste, which commonly results in environmental degradation. Landfills in Kuwait act as dumping grounds rather than safe disposal sites. Furthermore, the basic tools that assist in the protection of the environment such as a base liner, final cover, and a leachate collection system are not included in these units. In an effort to help Kuwait and developing arid countries build safe landfills for the disposal of the different waste materials; a strategy was adapted to select the best landfill protection tools that are environmentally acceptable and cost effective. The strategy included landfill classification, lab and field tests on natural soils to determine their applicability as liner and cover systems, and finally examining the effectiveness of the design models for the primary tools using Pollutev6 computer program. To examine the effectiveness of the previous strategy items, the strategy was implemented based on the State of Kuwait environment and wastes generation data. The results showed that native cemented calcareous sands (gatch) when compacted could be used as liner and cover systems in Kuwait. Moreover, high-density polyethylene liners are not recommended in this arid region and a leachate collection system is needed due to improper dumping. Overall, the results showed that this strategy is practical and efficient to introduce the minimum requirements for environmentally acceptable landfill sites in such countries.

The feasibility of using landfill gas (LFG) for electricity generation at four St. Louis, Mo., area landfills was explored using the U.S. EPA's E-PLUS (Energy Project Landfill Gas Utilization Software). The estimated break-even generation price of the electricity was about 4;ct/kW⋅h. This price is higher than the current avoided cost provided by utilities. These results are consistent with the current situation for the entire renewable energy industry. Renewable technologies, in general, are characterized by relatively high capital costs and low operation and maintenance costs, and with the development of electricity deregulation throughout the United States, renewable energy is facing more competitive challenges. With the loss of federal tax incentives and relatively low electricity prices, fewer LFG-to-electricity projects are being implemented. LFG-to-energy facilities may be able to take advantage of increasing demands for green energy and markets for greenhouse gas emission reductions, but to make LFG projects economically feasible, it appears that some type of subsidy will be necessary to take into account the pollution reduction benefits derived from utilizing LFG.

Fly ash, a waste from thermal power stations, has been used in many countries to build highway embankments, fills, landfill liners, and covers. The maximum dry density (MDD) and optimum moisture content (OMC) of fly ash or fly ash–soil mixtures are determined by conducting compaction test. There is a large variation in the MDD and OMC of different fly ashes due to the differences in their characteristics. In the present study, data regarding the compaction characteristics and specific gravity (G) of different fly ashes were collected. Correlation analyses of the data for 57 samples for light (standard Proctor) compaction and 21 samples for heavy (modified Proctor) compaction were carried out. Correlations have been developed for MDD and OMC for both light and heavy compaction. The correlation for MDD in terms of OMC and G and that between MDD and OMC have been expressed in the form of log-log, exponential, and linear curves. The general applicability of the correlations for light compaction has been tested with the data of 19 additional samples that were not used in establishing the correlations. The correlations between MDD and G, and between OMC and G, can be used to make a preliminary estimate of the likely range of MDD and OMC if the specific gravity of fly ash is known. This will be useful for the efficient design of the compaction test and for field compaction control in sites where establishing site-specific correlations is expensive and time consuming.

The city of Boston owns a 40-ha (98-acre) site that contains a 34-ha (85-acre) landfill along the banks of the scenic Charles River. Faced with a multimillion dollar state-mandated closure, the city decided that it wanted to utilize this significant piece of real estate (which is bigger than the Boston Gardens and Common combined) for a postclosure use. The mayor's office, Department of Public Works and Parks, Community Advisory Committee, and a consultant developed a postclosure master plan for the site that included landfill closure and constructing a public park on the capped landfill. The total project was initially estimated at >$20,000,000. The city realized early that, to move this ambitious project forward, it would need to be creative in funding. Therefore, during the planning stage, areas were identified for potential cost savings: modification of state closure standards, substituting/manufacturing a portion of the required landfill cap, and utilizing creative/alternative funding sources. Implementing these ideas resulted in significant cost savings.

This paper presents a case study of leachate recirculation at the Trail Road landfill site, located in Nepean, Ontario, Canada. The leachate collected from the landfill leachate collection system is pumped into infiltration lagoons that were built on the working face of the landfilled waste. The locations of these infiltration lagoons are constantly changing to accommodate the landfilling of the municipal solid waste in Stage 3, which has a composite liner consisting of 600 mm of compacted clay and an 80 mil high-density polyethylene geomembrane. The initial estimation of the leachate generation rates in 1991, using the Hydrological Evaluation of Landfill Performance model indicated that leachate recirculation into the landfill could be feasible for a period of 5 to 6 years, after which time a substantial amount of leachate would have to be removed from the system. The average pH of the leachate in the early stage of recirculation was on the acidic side of the pH scale; however, the pH value was in the range of 7 to 8 after 2 years of leachate recirculation. The leachate recirculation accelerated the reduction of organic load, measured as BOD and COD. The concentration of chloride remained fairly constant at about 1,000 mg/L during the leachate recirculation period. The recovery of landfill air space was also noted as a during active periods of landfilling as an added benefit due to the enhanced subsidence of the solid waste.