Leachate collection

MAIN LEACHATE COLLECTION LINE, USE OF PERFORATED LATERALS will depend on topography AND EXTENT OF LANDFILL. MAINLINE AND LATERALS SHOULD BE GRAVEL-PACKED. 

Reduce Head on Liner and/or in Leachate Collection System Inspect Leachate Collection/Removal System or French Drain Repair Leachate Collection/Removal System or French Drain Temporary Cap... 

Case 2 - The Hyde Park Landfill site, located in an industrial complex in the extreme northwest corner of Niagara, New York, was used from 1953 to 1975 as a disposal site for an estimated 80,000 tons of chemical waste, including chlorinated hydrocarbons. A compacted clay cover was installed in 1978 over the landfill and a tile leachate collection system was installed in 1979. Hazardous compounds such as ortho-, meta- and para-chlorobenzoic acid toluene ortho- and meta-chlorotoluene 3,4-dichlorotoluene and 2,6-dichlorotoluene were detected in the leachate (Irvine et al., 1984). Since 1979, the existing leachate treatment system has used activated carbon as the technology for removing organic carbon. Although... 

National capacity variance When developing a treatment standard, U.S. EPA examines the available treatment capacity to determine whether it is sufficient to handle current and future waste management needs. If U.S. EPA determines that nationally there is not enough capacity to treat a waste, it can automatically extend the effective date of the waste s treatment standard. Such an extension to the effective date is intended to give the waste treatment industry more time to develop the capacity to handle the waste. Wastes under a national capacity variance can be disposed of, without meeting the treatment standards, in landfills and surface impoundments that meet minimum technical requirements (e.g., liners, leachate collection and removal systems, and leak detection systems). 

In engineering terms, a sanitary landfill is also sometimes identified as a bioreactor due to the presence of anaerobic activities in the wastes. As such, landfilling sites need the incoming waste stream top be monitored, as well as placement and compaction of the waste, and installation of landfill environmental monitoring and control facilities. Gas vent and leachate collection pipes are important features of a modem landfill. 

The site conditions for an on-site landfill, such as location, geology, hydrogeology, physiography, climate, and so on, should also be suitable. Landfill should meet the minimum technology requirements and regulations for hazardous waste landfills such as double liners and leachate collection and removal systems, leak detection systems, closure procedures and final cover, and construction quality assurance.59... 

Percolation monitoring can also be evaluated indirectly by using leachate collection and removal systems. For landfills underlain with these systems, the amount and composition of leachate generated can be used as an indicator of the performance of a cover system (the higher the percolation, the more leachate that will be generated).22... 

FIGURE 26.1 Schematic of a double-liner and leachate collection system for a hazardous landfill. (Adapted from U.S. EPA, Training Module Introduction to Land Disposal Units, EPA530-K-05-014, U.S. Environmental Protection Agency, Washington, DC, September 2005.)... 

Leachate collection system between liners o o Top liner designed, constructed, and operated to prevent migration—AL PCCP Leachate collection system between o liners o... 

Figure 26.3 compares theoretical leachate collection efficiencies for landfills having compacted soil bottom liners with those having composite bottom liners. Leachate collection efficiency... 

The numerical results indicate superior performance of composite liner systems over CCLs in preventing hazardous constituent migration out of the unit and maximizing leachate collection and removal. Consequently, owners of new units subject to the double-liner requirement of FISWA are now installing composite bottom liners or double composite liner systems.3... 

Figure 26.16 is a profile of a liner according to U.S. EPA s MTG. The minimum hydraulic conductivity in the secondary leachate collection system is 1 x 10 2 cm/s. To meet this requirement, either a granular material or a net made of synthetic material must be used to build the secondary leachate collection system. 

An example of the effects of waste settlement can be illustrated by a recent incident at a hazardous waste landfill facility in California.5 At this facility, waste settlement led to sliding of the waste, causing the standpipes (used to monitor secondary leachate collection sumps) to move 60-90 ft downslope in 1 day. Because there was a very low coefficient of friction between the primary liner and the geonet, the waste (which was deposited in a canyon) slid down the canyon. There was also a failure zone between the secondary liner and the clay. A two-dimensional slope stability analysis at the site indicated a factor of safety (FS) greater than 1. A three-dimensional slope stability analysis, however, showed that the safety factor had dropped below one. Three-dimensional slope stability analyses should therefore be considered with canyon and trench landfills. 

The secondary leachate collection system is accessed by collection standpipes that must penetrate the primary liner. There are two methods of making these penetrations rigid or flexible. In the rigid penetrations, concrete anchor blocks are set behind the pipe with the membranes anchored to the concrete. Flexible penetrations are preferred since these allow the pipe to move without damaging the liner. In either case, standpipes should not be welded to the liners. If a vehicle hits a pipe, there is a high potential for creating major tears in the liner at depth. 

The drainage materials for the liquid management system must allow for unimpeded flow of liquids for the intended lifetime of the facility. In a leachate collection system, the drains may consist of pipes, soil (gravel), geonets, or geocomposites. 

Table 26.5 shows some of the ASTM test methods and standards for drainage and filter materials used in primary leachate collection and leachate detection and collection systems. 

Lead may leach from loamy soils of clay target shooting sites, where soils contain about 50,000 mg Pb/kg (about 40% Pb as particulate Pb shot in the most contaminated areas) leachates at 100 mm depth contained up to 3.4 mg Pb/L vs. little or no lead in leachates collected from soil containing background concentrations of lead (Rooney and McLaren 1999). 

Other disposal options for the sewage sludge are landfill, dumping at sea (forbidden in the EU since 1998) [30], and incineration. The most popular for solid waste disposal is landfill. However, many of the disposal sites are open dumps without protective barriers or leachate-collection systems, which represent a potential risk to the quality of the nearby groundwater. 

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