Summary of Wisconsin's Solid Waste Landfill Program

The Wisconsin solid waste management program has been in-place for almost 30 years. The regulation of existing solid waste landfills and assistance to local governments in developing new environmentally safe landfills has been the major thrust of the State's solid waste program.

As a first step, in the early 1970's all operating solid waste facilities throughout the state were identified and licensed. Approximately 2,000 land disposal sites (primarily small town dumps) existed in the state at that time. Solid waste facilities located too close to navigable surface waters, within a floodplain, wetland or critical habitat were ordered to close. In addition, a change in operations from open, burning dumps to sanitary landfills was enforced at all of the large landfills throughout the state. The remaining landfills, which posed the greatest threat to the environment due to their hydrogeologic setting or poor operations, were required to monitor groundwater and surface water. By the mid to late 1970's groundwater monitoring data from numerous unlined landfills provided documentation that such "natural attenuation" sites were causing significant groundwater quality impacts and, as a result, many were required to close. These combined efforts, in conjunction with the completion in 1980 of the U.S. Environmental Protection Agency funded Open Dump Inventory, led to the closure of a majority of the 2,000 land disposal sites which previously existed.

In 1984, the Wisconsin legislature in cooperation with the Department of Natural Resources (DNR) passed a comprehensive groundwater law (1983 Wisconsin Act 410). The law created chapter 160, Wis. Stat. and designated the DNR responsible for establishing a list of substances which have been detected in or have a reasonable probability of entering groundwater. The DNR, in conjunction with the Wisconsin Department of Health and Social Services and in accordance with the procedures in ss. 160.05 to 160.15, Wis. Stats., categorized and ranked substances on the list according to risk and established enforcement standards (ESs) and preventive action limits (PALs). The ESs are generally equivalent to federal maximum contaminant levels (MCLs) and cannot be violated beyond a set distance from a solid waste landfill (300 feet for those facilities existing prior to October 1, 1985, and 150 feet for those facilities constructed after October 1, 1985), or at their property boundary, whichever is the least distance. The PALs are more stringent trigger levels and range from 10% to 50% of the ES, and are based on the threat a particular contaminant poses to public health and the environment. The PALs are applicable at any location where groundwater is monitored, including directly beneath a landfill, whereas federal law only requires municipal solid waste landfills to meet the Federal MCLs at a maximum distance of 492 feet from their limits of filling or at their property boundaries. Chapter NR 140, Wis. Adm. Code also requires the owner/operator to "take whatever actions are necessary" to avoid exceeding the ESs and, since October 1, 1985, all new solid waste landfills in Wisconsin must be designed to meet the PALs.

Based primarily on the landfill performance and design experience gained in Wisconsin during the 1980's and the state's groundwater legislation, a revised set of solid waste rules (chs. NR 500 to 520, Wis. Adm. Code) were established in 1988. The 1988 rules required all landfills to be designed with a 5-foot thick clay liner and a leachate collection system and contained locational criteria, specific design and construction documentation criteria, operating criteria, environmental monitoring standards, and closure and post-closure care standards.

In 1989, Wisconsin provided an incentive to municipalities to close their un-engineered landfills (dumps). Municipalities which closed these facilities between January 1, 1988 and October 1, 1992, were paid 50% of the cost of closure after deducting $10 per capita. The program provided financial assistance for the closure of 373 dumps.

In 1996, Wisconsin further revised its solid waste rules to require all municipal solid waste landfills to be designed with a composite liner (a geomembrane liner on top of a 4-foot thick clay liner) and a composite final cover system. The revised rules, which also include financial assurance standards set in the early 1980's, now exceed the Federal (Subtitle 'D') rules for municipal solid waste landfills. In fact, Wisconsin is the first state in the nation to receive approval of its solid waste program by the U. S. Environmental Protection Agency.