NEWS ITEM AS PUBLISHED IN THE NOVEMBER/DECEMBER EPA BROWNFIELDS 2005 CONFERENCE ISSUE
Redeveloping property formerly used as landfills or “dumps” to provide for new uses is increasingly taking place across the country and continent. Public interest in making new uses of these properties is forcing the issue of landfill re-use into prominence. When, where, how, and in some cases “if” such redevelopment should be pursued are questions being considered by property owners, developers, and all levels of government. This article identifies some of the relevant considerations for landfill redevelopment, including state regulation and/or support for such redevelopment.
WIDE RANGE OF CONDITIONS
The range of conditions that may be present at landfills/dumps being considered for redevelopment extends from those associated with historical neighborhood or industrial dumps to those of regulated monofills and solid waste landfills. A clear and accurate understanding of the pre-existing conditions will determine the level and type of effort required to redevelop the land. For instance, a modern-day regulated landfill (i.e., liner system, landfill gas collection system, etc.) can be more directly evaluated and designed for re-use than an orphaned landfill or dump that would first require substantial assessment to understand property conditions.
MITIGATING ADVERSE CONDITIONS
Adverse conditions that may need to be addressed for redevelopment include landfill gas (LFG), strength of the waste materials, direct contact with hazardous substances, soil erosion, leachate generation, water quality, and runoff.
LFG is formed principally from the decomposition of organic material (including typical municipal solid waste, or MSW) and consists of methane and carbon dioxide. The methane can be a fire and explosion hazard if the gas is allowed to build in a confined area. In addition to the formation of methane and carbon dioxide, many wastes settle over time. This settlement can occur over several years depending on the depth of waste, type of waste (MSW or construction and demolition debris), and method of placement (trench or area fill). In order to maintain any needed cover over waste materials, the types of soils available and a stormwater analysis should be performed. Engineered controls for landfill conditions can involve addressing substantially steep slopes, and redirecting drainage (which can result in large increases in off-site flows and sediment deposition).
While these issues are broad in scope, their engineering control measures are usually simple and direct. For example, methane can be controlled with a passive or active control system. Settlement can be addressed using various foundation designs and interactive systems that “float” with the topography. Typical design challenges and common solutions to address them are presented in Table 1.
SUCCESS IS BEING ACHIEVED – SITE CHARACTERIZATION IS KEY
Inappropriate development on or adjacent to landfills/dumps with inadequately controlled conditions can indeed result in hazards and harm. Proceeding in a manner that recognizes the need for good property assessment such as the process illustrated in the flow diagram (Figure 1) can and does result in successful landfill redevelopment projects.
STATE RESTRICTIONS ON NEW USES – “IT ALL DEPENDS”
Although standard measures to address given redevelopment challenges, as listed in Table 1, may be technically and economically viable, it is not as clear whether given jurisdictions will allow their use and a given redevelopment will be allowed (or encouraged). Issues such as: a) the legal and regulatory status of the landfill/dump property and activity, b) past, current, and future property ownership, and c) liability for existing or future contamination, may all be factors in the decision to allow or support a given project. Additionally, each of these factors is governed and interpreted according to laws and regulations that vary from state to state.