Contaminated ’’Brownfields” sites

The process can handle a wide range of materials, including heavy metal contaminated wastes. It is very fast compared to conventional processes and produces an easily handled product that can be used in construction. Waste CO2 can be captured and converted into carbonate to yield carbon credits. Target applications include pre-treatment of waste prior to disposal, recychng and reuse of industrial waste, and remediation of contaminated brownfield sites. 

Lead at a lightly contaminated brownfield site has a concentration in soil of 600 mg/kg to a depth of 1 ft. The cleanup standard has been set at 400 mg/kg. Indian mustard, Bmssica juncea, will be planted, fertilized, and harvested three times each year for phytoextraction. Using small doses of EDTA, it is possible to achieve concentrations in the plant of 5000 mg/kg (dry weight basis), and harvestable densities of 2.721 (3 short tons) dry matter per crop. Estimate the time required for cleanup ... 

Many large cities are ced with soil contamination problems inherited from past industrial activities. There are some 3,000 contaminated "Brownfields" sites in Canada (1) and some 450,000 such sites in the United States (2). A number of these urban sites within the Idand of Montreal, have mixed contamination problems. Ha dous (mixed) contamination can be found in soils and groundwater where it commonly corresponds to a mfarture of inorganic and organic contaminants. Lands that contain such contaminants, in varying concentrations, caimot be redeveloped unless they have been decontaminated. 

The biopUe process was used at brownfield site in Hackensack, New lersey. This site was contaminated with TPH at concentrations averaging 18,000 ppm. Twenty-two thousand cubic yards of soil at the site were treated, and final TPH concentrations were less than 1000 ppm. The cost for this project was 500,000, which was less than the 10 million estimate for using an alternative treatment technology (D21947Q, pp.3, 4). 

At a brownfield site in Illinois, the biopile process was used with air sparging to treat soils contaminated with petroleum hydrocarbons and by-products of asphalt production. Treatment at the 13- to 15-acre site occurred for one year, and site closure was achieved as a result of the process. The project cost was approximately 100,000, which was significantly less than the estimated cost of landfilling the contaminated soil (D21948R, pp. 3, 5). 

In 1999, HRC was used with other treatment technologies at a brownfield site in Aurora, Colorado. An in situ air sparge/soil vapor extraction system was first used at the site to treat TCE contamination however, additional measures were needed to prevent the migration of PCE off-site. After an unsuccessful application of zero-valent iron injection, 240 lb of HRC were injected at five locations by direct-push methods. Total project costs were 110,000, which... 

Industrially contaminated soil. The investigation, remediation (where necessary) and re-use of derelict and industrially contaminated land is a major concern, particularly in developed countries where legislation exists or is being enacted to promote re-use of brownfield sites and discourage greenfield development. 

Under CERCLA and similar state hazardous waste laws, liability for contamination at a site is strict, joint and several, as well as retroactive. Anyone who was ever involved with the site—generators of hazardous substances, transporters of materials to or from the site, and any past or present owner—can all be held liable for the costs of cleanup. A fear of perpetual liability kept many private buyers, developers, lenders, and potential future owners of contaminated properties from investing in brownfields sites. 

For many years, prospective owners or investors shied away from undertaking the first step—site assessment—needed to determine the actual condition of a brownfields site. In fact, a significant percentage of brownfields sites have only limited amounts of contamination, and much of the contamination present does not pose a threat to human health or safety. Despite this reality, the fear of lengthy and costly site assessment requirements have impeded brownfield redevelopment. 

In addition, the 2002 Brownfields Law addressed investor and community concerns about future liability for contamination at brownfields sites, even after they have undertaken cleanup and redevelopment. The act relieved prospective purchasers and other innocent landowners from future liability for contamination if they take reasonable steps to identify and prevent release of any hazardous substances at the time they purchase or acquire a brownfield property. 

The 2002 Brownfields Law greatly expanded the availability of Federal funds for brownfields cleanup. In addition to revolving loan funds, US EPA now offers direct grants to allow communities and nonprofit organizations to clean up brownfields sites. Eligible entities may apply for up to 200,000 per site, and may use the funds to address sites contaminated by petroleum and hazardous substances. The grants require a 20% cost share, which may be in the form of a contribution of money, labor, material, or services, and must be used for eligible and allowable costs. 

The remainder of this report will demonstrate the successful application of several of these innovative financial, technical, and policy approaches to a brownfields site in urban Connecticut. This case study will highlight the contribution of these new approaches to the success of this brownfield redevelopment project. Without the changes in the US brownfields program that have evolved over the past decade, this contaminated site would have continued to languish for many more years, continuing to contribute to community degradation and local blight. 

Hazardous-waste disposal is the cradle-to-grave management of materials that threaten human health and the environment. Hazardous wastes are ubiquitous and their proper disposal is a global issue. In fact, industrialized nations are stiU involved in cleanup of hazardous wastes that contaminated land and waters before disposal laws were adopted and enforced. One method of recycling hazardous waste sites is to clean up the wastes and designate the land as a brownfield site that can be reused by commercial and industrial enterprises. 

Laidler, D. W., ed. 2002. Brownfields Managing the Development of Previously Developed Land. London CIRIA (C578). Very much aimed at the management of the development of brownfield sites rather than the detailed technical measures necessary to deal with issues, such as contamination. 

Sladen J. A., Parker A. and Dorrell G. L. (2001) Quantifying risks due to ground gas on brownfield sites. Land Contamination and Reclamation, 9(2), 191-207. 

As the value of real estate continues to increase, developers have mmed to sites that have been previously deemed too difficult to develop owing to poor soil conditions and/or topography. These sites include soft soils that require ground improvement or removal and replacement with suitable soils. In urban areas, commercial housing has been developed on former industrial or brownfield sites. These sites require barriers below the proposed structures to separate potential contaminants and vapors from the soil or rock beneath them. 

The U.S. EPA has identified some historically contaminated areas as Superfund sites. What does this mccm for someone living near a Superfund site Recently, redevelopment agencies have begun to redevelop properties that have long been unused because of chemical contamination. These cu e known as Brownfield sites. How much cleanup is needed at these sites before it is Scife to use the property It is safe to live or work there ... 

Table 2 presents vendor-supplied cost estimates for implementing their frozen barrier technology at brownfield redevelopment sites. Costs for RKK s system are compared with costs for a sheet pile wall barrier. The estimates are based on the cost of containment at a 3.5-acre site with contamination 50 ft below ground surface (D221647, p. 3). 

TABLE 2 Vendor-Supplied Cost Estimates for Using Frozen Barriers and Sheet Pile Wall Barriers at Brownfield Redevelopment Sites (Assumes a 3.5-Acre Site with Contamination 50 Ft Deep)... 

The Town of Greenwich realized that the costs of cleanup were going to be well beyond the capability of the community to pay. In 2004, the town applied for a US EPA brownfields cleanup grant. In its grant application, the town stated that it is committed to redeveloping the site as a public access and recreational park and that it planned to use the grant to excavate PCB-contaminated soil to depth of 4 ft over an area of approximately one-quarter acre. The town committed to backfilling the excavation with clean material, possibly from a local construction project. 

Although Part IIA is essentially an enforcement regime, it is intended to play a part in encouraging the voluntary remediation of land affected by contamination. For example, the discussion above of the Government s objectives in introducing Part IIA noted the role in this process of reducing uncertainties about residual liabilities on brownfield development sites. 

Restoration of brownfields may entail physical remediation as well as treatment or removal of chemical contamination. Often, particularly where they are located at abandoned mine sites, brownfields are afflicted by subsidence. In some cases, concrete and stone salvaged from old structures and their foundations can be used as fill to treat subsidence. Some kinds of chemical contamination can be treated in place. If excavation and disposal of contaminated soil is required, the costs of brownfield restoration may increase dramatically. 

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