Best Practices to Prevent or Mitigate Air Quality Problems
• Conduct a risk assessment study of the area affected by the placement of central collections systems, incinerators, and sanitary and hazardous waste landfills. Determine the source of the risk, the quantity of the materials and gases being introduced into the ambient air, the nature of the risk, and potential effects on human health, ecosystems, and the general environment. Utilize the data in establishing the plan of operation, control, and how to deal with spills and emergencies.
• Identify specific chemicals being released, specific exposure assessment for humans and the environment, stability of the atmosphere, and prevailing wind patterns, and determine how best to protect workers, the community, food, land, and water.
• Use the Industrial Waste Air Model (IWAIR), which is an interactive computer program with three main components including: an emission model which estimates the release of constituents from waste management units; a dispersion model which estimates the fate and transport of the constituents in the atmosphere and determines ambient air concentrations at specific places; and a risk model that calculates the risk to exposed individuals or the concentrations of contaminants which may be managed successfully. All this information helps establish an appropriate plan for mitigation and control of potential air pollutants from a given unit. (See endnote 113.) The model is user-friendly and flexible but has certain limitations because it does not discuss the potential risk from a particular release or indirect routes of exposure. Other site-specific risk analysis models include AP-42 from the US EPA; Exposure Related Dose Estimating Module (ERDEM) from the US EPA; Landfill Air Emissions Estimation Model from the US EPA; etc.
• Control particulate matter, known as fugitive dust, from becoming airborne by: keeping unpaved roads wetted down with water or a chemical dust suppressant; limiting the vehicles within the landfill to a given area to avoid traveling substantial distances and creating more dust; washing the equipment in a special area with concrete floors and drains to trap the dust and fluid for treatment purposes; using experienced operators of equipment to avoid extra work which would create more dust; and using cover material at the end of each operation within the day and at the end of the day to prevent wind erosion.
• Control volatile organic compound emissions by: using pollution prevention and pretreatment procedures to reduce the risk of the chemicals; choose a site which is sheltered from wind by trees and make sure that the prevailing winds are such that the site is downwind from communities and businesses; enclose the units where possible with a flexible membrane, and capture the air and send it through air pollution devices to neutralize the volatile organic compound emissions by using techniques of carbon adsorption, biofiltration, condensation, absorption, and vapor combustion.
• Do not spray wastes on land if there are volatile organic compounds present.
Land and Superfund Sites
(also see Chapter 3, “Built Environment—Healthy Homes and Healthy Communities”)
Land has become contaminated from the illegal disposal of a large number of chemicals over many years from factories and businesses. There have been numerous examples of this action as exemplified by the Love Canal episode where chemical waste was buried in drums in an area that eventually became the yards and basements of homes and other structures. The drums corroded and leakage occurred. A total of 89 chemicals were identified, several of which were suspected carcinogens. It was not uncommon for various industries to bury their wastes on their land and then when the industry went out of business and the structures were torn down, the land was reused for other purposes. The land and the water on these sites are typically contaminated and this has led to contamination of other areas to which the chemicals have migrated. In some areas, specific land sites are set aside for hazardous waste land disposal facilities. These facilities must receive specific special permits to operate and for postclosure actions.
Best Practices for Land and Superfund Sites (See the sections on “Hazardous Waste Landfills”
and “Land Treatment of Wastewater” earlier in this chapter) (See endnote 114)
• Establish a Superfund site on the National Priorities List if an area of land has had uncontrolled hazardous waste placed there and it has the potential to damage human health or the environment or both. When the land has been abandoned, there are accidental spills or illegally dumped hazardous wastes, and there is a current or future threat to health or the environment, the EPA under the Superfund program will work closely with the communities and other individuals to test the conditions at the site, develop clean-up plans, and then clean up the site. The site once it has had all hazardous wastes neutralized or removed, can be reused for a variety of purposes that all enhance the community. Superfund sites are the country’s worst hazardous waste sites in comparison to brownfield sites which are also contaminated but are much smaller and easier to control.
• Obtain permits from the operating authority for the operation and closure of all land disposal facilities which include surface impoundments, waste piles, hazardous waste landfills, and both ground and below-ground tanks which have stored hazardous waste and have leaked into the surrounding soil and groundwater. The land disposal permits require information on the design and performance standards for the liner, the leachate collection and removal system, and the leak detection system; restrictions on the type and amount of waste; a waste analysis in writing; a facility inspection and maintenance program; a groundwater and surface water monitoring program; control systems for water from storms that either run onto the land site or run off of it; a plan for emergencies; and closure and postclosure plans.
See discussions on hazardous landfills, land treatment of waste, municipal solid waste landfills, and underground injection wells above. Also see: Chapter 11, “Sewage Disposal Systems”; Chapter 13, “Water Systems (Drinking Water Quality)”; and Chapter 14, “Water Quality and Water Pollution.”
More than 80% of the most serious hazardous waste sites in the United States have contaminated groundwater. Rainwater has percolated through the soil where hazardous waste has been buried and has carried the chemicals into the groundwater supply. Chemicals in the ground have corroded storage barrels and seep through openings in the soil and rock into the groundwater supply. Different chemicals which should never have been stored together have reacted, and the chemicals and byproducts have seeped into the groundwater supply. This is of great importance since the drinking water supply for half of the country comes from groundwater. Unfortunately, the cleanup of the groundwater supply is very difficult and may take many years to accomplish.
Best Practices in Preventing and Mitigating the Effects of Chemicals on the Groundwater
• Establish a groundwater risk evaluation study to determine the areas of contamination, the source of contamination, and the level of problems. An effective means of doing this is by utilizing the Industrial Waste Management Evaluation Model (IWEM). This is a threetiered approach with the first tier being based on national data and if it satisfies the need for establishing an appropriate system, this is fine. The second tier is used when the first one does not give enough data for the specific site. This includes in the model the most important site-specific factors in a simple manner and can be used by industry and various governmental agencies. If this does not provide enough data, then third tier is used where experts using groundwater modeling study the specific area and come up with the appropriate set of controls to mitigate the hazardous waste problems related to contamination of the groundwater supply.
• Make a determination of the leachate concentrations, their source and composition, and why they are moving through the ground into the groundwater supply. Various models are available for this purpose.
• Based on the previous data, determine the liner and the type and nature of the hazardous waste site, construct the necessary facility, and install the proper liners and various pollution control devices.
• Establish a leachate collection and treatment system which has appropriate warning systems.
Best Practices in Preventing and Mitigating the Effects of Chemicals on the Surface Water Supply
• Determine the quality as well as the level of microbiological and chemical contamination of surface bodies of water by conducting various tests.
• Do not permit discharge of pollutants to any waters of the United States unless specifically granted under special permits from the authorizing authority.
• Separate all wastewater from stormwater before it enters a surface body of water.
• Reduce stormwater discharges by a large number of barriers which help allow the water to seep into the groundwater supply. (See Chapter 14, “Water Quality and Water Pollution” for specific techniques.)