How to Keep Hazardous Wastes from Haunting YouBack to The PIG® Library
Under the Resource Conservation Recovery Act (RCRA), facilities remain liable for the hazardous wastes they generate, from cradle to grave. Because of the magnitude of this responsibility, it is essential for waste generators to know what disposal options are available, so that they can choose the best options for their waste streams.
Qualified hazardous waste contractors can suggest legal disposal methods. However, it is in the generator's best interest to be familiar with common treatment and disposal options, and to understand the advantages and disadvantages of each.
Landfilling has traditionally been the least expensive disposal option. However, buried waste has a way of coming back to haunt generators. Indeed, many Superfund sites being remediated today were once legal landfills.
Historically, all waste was accepted into landfills. Now, regulations severely restrict what can be accepted. Today, only EPA-permitted landfills can accept hazardous wastes. However, before these landfills will accept wastes, they often must meet strict standards that sometimes involve pretreatment.
Today's landfills are engineered to prevent leaks with systems that collect all runoff and leachate. In addition, landfills are required to have high-tech monitoring and leak detecting systems. However, many landfills have been shut down and many more are reaching capacity. Moreover, increased concern for the environment is preventing new landfills from being built.
Pretreatment includes processes such as neutralization, which renders certain wastes less hazardous by raising or lowering their pH. The neutralized waste can then be further treated, incinerated or disposed of in an approved landfill. Stabilization may also be required. Stabilization mixes lime, fly ash or other substances with a toxic waste to produce a solid, impermeable mixture that will not leach when placed in a landfill. If a generator chooses to engage in pretreatment practices, treatment permits are usually required.
Deep well injection disposes of hazardous waste in underground steel or concrete encased shafts. Wastes are deposited under pressure into the shafts placed deep in the earth. In some areas, suitable geology prevents contact with usable groundwater. However, not every site is suitable and some wells that were believed to be safe have leaked into sources of drinking water, costing generators millions of dollars in cleanup costs.
Incineration is one of the best options for wastes that contain either listed or characteristic toxic organic compounds, such as solvents. In fact, regulations require thermal destruction for some of these wastes. Temperatures ranging form 1000 degrees to 2500 degrees F can achieve high destruction efficiencies. Federal law requires incinerators to operate at destruction efficiencies of 99.99% for many hazardous organic constituents. However, incineration does produce a quantity of ash, which needs to be disposed of as hazardous waste usually in a landfill.
The chief advantage of incineration is that it destroys many toxic constituents rather than merely containing them. This limits the risk to the environment and the generator's liability. While incineration has traditionally cost more than disposal in a landfill, ever-increasing costs for wastes in landfills are beginning to narrow the gap.
Burning in boilers and industrial furnaces is becoming a very popular option for wastes such as used oil. The used oil is used as feedstock for the furnace, producing usable energy or heat. Boilers and furnaces are not permitted in all states, however.
Supplemental fuels programs take advantage of the fuel value in many organic wastes. Commercial firms, known as fuel blenders, convert wastes to produce a fuel with a high heat value. Wastes are delivered to licensed and regulated cement kilns or other processing facilities to supplement their fuels resources. Burning in cement kilns is a particularly effective way to dispose of hazardous waste because of the constant rotary action, long residence time and high temperatures (exceeding 2500 degrees F). Any residues remaining after the burning are incorporated into the cement without effect to the environment or product quality. Costs to the generator are generally less than incineration, yet still somewhat more than landfilling. The greatest benefit to the generator is the minimization of future liability because no residues have to be landfilled.
Other disposal options are also available, and one disposal method may not be the best for all of waste streams generated by a facility. The EPA has published a guidance document entitled RCRA: Reducing Risk from Waste that helps explain generator liability and the problems presented by hazardous waste disposal. Click here to view a copy of this document at http://www.epa.gov/epawaste/inforesources/pubs/risk/risk.htm.