On November 8, 1984, the President signed into law the Solid and Hazardous Waste Amendments (HSWA) to the Resource Conservation and Recovery Act (RCRA). These amendments require the Environmental Protection Agency (EPA) to evaluate all hazardous wastes included in the list and characteristics to determine which wastes should be restricted from disposal on land. These restrictions are known as Land Disposition Restrictions (LDR). As a result, most hazardous waste must now be treated to comply with these regulations before being disposed of in hazardous waste landfills or permitted surface reservoirs. The LDR rule prohibits dilution of restricted waste as a substitute for adequate and effective treatment.
The fourth and final strategic level for laboratory waste management includes incineration, other treatment methods, and land disposal. Decisions within this level take into account the environmental fate of the waste and its components, as well as the by-products of the process once they leave the institution or company. The goal is to minimize the risk to health and the environment. Land disposal is generally considered to be the least desirable disposal method. While modern hazardous waste landfills can hold waste for many decades, there is always a future risk of leaks, contaminated runoff, or other harmful emissions to the environment.
Laboratories that ship chemical waste out of facilities must address land disposal restrictions and treatability standards, which were established to discourage landfilling. Other reasons to consider an environmental destination include exhibiting good environmental stewardship, teaching students and employees responsible waste management practices, and maintaining a good public image. There are several methods for the physical and chemical treatment of hazardous waste, as well as methods for recycling, recovery, and recovery of valuable materials contained in waste. Storing mixed waste for decomposition for more than 90 days may require approval from the state's hazardous chemical waste authority. Contracting for all hazardous waste disposal operations often has an advantage, especially for smaller facilities.
In most laboratories, aqueous waste, rinsing, and certain hazardous and laboratory waste (within limits) are allowed to be disposed of through the sanitary sewer. For example, replacing non-flammable liquid scintillation fluid (LSF) with toluene-based LSF reduces chemical-radioactive waste to radioactive waste. Incineration can destroy oxidizable organic chemicals and infectious agents; waste feed rates can be controlled to meet volatile radionuclide emission limits; and radioactive ash can be disposed of as dry radioactive waste. Most of these methods are for commercially available chemicals; therefore, approved analytical procedures may not be available for some laboratory chemicals. Federal regulations allow indefinite accumulation of up to 55 gallons of hazardous waste or 1 quart of extremely hazardous waste at or near the point of generation. The legal rules for accumulation of satellites are included in this section; they are also good practices for management of unregulated waste.
It is very important that laboratory staff accurately and fully identify and label all chemical and waste containers in their laboratory, as well as maintain the integrity of labels on source materials. Table 8.1 describes tasks needed to initiate off-site phase-out and provides recommendations on what staff should do internally and what should be hired to professional services companies. Other documents that are normally required for disposal include a land disposal restriction form, which provides information on proper disposal of each category of waste contained in manifest. There are no commercial mixed-waste disposal facilities for waste contaminated with most toxic metals (such as mercury) or for oils contaminated with lead.