When safe and allowed by regulation, disposal of nonhazardous waste via the normal trash or sewer can substantially reduce disposal costs. Many state and local regulations restrict or prohibit the disposal of waste in municipal landfills or sewer systems, and so it is wise to check the rules and requirements of the local solid waste management authority and develop a list of materials that can be disposed of safely and legally in the normal trash. The common wastes usually not regulated as hazardous include certain salts (e.g., potassium chloride and sodium carbonate), many biochemicals, nutrients, and natural products (e.g., sugars and amino acids), and inert materials used in a laboratory (e.g., noncontaminated chromatography resins and gels). In some places, the laboratory’s hazardous waste disposal firm may assist with disposal of nonregulated materials.
8.B.6 Treatment and Disposal Options
As described in the introduction to this chapter, the third tier of waste management entails reclamation and recycling of materials from the waste. These methods should be considered in conjunction with the fourth tier, disposal. Reclamation, recycling, and disposal methods for chemical hazardous waste are described in this section.
The question of what forms of treatment are allowed under federal regulations poses a dilemma for laboratory professionals. Federal regulations define treatment as “any method … designed to change the physical, chemical, or biological character or composition of any hazardous waste so as to neutralize such waste, or so as to recover energy or material resources from the waste, or so as to render the waste nonhazardous or less hazardous ….” In most cases, treatment requires a state or federal permit. The regulatory procedures and costs to obtain a permit for treatment are beyond the resources of most laboratories. Under federal law, laboratory treatment of chemical hazardous waste without a permit is allowed in the following instances:
• small-scale “treatment” that is part of a laboratory procedure, such as the last step of a chemical procedure;
• a state that allows “permit-by-rule,” treatment, that is, by allowing categorical or blanket permitting of certain small-scale treatment methods;
• elementary acid-base neutralization; and
• treatment in the waste collection container (see section 8.D for regulatory information).
Of course, treatment restrictions apply only to chemical hazardous wastes that are regulated by EPA. Some biological toxins not listed by EPA can be easily denatured without a permit by heat or an appropriate solvent. No permit is required to irretrievably mix small amounts of controlled substances (not regulated by EPA) into bulk waste flammable solvents. Because illegal waste treatment can lead to fines, it is most important that, before carrying out any processes that could be considered treatment, the responsible laboratory personnel or the institution’s EHS office check with the local, state, or regional EPA to clarify its interpretation of the rules. Some states do allow small-scale treatment of waste, but many do not.
(Section 8.D, below, provides methods for small-scale treatment of common chemicals.)
To minimize costs and manage laboratory waste most efficiently, it is important to consider treatment and disposal options as early as possible, and plan ahead. For example, the method of waste collection impacts how waste will be stored, as well as its efficient transfer to a treatment or disposal facility. In addition to the hazard reduction procedures described above, laboratories utilize several treatment and disposal options because of the great variety of waste generated, and because each option (described below) has its own advantages for Specific wastes, and so planning can be difficult. Although landfill disposal is not described separately below, it is often the disposal method for encapsulated waste, treatment residues, and ash from incineration. Note that disposal options change as technology and environmental concerns change. When feasible, waste minimization is always a best practice. (See Chapter 5, section 5.B, for step-by-step instructions on source reduction, and section 8.C, below, for general information on minimizing hazardous waste.)
8.B.6.1 Treatment and Recycling
There are various methods for physical and chemical treatment of hazardous wastes, as well as methods for recycling, reclamation, and recovery of valuable materials contained in the waste. These methods include neutralization, oxidation-reduction, distillation, digestion, encapsulation, and several forms of thermal treatment. While the expense and practicality of these technologies is largely based on the specific nature and volume of the material, treatment or recycling is preferable to incineration for some hazardous wastes. For example, high- and low-pH wastes may be neutralized, resulting in treatable wastewater and salts. Incineration of mercury and other toxic metals is restricted; recycling, recovery, or encapsulation is environmentally preferred. Filtration of aqueous-based wastes may also significantly decrease volumes and result in wastewaters suitable for treatment in a sewage treatment facility. Note that recycling and reclamation extend to reclamation of energy as well as materials,