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Office of Security, Safety and Risk Management

Hazardous Waste Disposal

Waste Minimization

Disposal of waste chemicals, strictly regulated by EPA and DOT, is becoming increasingly expensive and difficult. Virtually all hazardous chemicals are now banned from landfills, leaving incineration as the main disposal route. It is imperative that researchers work to minimize disposal problems through the following measures:

  1. Purchase the smallest reasonable quantity of chemicals. Avoid the need to dispose of a surplus. Disposal cost is frequently much higher than the original cost of the chemical.
  2. Exchange surplus chemicals with other research groups. Check the inventory to be sure that the reagent in not already on hand. If a dated bottle is available, consider purification and using it.
  3. Reduce the scale of reactions whenever possible.
  4. Before running a reaction, consider the waste products produced and determine a safe disposal method. The Chemical Hygiene Officer may also be able to provide you with additional information.
  5. When possible, treat waste to reduce their hazards before packaging for disposal. A simple neutralization or oxidation may considerably downgrade the hazards of a reaction waste and make it easier to dispose of it.
  6. Consider alternative methods using less hazardous reagents.
  7. Recover and reuse solvents when feasible.
  8. Determine methods of decontaminating disposable (such as filter paper, tubing, weighing boats, etc) to allow disposal in trash or reuse. Contaminated non-chemical waste cannot be disposed of with the chemical waste.
  9. Above all, remember that it is the responsibility of the individual researcher to determine acceptable disposal procedures. If you do not know how to dispose of the waste safely and legally, do not buy the chemical and do not run the reaction! The department may be left with waste material that cannot be legally disposed of.

Disposal Methods

Most waste chemicals are disposed of annually through the supervision of the CHO. Waste solvent container located in some labs are for routine waste solvent of volumes of less than one liter. If you anticipate more than one liter of waste will be generated, it is better to collect the waste in a labelled bottle. When the bottle is full or you will no longer be adding waste to it, it can be stored in a safe place until the annual disposal.

A few chemicals cannot be disposed of in this manner, such as radioactives, metallic mercury and asbestos. Some nonhazardous materials, such as chromatographic supports, low-toxicity inorganic salts, and some water-soluble organics, may be disposed of in the trash or down the drain. Special procedures are given below for these exceptions.

Storage of Waste -- Each research group should establish chemical waste holding points. An enclosed cabinet is the preferred location, although open shelving may be acceptable. Storage of waste on the floor, with or without a tray , is unacceptable. Active collection bottles should be capped and generally should be kept in a hood. But do not allow the waste to accumulate more than one four-liter bottle.

Packaging

  1. Glass bottles are preferred for all waste. Polyethylene is acceptable for nonreactive solid waste. The main stockroom can supply small numbers of glass and polyethylene containers if your emptied reagent bottles are inadequate.
  2. Metal cans are not acceptable because they may corrode.
  3. Screw caps are required. Corks, rubber stoppers, and ground glass stoppers are unacceptable because they are not secure. An exception is a permanently frozen ground glass stopper. Indicate on the label that the stopper is frozen.
  4. Leaking containers are not acceptable. The most common cause of leakage is use of a cap from a different brand of solvent bottle. Caps are not always interchangeable and may not seal properly. Check for leakage by tilting the bottle. Vented caps also leak and are unacceptable.
  5. Fill containers only to the shoulder of the bottle to allow for thermal expansion.
  6. Size the container to the contents, e.g., do not dispose of one liter of liquid in a four liter bottle.
  7. Compatible chemicals may be combined to fill containers. For example, common nonhalogenated solvents such as acetone, ethanol, hexane and toluene may be combined. Do not combine halogenated and nonhalogenated solvents if at all possible; halogenated solvents must undergo more rigorous (and more expensive) treatment.
  8. The outside of containers must be free of chemical residues to avoid injury to personnel picking up the waste.

Labelling

  1. Before using a bottle as waste container, obliterate the original label unless it accurately describes the contents. Even if it does describe the contents, mark the label clearly "WASTE" while using it as a collection container, to prevent someone mistaking it for a pure reagent.
  2. Keep a running list, securely attached to the bottle, of each chemical added to the bottle. Do not rely on memory, especially if several people are using the same waste container. The final waste label MUST accurately reflect the contents of the bottle.
  3. Use a ballpoint pen or waterproof marker.
  4. Fill out the label completely, including the chemical names of all chemicals present. Generic classes such as "halogenated organics" are not acceptable. Waste chemicals cannot be disposed of without chemical names. "unknown" chemicals MUST be identified by the generator.
Metallic Mercury, Mercury Solutions and Compounds -- Metallic mercury should be collected for recycling. Mercury should be taken to Philip Waite in the chemistry main stockroom (ground floor, Ebaugh Laboratories). Mr. Waite maintains mercury containers into which you may deposit your mercury. This is for mercury only, not mercury compounds or debris from mercury spill cleanups. Solutions of mercury should be treated with sulfide to precipitate the mercury compounds before submitting for disposal. The resulting HgS is acceptable for disposal. Decant the supernatant liquid; do not filter it because you will not be able to dispose of the mercury-contaminated filter paper. Label mercury salts and arrange disposal in the normal manner.

Asbestos-Containing Materials -- The use of asbestos should be avoided if at all possible. However, if you do need to dispose of asbestos, first place it in plastic bags, label its origins and give it to the Chemical Hygiene Officer, Mr. Waite for disposal.

Pump Oil and Mineral Oil -- Uncontaminated waste oils (meeting specified levels of arsenic, chromium, lead, sulfur, halogens, and PCBs) are not considered hazardous waste. Vacuum pump or heating bath oil that you have no reason to believe is contaminated will be accepted for disposal by the Chemical Hygiene Officer, Mr. Waite. The following procedures apply:

  1. Plastic bottles are acceptable containers.
  2. Clearly label the bottle "Waste Pump Oil" (or mineral oil, as appropriate). Take it to the chemistry main stockroom and submit it to Mr. Waite.
  3. Do not use this procedure to dispose of oil mixed with solvents or other contaminants.
  4. Motor oil will not be accepted. Dispose of this through one of the local garages that accepts used motor oil, (BP station on Columbus Rd.).

If you know or have good reason to believe that waste oil is contaminated, label it as hazardous waste, including the chemical names and approximate levels of all contaminants.

Drain Disposal of Chemical Wastes -- Many organic and inorganic chemicals are suitable for disposal down the drain if they are water soluble to at least 3%, low toxicity, and (for organics) readily biodegradable. This includes many low-molecular weight organics containing oxygen or nitrogen, and soluble inorganics containing both cations and anions of low toxicity.

Avoid flushing inorganic salts containing heavy metals such as: chromium, lead, mercury, nickel, silver, cadmium, and antimony. In addition never flush down the drain cyanide or sulfide salts. These inorganic compounds should be precipitated out of the solution, separated from the supernatant liquid, and packaged and labelled for disposal.

If you are not sure the solution may be flushed down the drain, first check with a lab supervisor or the CHO to be sure it is not harmful to the environment. If it is OK to flush follow these precautions:

  1. Flush down the drain with large volumes of excess water.
  2. Neutralize acidic or basic inorganics before disposal.
  3. Dispose of only small quantities at one time (less than 100 g).
Disposal of Nonhazardous Chemicals Waste in Trash --Some solid chemical waste are considered nonhazardous by EPA criteria and may be disposed of by simply placing them in the trash baskets. These include sugars and starches; naturally occurring alpha-amino acids and their salts; citric acid and its salts; various insoluble or otherwise innocuous sulfates, oxides, carbonates, and other salts; and chromatographic adsorbents (silica gel, alumina) and molecular sieves, if not contaminated with hazardous chemicals. These may be disposed of in the ordinary trash using the following precautions:
  1. Remove solvents from adsorbents.
  2. Package materials in at least two layers e.g., plastic bags or jars, packed in a cardboard box.
  3. Affix an identifying label to the inner packaging so its identity may be determined in cast the packaging breaks open. Do not label as Hazardous Waste.
  4. Deposit the package in the dumpster yourself. The custodians will not handle even nonhazardous chemical waste.

Empty Glass Containers -- Bottles and unbroken glassware MUST be empty and cleaned inside and out before they are placed without a cap in the trash. It is imperative that no flammable vapors are remaining in bottles when they are placed in the trash. If the contents are water soluble and not toxic, rinsing them with water several times should suffice. If the contents are not water soluble, the bottle should be rinsed several times with an appropriate solvent such as alcohol or acetone and the rinsing treated as waste solvent. Traces of residual water can remain in the bottles; residual solvents should be allowed to evaporate in the hood before the bottle is discarded. Discard only clean containers to avoid injury to persons emptying the trash.

Broken Glassware -- In each laboratory a "sharps container" should be available for broken glassware. If you break a common piece of laboratory glassware such as a beaker or flask, the pieces should be collected in a dust pan and deposited into oneof the sharps container. The exception to this is any glassware that might have salvageable parts such as ground glass joints. Ask the laboratory supervisor if you arenot sure. These sharps container are not intended for sample vials or empty glass containers. Broken mercury thermometers should not be placed in these containers.