Hazardous Waste Minimization

An essential element of any successful hazardous waste management program is that of waste minimization. Limiting the quantities of hazardous wastes being generated benefits the University in a number of ways. Most importantly, it reduces the risks associated with hazardous materials to University students, faculty, and staff. Secondly, it decreases the amounts of hazardous wastes which need to be safely handled, stored, and eventually moved from the various points of generation to the University's waste storage facility. Finally, it reduces the costs of packaging, transportation, and disposal.

A number of methods can be used to minimize the amounts of hazardous wastes being generated. A variety of methods are identified below including an explanation of how the techniques can be applied. This review should assist in determining which techniques can be used in your particular situation. Any questions regarding waste minimization may be directed to the Hazardous Waste Coordinator in the Department of Environmental Health and Safety (EHS) at 372-2173.



The PRIMARY option for waste minimization is the replacement of a hazardous material (according to 40 CFR 261) with a less or non-hazardous material. A major consideration in successful substitution is whether the substituted material provides acceptable results. Optimally, the determination of whether substitution is possible should be made prior to obtaining the new material.

Initially, hazardous materials need to be identified. Reviewing product inventories and examining the uses of existing materials can detect materials that are potential candidates for substitution. Once identified, the individual having the administrative responsibility for the use of the material should investigate the substitution potential. This may be accomplished by requesting information from the manufacturer or supplier of alternative products. A Safety Data Sheet (SDS), formerly known as Material Safety Data Sheet (MSDS) or product label should be obtained for the potential substitute (as well as for all chemical materials on hand) to verify its "less or non-hazardous" status. A pilot application of the material should then be initiated to determine the effectiveness of the product during actual use. Unless unreasonable purchase price differences exist between the hazardous material and the less hazardous/non-hazardous substitute, replacement of the hazardous material in question should proceed. In an academic setting, identifying viable chemical substitutes may be difficult. Contact with colleagues or chemical suppliers may be useful in obtaining information on potential substitutions. Assistance in determining th hazardous/non-hazardous status of the product or material may be obtained through EHS as indicated above.


Implementing an on-going chemical inventory management system will serve to reduce the amounts of overstocked chemicals that would require additional management. Even though other waste minimization options may still be available for management of these additional chemicals, it should not be necessary to have to deal with over-stocked chemicals.


If substitution for the hazardous materials cannot be accomplished, a SECOND option would be using micro-quantities of the material. Reducing these amounts decreases the quantities of hazardous wastes that require formal handling. Initial expenditures may be necessary for equipment needed to implement the micro-quantity techniques. However, once these "start-up" costs have been defrayed, an on going cost savings should be realized by limiting the purchase of virgin materials. Again, in order for this minimization technique to be viable, the process must achieve the intended results.


The management techniques addressed in this section mainly apply to academic settings. Only individuals experienced in the technique (i.e. treatment) and the materials with which they are working should consider implementing any of the procedures identified below.

The information provided has been taken in part from Prudent Practices for Disposal of Chemicals from Laboratories, National Academy Press, Washington, D.C., 1983. These methods of disposal are acceptable to the Wastewater Treatment Division for the City of Bowling Green and the Ohio EPA.


With appropriate dilution (100 times the volume), there are certain organic and inorganic compounds that can be properly disposed of in the sanitary sewer system in quantities of approximately 100 grams at a time. As a general rule, water-soluble organic compounds with a boiling point <50o C should not be disposed of in the sanitary sewer system. The compounds identified below are water soluble to at least 3% and present a low toxicity hazard. The organic compounds listed on the following pages are readily biodegradable. Some chemicals suitable for drain disposal are:

Organic Chemicals


Alkanols with less than 5 carbon atoms
t-Amyl alcohol
Alkanediols with less than 8 carbon atoms
Sugars and sugar alcohols
Alkoxyalkanols with less than 7 carbon atoms


Aliphatic aldehydes with less than 5 carbon atoms


RCONH2 and RCONHR with less than 5 carbon atoms
RCONR2 with less than 11 carbon atoms


Aliphatic amines with less than 7 carbon atoms
Aliphatic diamines with less than 7 carbon atoms

Carboxylic Acids

Alkanoic acids with less than 6 carbon atoms *
Alkanedioic acids with less than 6 carbon atoms
Hydroxyalkanoic acids with less than 6 carbon atoms
Aminoalkanoic acids with less than 7 carbon atoms
Ammonium, sodium, and potassium salts of the above acid classes with less than 21 carbon atoms
Chloroalkanoic acids with less than 4 carbon atoms


Esters with less than 5 carbon atoms
Isopropyl acetate

Those with disagreeable odor (i.e. dimethylamine, 1,4-butanediamine, butyric and valeric acids) should be neutralized and the resulting salts disposed of in a sanitary sewer drain with at least 1000 volumes of water.


Ketones with less than 6 carbon atoms



Sulfonic Acids

Sodium or potassium salts of most are acceptable

Inorganic Compounds

Compounds of any ions listed below which are strongly acidic or basic should be neutralized before being disposed of in a sanitary sewer drain.

Cations Anions
Al3+ (BO3)3- , (B4O7)2-
Ca2+ Br-
Fe2+, Fe3+ (CO3)2-
H+ (HSO3)-
K+ (OCN)-
Li+ (OH)-
Mg2+ I-
Na+ (NO3)-
(NH4)+ (PO4)3-
Sn2+ (SO4)2-
Sr2+ (SCN)-
Ti3+,Ti4+ Zn2+


If other methods of waste minimization are inappropriate for your particular situation, a final option may be chemical treatment of the hazardous waste generated during use. Neutralization, precipitation, oxidation/reduction, and distillation are examples of treatment techniques that may be applied to reduce hazardous waste quantities.

REMINDER: All of the treatment procedures identified below necessitate the involvement of an individual experienced in such activities.

Neutralization involving acids and bases is the most common type of treatment. Adjustments in pH can be made to neutralize a highly acidic or highly alkaline solution. A final pH level of between 6 and 9 is desirable. If the solution contains no other hazardous component as defined by 40 CFR 261 (i.e. one which is toxic), the neutralized solution can be treated as normal waste and disposed of in a sanitary sewer drain with proper

Precipitation and oxidation/reduction reactions can remove hazardous components from waste. Disposing of these materials may then be accomplished through normal means. Precipitates from these reactions may need to be treated more effectively in a formal disposal mode.

Incorporating treatment procedures as a part of experimentation within teaching laboratories serves a dual purpose. It not only reduces the hazardous wastes being produced, but it also teaches students responsible waste management. Providing students with the knowledge and understanding of correct minimization techniques would seem only to benefit the future generations of scientists.

An alternative to specific destruction of hazardous wastes in teaching laboratories would be to include within another experiment the hazardous waste generated. This procedure would serve the purpose of limiting waste production as well as supplying the "raw" materials for additional experimentation.

Recycling of spent materials (mainly solvents) allows the handler the opportunity to reuse material that would otherwise be disposed as hazardous waste. This procedure also reduces the need to purchase additional quantities of "fresh" product which, in turn, decreases overall departmental expenditures. The major factors involved when considering recycling are whether sufficient quantities of recyclable wastes are being generated to warrant the expense of appropriate distillation equipment and whether the quality of the recycled material is acceptable for reuse.

Both of the latter two alternative waste handling methods require prior planning in order to be incorporated within teaching lab activities. The benefits of doing so would be directed to the University (minimizing risks, overall waste reduction, lowering management costs), the academic department (minimizing waste generation, limiting waste handling), and the students as well (learning proper waste management responsibility, realizing the University's commitment to the reduction of hazardous waste).


In order to adequately reduce the quantities of hazardous waste which necessitate formal disposal, the University must be committed to the implementation of waste minimization procedures. Academic and nonacademic departments alike must share this common goal of waste reduction. Together, through cooperative efforts in conjunction with the Department of Environmental Health and Safety, University departments and areas have the ability to achieve this goal. Implementing waste minimization procedures will not only result in posing less of an environmental hazard to students, faculty, and staff, but it should also result in costs savings to the individual departments as well as to the University in general.