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Bemidji
State University Reduces Chemistry Lab Waste by Almost 35%
Downsizing Instructional
Chemistry Lab Experiments
Company |
Bemidji State University, Chemistry Department, Bemidji, Minnesota |
Results |
Reduced chemistry lab waste by almost 35 percent. Reduced reagent use by 33 liters per year, saving $1,800 annually. |
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Bemidji State University (BSU) had an undergraduate
enrollment of 5,366 in the 1997-1998 academic year. The Chemistry
Department offered approximately 15 courses each year, with
115 students enrolled in the classes.
Incentives
for Change
In one year, BSU's chemistry
labs generated 57 liters of hazardous waste. The majority
of the waste, 38 liters, came from the organic chemistry labs.
Of those experiments, 90 percent produced hazardous waste.
The department wanted to reduce hazardous
waste from its instructional chemistry laboratories. It wanted
to reduce exposure to chemicals, decrease the likelihood of
spills and reduce the inventory of toxic materials. Achieving
these goals would increase student safety and decrease exposure
liability. The department also hoped to reduce the cost of
experiments. By better characterizing the lab waste, BSU hoped
to decrease the need to test it and allow for a less expensive
disposal method. Disposal cost for lab waste was greater than
the cost of reagents.
The department started integrating microscale
experiments in its general organic chemistry course in 1990.
For each experiment, half of the students used microscale
procedures and equipment. The other half used conventional-or
macroscale-glassware with semi-microscale procedures. Students
alternated in their use of the two techniques.
A MnTAP intern reviewed BSU's undergraduate
instructional chemistry laboratories during the summer of
1998. She identified alternative experiments and modified
current experiments to produce fewer types and smaller quantities
of hazardous waste. The intern's work built on some experiment
evaluation that the department had already done.
Bemidji
State University-Success at a Small Educational Institution
With the help of the intern, Bemidji State decreased lab waste
by nearly 35 percent and reduced reagent use by 33 liters
per year. The department estimates $1,800 in annual savings
from purchasing less reagent and reduced disposal cost. By
reducing inventory, it also has recovered storage space, allowing
for better organization.
Changes at BSU included scaling down additional
experiments to small and microscale, distillation and reuse,
and eliminating or finding alternative experiments. Over 90
percent of the savings from the intern project resulted from
microscaling experiments.
Education
and Lab Practices
The university's first priority was to meet all of the educational
objectives for teaching chemistry. Lab experiment changes
could not compromise learning.
Students need exposure to microscale techniques
and equipment. By promoting laboratory waste reduction, educational
institutions can train future generations of scientists to
be environmentally sensitive and conservation minded.
Microscale techniques teach precision and
accuracy. Working with reduced quantities of chemicals promotes
attention to detail, improving the quality of the science
being done. Students develop excellent laboratory manipulative
techniques and good lab practices. Also, shorter experiment
time is needed for reactions to occur.
Concerns. Bemidji State found that
students who are inexperienced in chemistry may have difficulty
producing a product in a microscale experiment. Without a
product to analyze, students potentially miss out on the learning
derived from product characterization. Some students may also
find this lack of success discouraging.
The National Research Council notes that
students who learn using microscale techniques need to understand
potential hazards-due to rates of reactions and the hazards
of exothermic reactions-when reactions are run on a larger
scale.
Eliminate,
Substitute Experiments
BSU eliminated the experiment Nine Bottles: An Adventure
in Chemical Identification. This eliminated a large quantity
of toxic precipitate waste produced from mixing solutions
for identification purposes.
Less hazardous reagents can substitute for
more hazardous ones. Bemidji State substituted sodium chloride
(NaCl) solution for isopropyl alcohol in its inorganic analytical
class's thin layer chromatography experiments. This change
also required adaptations in the food dyes. Now the experiment
generates no hazardous waste.
Scaling
Down
When the use of nonhazardous or less hazardous materials cannot
be avoided, many experiments still can be carried out on a
smaller scale. Scaled down experiments use smaller quantities
of reagents and result in smaller quantities of other waste-filter
cakes, filter papers, filtrate from washings, and distillation
residues.
Small Scale. According to Battelle
Memorial Institute, most macroscale experiments can be scaled
down by about 50 percent with little effort or cost, and without
sacrificing quality. This usually can be done using conventional
glassware.
Microscale. This reduces chemical
use to the minimum level at which experiments can be run effectively.
| Microscale
Experiments Reduce Chemical Use |
| |
Solids |
Liquids |
| Traditional |
10-50 g |
100-500 mL |
| Microscale |
25-100 mg |
100-2,000 mL |
|
| National Microscale Chemistry Center,
1995 |
Equipment. In general, revised laboratory
methods, glassware and means of chemical analysis are necessary
to carry out experiments on a microscale level. Smaller equipment
is required for these experiment. BSU had to purchase 96-well
plates, 24-well plates and disposable micropipets for General
Chemistry labs. The Organic Chemistry labs required the purchase
of microscale kits.
For many microscale experiments every day
supplies can be used. Toothpicks can be used as mixing rods.
Straws, forceps and a Beral pipette serve as a buret.
Glassware used in microscale procedures
is generally not as fragile as conventional glassware. Less
broken glass improves safety and decreases equipment cost.
Distillation
and Reuse
The BSU Chemistry Department's stockroom now distills
more spent solvents for reuse. BSU distills potassium acid
phthalate (KHP), standardized sodium hydroxide (NaOH) and
hydrochloride (HCl) for use in freshman analytical labs where
accuracy is less important. These less selective solvents
are used in initial washes to remove reactants from the bound
product. These washes are followed by a pure solvent. Staff
time for distilling was calculated in assessing the value
of reuse.
In some circumstances, the products of one
experiment can be used as reagents in another. This reduces
the amount of reagent purchased and eliminates waste shipping
costs. BSU's organic labs run a multistep synthesis using
products of one experiment as reagents for another. The extra
products from each step are saved to supplement the next class's
reagents. In BSU's thin layer chromatography experiments,
developing solvents are reused.
Additional
Considerations
Neutralizing acids and bases. Pure acid and base solutions
can be neutralized and disposed down the sewer. Although this
eliminates the shipping of waste, it is not a true waste reduction.
The amount of acids and bases must still be reported as hazardous
waste. The salt formed from neutralizing contributes to water
pollution.
More accurate labeling. Much of BSU's
lab waste was not properly labeled. As a result, the department
had to lab pack it-carefully pack together each waste in separate
containers for safe shipping. This method of disposal is much
more costly than bulking wastes that are readily identified.
Reviewing Your Experiments
- Assess What Waste is Generated
Review current laboratory experiments to determine the amount of reagents used, and the amount and type of waste produced.
Have the environmental services staff from facilities management determine if the waste from each experiment is considered hazardous by law. Bemidji State found that 35 of its 63 lab experiments produced hazardous waste. Twenty four experiments produced waste that was not hazardous but could be reduced.
- Outline Educational Objectives
Determine the desired educational objectives.
- Evaluate Experiments
See if the current experiments can be modified to produce less waste by changing a procedure or substituting another reagent.
Changing experiments can be time consuming. Plan for the greatest reduction possible. Many excellent sources for alternative experiments are available (see Additional Resources below). Assess the waste that will be generated from all the new experiments you are considering.
New experiments need to be tested for clarity.
A small number of students should test the new procedures
before full scale use in a classroom.
University
of Minnesota-Success at a Large Educational Institution
Using microscale techniques, the University of Minnesota,
Department of Chemistry, reduced the volume of waste generated
per student from 3.1 liters to 0.03 liters. With about 3,350
students enrolled in chemistry courses, total waste per year
is decreased from approximately 10,400 liters to 100 liters.
Changes to general chemistry undergraduate courses resulted
in $35,000 in savings annually. In 1992, revised experiments
were introduced to all chemistry labs.
More
Information
MnTAP has a variety of technical assistance services available
to help Minnesota companies reduce and manage their industrial
waste. If you would like assistance or more information about
MnTAP's Intern Program, call 612.624.1300 or 800.247.0015
from greater Minnesota.
Additional
Resources
A number of good sources are available for alternative experiments.
Here are a few favorites:
Davis, Michelle, et al. Laboratory Waste
Minimization and Pollution Prevention, WA: Battelle.
Schaap, T. Combs and J. Young, J., Microchemistry
1. West Chester, OH: Kemtec, 1996. pp 57-59.
Schaap, T. Combs and J. Young, J., Microchemistry
2. West Chester, OH: Kemtec, 1996. pp 55-56, 64-70.
Partnership
for Environmental Technical Education (PETE). North
Central PETE 319/398-5893.
This project was conducted in summer
1998 by MnTAP intern Sarah Grove, a chemistry junior at Bemidji
State University.
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