DISPOSAL OF LABORATORY WASTES TO
SANITARY SEWER
Guide for Drain Disposal of Laboratory
Chemicals
1.0 INTRODUCTION
MSU Safety and Risk Management
(SRM) prepared this guide with assistance from various resources in the
toxicology, chemistry, and environmental sciences.
Staff at the Bozeman Area
Waste Water Treatment Plant, the destination of MSU’s wastewater, were
consulted in developing these guidelines to assure that local government
regulations are followed.
2.0 RESPONSIBILITIES
Within
individual laboratories, authorization for specific operations, delineation of
appropriate safety procedures and instruction about these procedures is a
responsibility of the principal investigator (PI).
It is the responsibility
of each MSU laboratory worker to be sure that chemical waste generated from his
or her activities is disposed of properly.
Some materials can be safely let into the sanitary sewer and others can
cause damage to health, the environment, or the functioning of the wastewater
plant.
Inappropriate
chemicals put down the drain may be incorporated into sludge formed in
wastewater treatment, contaminating it enough to be classified as a hazardous
waste where otherwise it might have been recycled. After treated wastewater
leaves the plant, it flows to East Gallatin River, a major recreational and
drinking water resource for this area. The stewardship of this important
natural resource is our collective responsibility.
Laboratory
workers should consult this guide before undertaking drain disposal of any lab
chemicals.
3.0 GENERAL GUIDELINES
Send down the drain only those materials found on the safe list.
Compounds not listed are not suitable for drain disposal.
Drain disposal must only be used when the drain flows to a sanitary
sewer system* which eventually goes to the wastewater treatment plant. Storm
drain systems flow directly into surface water (East Gallatin for example) and
should NEVER be used for chemical disposal.
Laboratory sinks should be used for disposal of chemicals on the safe
list as discussed below.
Quantities of chemical waste
for drain disposal should be limited generally to a few hundred grams or
milliliters or less per day.
Larger amounts should have prior approval from Chemical Safety. Only materials listed as safe for drain
disposal in this document are approved for drain disposal in quantities up to
100 grams or 100 milliliter per discharge.
Disposal should be followed by flushing with at least 100-fold excess of
water at the sink. (That means for 100 ml of chemical run the water for about
two minutes at maximum flow.)
Understand the hazards and
toxicity of the materials you work with by consulting material safety data
sheets (soon to be available in every department). Work slowly to avoid
splashes and wear the proper protective equipment (lab coat, goggles, face
shield, gloves) during drain disposal.
*Sanitary sewer is the
system of sinks, toilets, drains and associated pipes that send wastewater to a
treatment plant where it is biologically and chemically treated before
discharge into the environment.
The MSU Chemical Safety Team
will collect chemicals that are not appropriate for drain disposal. See appropriate section.
4.0 NOT SAFE
FOR DRAIN DISPOSAL
THE FOLLOWING MATERIALS ARE PROHIBITED FROM DRAIN
DISPOSAL BY THE CITY OF BOZEMAN:
Ashes, cinders, sand, mud,
straw, shavings, metal, glass, rags, feathers, tar, plastics, wood, manure,
hair and fleshing, entrails, paint residues, solid or viscous substances
capable of causing obstruction to the flow of sewers.
Some chemicals that are not
appropriate for drain disposal include:
Halogenated hydrocarbons
Mercaptans
Flammables (immiscible in water)
Explosives such as azides and peroxides
Water soluble polymers that could form gels in the
sewer system
Water reactive materials
Malodorous chemicals
Toxic chemicals such as carcinogens, mutagens,
teratogens
Substances that boil below 50° C.
Mixtures that have a component not found on the safe
list.
Any material not found on the safe list.
Check with Chemical Safety
at 994-3572 if you are not certain about drain disposal for a particular
material. We may also be able to provide you with instructions for laboratory
detoxification for some materials.
5.0 SAFE FOR DRAIN DISPOSAL
Dilute solutions of
inorganic salts where both cation
and anion are listed below are suitable for drain disposal. Materials listed are considered to be
relatively low in toxicity. Compounds of any of these ions that are strongly
acidic or basic should be neutralized before drain disposal.
Cation Anions
Al+3 BO3-3
Ca+2 B4O7-2
Fe+2, +3 Br-
H+ CO3-2
K+ Cl-
Li+ HSO-3
Mg+2 OCN-
Na+ OH-
NH4+ I-
Sn+2 NO3-
Sr2+ PO4-3
Ti+3, +4 SO4-2
Zr+2 SCN-
Mineral acids and bases
should be neutralized to pH 5.5 to 9 range before disposal, following
procedures in Appendix A.
Copper and Zinc have
specific discharge limits required by the Sewage Treatment Plant. Contact
Chemical Safety at 994-3572 prior to discharging any copper or zinc solutions.
Materials listed below in
quantities up to about 10g or 100 ml at a time are suitable for disposal
down the drain while flushing with excess water. These materials are soluble to
at least 3 percent; present low toxicity hazards and are readily biodegradable. Larger volumes must be collected by the
Chemical Safety Team.
methanol
ethanol
propanol and isomers
butanol and isomers
Alkanediols with 7 or fewer
carbon atoms
ethylene glycol
propylene glycol
butylene glycol
butanediol + isomers
pentylene glycol
pentanediol + isomers
hexylene glycol
hexanediol + isomers
heptamethylene glycol
heptanediol + isomers
Alkoxyalkanols with 6 or
fewer carbon atoms:
methoxyethanol
ethoxyethanol
butoxyethanol
2-methoxyethoxyethanol
n-C4H9OCH2CH2OCH2CH2OH (2(2-butoxyethoxy)
ethanol)
Aliphatic aldehydes with 4
or fewer carbon atoms:
formaldehyde (10% or less aqueous
solution) <100mls per discharge!!
propanal (propionaldehyde)
butanal (butyraldehyde)
isobutyraldehyde
RCONH2 and RCONHR with 4 or
fewer carbon atoms and RCONR2 with 10 or fewer carbon atoms:
formamide
N-methyl formamide
N,N-diethyl formamide
N,N-dimethyl formamide
N-ethyl formamide
acetamide
N-methyl acetamide
N,N-dimethyl acetamide
N-ethyl acetamide
propionamide
N-methyl propionamide
N, N-dimethyl propionamide
butyramide
isobutyramide
Aliphatic amines with 6 or
fewer carbon atoms:
methylamine
ethylamine
trimethylamine
N-ethyl methylamine
N-methyl propylamine
dimethyl propylamine
isopropylamine
1-ethyl propylamine
butylamine
methyl butylamine
N-ethyl butylamine
isobutylamine
amylamine
hexylamine
Aliphatic diamines with 6 or
fewer carbon atoms:
1,2- or 1,3- propanediamine (1,2- or 1,3-
diaminopropane)
*Amines with a disagreeable
odor, such as dimethylamine and 1,4-butanediamine should be neutralized, and
the resulting salt solutions flushed down the drain, diluted with at least 100
volumes of water. Disposal limit is 100ml of material.
Alkanoic acids with 5 or
fewer carbon atom: *
formic acid
acetic acid
propionic acid
butyric acid*
isobutyric acid
valeric acid*
isovaleric acid
Alkanedioic acids with 5 or
fewer carbon atoms:
oxalic acid (1,2-ethanedioic acid)
malonic acid (1,3-propanedioic acid)
succinic acid (1,4-butanedioic acid)
glutaric acid (1,5-pentanedioic acid)
Hydroxyalkanoic acids with 5
or fewer carbon atoms:
lactic acid (2- hydroxypropanoic acid)
3-hydroxybutyric acid
2-hydroxy isobutyric acid
Aminoalkanoic acids with 6
or fewer carbon atoms and the ammonium, sodium and potassium salts of these
acids.
Amino acids and the ammonium,
sodium and potassium salts of these acids.
*Organic acids with a
disagreeable odor, such as butyric acids and valeric acids should be
neutralized and the resulting salt solutions flushed down the drain, diluted
with at least 100 volumes of water. Disposal limit is 100 ml. of material.
Esters with 4 or fewer
carbon atoms:
methyl formate
ethyl formate
isopropyl formate
propyl formate
methyl acetate
ethyl acetate
methyl propionate
Isopropyl acetate
Ketones
Ketones with 4 or fewer
carbon atoms:
acetone
methyl ethyl ketone (butanone)
methyl isopropyl ketone (3-methyl
butanone)
Sulfonic Acids and the
Ammonium, Sodium, and Potassium Salts of these Acids:
methane sulfonic acid, sodium or potassium
salt
ethane sulfonic acid, sodium or potassium
salt
1-propane sulfonic acid, sodium or
potassium salt
1-butane sulfonic acid, sodium or
potassium salt
1-pentane sulfonic acid, sodium or potassium
salt
1-hexane sulfonic acid, sodium or
potassium salt
1-heptane sulfonic acid, sodium or
potassium salt
1-octane sulfonic acid, sodium or
potassium salt
1-decane sulfonic acid, sodium or
potassium salt
1-dodecane sulfonic acid, sodium or
potassium salt
1-tetradecane sulfonic acid, sodium or
potassium salt
1-hexadecane sulfonic acid, sodium or
potassium salt
APPENDIX A
NEUTRALIZATION PROCEDURES
General
Do neutralizations in a fume
hood behind a safety shield, as fumes and heat may be generated. Wear lab coat
or apron, gloves and goggles.
Keep containers cool during
process.
Work slowly.
After neutralization is
complete, flush to sewer with 20 parts water.
Acid Neutralization
1.
While stirring,
add acids to large amounts of an ice water solution of base such as sodium
carbonate, calcium hydroxide, or sodium hydroxide for concentrated acids.
1.
When a pH of at
least 5.5 and less than 9.0 is achieved,
dispose of the solution into the sewer, followed by 20 parts water.
Base Neutralization
1.
Add the base to
a large vessel containing water. Slowly add a 1M solution of HCI.
2.
When a pH of
less than 9 and greater than 5.5 is achieved,
dispose of solution into sewer system followed by 20 parts water.
APPENDIX B
USED OIL COLLECTION AND DISPOSAL
1.0 USED OIL COLLECTION
Oil should be collected
locally and stored temporarily in approved and properly marked containers
provided by Chemical Safety. The containers must be clearly marked "USED
Oil only: No solvents."
2.0 DISPOSAL OF USED OILS
When the oil drums are full
please contact the Chemical Safety at 994-2711 to obtain information on the
disposal of oils. A contract with a
recycling company has been made through facilities. Chemical Safety must handle the collection
and addition to the recycle container.
References:
National Research Council,
Prudent Practices in the Laboratory, Handling and Disposal of Chemicals,
National Academy Press, 1995.
American Chemical Society,
Safety in Academic Chemistry Laboratories, 1995.
Safety Manuals from the
Universities of Wisconsin and Cincinnati.
Bozeman Area Sewer Ordinance