flinnsci.com SAFETY REFERENCE CHEMICAL DISPOSAL PROCEDURES
751
FLINN METHOD
#26b Waste for Drain Disposal Without Pretreatment
Aqueous solutions containing nonhazardous wastes (as defined by the EPA) may
be suitable for drain disposal if—and only if—the school drains are connected to a
sanitary sewer system with a water treatment plant operating on the effluent from
your drains. These guidelines must be followed:
• Do not use this procedure if your drains empty into groundwater through a septic
system—or into a storm sewer.*
• These materials may generally be disposed of in quantities not to exceed 100
grams each day for each substance by rinsing them down the drain with a large
excess of water.
• Do not put combinations of materials down the drain at one time.
Local regulations may be more strict on drain disposal than the practices we
recommend. You must determine what is permitted in your area. Sewer disposal in
your community is regulated by an ordinance of your local water treatment facility.
The regulations will spell out in considerable detail the allowable limits for various
waste components. Because each water treatment facility is unique, you must
contact the facility and get a copy of the ordinance. We also recommend meeting
with representatives of the local treatment facility if a major laboratory clean-up
and disposal is planned. A good working relationship with the treatment facility
will make everyone more comfortable with the appropriate use of the sewer as a
disposal method. For example, in some areas, compounds of aluminum, copper and
zinc are not permitted in sanitary sewers. In most cases, we recommend that you
substitute Flinn Disposal Method #26a for this one. All the materials recommended
for this procedure are water-soluble to the extent of at least 3% and represent a
very low toxicity hazard. In addition, the organic materials are readily biodegradable.
*Note: If your drain system does not empty into a wastewater treatment facility,
do not put these substances down the drain. Rather, landfill the nonflammable
substances and aqueous solutions according to Flinn Disposal Method #26a, and
dispose of all others using a licensed hazardous waste disposal company according
to Flinn Disposal Method #26c.
FLINN METHOD
#26a Solid Waste Disposal in Landfill
The majority of inorganic solid wastes are salts consisting of a cation and an anion.
In planning the disposal of these inorganic salts, the hazards associated with the
cation and anion must be determined separately. If either part presents a potential
hazard, the substance should not be disposed of in a municipal landfill.
Cations that have a relatively low level of toxicity are Al, Bi, Ca, Cu, Fe, Li, Mg, Mo(VI),
K, Sc, Na, Sr, Ti, Zn and Zr. Anions that have relatively low hazards are:
Bisulfite (HSO3¯) Cyanate (OCN¯) Phosphate (PO43–)
Borate (BO33–) Hydroxide (OH¯) Sulfate (SO42–)
Bromide (Br¯) Iodide (I¯) Sulfite (SO32–)
Carbonates (CO32–) Oxide (O2¯) Thiocyanate (SCN¯)
Chloride (Cl¯)
This list of less hazardous cations and anions is presented only as a guideline. Your
chemical judgment, vlume of waste and local regulations must also be considered.
For example, sodium hydroxide contains an acceptable cation (Na) and anion (OH),
but is in fact a toxic and corrosive material that should be treated before disposal.
Materials Required
Cardboard boxes
Crumpled newspaper
Heavy tape to seal boxes
Procedure
Bury solids in a landfill site approved for the disposal of chemical waste. Do not
mix different materials by removing them from their separate containers because
unpredictable chemical reactions may occur. Pack separate containers into sturdy
cardboard boxes, separating containers from each other with crumpled newspapers
to avoid inadvertent breakage. Seal the cardboard boxes with heavy tape.
This procedure is recommended for a wide array of materials, from aspirin to zinc.
We use the term “landfill site approved for the disposal of chemical waste” with the
full realization that many of these substances can go into the school trash. However,
regulations about landfill use change with great frequency. Local regulations should
be consulted about exactly what you can and cannot place in the landfill in your
area. You must determine what is permitted in your area. Do not assume that it is
acceptable to dump materials into the school trash. Take the time to investigate.
Some instructors have made this “investigation” a student project and have learned
a great deal in the process.
If you have made aqueous solutions of the water-soluble or alcohol-soluble
materials classified for disposal under this procedure, we recommend that you
dispose of these solutions according to Flinn Disposal Method #26b.
Please… Read the Narratives
Important narratives precede these specific chemical disposal methods!
Please read each narrative carefully! Do not use these procedures if you are
not comfortable with the chemistry. Do not use these procedures without
first consulting with your local government reg ulatory officials. These
procedures may not be used in some jurisdictions. All procedures involve
some hazards and risks. Once again… read the narratives that precede
these specific chemical disposal methods.
/flinnsci.com