1. Chemical Waste Management and Disposal1

2. Waste Management Nonhazardous waste
General guidelines- Storage - Packaging
Special categories
Metal waste
Radioactive and mixed waste
Biological waste
Unknown and orphan waste
Treat on-site 2 2

3. Waste management: nonhazardous waste
Used oil (uncontaminated) is not considered hazardous waste. Label Containers "USED OIL", not "hazardous waste."
Uncontaminated PPE (gloves, wipes)
Triply rinsed glassware (bottles, droppers, pipettes)
Salts (KCl, NaCl, Na2CO3)
Sugars - Amino acids
Inert materials (uncontaminated resins and gels) 3 3

4. Waste management: General guidelines
Secure and lock waste storage area
Post signs to warn others
Keep area well ventilated
Provide fire extinguishers and alarms, spill kits
Provide suitable PPE
Provide eye wash, safety showers
Do not work alone
Chemical waste needs to be stored and handled correctly, too. 4 4

5. Waste management: General guidelines
Insure against leakage; dyke area if possible
Label all chemicals, containers, vials
Separate incompatible chemicals
Keep gas cylinders separate
Keep radioactive material separate
Know how long waste can be stored
Provide for timely pick-up
Dyke area means to build up secondary containment to keep spills from spreading.
Storage time mostly regulatory requirement in US. But some things don’t age gracefully as waste, either (such as peroxides). 5 5

6. Waste - Storage guidance
Container should not react with the waste being stored (e.g. no hydrofluoric acid in glass). 
Similar wastes may be mixed if they are compatible
Whenever possible, wastes from incompatible hazard classes should not be mixed (e.g. organic solvents with oxidizers).
Containers must be kept closed except during actual transfers. Do not leave a funnel in a hazardous waste container.
Chemical containers that have been triple-rinsed and air-dried in a ventilated area can be placed in the trash or recycled.  6 6

7. Waste – General guidance
Certain metals cause disposal problems when mixed with flammable liquids or other organic liquids
Pressure can build up in a waste vessel
Corrosion can occur in storage vessel
Secondary containment is necessary
Glass waste containers can break 7 7

8. Dangerous waste management
Barrels have clearly been sitting around too long. They are rusty, bulging, not labeled. Bulging indicates unknown chemistry is going on inside.
Photo credit Doug Walters 8 8

9. Video – Fire at Apex Waste Facility9

10. Best practice – Orphan control
Before moving to new job meet with new lab occupant
This can be a new employee or new student
Label all chemicals and samples carefully
Make notations in common lab book
Dispose of all unneeded or excess chemicals
Put into chemical exchange program
Dispose of as hazardous waste
Do not leave any chemicals behind except by agreement
Before moving out of a work area or leaving, go through the laboratory or work area with your supervisor or the new occupant to determine which chemicals need disposal and to identify anything that is ambiguously labeled.
When relocating from one work area to another, do not leave any chemicals behind unless specific arrangements have been made with the new occupant. 10 10

11. Waste management Recycle, reuse, redistill, if possible
Dispose by incineration, if possible
Incineration is NOT the same as open burning
Recycle/reuse depends on specific process, especially scale. 11 11

12. Emissions from incineration vs. open burning
(µg/kg)
Municipal Waste Incinerator
PCDDs 38
0.002
PCDFs 6
Chlorobenzenes
424150
1.2
PAHs
66035 17
VOCs
Burn barrel temperatures rarely exceed 500 degrees F so combustion is incomplete. Municipal incinerators operate at 2,200 degrees F to insure complete combustion and they use efficient filters to reduce harmful emissions.
Pound for pound-garbage burned in a burn barrel, gives off twice as many furans, 17 times as much dioxin, and 40 times as much ash as a municipal incinerator. A 1997 EPA study shows that two to forty households burning garbage produce as much dioxin as a 200 ton/day municipal incinerator.
Wisconsin DNR
Source: EPA/600/SR-97/134 March 1998 12 12

13. Laboratory wastes are packaged in small containers
Lab packs consists of small containers of compatible waste, packed in absorbent materials.
Lab packs segregated at hazardous waste facility 13 13

14. Waste management: Waste disposal service
Is disposal service licensed?
How will waste be transported?
How will waste be packaged?
Where will material be disposed?
How will it be disposed?
Maintain written records
I don’t know how you generally dispose of chemicals, but you generally don’t want to contribute to this sort of thing. 14 14

15. Battery recycling and disposal
Hazardous waste
Lead acid (Pb) - recycle (90% car batteries)
Sealed lead (Pb) - recycle
Mercury-oxide (HgO) button, silver-oxide (AgO) button - recycled by jewelers
Nickel Cadmium (NiCd) recycle
Nonhazardous waste
Nickel Metal Hydride (Ni-MH) recycle
Carbon – zinc
Alkaline
Zinc-air button 15 15

16. Mercury metal disposal
Collect pure liquid mercury in a sealable container.  Label as "MERCURY FOR RECLAMATION"
Place broken thermometers and mercury debris in a sturdy sealable plastic bag, plastic or glass jar.  Label the container "Hazardous Waste - MERCURY SPILL DEBRIS".
Never use a regular vacuum to clean up a mercury spill - contaminates vacuum, heat evaporates the mercury
Never use a broom to clean up mercury – spreads smaller beads - contaminates the broom.
Special mercury spill kits should be used 16 16

17. Mixed Waste (chemical radioactive)
These wastes must be minimized - heavily regulated
Universities, hospitals
Low level radioactive with chemical
Scintillation cocktails
Gel electrophoresis waste
Nuclear energy research
Low and high level radioactive with chemical
Lead contaminated with radioactivity
Mixed wastes are very highly regulated and should be minimized
Several suggestions for this are:
Use microscale chemical techniques
Use disposable plastic liners in lead containers to prevent lead contamination
Substitute a nonhazardous scintillation fluid –biodegradable or sewer disposable
Substitute enriched stable isotopes and use ICP-MS rather than counting methods (example 18O rather than 19O, 2H rather than 3H)
Use nonradioactive assays (scintillation proximity assays)
Substitute shorter half life radionuclides
For a full set of techniques look in “Multihazardous Waste” Section 7C in Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy Press, 1995 17 17

18. Mixed Waste (chemical-biological)
Medical wastes
Blood and tissue
Sharps – needles, scalpels
Contaminated glassware, ppe
Autoclave or sterilize
Bleach incompatible with autoclave
Do not autoclave flammable liquids
Incinerate
Procedures for biological waste should be followed with special attention to infectious wastes.
In the USA sewer discharge is permitted for some body fluids but close attention should be paid to hygiene and good laboratory practices.
Tissues and animal carcasses are best disposed of by incineration. They should be kept refrigerated before disposal since they are putrescible. 18 18

19. Mixed Waste (radioactive-biological)
Medical wastes
Often disinfect high biohazard to minimize handling risk
Let short-lived isotopes decay and then use sanitary sewer
Refrigerated storage for putrescible waste (carcasses- tissue)
Autoclave or disinfect labware and treat as low level radioactive
On-site incineration of low level rad waste if allowed (sharps as well)
These wastes do not have a hazardous waste component but comprise a stream of lab waste in the university or hospital laboratory environment.
Major isotope is 99Mo or 99Tc for single photon emission tomography (SPECT) analysis and Fluorodeoxyglucose (18F) for positron emission tomography (PET) 19 19

20. Unknown “orphan” waste
Avoid if at all possible -- requires analysis before disposal!
Pre-screen
Crystals present ? (potential peroxide formation)
Radioactive (Geiger counter)
Bio waste? (interview history)
Screen
Prepare for the worst – wear gloves-goggles-hood
Air reactivity
Water reactivity
Flammability
Corrosivity
1. Air reactivity
Pour a small amount (a few drops or crystals) of the material into your container in the hood. If the material is air reactive, a reaction will be apparent within 30 seconds and should be labeled "UI#7078-Characterized Waste-Air Reactive." If not air reactive, proceed to step two.
2. Water reactivity
Pour a small amount (a few drops or crystals) of the material into your container in the hood. Using a wash bottle filled with water, add a few drops of water to the compound. If the material is water reactive, a reaction will be apparent within a few seconds. If reactive, label the container "UI#7079-Characterized Waste-Water Reactive"; if not, proceed to step three.
Note: Steps 3 and 4 should both be performed if classification is not determined in steps 1 or 2.
3. Corrosivity
Obtain the pH of the sample using pH paper or a pH meter. Record the pH to the nearest whole number on the container label.
4. Flammability (Perform only on liquids)
Pour a few drops of the material into your container in the hood. Hold the dish over a Bunsen burner for a few seconds. If the material has not started burning, hold the flame from the burner in direct contact with the material. If the material has not started burning after 10 seconds of direct contact with the flame, it is considered to be not flammable.
Labeling containers
a. If steps 1 or 2 are positive, label container as instructed above.
b. If steps 1 and 2 are negative, label the container according to the following:
If flammable and pH = 3-11: "UI#7080- Characterized Waste-Flammable"
If flammable and pH = 2 or less: "UI#7083- Characterized Waste-Flammable, Acid"
If flammable and pH = 12 or more: "UI#7084- Characterized Waste-Flammable, Base"
If not flammable (or solid) and pH = 2 or less: "UI#7081- Characterized Waste-Acid"
If not flammable (or solid) and pH = 12 or more: "UI#7082-Characterized Waste-Base"
If not flammable (or solid) and pH = 3-11: "UI#7085- Characterized Waste-Other"
c. Any other information about the contents of the container should also be shown on the container. 20 20

21. Unknown waste characterization*
Physical description - Water reactivity - Water solubility
pH and neutralization information
Presence of:
Oxidizer
Sulfides or cyanides
Halogens
Radioactive materials
Biohazards
Toxics
*Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy Press, 1995 Section 7.B.1
4 criteria
ignitability, corrosivity, reactivity and toxicity
“Disposal Parameters”: RCRA (Resource Conservation and Recovery Act)
METHODS OF ANALYSIS
Metals byEPA Methods 6010/7000
Benzene by EPA Method 8021 on the TCLP (Toxicity Characteristic Leaching Procedure) extract as prepared by EPA Method 1311;
Total Petroleum Hydrocarbons (TPH);
Ignitability (USEPA method 1030);
Corrosivity (USEPA method 9045); and
Polychlorinated Biphenyls (PCB's) (by USEPA method 8082). 21 21

22. Waste management: Down the drain?
If legally allowed:
Deactivate & neutralize some liquid wastes yourself
e.g., acids & bases
Don’t corrode drain pipes
Dilute with lots of water while pouring down the drain
Be sure that you do not form more hazardous substances
Check reference books, scientific literature, internet
So NaOH + HCl = salt water is safe, but dumping KCN down the drain probably isn’t a good idea.
Have been a number of incidents in which people poured solvent down the drain that have been “dried” with sodium metal, that unfortunately still had some sodium in it, resulting in fires.
Another example of forming more hazardous substances could be the bleach + ammonia => chloramine reaction. 22 22

23. Treating on site – volume reduction
Evaporation – if not excessive
Roto evaporation for recovery
Do not evaporate corrosives or radioactives
Only in laboratory hood
Beware toxics and flammables
Adsorption
Activated carbon
Ion exchange resin
Activated alumina
Precipitation - Extraction
Rotovap photo from Fisher Scientific catalog,
Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, ISBN 23 23

24. Treating on site – chemical conversion
Requires chemical expertise - may not be allowed by regulations - specific to each chemical
Dilution to reduce hazard
H2O2, HClO4, HNO3
Never add water to concentrated acid
Neutralization acid base -gentle
Hydrolysis (acid and base)
Active halogen compounds with NaOH
Carboxamides with HCl
Oxidation-reduction
The requirement for chemical expertise cannot be stressed too much. Other techniques for hazard reduction involve extreme care.
Alakali metal oxidation - (Na and Li- not K)
Fine metal catalysts – mix in water and spread on metal tray outdoors
Red and white phosphorous – incineration or reaction with copper sulfate
Metal hydrides –(NaH, Kh, LiH, CaH2 – convert to hydroxides by gentle exposure to water (humid nitrogen gas percolation)
Carboxamides are often drugs or other bioactive chemicals
Handbook of Laboratory Waste Disposal, Martin Pitt and Eva Pitt, ISBN 24 24

25. Chemical Waste Example: Tollens Reagent
Ag(NH3)2NO3 (aq)
The reagent should be freshly prepared and stored refrigerated in a dark glass container. It has a shelf-life of ~24 hours when stored in this way.
After the test has been performed, the resulting mixture should be acidified with dilute acid before disposal. These precautions are to prevent the formation of the highly explosive silver nitride. 25 25

26. Chemical Waste Example: Sodium Cyanide
Wear PPE, work in hood
Add sodium cyanide to a solution of 1% sodium hydroxide (~50mL/g of cyanide).
Household bleach (~70mL/g of cyanide) is slowly added to the basic cyanide solution while stirring.
When addition of the bleach is complete, test for the presence of cyanide using the Prussian blue test:
To 1mL of the solution ot be tested, add 2 drops of a freshly prepared 5% aqueous ferrous sulfate solution.
Boil this mixture for at least 60 seconds, cool to room temperature, then add 2 drops of 1% ferric chloride solution.
Take the resulting mixture, make it acid (to litmus paper) using 6M hydrochloric acid.
If cyanide is present, a deep blue precipitate will be formed.
If test is positive, add more bleach, then retest.
From “Hazardous Laboratory Chemicals Disposal Guide”, Armour, 2003. 26 26

27. Waste management: Treatment in Lab
References:
“Procedures for the Laboratory-Scale Treatment of Surplus and Waste Chemicals, Section 7.D in Prudent Practices in the Laboratory: Handling and Disposal of Chemicals,” National Academy Press, 1995, available online:
“Destruction of Hazardous Chemicals in the Laboratory, 2nd Edition”, George Lunn and Eric B. Sansone, Wiley Interscience, 1994, ISBN
“Hazardous Laboratory Chemicals Disposal Guide, Third Edition”, Margaret-Ann Armour, CRC Press, 2003, ISBN
“Handbook of Laboratory Waste Disposal”, Martin Pitt and Eva Pitt, ISBN 27 27

28. On-site Recycling and Waste Treatment28

29. Waste Management: Recycling
Recycling by redistribution
Recycling of metals
Gold-mercury–lead- silver
Recycling of solvents
Clean for reuse-rotovap
Distill for purity
Recycling of oil
Recycling of E-waste 29 29

30. Chemical recycling Reuse by others in the organization or community
An active chemical exchange program
Beware of accepting unusable chemicals
Reuse in experiments in the laboratory
Exchange for credit with suppliers by agreement 30 30

31. What should not be recycled
Gas cylinders past their pressure testing date
Used disposable pipettes and syringes
Chemicals and assay kits past their expiration
Obviously degraded chemicals
Used tubing, gloves and wipes
Others? 31 31

32. What should be recycled or redistributed?
Excess unopened chemicals
Excess laboratory glassware (unused or clean)
Consumables with no expiration
Solvent that can be purified
Lower purity suitable for secondary use?
Precious or toxic metals
Hg, Ag, Pt, Pd, Au, Os, Ir, Rh, Ru
Others?
Items in blue are those that can be redistributed throughout an organization. They are new and unopened. If the organization is small and the chemicals are fresh and their purity and age are acceptable , agreements can be reached to redistribute the chemical. Chemicals like open paint thinners can be given to paint departments, excess cleaning agents (such as Alconox) can also be redistributed after being opened.
Redistribution often happens when one project is being concluded and therefore the chemical stocks can be given to others and legacy or orphan chemicals can be avoided. 32 32

33. Chemical Recycling - Precious Metal
For reuse in lab or for exchange
Requires chemical knowledge for lab reuse
Recover from solution - evaporate then
Ignite (Au, Pd, Pt)
Reduce with NaBH4 for metal powder or by electroless plating (Pt, Au, Pd, Ag, Rh).
Electroplate
Metal recovery Ion exchange-then ash
These are particularly valuable metals and private recycling firms can be contacted for recycling.
Source : Handbook of Laboratory Waste Disposal, Pitt &Pitt, John Wiley, 1986 33 33

34. Chemical Recycling - Silver
Recovery from chemical oxygen demand (COD) test
Acidification and ppt as AgCl
Recovery from photographic fixing solution
Precipitate as sulfide
Precipitate with TMT (trimercapto-s-triazine)
Electrolysis (terminal and in-line)
Metal replacement (iron containing cartridges)
Ion exchange
Many companies will buy the recovered silver
Solutions Solution Amount
Developer Contains negligible amounts of silver
Fixer/Bleach-Fix 3000–5000 milligrams/litre
Wash Water/Stabilizer 1–5 milligrams/litre 34 34

35. Chemical Recycling - Mercury
Mercury can be recovered for subsequent lab use or for recycle by vendor
Remove particulates and moisture by allowing slow drip through a hole in a conical filter paper
Never distill Hg on-site
If mercury gets in carpet or cracks in floor it will continue to vaporize. Possibly remove patch of carpet or seal floor with sealer. Sulfur can reveal the presence of Hg. Will turn from yellow to brown. There are many companies that will recycle mercury. 35 35

36. Solvents can be recovered by distillation
Boiling point must be widely different
Azeotropes may prevent separation
Sometimes hazards are created
Some solvents do not need complete separation
Hardware for separation 36 36

37. Solvent recycling – general guidance
Solvent recycling requires care and organization
Keep solvents segregated prior to separation (single product solvent)
No unnecessary dirt due to careless handling
Requires good labeling
A small amount of the wrong chemical can ruin a desired separation
Care must be taken not to concentrate peroxides
Care must be taken with a rotovap to secure the solvent flask the solvent can bump. This can lead to overpressure, frothing, expansion into receiving flask and pop off of the bottom flask into the water bath and unnecessary exposure to hot solvent. 37 37

38. Solvent recycling – general guidance
Solvent recycling requires care and organization
Try other purification methods before distillation
Convert to precipitate
Convert to water soluble
Use an adsorbent
Need BP difference of > 10°C
Can form azeotrope*
water / ethanol (100°C/ 78.3°C)
cyclohexane / isobutanol (81°C / 108°C)
Mixture of 4 solvents not practical
Distillation can be incorporated into curriculum
Care must be taken with a rotovap to secure the solvent flask the solvent can bump. This can lead to overpressure, frothing, expansion into receiving flask and pop off of the bottom flask into the water bath and unnecessary exposure to hot solvent.
* Consult CRC Handbook of Chemistry and Physics for list of azeotropes 38 38

39. Solvent recycling – low efficiency
Rotovap can be used to pretreat
Toxic material may be kept from the distillation
May be sufficient if purity is not crucial
Separation of solvent from solids
Care must be taken with a rotovap to secure the solvent flask the solvent can bump. This can lead to overpressure, frothing, expansion into receiving flask and pop off of the bottom flask into the water bath and unnecessary exposure to hot solvent. 39 39

40. Solvent recycling – basics
Reflux ratio TP
120 25 80 24 40 21 20 16 10 4 5
Distillate
Reflux
Higher reflux ratio leads to increased separation efficiency
TP = theoretical plates 40 40

41. Solvent recycling – medium efficiency
Even high efficiency stills are not perfect
Continuous better than batch for large volumes
Control reflux
Monitor head temperature
Reduce heat loss to get more efficiency
Do not let still operate to dryness
Use boiling chips but do not add when solvent is hot
Example: 200mm long column for separating benzene and toluene
Packing TP
Empty
0.5
Coarse packing 1
Fine packing 5
TP = theoretical plates 41 41

42. Diagram of packed and spinning band distillation columns
Diagrams from B/R Instruments: 42 42

43. Boiling point of common solvents (C)
Halogen Containing
Dichloromethane 40
CH2Cl2
Chloroform
61.6
CH3Cl
Carbontetrachloride
76.5
CCl4
Trichloroethane 87
C2H3Cl3
Perchloroethylene or Tetrachloroethylene
121
C2Cl4
Trichloroethylene
C2HCl3
Trichlorobenzene (TCB)
208.5
C6H3Cl3 43 43

44. Boiling point of common solvents (C)
Oxygen Containing
Acetone
56.1
C3H6O
MEK (Methyl ethyl ketone)
79.6
C4H8O
Acetic acid
118.1
C2H4O2
Ethyl acetate 77
C4H8O2
Ethylene glycol
197
C2H6O2
Propylene glycol
187
C3H8O2
Ethyl ether
34.5
C4H10O
THF (tetrahydrofuran) 66
MIBK (Methyl isobutyl ketone)
116.8
C6H12O 44 44

45. Oxygen Containing (cont)
Boiling point of common solvents (C)
Oxygen Containing (cont)
Methanol
64.5
CH4O
Ethanol
78.3
C2H6O
n-Propanol 97
C3H8O
Isopropanol
82.5
n-Butanol
117.2
C4H10O
sec-Butanol
99.5 45 45

46. Boiling point of common solvents (°C)
Hydrocarbons
n-Pentane
36.1
 C5H12
n-Hexane
68.7
 C6H14
Cyclohexane
80.7
 C6H12
n-Heptane
98.4
 C7H16
n-Octane/iso-octane
125.7 / 117.7
 C8H18
Toluene
110
C7H8
Ethylbenzene
136.2
C8H10
p/m/o-Xylene
138.3 / / 144.4 46 46

47. Boiling point of common solvents (C)
Nitrogen Containing
Pyridine
115
C5H5N
Aniline
184
C6H7N
n,n-Dimethylformamide
C3H7NO
n-Methylpyrolidone
202
C5H9NO
Piperdine
106
C5H11N
Acetonitrile
81.6
C2H3N 47 47

48. Solvents that should not be recycled by distillation
Accidents have been reported for these distillations
Individual Substances
Di-isopropyl ether (isopropyl alcohol)
Nitromethane
Tetrahydrofuran
Vinylidene chloride (1,1 dichloroethylene)
Mixtures
Chloroform + acetone
Any ether + any ketone
Isopropyl alcohol + any ketone
Any nitro compound + any amine
Source : Handbook of Laboratory Waste Disposal, 1986.
Marion Pitt and Eva Pitt, John Wiley and Sons, ISBN 48 48

49. Practical examples of recycling
Hexane contaminated with small amount of inert solvent used in prep lab
Chemistry students given a finite quantity of solvent, then had to recycle for subsequent experiments
Acetone 50% in water for washing. Azeotrope is 88.5% which is then diluted back with water for reuse
Use rotovap recovery rather than evaporation. Student will redistill; 60% recovery.
Third wash was captured and used as first wash on next experiment
This slide shows some inventive ways that instructors have used the knowledge of chemistry to save solvents and reuse them based on sound science. The instructor uses knowledge of solvent compatibility, distillation and chemical reactivity to encourage conservation
It is similar to the old expression that a thrifty person will “use everything but the squeal”
A group of research and development labs agreed to standardize as far as possible on a few solvents. Each scientist assessed whether their waste was recoverable and if so used rough separation like a rotovap to produce a recyclable solvent. The solvents were then put into clearly marked “recoverable solvents” can, that would not be confused with a waste can. As mentioned previously it is important to segregate this type of recycle waste than to “batch” it.
Source : Handbook of Laboratory Waste Disposal, 1986.
Marion Pitt and Eva Pitt, John Wiley and Sons, ISBN 49 49

50. Solvent recycling HPLC Solvent Recycling GPC Solvent Recycling
Automated systems help with large needs
HPLC Solvent Recycling
GPC Solvent Recycling
Environmental Laboratory Solvent Recycling
Freon Solvent Recycling
Histology Laboratory Solvent Recycling
General Lab Solvent Recycling Services Can also be Purchased
GPC = gel permeation chromatography?
Pictures from B/R Instruments: 50 50