Download presentation
Presentation is loading. Please wait.
1
Chemical Waste Management and Disposal
1
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 Facility
9
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 Treatment
28
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
Similar presentations
© 2025 SlidePlayer.com Inc.
All rights reserved.