Disposal of Waste Chemicals

WASTE TYPE

PRE-DISPOSAL PROCESS

INSPECTION PROCEDURE

WASTE CONTAINER CHARACTERISTICS

BIOLOGICAL WASTE (microbiological/infectious contaminants)

Sharp waste

Any material, regardless of its intended use, is classified as “medical waste” and must never be disposed of in regular trash.

A sturdy and durable special sharps waste container bearing the “biohazard” logo and capable of being tightly sealed

Disposable (single-use) contaminated materials

Place in an autoclave bag. Avoid overfilling. Autoclave under the necessary conditions and dispose of in the waste container.

Sent directly to the medical waste container without using an intermediate collection container.

Recyclable contaminated materials

Collected directly (without a bag) in the autoclave bin. Avoid overfilling. Autoclave under the necessary conditions and send for post-processing washing.

Liquid waste

Collected in a desktop waste collection container lined with an autoclave bag; autoclaved along with the collection container as soon as the task is completed, without waiting for it to fill up.

It is sent directly to the medical waste container without using an intermediate collection container.

NOTE:
1. When buckets (disposable or reusable for soiled items) are approximately ¾ full, carefully add 250–500 ml of water. Take care to avoid splashing or spilling water while adding it.
2. Gather the top of the bag, but do not tie it!
3. NEVER remove the autoclave bag from the bucket! Close the bucket lid and affix the autoclave label. Write the nature of the waste contained in the bucket and the laboratory it belongs to on the label.
4. The outer surface of the bucket/contaminated container is disinfected with a disinfectant spray (1–2 mg/L chlorine).
5. The contaminated bucket is taken to the autoclave room by a laboratory staff member (technician, assistant, or specialist) when the autoclave is available and is placed in the autoclave immediately. The dirty bucket MUST NEVER be HANDED OVER to non-technical staff (janitor, office staff, etc.)!
6. Autoclave bags and buckets MUST NEVER be left in the autoclave room to wait their turn.
7. After autoclaving, reusable materials are sent for washing. Disposable waste is sent to the municipality’s medical waste container under the supervision of the Unit’s biological waste officer!

CHEMICAL WASTE

Halogenated acyls, sulfonyl halides, and anhydrides RCOX, RSOX, and (RCO)₂O

Add drop by drop to 600 mL of 2.5 M NaOH (50% excess). A rise in temperature indicates that the reaction has occurred, but care must be taken to ensure the temperature does not exceed 45°C. A clear solution should be obtained.

The final pH is adjusted to 7 using HCl or H₂SO₄.

It is collected in a separate container without allowing it to mix with other waste.

Aldehydes RCHO

3 RCHO + 2 KMnO₄ -----> 2 RCO₂K + RCO₂H + 2 MnO₂ + H₂O
0.1 mol aldehyde / 0.08 mol permanganate
Since the neutralization process is hazardous and difficult, neutralization is not recommended. Store without performing any further processing, using separate containers for each aldehyde.

Collect them in a separate container without allowing them to mix with other wastes.

Alkyl sulfates

Add drop by drop to ice-cooled ammonia while stirring vigorously

until the pH reaches approximately 7.

Check the pH with indicator strips (M109535)

Salt solution container

Aromatic amines

0.01 mol of aromatic amine is dissolved in 1.7 N, 3 L of sulfidic acid (M100716). 0.2 M potassium permanganate (M105082) is added, and the solution is allowed to stand at room temperature for 8 hours.

If the solution contains halogen, it is collected in a halogen-containing solvent container; if not, it is collected in a halogen-free solvent container.

Acid Halides

Add dropwise to a large volume of methanol (M822283); a few drops of hydrochloric acid (M100312) may be added to accelerate the reaction. Neutralize with sodium hydroxide (M105587).

pH is checked using indicator strips (M109535).

Collect in a container for halogenated organic solvents.

Acids / Bases (concentrated)

First, dilute with cold water until the concentration falls below the specified level. Neutralize with an appropriate acid (e.g., M100312) or base (e.g., M105587).

pH Check with Indicator Strips (M109535)

Salt solution container

Mercury

Avoid inhaling its vapors; spilled mercury droplets should be collected with a fine-tipped pipette or made to react chemically with activated carbon.

Mercury and inorganic mercury salts are collected in a container.

Hydrogen fluoride and inorganic
fluoride solutions

They are precipitated as calcium fluoride by treatment with calcium carbonate (M102063) in a 2:1 molar ratio.

The precipitates are collected in the inorganic solids container, and the filtrates are collected in the salt solutions container.

Calcium hydride (CaH₂)

Add 25 mL of methyl alcohol to 1 g of hydride and mix under nitrogen. When the reaction is complete, add an equal volume of water to the resulting calcium methoxide and mix; the solution is then neutralized by adding acid.

pH check using indicator strips (M109535)

Dilute and discharge into the sink.

Chromic acid

Collected in a separate container without allowing it to mix with other waste.

Metal Azides (MN3)

The solution must not contain more than 5% sodium azide. First, add 7 mL of a 20% aqueous sodium nitrite solution (40% excess) to 1 g of sodium azide and mix. Add a 20% sulfuric acid solution until the solution becomes acidic. After neutralization, transfer the waste to a waste bottle with water.

Check neutralization using starch-iodine paper (a blue color should be observed).

It is collected in a separate container without allowing it to mix with other waste.

Metal hydrides (MH4)—

To reduce reactivity, they are placed in alcohol (methanol, ethanol, n-butanol, t-butanol) and cooled. It is then transferred to diethyl ether, tetrahydrofuran, or toluene, purged with nitrogen gas, and transferred to a storage container.

They are collected in a separate container without allowing them to mix with other wastes.

Organic Solvents

If they contain halogens, they are collected in halogen-containing containers; if they do not contain halogens, they are collected in halogen-free containers.

Organic peroxides

Add 1.5 g of KI and 28 mL of glacial acetic acid to 1 g of peroxide. A dark-colored solution forms; after waiting half an hour, add solid sodium metabisulfite to obtain a colorless solution.

Peroxide testing with indicator strips (M110011)

If organic waste contains halogens, it is collected in halogen-containing solvent containers; if it does not contain halogens, it is collected in halogen-free solvent containers. Aqueous solutions are collected in salt solution containers.

Raney nickel

It is added to hydrochloric acid (M100312) in the form of an aqueous suspension until it dissolves. Raney nickel or the filtered precipitate must not be dried; otherwise, it will spontaneously ignite upon contact with
air.

It is collected in a separate container without allowing it to mix with other wastes.

Cyanide (CN)

After adjusting the solution temperature to 4–10 °C, add 50% more sodium hypochlorite. After letting it stand for a few hours, water is added, and the solution is collected in a waste bottle. If the solution contains hydrogen cyanide, it is first poured into ice water; after adding 1 M NaOH, the procedure for cyanides is followed.

NaCN + NaOCl ----> NaOCN + NaCl

Warning: NaOH and other basic solutions containing sodium cyanide must not come into contact with liquid HCN.

It is strictly prohibited to pour alkyl cyanides and HCN down the drain.

Thiols (Mercaptans) R-S-H; Sulfides R-S-R’

Add a thiol solution (0.1 mol) drop by drop to 500 mL of sodium hypochlorite (0.4 mol) containing a 25% excess. Oxidation begins as the temperature rises and the solution dissolves. If the reaction does not start despite the addition of the thiol solution,

heat the mixture to 50 °C to initiate oxidation. The pH should not fall below 6. Sulfonic acid is formed.

RSH + 3OCl⁻ → RSO₃H + 3Cl⁻

0.4 mol hypochlorite / 0.1 mol thiol
Na₂S + 4OCl⁻ ----> Na₂SO₄ + 4Cl⁻

0.4 mol hypochlorite / 0.1 mol sulfide

It is collected in a separate container without allowing it to mix with other wastes.

Non-hazardous organic chemicals: Harmless organic biochemical substances such as sugars, starches, sugar alcohols, naturally occurring alpha-amino acids and their salts, citric and lactic acids, and Na, K, Mg, Ca, and NH₄ salts, as well as dry biological culture media

Dilute and discharge down the sink.

Non-hazardous inorganic chemicals:

Sulfates (Na, K, Mg, Ca, NH₄, Sr, Ba)

Phosphates (Na, K, Mg, Ca, NH₄, Sr)

Carbonates (Na, K, Mg, Ca, NH₄, Sr, Ba)

Oxides (Ba, Mg, Ca, Sr, Al, Si, Ti, Mn, Fe, Cu, Co, Zn) Borates (Na, K, Mg, Ca)

Dilute and discharge into the sink.

Laboratory materials not contaminated with hazardous chemicals (chromatographic adsorbents, glassware, paper filters, filtration aids, rubber, and PPE)

Appropriate solid waste container

Vacuum pump oils and heating bath oils

Collected in a separate container without allowing it to mix with other waste. The container must be labeled “Waste Oil Only—Do Not Add Solvents.”

NOTE:
1. Each institution must develop its own hygiene plan for the laboratories it operates. A preliminary study should be conducted regarding the chemical waste generated in all laboratories, and the chemical waste should be classified. However, as chemical waste accumulates over time, the types of chemical waste will become clearer. Therefore, this protocol must be reevaluated at regular intervals, taking into account any issues encountered in the system and potential types of waste. You may refer to the website www.laboratuvarguvenligi.com.tr when developing the hygiene plan.
2. Efforts should be made to recycle waste whenever possible. If recycling is not possible, the waste should be converted into a less harmful form before being stored.
3. The chemical storage matrix specified for the laboratory should also be applied to the storage of waste.
4. If there is any uncertainty regarding which waste container a particular waste should be placed in, a separate waste bottle should be created and labeled.
5. The type of waste, hazard classification (toxic, carcinogenic, etc.), date, name of the person who disposed of the waste, and approximate quantity must be written on the waste containers.
6. Empty chemical containers containing arsenic compounds, allyl alcohol, acrolein, carbon disulfide, cyanide compounds, 2,4, dinitrophenol, nitric oxide, nitrogen dioxide, p-nitroaniline, osmium tetroxide, phosgene, phosphine, sodium azide, or vanadium pentoxide are not classified as hazardous waste. These empty chemical bottles can be reused as waste containers by rinsing them three times with water while wearing thick gloves and removing the label.
7. You can find information on licensed waste disposal/recovery facilities in your province at www.atikyonetimi.cevreorman.gov.tr/lisans/lisans/tehlikelilisans.xls.
8. Acetic acid, nitric acid, perchloric acid, and chromic acid must never be mixed together.
9. Sodium must never be dropped into water, as this will cause an explosion.
10. When working with solutions containing silver ammonia compounds, a black precipitate will accumulate at the bottom of the containers over time. Known as “explosive silver,” this precipitate can explode violently as a result of stirring, shaking, or even touching. For this reason, these solutions should not be stored in the laboratory for long periods and must be disposed of before they deteriorate.
11. When working with borane-tetrahydrofuran reagents, the pressure that may build up inside the bottle must first be released by inserting a hypodermic needle through the cap before use.

RADIOACTIVE WASTE

Solid Radioactive Waste

Must be collected separately from non-radioactive solid waste. Any waste suspected of being radioactive must be treated as radioactive. Hazardous chemicals or other toxic substances must not be mixed with radioactive waste; however, any unavoidable mixtures must be indicated on the labels.

It must be placed in a labeled, radiation-shielded waste collection container (lined with lead or similar suitable material) and stored in lockable cabinets, closets, or rooms.

Liquid radioactive waste

It must be soluble and dispersible in water. If the radioactive liquid contains insoluble solid particles or sediment, it must first be filtered. The waste must be diluted with at least 10 times its volume of water.

It is discharged into the wastewater system via a sink designated within the unit. An international standard radioactive material sign is affixed to this sink, and non-radioactive work is not conducted here.