Waste Management

Proper waste management and disposal procedures for sorting and handling hazardous waste will ensure a safe school and protect human health and the environment.

Table of Contents

Advice for Handling Hazardous Waste in Schools

The general advice for handling hazardous waste in school laboratories is in line with the hierarchy of waste management.

The waste hierachy pyramid model: A bottom-up pyramid is vertical divided into five sections. The upper and widest section of the pyramid is: Prevention. The second section of the pyramid is: Preparing for re-use. The third section of the pyramid is: Recycling.The fourth section of the pyramid is: Recovery. The last and smallest section at the bottom of the pyramid is: Disposal.
The Waste Framework Directive defines a hierarchy in waste management.
  • Optimize the process to reduce or avoid waste and hazards (more about Green Chemistry).
  • Replace hazardous substances with less hazardous substances (more about Substitution).
  • Make the waste less hazardous by e.g. neutralization, dilution, evaporation, oxidation, decomposition, precipitation or filtration.
  • Hazardous waste that cannot be treated and made harmless in the laboratory, must be collected and disposed according to applicable regulations for sorting and handling hazardous waste.
  • Label and store your waste properly prior to disposal or recycling.

Classification of Hazardous Waste

Hazardous waste may pose a risk to human health and the environment, and thus requires a control regime. Waste which displays one or more of the hazardous properties listed in Annex III of the Waste Framework Directive is considered hazardous waste. The table below gives an overview of some hazard classes that are highly relevant for school chemistry. The complete list of chemicals is found in Annex III. The hazard statements for a chemical and information about the hazard classes can for example be found in the safety data sheet (SDS) section 2.1. Be aware that a solution that is not classified as a hazardous chemical can be classified as hazardous waste. The following example shows how to use the table to determine whether 1 mol/L HCl is classified as hazardous waste: In the SDS of concentrated HCl, it is stated that this solution is classified as skin corrosive 1B (H314). According to the table below the concentration limit is then 1 % (mass/mass). Since 1 mol/L HCl is approximately 3.6 %, this solution is classified as hazardous waste, and needs to be handled as such. Furthermore, concentrated HCl is classified in other hazard classes. However, we do not need to consider them because we already have classified 1 mol/L HCl as hazardous waste.
Overview of some hazard classes that are highly relevant for school chemistry.
Hazard pictogram Hazard Class and Category Hazard Statements Concentration Limit Examples
Flammable Flammable liquid 2 H225 Propan-1-ol
Flammable liquid 3 H226 Pentan-1-ol
Flammable solid 1 H228 Iron powder
Flammable reactant 1 H260 Magnesium, sodium, calcium carbide
CorrosiveHealth hazard/Hazardous to the ozone layer Skin corrosive 1A/B/C H314 1 % Hydrochloric acid
Eye damage 1 H318 10 % Zink sulfate
Skin irritant and/or eye irritant H315 and/or H319 20 % Sodium carbonate
Acute toxicityHealth hazard/Hazardous to the ozone layer Acute toxicity 3 (oral) H301 5 % Barium chloride, methyl orange
Acute toxicity 4 (oral) H302 25 % Ammonium chloride
Acute toxicity 3 (dermal) H311 15 % Methanol
Acute toxicity 4 (dermal) H312 55 %
Acute toxicity 3 (inhalation) H331 3.5 % Nitric acid
Acute toxicity 4 (inhalation) H332 22.5 %
Hazardous to the environment Aquatic acute 1 H400 25 %
Aquatic chronic 1 H410 0.25 % Copper(II) sulfate, silver chloride
Aquatic chronic 2 H411 2.5 % Manganese(II) chloride
Aquatic chronic 3 H412 25 %

How to Dispose of Laboratory Waste

School science and chemistry laboratories should have waste disposal stations for hazardous waste that complies with the applicable requirements. The waste containers must be labelled with appropriate pictograms and stored in cabinets according to the hazards of the content. The school needs routines for what to do with the waste when it needs to be disposed of. Local and national regulations are often stringent; for this reason, you should contact the local authorities to get guidance.

Advice for Waste Disposal Stations

Designate a hazardous waste storage area that is out of the way of normal activities, yet easily accessible and recognizable for the users.

The containers at a waste disposal station should:

  • be chemically compatible with the waste they will hold (e.g. acidic and alkaline solutions in high-density polyethylene containers)
  • be sturdy and leak-proof
  • have screw-on caps
  • be placed in a secondary container (e.g. polyethylene retention tray) in the case of liquid waste to prevent leaks and spills
  • be labelled in accordance with local and national requirements
Chemically compatible container with screw-on cap, labelled according to the local and national regulations, placed in a secondary container.

 

An example of storage container for liquid waste.

The tables below suggest how to organize chemical waste and other laboratory waste. Below the tables there is a decision tree that can be helpful to determine which container to use for different hazardous waste.

If a professional company is handling the waste, consult with this company on the choice of containers and what to dispose of in the different containers.

Containers for hazardous chemical waste
Container 1

Acidic solutions

E.g. hydrochloric acid

Container 2

Alkaline solutions

E.g. sodium hydroxide

Container 3

Solutions of toxic inorganic salts

E.g. heavy metal salts, copper salts

Container 4

Non-halogenated organic substances

E.g. ethyl acetate, methanol, heptane

Container 5

All halogenated organic substances and waste from halogenation reactions of organic substances

E.g. chlorobenzene, bromopropane

Notes

Solid metals should be reused (e.g. copper electrode) or reacted to completion (e.g. magnesium in acid when making hydrogen gas)

Small amounts of liquid fats and oils can be put in a sealed container (e.g. a milk carton) and disposed with the regular waste. Larger amounts should be collected and delivered along with the hazardous waste.

Containers for other types of laboratory waste
Container 6

Contaminated pointed and/or sharp objects

E.g. heavily contaminated Pasteur pipettes, broken laboratory glass

Container 7

Contaminated solid waste

E.g. heavily contaminated gloves, paper towels, filter paper

Container 8

Uncontaminated laboratory glass

E.g. uncontaminated laboratory glass non defined as recyclable glass (broken or not)

Decision tree for choosing waste storage containers

Interactive decision tree:
Is your waste hazardous chemical waste?
  • Yes
    Does your waste contain organic substance?
    • Yes
      Is your waste halogenated?
      • Yes
        Container: All halogenated organic substances and waste from halogenation reactions of organic substances
      • No
        Container: Non-halogenated organic substances
    • No
      Does your waste contain toxic inorganic salts?
      • Yes
        Container: Solutions of toxic inorganic salts
      • No
        Is your waste acidic?
        • Yes
          Container: Acidic solutions
        • No
          Is your waste alkaline?
          • Yes
            Container: Alkaline solutions
          • No
            Please start over
  • No
    Is your waste a laboratory waste?
    • Yes
      Is your waste heavily contaminated?
      • Yes
        Is your waste pointed and/or sharp?
        • Yes
          Container: pointed and/or sharp contaminated solid waste
        • No
          Container: Other contaminated solid waste
      • No
        Is your waste a glass not defined as recyclable?
        • Yes
          Container: Uncontaminated laboratory glass
        • No
          Recycle in non laboratory bins
    • No
      Recycle in non laboratory bins
Published: 
30.06.2022

Last modified: 

16.09.2022
To cite this page, we suggest the following format (APA 7):
Online Resources for Chemical Safety in Science Education. (2022, September 16).
Waste Management.