CWTC Service Scope

• Enviropace provides collection or disposal service for:

– Spent chemical mixtures resulting from experiments

– Surplus and expired chemicals

• Enviropace does not provide collection or disposal service for:

– Non-chemical wastes– Asbestos waste– Radioactive materials– Explosives – Gaseous materials– Unknown chemicals

Non-chemical Wastes

• Apparatus rinse water and wiping tissues

• Household chemicals used in laboratories for cleaning (e.g.- soap, detergents)

• Stabilized salts (e.g.- NaCl, Fe2O3, Al2O3)

• Dilute acids and alkali with concentration below the definitions of chemical waste in Schedule 1 of the WDO Regulations

Schedule 1 Waste Disposal (Chemical Waste)(General) Regulations

Spent Chemical Mixtures

• For each school, Enviropace initially provides a set of three 20-litre pails.- Mixed Spent Organics- Mixed Spent Acids- Mixed Spent Alkali

• Collect the waste in 3 beakers of appropriate size, one for each of organics, acids and alkali.

• Perform a compatibility test between the content of the beakers and the pail before mixing.

• Complete a Waste Log Sheet for each pail.

Waste Log Sheet

Handling Surplus or Expired Chemicals

• Leave the chemical in original packing and label bearing the chemical name, quantities, safety precautions, etc.

• If the original packing presents a risk of leakage, wrap and seal the bottle in a polythene plastic bag

• Includes highly reactive (e.g.- moisture or water reactive) and concentrated compounds

• Complete a Labpack Waste Profile Sheet (WPS1) for Enviropace

Example of WPS1

Example of CCL

Collection of Highly Reactive Chemicals

• Do not open the bottle• The chemical to be disposed of remains in original

container with the lid tightly enclosed• The bottle to be wrapped in a plastic bag and

packed in a carton box as an extra cushioning material

• Place the carton box into the 20-litre pail• Complete a Labpack Waste Tracking form and

attach it on each waste collection pail containing carton box

Labpack Waste Tracking Form

Examples of highly reactive chemicals (collection in carton box) • Air and water reactive

• High toxicity

• Shock and heat sensitive

• Obnoxious or irritating odor

• Chemicals that are incompatible with many substances so that they must be containerized in original packing

Examples of other chemicals (collection in original bottles)

• Elemental mercury (<15 Kg per pail)

• Mercury compounds

• Mercury contaminated waste

• Solid organic compounds

• Solid cyanide compounds

Examples of other chemicals (transfer directly to pails)

• Inert inorganic salts– Water insoluble metal carbonates, oxides, hydroxides,

sulfides & sulfate salts

• Common solvents– Non-reactive aliphatic and aromatic hydrocarbons

– General non-halogenated and halogenated organic solvents

Transfer and Dilution of Chemicals

• Never pour concentrated acids directly into the waste collection pail

• Add the chemical slowly into water• Mixing ratio ~ (Waste : Water = 1:10)• Perform a compatibility testing before

transferring two or more types of wastes into the same collection pail

• Each pail to be filled up to 70-80% capacity

Compatibility Test Procedures

• Perform in a fume hood with the sash half lowered• Use a pipette to draw a 50-ml waste sample from

the target waste pail and move to a beaker• Insert a thermometer into the beaker• Mix the chemical waste that is intended to be

added into the waste collection pail• Waste compatibility fails if bubbling, fuming or

noticeable temp. rise of 10 degree °C in 5 minutes• Stop mixing and inform Enviropace to collect the

original bottle