Environment and Waste Management
Ceramic production generates dust, slurry, plaster and kiln emissions. The exam tests the 3Rs applied to a studio and the correct disposal route for each waste stream.
Waste streams and handling
- Clay and glaze slurry - reclaim, do not pour down the drain. Slurry sets in pipes and carries heavy metals.
- Settling tanks - three-chamber tanks with 24–48 h retention; clear water leaves only after settlement and a pH check, sludge is dried and reused or sent as hazardous waste.
- Plaster - cannot be recycled into clay; gypsum contaminates the body and blows pots in the kiln. Keep separate; cured plaster to authorised landfill.
- Fired waste and seconds - crush as grog, or sell as mosaic and seconds rather than dumping.
- Packaging and pallets - reuse, then recycle.
- Kiln emissions - fluoride and sulphur at high temperature, metal fumes from glazes; ventilate, and never fire lead glazes in a kiln also used for foodware without thorough cleaning.
Energy and water
Load kilns densely, fire full loads, use the correct cone, insulate well and maintain elements. Reuse rinse water in glaze mixing and route wash water through the settling system.
Worked example
A studio produces 40 kg of glaze slop containing 5 % copper oxide, i.e. 2 kg of copper. That cannot go to drain. The slop is settled, the clear water decanted and checked, and the dried sludge weighed and sent for hazardous waste disposal. The longer fix is to reformulate with a fritted colour so less material is lost in the first place.
Traps
- Mixing plaster waste into the clay reclaim bin.
- Pouring glaze down a sink on the grounds that it is only clay.
- Burning plastics or treated wood in a kiln.
- Firing small, partly empty loads - the biggest avoidable energy loss.