Letters to the Editor, April 1, 2013

I would like to thank Alain Lam, of the Environmental Protection Department ("Construction industry will be able to absorb all recycled glass", March 19) for replying to my letter ("Avoid Europe's mistakes in recycling glass", March 8).

I would like to share with readers more details of our experiences in Sweden, where we have two separate glass recycling systems.

For standard drinks containers (glass, PET and aluminium) we have a deposit system. When returned to the supermarket redemption centre for deposit refund, glass bottles are sent back to the beverage factory, cleaned and reused.

Other glass containers, collected in recycling bins, are crushed. The powder is reused for building material, as Mr Lam suggests, or glass jars. It requires less energy to make new products from glass powder than from raw materials.

I'm glad to hear that Hong Kong has lamp collecting programmes as do we, but we still have the problem of light bulbs being dropped in glass recycling bins. Also, most compact fluorescent lamps (CFLs) still end up in landfills, where the mercury spreads into the food chain - one teaspoon is enough to poison a medium-sized lake.

As mercury (Hg) vaporises at room temperature, it is a hazard to residents if broken in a closed space such as disposal rooms, to refuse collectors, to glass recycling workers when thrown in the wrong bin out of ignorance, and even to uninformed and unprotected lamp collectors. Hg vapour is 1,000 times more toxic than liquid mercury.