Biochar plan could cut waste

Turning waste timber into a charcoal-like substance is being investigated by the Timaru District Council.

If it proceeds, the project could divert up to 18 per cent of existing residual waste from landfill.

TDC waste minimisation manager Ruth Clarke said the council was liaising with Waste Transformation Ltd (WTL) to consider whether Timaru would suit as a pilot site for a slow pyrolysis kiln, which carbonises a range of timber materials into biochar (a charcoal-like substance).

"The processing unit is small-scale and can process relatively low volumes, or be scaled up to process larger volumes such as in Christchurch."

She said waste minimisation staff were consulting with neighbouring local bodies, waste contractors and businesses to assess the timber waste stream thatcould be extracted.

"According to a waste audit in 2011, 18 per cent of our waste is comprised of timber."

Clarke said it was still early days. "We are only at the consultation stage, so everything is still up in the air."

The next step was to investigate whether enough timber tonnage could be provided to set up the kiln.

The council approached the Waimate District Council asking it to provide estimates of treated timber weights that could be diverted from landfill at the tip face.

"Waimate has a good local source of timber and it has a transfer station."

Clarke said one of the issues also being looked at was how to sort useable timber.

"We did an anaylsis of the landfill and up to 18 per cent is an assortment of different timber. There's pallets, untreated timber, windows and furniture, so we need to look at how we can sort it."

One of the initial thoughts was that separation of building materials could be best achieved by an education programme or assistance at the tip face.

The Timaru Herald