Wetalla’s solar hall roof replacement boosts efficiency, cuts costs

Harnessing the sun’s power is delivering both environmental benefits and significant cost savings for Toowoomba Regional Council (TRC) at the Wetalla Water Reclamation Facility.

TRC Water and Waste Committee chair Cr Nancy Sommerfield said Council recently completed the replacement of fibre glass roof sheeting material for the solar hall structure that was commissioned in 2006.

“The solar hall is one of a handful of similar facilities in operation across Australia. Council’s wastewater operations staff identified that the ageing solar hall roof sheeting panels were not drying out the biosolids as efficiently as they could,” Cr Sommerfield said.

“Typically, the solar hall processes around 41-46% of the treated wet biosolids at the Wetalla Water Reclamation Facility. This dry treatment process aerates and condenses the biosolids, making it easier and cheaper to transport than wet biosolids.

“This process reduces Council’s biosolids transport costs by up to 30% per year.

“In mid-2018 officers found that the solar hall was processing 25-30% of the wet biosolids. This drop in the volume of treated biosolids had reduced the solar hall’s efficiency.

“I’m pleased that the solar hall roof replacement will not only reduce transport costs but restore the more efficient and environmentally friendly treatment of biosolids at Wetalla.”

TRC Water and Waste portfolio leader Cr Bill Cahill said from an operational aspect, Council was able to manage the Wetalla facility more efficiently.

“Council has improved the efficiency of the solar hall over the original installation,” Cr Cahill said.

“Research into the technology revealed that the original sheeting material was an optimal product, but a new profile and sheet colour would maximise the light transmission through the panel. The panels increase the heat gain in the solar hall at ground level and improve the efficiency of the dry treatment process.

“Council awarded the $298,000 tender for the project to the locally based Kelly Group.

“The contractors started work at Wetalla on July 1 this year. They removed the old roof and installed the new panels in stages. The facility measures 120m by 40m.

“The solar hall operation was fully restored within three weeks. This allowed wastewater operations staff to immediately increase the wet biosolid load to be treated at the renovated solar hall.

“Council staff anticipate that the solar hall will return to processing more than 40% of the total biosolids that are treated at Wetalla. Additional treatment volumes are expected to be gained through process improvements.

“It’s pleasing that investment in technological advances at one of Council’s most important treatment facilities will deliver more efficient practices with direct cost savings for ratepayers.”

Additional details: The Wetalla Waste Water Reclamation Facility receives more than 20 megalitres of sewage per day and uses biological processes, such as natural microbes, to breakdown human waste and food scraps to turn human waste into soil conditioner/fertiliser. (biosolids)

Council manages and tests the biosolids process to meet strict Environmental Protection Authority guidelines.

Biosolids are the dead bacteria that remain after the waste is broken down. These biosolids carry Phosphorous which helps crops to produce a better yield. The management of biosolids, which includes treatment and potential for exposure, is in place to prevent harm to the public.

Council does not sell biosolids for public use. Council pays for the collection, removal and transportation of biosolids by a private contractor.

The private contractor is then engaged by landholders to deliver and apply the collected biosolid as fertiliser/soil conditioner to growing areas for crops that bear grains above the ground e.g. wheat and sorghum.

Biosolids potentially could become a valuable source of fertiliser for farmers in our region.

Council is continuing to look at future viable cost recovery opportunities for biosolids.

Caption: Top: TRC Water and Waste Committee chair Cr Nancy Sommerfield and TRC Water and Waste portfolio leader Cr Bill Cahill at the refurbished solar hall.