ACWA biofilters ensure wastewater compliance

Bairds Malt’s new wastewater system built by ACWA Services.
Bairds Malt’s new wastewater system built by ACWA Services.

With an annual malt production capacity of 47,000 tonnes, the majority destined for the distilling industry, the Pencaitland Maltings Plant uses significant quantities of water in the steeping and germination processes.

Minimising its environmental impact is crucial and the new biofiltration system plays a key role in reducing the pollutant load in wastewater discharged from production processes. ACWA designed the system to reduce the BOD (Biological Oxygen Demand) load by more than 90%, which has directly reduced the plant’s trade effluent charges.

ACWA Services, part of the ACWA Group, an international water and wastewater solutions provider, was responsible as principal contractor for all aspects of the project including the decommissioning and demolition of the existing biofilters which had reached the end of their useful life and the design, supply, installation and commissioning of the new biofiltration solution.

This incorporates two identical biofilters complete with structured media and effluent distribution systems ensuring the effluent is evenly distributed through the biofilters to promote biological growth and hence effective treatment, recirculation pumps, together with electrical and minor civil works. The project was completed in eight months.

Ensuring the Pencaitland plant remained fully operational while the wastewater biofilters were replaced was a key challenge. This was achieved by installing a temporary Submerged Aerated Filter (SAF) unit to operate in parallel with the existing biofilters to enable each one to be replaced in turn.