It has designed, manufactured and installed a Sequencing Batch Reactor (SBR), which provides biological wastewater treatment for the brewery to such a high degree that it can be safely discharged direct into an ecosystem around the brewery which constitutes both an area of outstanding natural beauty and an area of special scientific interest with diverse fauna and flora.

Throughout the planning and implementation of this project Micromac worked closely with Sustainable Direction (SDL), which was recruited by Otter Brewery to oversee selection of the most appropriate enabling technology and supplier.

Using Micromac’s SBR system, wastewater is collected in a sump and screened. Then a batch of prepared wastewater is pumped to the reactor tank where it is aerated. This has the effect of mixing activated sludge already within the tank with the new wastewater and commencing the treatment of the whole.

The aeration causes the biological oxygen demand (BOD) components to be converted to sludge and the ammonia to nitrates. The mixed liquor suspended solids (MLSS) are measured, and the system configured to automatically maintain the optimum level for the processing of the wastewater. After a pre-set time, aeration ceases and the sludge is allowed to settle. During this phase, the nitrates are converted to nitrogen.

After settlement is completed, surplus sludge is pumped from the reactor for disposal. The treated wastewater is measured for suspended solids, ammonia, pH, etc. If these are within pre-set levels the wastewater is discharged. If outside the preset limits the wastewater remains in the reactor for reprocessing. Wastewater treated to the acceptable levels is passed to an outfall station for discharge. The outfall station is fitted with a flow meter to measure the volume and flow rate of the discharge.

The brewery makes 20,000 brewer’s barrels of beer per annum and every pint of beer made requires 2.5 pints of water to be used in the production process. The brewery is fed by its own stream and thanks to Micromac’s advanced wastewater treatment system it can return more than 80% of the wastewater direct into the watercourse at the brewery.

“Micromac’s SBR unit has settled in well and ticks all our boxes,” explains Patrick McCaig, sales director at Otter Brewery. “Ecologically sympathetic, future proofs production growth and is aesthetically pleasing. Long live those bugs and long may we continue to deal with our own waste water.”

“Otter Brewery is a real Devonian success story and our work here will help the company to continue to evolve and grow,” commented Richard Milton, managing director of Micromac Filtration. “The batch reactor is an ultra-reliable, cost-effective and low maintenance solution that will protect the brewery and the environment in which it operates for many years to come.”