In recent years, the number of small craft breweries has greatly increased and so has the wastewater generated by brewers. As for all other food and beverage sectors, effluents from microbreweries are regulated and required to meet wastewater discharge regulations.
In terms of treatment efficiency, footprint and cost, very few wastewater treatment technologies prove to be up to the challenge, which in part explains why most microbreweries discharge raw effluent to a municipal wastewater treatment plant, instead of having a dedicated on-site treatment system.
In April 2015, the Cartwright Springs Brewery, together with its representative Fieldstone Engineering, was looking for a solution for treating wastewater generated by its newly constructed microbrewery, located in Pakenham, Ontario, west of Ottawa. The brewery production capacity was limited to 2,000 L/week, which suggested that wastewater generation would be approximately 10,000 L/week. The wastewater to be treated was a combination of all the streams: the yeast dump and mash dump (i.e., high strength, low pH), wash water (i.e., low strength, high pH), and domestic wastewater from the pub (950 L/day). The combined flow after seven days of equalization was estimated to be 2,380 L/day.
After an extensive sampling campaign performed by the engineering firm on similar installations, the EcoprocessTM Moving Bed Biofilm Reactor (MBBR) from Premier Tech Aqua was selected. The objective-based design was for the combined streams to be pretreated to primary domestic effluent (i.e., BOD: 100 mg/L to 180 mg/L) and then discharged by gravity to a leaching bed. Treatment included a balancing tank, septic tank, MBBR units (two stages), final clarifier with sludge management, and leaching bed. To benefit from lower electricity rates, the treatment unit integrated a smart control strategy that made operating mainly at night possible, whenever the incoming wastewater flow was lower than the one set for the design.
The system was put into operation in July 2015 and has performed extremely well since then. BOD concentration at the inlet varies between 1,500 mg/L and 2,500 mg/L, and laboratory results show a steady removal rate of 99%.
The moving bed biofilm reactor is a compact and high-performance treatment system available as a ready-to-use solution or in a cast-on-site concrete basin. It applies to a host of commercial, institutional and municipal projects, including those to increase the performance of aerated lagoons.
This article appears in ES&E Magazine’s June 2017 issue.