When designing its new mill and wastewater treatment system in 1992, this Canadian Company had planned to discharge into a nearby creek. But, sensitive to the region’s pristine environment, they decided to design the most advanced effluent treatment system conceivable: a chlorine-free, closed loop, zero effluent treatment system using evaporation. The mill needed a quality aeration system to match its superior standards.
The mill and its consulting engineering firm jointly decided on the AIRE-O2® aspirator aeration system for its two lagoons, having volumes of 4.2 MG (15,897 m 3) and 6.36 MG (24,072 m 3). 'The AIRE-O2® aerator’s sub-surface aeration and strong circulation capabilities were considered ideal to prevent short-circuiting and reduce heat loss in winter due to extremely cold ambient conditions,' reported the mill officials. 'Surface splasher aerator types were rejected due to potential icing problems.'
The AIRE-O2® units have oxygenated the oxygen deficient condensate to promote bacterial growth. The mixing and directional capabilities have proved of major importance to keep solids in selected areas, away from the effluent flow, and to keep MLSS (mixed liquor suspended solids) as high as possible. This mill embraced the challenges of discharge as an opportunity and succeeded. 'Each drop of water is used six times before it is lost to evaporation.' Now, that is environmental conservation at its best!