Perth Submerged Attached Growth Reactor (SAGR)

The Town of Perth will add a Submerged Attached Growth Reactor (SAGR) to its existing wastewater lagoon that is reaching its design capacity to allow for future development. The SAGR is a cost effective and innovative technology, designed to provide nitrification in cold to moderate climates, and includes a Phosphorous Offset Program to address phosphorous loading. It will help to protect the Tay River, from which Perth and other communities draw their drinking water, and downstream water bodies by decreasing the level of contaminants and nutrients in the effluent while meeting growth needs at a low cost. A FCM funded field test of the SAGR (GMF 12065 - Perth's Submerged Activated Growth Reactor (SAGR) Field Test) was conducted in Perth from 2012-2013, demonstrating that the SAGR can facilitate increased hydraulic flows and influent loads, and enhance the existing lagoon treatment system. While the existing lagoon system already meets the regulatory requirements for wastewater effluent, the field test proved that treatment with the SAGR surpassed regulatory parameters for CBOD and TSS, and significant E.coli removal and total coliform reductions were also observed. The field test proves that this technology, which is easy to maintain and operate, can extend the service life and treatment capacity of its lagoon. This application is to support the construction of Phase I, which will be designed to accommodate the projected population growth up to approximately 8,200 by the year 2030. Other benefits of the SAGR include: - Wastewater lagoons are passive systems requiring minimal energy input when compared to the alternative of an activated sludge wastewater treatment plant (WWTP). - The SAGR system produces less waste than a conventional WWTP. - The proposed project minimizes waste by re-using the existing lagoon as opposed to decommissioning and building a conventional WWTP. The SAGR consists of a clean aggregate media bed, with linear aeration throughout the floor, providing aerobic conditions required for nitrification. It is a simple and environmentally sustainable method of treating sewage, and can be replicated in other small communities with existing lagoons that are seeking alternatives to undertaking the construction of a costly, conventional WWTP. (Project description from original funding application)