Studying EDGE technology for side-stream wastewater centrate treatment in the Regional District of Nanaimo

This proposed feasibility study aims to assess a new and highly efficient EDGE technology (Enhanced Dynamic Granular-sludge Engineered bioreactor) for the side-stream treatment of ammonia-rich centrate, to be diverted from main-stream wastewaters. This will be a cost-effective, innovative solution to effectively remove ammonia and COD generated from the Autothermal Thermophilic Aerobic Digester (ATAD) sludge dewatering at French Creek Pollution Control Centre (FCPCC) in the Regional District of Nanaimo (RDN).
This centrate generated from the existing ATAD sludge management process is a highly condensed liquid with high concentrations of ammonia (ranging from 900 - 1,200 mg/L) and COD (up to 10,000 mg/L). Currently, centrate is pumped back to the FCPCC headwork for treatment, where it contributes ~15% of the plant’s incoming nitrogen load and ~10% of the plant’s COD load, but only accounts for 0.5% of the total wastewater flow.  High ammonia is a significant challenge to plant operations and the environment as it contributes to the ammonia toxicity issues during the treatment process, which could result in discharge limits exceedances for effluent toxicity, and instability of the secondary treatment process. High COD load from the centrate also represents challenges to the already stressed secondary treatment with trickling filters at FCPCC.  Side-stream reduction of ammonia and COD is therefore critical to improving secondary treatment capacity, meeting regulatory requirements, reducing plant’s GHG emission, and improving effluent quality to a level better than required by FCPCC's permit to protect the marine environment.
The proposed feasibility study will assess the EDGE wastewater treatment process for high-rate ammonia and COD removal from the FCPCC waste streams. Developed based on energy-efficient nitrogen reduction mechanisms (nitritation/denitritation/anammox) and advanced granular sludge reactor design, EDGE is a simple single-reactor process, that is modular and scalable, and is ~10 times more efficient than comparable wastewater treatment technologies on the market today. This technology minimizes treatment footprint, GHG emission, and energy consumption (with more energy efficient nitritation-based bioprocess, saving >30% aeration energy) while delivering reliable treatment with low maintenance and operation requirements.   
Following a successful demonstration of EDGE technology at the University of Alberta, as well as a recent successful pilot-scale demonstration in Calgary for centrate treatment and in Edmonton for landfill leachate treatment, the scope of the proposed feasibility study includes: (i) gathering historical centrate waste stream characterization and conducting flow assessment, (ii) developing site layout and configuration of the process units, site utilization, access, operational and maintenance convenience and future expansion considerations, (iii) developing procurement strategies, risk assessment and project schedule, (iv) developing P&ID and control strategies, (v) conducting a life-cycle cost analysis including O&M and life cycle costing, and (vi) performing a life cycle assessment to provide GHG emission and carbon footprint impact assessment data for the proposed processes. 
With the successful implementation of this technology in the FCPCC plant, it could be replicated in other wastewater treatment plants (with anaerobic or aerobic digesters for biosolid treatment) across Canada. This approach addresses a major problem facing all Canadian municipalities: how to economically upgrade existing wastewater treatment processes to achieve more stringent effluent quality in terms of lowering ammonia, and total nitrogen concentration in the plant effluent and meet net-zero goals Energy-neutral wastewater treatment cannot be achieved without energy-efficient ammonia management. As Canada’s population increases, the demand for sustainable water management practices will continue to grow.