Water Online

January 2017

Water Innovations gives Water and Wastewater Engineers and end-users a venue to find project solutions and source valuable product information. We aim to educate the engineering and operations community on important issues and trends.

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on water quality and the overall water distribution system. From the design and development perspective it was important to: • Verify existing site flows and pressure dynamics • Verify electrical system integration requirements • Implement functional requirements for supervisory control and data acquisition (SCADA) monitoring and control • Complete the civil, mechanical, electrical, instrumentation, and control system designs, process and control narratives, and risk mitigation strategies • Procure, install, interconnect, test, and commission the ILT From the research perspective, it was important to: • Collect data and analyze turbine and distribution system operating characteristics • Investigate operational effects on the distribution system, such as pressure and flow characteristics and water quality impacts • Identify pressure and flow transients and develop control and risk mitigation strategies to protect water quality and mitigate other negative impacts The Orchard site was estimated to have a power capacity of 33.4 kW, a system availability of about 80 percent, and an annual energy output of 225,000 kWh/year, with an estimated annual revenue of $31,500 from the sale of electricity to the local electric utility, Nova Scotia Power. A simple payback of 9.1 years was calculated without accounting for WRF funding and other outside funding sources and 15.4 years had the outside sources not been available and the project funded solely by Halifax Water. The project has been operational since October 2014. In 2015, the turbine produced a total of 228,500 kWh of renewable electricity, the equivalent of the energy use of approximately 25 Nova Scotian households, and an annual revenue of $31,900. The system is currently on track to exceed these results in 2016, due primarily to operational optimization efforts. Some important recommendations and lessons learned during this project included: • Every successful project requires an internal project champion or project manager who is committed to seeing the project through to successful completion. This includes keeping finances in check, keeping the project on track, and helping with system integration when the project becomes operational. • Each site must be carefully evaluated for its energy recovery potential, taking into consideration the diurnal flows, pressure reduction, and long- term utilization of the site. The sites with the highest flows, pressure differentials, and longest operating hours are usually those to consider for technical and economic details. • Any project must meet provincial, state, or federal regulations established for the design and operation of water treatment and distribution systems. For instance, for this project "NSF/ ANSI 61 — Drinking Water System Components — Health Effects" certification was required for the PAT. • An accurate financial model must be developed, depicting realistic capital costs for the project, including accurate energy generation estimates. • Utility staff that will be responsible for the ongoing maintenance and operation of the turbine generator should be consulted early in the process. • Consider hiring a reputable contractor who can provide both mechanical and electrical installation services and has completed similar scale renewable energy projects in the past. • Conduct post-installation testing and condition monitoring to understand how the energy recovery system operates and affects the water distribution system and to maintain acceptable levels of water quality and service. • Monitor the turbine generator performance in terms of forecast versus actual energy revenues, operating costs, ROI, and payback to help evaluate the success of the project. Implementing an ILT energy recovery project can be achieved by water utilities if they undertake the careful front-end planning and evaluation, thorough system testing, and ongoing system monitoring and control. If implemented and operated correctly, ILTs can provide long-term clean energy recovery and energy revenues. n wateronline.com n Water Innovations 33 ENERGYRECOVERY Linda Reekie, WRF research manager, joined the Foundation staff in 1997. Prior to the Foundation, Linda worked at a county health department in Colorado for 10 years, coordinating the water qual- ity program for five years. She also has five years of experience as an environmental planner for a county planning agency in Pennsylvania. She graduated from Pennsylvania State University with a B.S. in environmental resource management. Energy recovery from PRV chambers Jeffrey Knapp, FEC, P.Eng., CEM, is manager of energy efficiency at the Halifax Regional Water Commission, Nova Scotia's largest water, wastewater, and stormwater utility. Halifax Water provides water, wastewater, and stormwater services to over 80,000 customers in the Halifax Regional Municipality. About The Authors

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