A Case Study: Pushing the Limits of Water Recovery at a Food Processing Plant

The Food Industry requires experienced water treatment professionals to meet their needs for water reuse and to push the limits of water recovery in regions of the world with growing water scarcity issues. To meet one clients needs and achieve the necessary level of reliability in treated water quality, treated water flowrate, and equipment availability a flowsheet based on Activated Sludge including cyclic nitrification/denitrification, followed by Ultrafiltration (UF), Granulated Activated Carbon (GAC), and Reverse Osmosis (RO) was recommended. To further optimize recovery, reliability and performance AMEC modeled a High Recovery Wastewater Reuse Reverse Osmosis system to recover 87.5% of the treated wastewater for reuse. AMEC’s responsibilities on the project included development of the plant water balance, inspection and process review of all existing systems and equipment, technical specification for all new water and wastewater systems and equipment, vendor bid reviews and recommendations. On-site engineering support was provided throughout the construction, start-up and commissioning periods to help control changes to the budget and schedule. A comprehensive three level training package was provided for the operations and maintenance staff, plant supervisors and management to ensure everyone involved with the project was comfortable with the new systems, their requirements and their controls. The RO recovery and permeate water quality during start-up and through the first six months of operation have met the design requirements. However, during the production facility’s initial start-up period increased demands for process water from the water reclamation system overlapped with the needs for backwashing and rinsing of the activated carbon in the GACs. Balancing these needs for water was a struggle as the GAC’s requirements for backwashing and rinsing were much greater than expected. The overlapping needs for water meant that the GAC was not sufficiently backwashed and rinsed until well after start-up. Notwithstanding challenges during the first few months of operation the wastewater treatment and water reclamation plants have performed well to-date and proved to be a reliable source of makeup water for the facility.