Converting Industrial Food Process Water into High Quality Drinking Water for Direct Reuse

摘要

Global water shortage problems and environmental sustainability targets are becoming increasingly attractive, not just at the international level, but also within the United States. Today, groundwater is being pumped faster than it is being replenished. Underground aquifers, the source of 60 percent of U.S.’s fresh water, are being depleted, and surface water in lakes and rivers is endangered by our population demands. More than 85 percent of the world’s fresh water is consumed in the agricultural and industrial sector. Manufacturing operations across the globe need to identify solutions to reduce their water footprint and begin working toward more sustainable water scenarios. One of the most promising sustainable solutions to the growing global water shortage is water recovery and reuse. The objective of this project was to identify the most viable technology to convert food process water into high quality drinking water for direct reuse at food manufacturing plants. Major treatment processes of this advanced water recovery and recycling system include screening, equalization, pH adjustment, primary clarifier, Membrane Bioreactor (MBR), Activated Carbon (AC), Ultraviolet (UV) disinfection, Low Pressure Reverses Osmosis (LPRO), water stabilization, and chlorination. Frito-Lay Inc. (A Division of PepsiCo), as part of its robust and thoughtful approach to sustainability and reducing its environmental footprint, has selected its manufacturing plant in Casa Grande, Arizona to be the first full-scale “Water recovery and reuse facility” in U.S. Several design, construction and operational lessons were learned during and after the start-up of this project. LPRO membrane fouling was the most challenging issue which required much time and investigation to resolve and develop a feasible solution. Currently the combined MBR-Activated Carbon-LPRO membrane system is running at 69% water recovery and producing high quality permeate which meets US EPA Primary and Secondary drinking water standards. Annually, this plant will save more than 100,000,000 gallons of fresh water in State of Arizona.