Metro - ECCV Zero Liquid Discharge Pilot Study_Application

Home Browse Search

East Cherry Creek Valley Water and Sanitation District l~~~~PUPw~l 1\ \ \. \, ." \ I l , fI .- s. - Introduction The Colorado Water Quality Forum's Membrane Treatment Workgroup has recommended to the Colorado Water Quality Commission that there is a need to examine zero liquid discharge (ZLD) technologies for treatment of membrane treatment concentrate. Drinking water providers increasingly have to make use of lower quality water sources and in many cases have turned to membrane treatment, which is a recognized technology that can treat these waters to meet or surpass most water quality objectives. Disposal of the waste stream (concentrate) from membrane treatment systems is often the critical issue with using membrane treatment technology. Discharge options for the concentrate are typically limited by lack of assimilative capacity and, in one instance, an application for a permit to discharge concentrate has been denied. Therefore, for drinking water systems that serve the most populated areas of the state, or systems treating impaired sources, ZLD of concentrate will likely be the only long-term solution. Existing ZLD technology, however, is energy intensive, relatively costly, and has not been demonstrated on a broad scale or for large systems. Initiation of research and development of ZLD technologies for use in Colorado is imperative and it is appropriate for these efforts to receive significant political and financial support from the state. Water Supply Limitations are a Driver for Membrane Treatment The Colorado Water Conservation Board (CWCB) completed the first phase of the Statewide Water Supply Initiative (SWSI) in 2004. SWSI explored at a statewide level the existing water supplies and existing and projected water demands through the year 2030. This analysis was conducted in each of Colorado's eight major river basins. In addition to examining water supplies and demands, SWSI explored the range of potential options to meet the state's future water demands. The study concluded that municipal and industrial (M&I) water needs will increase by over - 600,000 acre-feet per year by the year 2030. A portion of these future water demands will need to be met using lower quality water sources. SWSI predicted that 80 percent of the 2030 water demands will be met by water providers identified projects and processes (i.e., through local solutions). The 20 percent of the 2030 water demands that will not be met by identified projects and processes are termed "gap" areas by SWSI. The largest "gap" areas in the state are the South Metro area of Denver and unincorporated El Paso County near Colorado Springs. "Gap" areas were identified on the West Slope as well. The SWSI report identified options for addressing "gaps" throughout the state. One of these options, alternatives to traditional agricultural transfers of water for municipal uses, was explored during SWSI Phase 2. Examples of alternatives to traditional agricultural transfers of water for municipal uses include interruptible agricultural transfers and rotating fallowing arrangements. SWSI recognized that any alternative involving either traditional or alternative transfers of agricultural water or alternatives to permanent agricultural transfers need to address water quality issues with these water supplies. South P1atte- ( . - I 1_1 _.~ .. '-, \ June 2007