Why use recycled Water?
In today’s highly competitive markets, businesses and institutions must make wise use of available resources. Increasingly the most forward-thinking companies are partnering with local utilities to reduce their demands for energy and water, both to save costs and improve the long-term sustainability of their business.
Using highly treated recycled water for non-potable purposes is an effective way to reduce the demand for precious fresh-water resources. It is also a recognized green building practice. Recycled water has been used in industrial settings throughout California and the arid west for nearly 100 years.
Locally, Biogen Idec, a company specializing in the development of therapeutic products for the medical field, worked with the County and City of San Diego in 2006 to convert their cooling towers to recycled water. The cooling towers at Biogen Idec are the largest users of water in the facility.
Conversion to recycled water has allowed Biogen Idec to realize significant cost savings through discounted rates and has provided Biogen Idec with a drought-proof source of water. Elsewhere in Southern California, Orange County’s Irvine Ranch Water District provides recycled water for cooling tower and toilet-flushing use in over 40 high-rise office buildings. Los Angeles County’s West Basin Municipal Water District delivers service to the cooling towers at Cal State Dominguez Hills and the American Honda Campus.
In Riverside County, Inland Empire Utilities Agency’s headquarters building secured 52 LEED® points to achieve Platinum Certification from the U.S. Green Building Council. Among these points was credit in the “Innovation and Design Process” category because of indoor recycled water use. There is approximately 13,000 acre-feet of recycled water reused annually within the San Diego County Water Authority (SDCWA) service area. Roughly 70% of the recycled water is used for agriculture, landscape irrigation, and other municipal and industrial uses. The annual beneficial reuse of recycled water in San Diego County is projected to increase to over 53,000 acre-feet by the year 2020. By converting to recycled water, cooling tower customers can secure a drought-proof water supply that can protect future growth potential even when water supply shortages loom. Converting to recycled water enhances overall water use efficiency and helps customers comply with their green building goals.
Operational road map to converting cooling towers
The steps for establishing an operational regime for a cooling tower are outlined below. These steps can be performed by the system owner or, as is often the practice, by its maintenance contractor.
Step 1: Determine the materials used in the cooling system and the temperature, flow rates and hours of operation. By understanding these factors, system owners can narrow the list of water quality constituents that cause concern. For example, if a system contains 304 SS, chloride levels are an important concern. However if the system is constructed of fiberglass, this water quality parameter is less of a problem.
Step 2: Evaluate the source water quality in order to understand if treatment is necessary to make the water compatible with your system materials.
Step 3: Select a treatment system if source quality is problematic.
Step 4: Establish the desired cycles of concentration to minimize water and chemical use, without compromising system performance. While pretreatment can condition water to acceptable standards, each cycle of concentration will increase the TDS, Conductivity and Chlorine concentration in the water and at some point, these constituents will affect system performance. This point limits the cycles of concentration and establishes when blow-down should occur and make-up water added. The system manufacturer’s recommendations for conductivity and system performance with respect to TDS will likely be the limiting factors on cycles of concentration.
Step 5: Potable water back-up is necessary. This will provide increased reliability and assist with blending during conversion.
Step 6: Monitor Makeup and Blow-down water quality to confirm that the system is behaving as
anticipated.
Step 7: Reset chemical dosing and/or cycles of concentration as necessary to achieve desired performance.
Further Reading on Cooling Tower Resources:
.jpg) |
| Click Image Above to visit Hammam Industries & Co. CTI Mesan Product Range in Egypt |
The following resources provide more guidance on water best management practices.
-
-
-
Cooling Towers: Guide to understanding key components of cooling towers and how to improve water efficiency.
-
-
-
-
.jpg)
.jpg)
.jpg)
.jpg)
