chapter 14 - Drinking Water treatment and Distribution
Box 14-3 Prototype Desalination Facility
In an exclusive public sector partnership, Long Beach Water, along with the Los Angeles Department of Water & Power, and the US Bureau of Reclamation, has constructed a 300,000 gallon-per-day prototype desalination facility, the largest seawater desalination research and development facility of its kind in the United States.
The primary research at the prototype facility will be centered on further development of a breakthrough membrane technology known as the “Long Beach Method”. Already, two different—and independent—analyses have shown the technology to be 20 to 30 percent more energy efficient than more traditional desalination methods.
In addition, Long Beach Water and the US Bureau of Reclamation are undertaking design and construction of an “Under Ocean Floor Seawater Intake and Discharge Demonstration System,” the first of its kind in the world, and are seeking to demonstrate that viable, environmentally responsive intake and discharge systems can be developed along the coast of California.
Drinking Water Distribution in California
Water that is treated and/or conditioned to the point that it meets drinking water standards is considered to be “finished water”, suitable for distribution to consumers for all potable water uses. Water distribution systems consist of pipes, storage tanks, pumps and other physical features that deliver water from the source or water treatment plant to the customer’s connection. Even high quality drinking water is subject to degradation as it moves through the distribution system to the tap. For example, contaminants can enter the distribution system via backflow from a cross-connection, permeation and leaching, during water main repair or replacement, and contamination via finished water storage facilities. Within the distribution system, water quality may deteriorate as a result of microbial growth and biofilm, nitrification, corrosion, water age, effects of treatment on nutrient availability (contributing to microbial growth and biofilm), and sediments and scale within the distribution system (USEPA, 2006).
CDPH has established laws and regulations for the design, construction, operation and maintenance of distribution systems primarily through the California Waterworks Standards (CDPH, 2008a). Regulations mandate monitoring distribution system water quality for coliform bacteria, chlorine residual, lead, copper, physical water quality parameters, and disinfection byproducts. California also has adopted regulations for the control of cross-connections and backflow prevention within a water distribution system to protect the quality of the water.
In 2000, a federal advisory committee working on the development of more stringent USEPA regulations for disinfectant byproducts and microbial contamination noted the following as part of its key considerations on developing further regulations in these areas:
Finished water storage and distribution systems may have an impact on water
quality and may pose risks to public health.
caLifoRnia WateR PLan | update 2009
iMPRove WateR QuaLitY