Case Study: UV Wastewater Treatment System Improves Mt. View Sanitary Water District

In 1974, an unusual project was initiated near Martinez, California. It involved the creation of the first wastewater wetlands on the West Coast, and it now stands as one of the great environmental success stories.

Rather than constructing a deep-water outfall line and discharging its sewage effluent to the Carquinez Straits, and ultimately into the San Francisco Bay, the Mt. View Sanitary District (MVSD) decided to take a very different approach. It reclaimed low-lying tide-lands, constructed a series of ponds and marshes, and then directed its treated wastewater into this area.

Not only did the solution save local ratepayers millions of dollars, it established a valuable wetlands ecosystem that today supports more than 200 species of birds, fish and other wildlife.

What makes this unique and innovate project possible is the UV wastewater treatment system supplied by TrojanUV. Installed in 1994, the UV system replaced an earlier chlorine-based system. Since switching to UV treatment, MVSD finds that it can now consistently meet shallow-water discharge requirements (five-day median coliform limits of 23 MPN/100ml) which it could not achieve using chlorine.

UV removes the risk of toxic spills and leaks. As well, there are no chlorine residuals that would be detrimental to this fragile ecosystem.

MVSD realized other significant benefits by moving to UV. Because it was no longer using Acutely Hazardous Materials (AHMs) such as chlorine, sulphur dioxide, and ammonia gases, it was exempted from having to establish a Risk Management Prevention Plan and install expensive safety equipment. In addition, operator safety is much improved with the elimination of toxic chemicals from the workplace.

MVSD also found that UV was far more cost effective. It was able to eliminate the signinficatn operating expensive associated with the chlorine system, which required feeders, chlorinators, metering pumps, storage tanks and extensive safety training.

Today, treatment consists of clarification, biofiltration, ammonia removal, sand filtration and UV disinfection. The facility serves a population of about 25,000 residents. It treats an average of some 1.8 MGD, although it is capable of handling peak flows of up to 8-10 MGD.

The 135-acre wetlands project has become a model throught North America and other parts of the world. More thatn 2,000 people visit the facility each year - students, plant operators, engineers, regulators, bird-watchers, environmentalists and the general public.

"TrojanUV works. It is safe, non-chemical, and environmentally friendly."

Source: Trojan Technologies