San Jose Water Company (SJWC) installed an innovative aeration system in its Los Gatos 12-million-gallon water storage tank to protect declining water supplies from contaminants such as trihalomethanes (THMs). As reservoirs filled in 2011 continue to be depleted during the drought, the organic matter in these reservoirs has become more concentrated resulting in higher THM levels. Additionally, more frequent taste and odor issues have also been reported due to the formation of algal blooms that typically occur during periods of warm weather and low water levels.

“With the California drought, there’s more pressure than ever to keep our remaining water supply at a high standard,” said Francois Rodigari, SJWC’s Director of Water Quality and Environmental Compliance. “We wanted to get out in front of this potential issue and ensure a high-quality supply for customers – our top priority at San Jose Water.”

PAX Water Technologies and Utility Service Group were selected to perform the system analysis, energy optimization, installation and commissioning. Their design consisted of an array of seven high-efficiency surface aeration units along with a large-scale air handling system and two water mixers. The system is designed to treat eight million gallons of water a day and creates bubbles on the surface of the water to ventilate THMs out of the drinking water. Additionally, an Aqua Metrology AMS-100 THM analyzer was added to the design to continuously monitor THM levels in the reservoir and dynamically control aeration to meet target levels while minimizing energy cost.

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