There are over 8,000 acoustic, leak-detecting sensors installed on hydrants in San Jose Water’s distribution system. The initial deployment of 2,000 of these sensors used 3G to communicate changes in acoustic noise — signifying a potential leak. As all cell carriers are phasing out 3G by the end of 2022, SJW proactively replaced these with newer, 4G nodes this year. However, disposing of 2,000 sensors had to be done carefully and thoughtfully.

Each sensor contains a non-rechargeable lithium metal battery, allowing it to communicate for 5 years before replacement. The batteries contain heavy metals and chemicals which impact the environment, and require special care for disposal. We worked with our sensor manufacturer, Echologics, to make sure that we handled this process in an environmentally responsible way in line with SJW’s mission.

First, the sensors were disassembled, and the metal casings were recycled. Next, 1,103 pounds of lithium batteries were taken to Corporate Ewaste Solutions. They partner with a downstream battery vendor to recycle these in order to create other products. This lessens the demand for virgin mined, or salt desert produced metals. It is also environmentally safe and compliant with state and federal laws.

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acoustic leak detection sideview
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acoustic leak closeup
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echologics logo CEWS logo and SJW logo