Overview
The South San Francisco – San Bruno Wastewater Treatment Plant relied on the ChemScan mini Sulfite Analyzer to monitor residual sulfite before discharging clean water into the San Francisco Bay. After two years of operation, the device has helped optimize chemical usage, eliminating excess sodium bisulfite.
The plant plays a key role in secondary wastewater treatment for the cities of South San Francisco, San Bruno and Colma, and also performs the dechlorination process for wastewater from Burlingame, Millbrae and San Francisco International Airport before discharge into San Francisco Bay.
Challenge
As a 13 MGD activated sludge plant, South San Francisco – San Bruno uses sodium hypochlorite for disinfection, followed by dechlorination prior to discharge. To ensure regulatory compliance, the plant uses sodium bisulfite and monitors residual sulfite levels with analyzers.
However, the previous equipment required frequent maintenance, was prone to misalignment, and was prone to contamination, creating the risk of chemical dosing errors. This increased costs as the plant was forced to use higher levels of bisulfite than was necessary to ensure safety.
Applications
In mid-2020, the plant decided to upgrade its equipment and install a ChemScan mini Sulfite Analyzer. This is a highly accurate sulfite measuring device that eliminates guesswork in chemical dosing.
“We have used several sulfite analyzers before, but ChemScan has been the most consistent and reliable,” said Nicholas Talbot, Assistant Plant Supervisor. “Our performance has increased by a thousand times over what we had before.”
Result
The ChemScan mini Sulfite Analyzer not only helps the plant stay compliant with chlorine regulations, it also significantly reduces sodium bisulfite consumption. According to Talbot, the system now saves up to 100 gallons of the chemical per day. At $1.47 per gallon, that equates to about $53,000 per year – money that can be reinvested in other upgrades at the plant.
Talbot stresses that while the initial investment may be a deterrent for many businesses, the accuracy and reliability of the device makes it well worth it. “You can trust the data you get – and that’s invaluable.”
In addition to operating reliably under normal conditions, the analyzer also proved its durability during recent major storms in the San Francisco Bay Area. Despite the extreme weather conditions that put a lot of stress on the wastewater treatment system, the device maintained optimal performance. “It makes us more proactive in responding to natural disasters, increasing our ability to protect the system in emergency situations,” said Talbot.
Vietnamese 
English