Silicon Valley has long been the birthplace of many of the technologies we use today, so it only seemed fitting that a wastewater treatment plant in the area tapped into the power of technology to tackle an age-old problem in wastewater management: odour. The Silicon Valley Clean Water treatment plant needed an odour elimination technology. The plant that was located in Redwood City, California, had a trickling filter wet well which produced such foul odour that the staff couldn’t eat lunch at the picnic tables on the deck outside the office.
To solve their problem, the management team decided to try a new odour elimination technology to handle the smell. They installed a MILLI hydroxyl radical misting system called “Vapex” to dissolve and eliminate the grease layer. The system worked and not only did it eliminate the offensive odours, it also reduced the corrosion of plant infrastructure from hydrogen sulfide.
Monte Hamamoto, chief operations officer of the plant, was very pleased with the outcome. He was familiar with the odour eliminating technology. “It had always been appealing to me, so I felt it was worth a try,” he said. They initially pilot-tested the technology for six months, but because of the favorable results, the plant decided to purchase the unit.
Vapex has spent 15 years perfecting their system and has been installed across 350 odour control systems. The hydroxyl radical mist itself is made from ozone, water and air and is designed to break up grease while eliminating hydrogen sulfide which is the source of the odours.
A six-nozzle MILLI unit was used on the trickling filter wet well for about six months. Before the system was installed, the grease layer build up was as much as 18 inches high in the influent channel. Corrosion was also showing around the concrete walls and aluminum hatch covers because of this debris.
“We cleaned the channel out to give the Vapex unit a fresh start,” Hamamoto says. Since the unit was installed, the grease layer has never exceeded 1 inch. The broken-down grease is simply washed away with the wastewater and does not congeal in downstream processes.
The plant even purchased a second smaller unit to eliminate grease and odours at a receiving station where grease is trucked in from restaurants. The Vapex system is so easy to maintain that nozzle cleaning is the only regular maintenance required. Vapex requires no chemicals and operates on electricity and water supplied by the treatment plant. Simple spin-down cyclone filters are used to remove particles that might plug the misting nozzles.
“We used to use permanganate to try to scrub these odors. It was ineffective, and the operators hated it. It was not fun to deal with,” Hamamoto says.
Hamamoto is appreciative of the technological innovations that surround them in the area.
Being located very close to Stanford University, it made sense to partner with them to try novel solutions.
The plant is continuing to try out new things such as the construction of new storage and flow equalization structures. They also plan to add new drying technologies to their biosolids processing using a new pyrolysis unit that will turn dried solids into carbon biochar for use as an agricultural soil amendment.
If you are a municipality in Ontario and in need of a biosolids management solution, please feel free to contact us at 1 (877) 479-1388.