Community treatment combats saltwater intrusion and recharges aquifer
Problem: The coastal community of Los Osos, California, had outdated wastewater systems and a history of nitrogen issues. Many lots in the community were too small for code-compliant septic systems. With existing systems far exceeding their design life, the regional water quality control board declared a prohibition zone that included a building moratorium. Meanwhile, farms were experiencing saltwater intrusion as groundwater was pumped to meet demand for irrigation and drinking water.
Solution: Initial studies recommending an ocean outfall for a centralized wastewater treatment system raised concerns that saltwater intrusion would increase. Los Osos chose a decentralized solution from Delta Treatment Systems that discharges to a community drainfield, recharges groundwater, and minimizes saltwater intrusion. The system treats a design flow of 1.6 mgd.
Result: Treated effluent is pumped to a large chamber dispersal field installed along a hillside with ideal soils to facilitate aquifer recharge. With this solution, the town-owned property was converted to open space walking trails. Therefore the land was still functional while providing active recharge to the aquifer. 800-221-4436; www.infiltratorwater.com
Cheesemaker uses nanobubbles to increase production
Problem: Wisconsin-based Meister Cheese treats its wastewater solids using anaerobic digestion. The biogas is converted to electricity to power the plant. The wastewater is high in antimicrobial chemicals from surface disinfection to meet food safety standards. These chemicals disrupt biological wastewater treatment. For years the company struggled to maintain digester performance from biological inhibition. The only option was to reduce cheese production or pay costly hauling fees to dispose of high-strength waste.
Solution: In 2022 the company began treating its influent wastewater with Moleaer technology that injects nanobubbles, a clean chemistry generated on site using air and water, to remove cleaning chemicals.
Result: The company saw immediate improvement in digestion and was able to increase cheese production by 20% and biogas production by 30%. The technology had a payback of about 30 days, and the process improvements enabled the company to avoid more than $10 million in costs. “With nanobubble technology, we’ve become more than energy neutral at the wastewater treatment facility,” says Larry Harris, director of technology and cheese master. “In a normal month, we would spend about $11,000 in electricity costs. Currently our average is about $2,000.” 424-558-3567; www.moleaer.com
Ozone technology helps a water treatment facility handle source fluctuations
Problem: Pure Water Monterey, an advanced water purification process that treats four sources of water for domestic, irrigation, and aquifer recharge in Monterey County, California, also has to deal with seasonal and source-related fluctuations in contaminants and volumes. Source flows include winter stormwater, agricultural runoff during the growing season, wastewater during the tourist high season, and vegetable processor rinse water in summer and fall.
Solution: Monterey turned to ozone to help control pathogens, taste and odor, and minerals across the variations in source water. To guarantee that the ozone performed optimally, design engineers selected a sidestream injection system for ozone dissolution from Mazzei Injector for its mass transfer efficiency, small footprint, low pumping energy, turndown flexibility and low maintenance.
Result: The ozone effectively keeps pathogens, taste and odor, and minerals under control. It also improves the performance of downstream filtration and polishing by reducing the size of organic particles, increasing their polarity and enhancing their hydrophilicity. Improved performance in microfiltration, reverse osmosis and UV advanced oxidation is measured in runtimes and flux, intervals between cleaning and consumption of backflush water and chemicals. 661-363-6500; www.mazzei.net
