Problem: With 16 mgd capacity, the Newport (Rhode Island) Water System draws from nine surface reservoirs. When one aboveground tank experienced high trihalomethanes, the city sought remedies. While exploring an alternative to carbon filtration pressure vessels, the city required a performance guarantee of 50% average total THM removal for the new solution.
Solution: The city chose a PAX TRS THM removal system from USG Water Solutions. The company installed a custom-designed, energy-optimized system of mixers, aerators and ventilators to convert water storage tanks into water treatment systems. The solution consists of a PWM400 mixer, two SA-75 surface aerators, a PPV-600 Powervent and an integrated control panel. The mixer at the tank bottom circulates water to the top where it contacts the air. The aerators blow air into the tank to freshen the air in the headspace while creating a splashing effect to help THMs escape. The high-efficiency Powervent then exhausts the THM-rich air.
Result: After several months, the system achieved an 81% total THM removal. 855-526-4413; www.usgwater.com
