The Critical Role of Piloting in Wastewater UV Disinfection

EXECUTIVE SUMMARYBeginning in the spring of 2001, the Town of Hanover, New Hampshire wastewater treatment facility began experiencing effluent E.coli values exceeding their permit limits. An evaluation of the problem resulted in the issuance of an Administrative Order by Consent from the New Hampshire Department of Environmental Services to replace the existing UV disinfection system.To provide a basis for the design for the replacement UV disinfection system, a UV disinfection pilot study was performed. The pilot unit consisted of a 4-lamp, low pressure-high output (LPHO), horizontal, open channel UV disinfection system, capable of providing a dose of approximately 35,000 μWs/cm2 at 165 gpm with new, clean quartz sleeves.