THERE’S STUFF GROWING ON MY UV SLEEVES!Pilot Study of UV Systems in Hard WaterAt South Valley Water Reclamation Facility

摘要

Three UV systems were pilot tested at the South Valley Water ReclamationrnFacility (SVWRF) in Salt Lake City, Utah: two low-pressure low-intensity systems (one withrnhorizontal lamp orientation, the other with vertical lamp orientation), and one low-pressure highintensityrnsystem. Wastewater effluent at SVWRF is high quality (75 to 85% UVT) but very hardrn(averaged 309 mg/l as CaCO3 during the pilot study). Therefore, the pilot study was primarilyrnstructured as a fouling study, and testing objectives included estimation of fouling rate, andrncomparison of performance and operational characteristics for the three pilot units. It alsornevaluated the effectiveness of the LPHI pilot unit automatic cleaning system (which isrnmechanical only) under these hard water conditions. Pilot testing occurred over a four-monthrnperiod during the summer of 2000.rnResults indicated a small amount of fouling from mineral deposits. Significant biological foulingrnoccurred on UV systems without operating automatic cleaning mechanisms, when the lampsrnwere off for more than one week.