AWWA WQTC69440

This powerpoint presentation begins by providing a brief overview of the Coquitlam Water Treatment Facility (WTF). Study objectives included the following: evaluate fouling occurrence in low-pressure high-output (LPHO) and medium pressure (MP) reactors; indirect fouling/aging evaluation through monitoring of UV intensity (real and theoretical) for MP reactor; direct fouling measurement using a modified spectrophotometer; correlation between direct and indirect fouling measurements; analytical measurement of fouling layer constituents (e.g., metals, alkalinity, hardness); visual MINTEQ evaluation (solubility modeling software); and, recommendations with regards to UV technology and system redundancy. Materials and methods included a pilot-scale study set-up of Calgon Sentinel 12" and Trojan SWIFTSC B08. Experimental matrix, testing sequence, direct transmittance measurements, monitored parameters, and water quality are all presented. Presentation conclusions indicate the following: low metal concentration waters can still provide for super-saturated environments; considerable Al, Fe, Mn and Ca fouling, increase in Al content higher for longer tests; higher fouling along the influent-to-effluent flow line (lamps are parallel to flow); mechanical wipers were very effective for the LPHO system; direct and indirect fouling measurement needs further testing; based on results CIP would likely be required every 40 to 60 days in average for LPHO systems; numerous problems with MP lamps, including loss of UV intensity output during testing; plants should have mechanisms in place to detect problems; MP systems fouled very fast (within one to two days) when wiper mechanisms were not activated; fouling was higher in the middle of the sleeve (lamps are perpendicular to flow); wiper mechanisms were effective in controlling fouling, however, metals were detected in wiped sleeves; significant variability was obtained for all fouling measurements; and, no relationship between lamp location and fouling potential was identified. Includes tables, figures.