Synergistic Evaluation of Ozone and UV at the Coquitlam Source for Enhanced DBP Control and Cryptosporidium Inactivation

Abstract

A study was performed for the GVRD to select the ozone dose that results in a higher UVT (UV Transmittance) and reduced DBP formation potential, at the most economical life cycle costs of ozone and UV treatment. The GVRD treats its Coquitlam source with ozone, to meet Giardia and virus inactivation requirements. Currently, the Coquitlam Facility does not meet Cryptosporidium inactivation requirements (3-log). Because the ozone dosage required for Cryptosporidium inactivation is cost prohibitive, UV treatment was selected to provide for adequate log inactivation. Based on pilot and full-scale test results, a model was developed to predict the ozone treated water UVT, which was applied to historical water quality data to evaluate life cycle costs of ozone and UV treatment. In addition, the dosage necessary for control of DBPs, the change in ozone decay rate with increases in pH, and the impact of three quenching chemicals on treated water UVT were evaluated.

Organic pollutants removal in wastewater by heterogeneous photocatalytic ozonation

“…Actually, the complementary mechanisms of each process can result in momentous savings in both capital and operation and maintenance (O&M) costs when they are designed to meet the desired water quality goals. The use of ozone to reduce the color and increase the UV transmittance would result in cost savings of a UV system (Burns et al, 2008). Furthermore, the dosages of UV and ozone could be substantially decreased in this combined technology to attain the required mineralization levels, making the operational costs even lower.…”