AWWA ACE70776

This powerpoint presentation begins by providing a brief overview of desalination processes. A 3-stage concentrate treatment research project is presented, along with the experimental design that includes antiscalant oxidation, and zone decomposition in water - with and without H₂O₂. Research objectives were to: determine the effect of water composition on phosphonate oxidation; determine the effect of pH on phosphonate antiscalant oxidation; and, determine the primary oxidation pathway for phosphonate oxidation. Conclusions indicate that: application of RO inland requires significant reduction in concentrate volumes, and concentrate treatment is necessary to achieve smaller volumes; antiscalant oxidation increases when calcium coordination occurs, and the effect of calcium on antiscalant oxidation is different for each antiscalant; antiscalant oxidation increases with ozone concentration; antiscalant oxidation increases slightly with H2O2 addition, and has an optimal pH of 6; and, with calcium chelation, the primary oxidation pathway is through direct reaction with ozone. Includes figures.