AWWA WQTC65904

This powerpoint presentation presents a study of several treatment issues covering pre-oxidation, coagulation and dissolved air flotation (DAF) clarification, post-oxidation, filtration and residuals management at a 160 gpm pilot unit (10 L/s) at United Water New Jersey's (UWNJ's) Haworth Water Treatment Plant. The presentation focuses on the results regarding the evaluation of preoxidation alternatives, namely: no pre-oxidation; chlorine (discarded early in the trials due to lab results on THM formation); ozone; chlorine dioxide; and, potassium permanganate. In regard to pre-oxidation, the objective of the pilot study revolves around the following questions: is there a need for a pre-oxidation treatment considering the expected benefits in terms of algae removal/control, turbidity removal (micro flocculation effects), organic matter removal, manganese removal and taste/odor; if so, what is the most adequate reagent considering risk of disinfection byproduct (DBP) formation and risk of toxin release; what are the expected doses/chemical consumption; and, what are estimated operating/design requirements (contact time, injection system, safety and handling, chemical storage)? Based on the results of the pilot program in combination with site, economic, and schedule considerations, UWNJ has selected the following treatment process: pre-oxidation with ozone; high rate DAF; intermediate disinfection/oxidation with chlorine as sodium hypochlorite; filtration with existing dual media sand/anthracite; and, final chloramination. In regard to pre-oxidation, ozone provided superior turbidity performance particularly at the downstream filtration stage and helped reduce disinfection byproducts. Manganese issues are managed by catalytic oxidation on dual media filters.

Product Details

Edition:

Vol. - No.

Published:

11/01/2007

File Size:

1 file , 1.6 MB