AWWA ACE65188

The Town of Smiths Falls' (Ontario, Canada) existing water treatment plant (WTP) was built in the late 1800's, and although there havebeen many upgrades throughout the past century, the plant has had difficulty treating water tothe level expected by its customers. Drinking water treatment at the existing facility consists ofcoagulation, flocculation, sedimentation, granular activated carbon capped dual media filters,and gaseous chlorination. There is currently no residue management at the plant, andbackwash water from the filters and sludge from the sedimentation tanks are sent directly to theRideau River without treatment. An environmental study performed in 2003 recommended thatthe existing water treatment plant be replaced with a new facility to help meet regulatoryguidelines and increase the aesthetic level of treatment. Although a potential treatment train was identified at that time, it was not finalized. When the Town of Smiths Falls commissioned the services ofR.V. Anderson Associates Limited (RVA) for the design of the new WTP, it was determined thatdual media filtration would be used as it was successful at the existing plant, and ultraviolet (UV)disinfection would be used to help meet future regulations. However, there was not enoughinformation available to definitively determine the remaining components of the treatment train.The Town of Smiths Falls identified that the new water treatment plant design would focus onthe following primary objectives:meet current and potential future drinking water regulations;effectively remove taste and odor causing compounds; effectively remove color;provide for ease of operation and maintenance; and,offer multi-barrier protection.The Town, based on the recommendation of RVA in conjunction with Andrews, Hofmann andAssociates, decided to conduct a pilot study to determine which treatment(s) would effectivelyremove the aesthetic parameters while offering safe drinking water. It is unlikely that onetreatment process could effectively control both color and T&O. Therefore, it was determinedthat some kind of pretreatment would be necessary to control color and that another processwould be necessary to control T&O.The pretreatment processes that were considered for further investigation for color removalinclude pre-oxidation, conventional treatment (coagulation, sedimentation, filtration), and theproprietary high rate clarification processes Actiflo and AquaDAF. Processes that wereconsidered for further investigation for T&O removal include: advanced oxidation (AO) with UVand hydrogen peroxide; granular activated carbon (GAC); and, ozone.The primary objective of the pilot study was to identify which processes would be capable ofconsistently meeting the treatment and operation goals of the Town (including all threesignificant events). The ineffective processes could be ruled out, and the successful processescould then be compared using detailed information collected during the pilot study. Includes tables.

Product Details

Edition:

Vol. - No.

Published:

06/01/2007

Number of Pages:

8

File Size:

1 file