The Town of Smiths Falls' (Ontario, Canada) existing water treatment plant (WTP) was built in the late 1800's, and although there have
been many upgrades throughout the past century, the plant has had difficulty treating water to
the level expected by its customers. Drinking water treatment at the existing facility consists of
coagulation, flocculation, sedimentation, granular activated carbon capped dual media filters,
and gaseous chlorination. There is currently no residue management at the plant, and
backwash water from the filters and sludge from the sedimentation tanks are sent directly to the
Rideau River without treatment. An environmental study performed in 2003 recommended that
the existing water treatment plant be replaced with a new facility to help meet regulatory
guidelines 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 of
R.V. Anderson Associates Limited (RVA) for the design of the new WTP, it was determined that
dual 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 enough
information 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 on
the 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 and
Associates, decided to conduct a pilot study to determine which treatment(s) would effectively
remove the aesthetic parameters while offering safe drinking water. It is unlikely that one
treatment process could effectively control both color and T&O. Therefore, it was determined
that some kind of pretreatment would be necessary to control color and that another process
would be necessary to control T&O.
The pretreatment processes that were considered for further investigation for color removal
include pre-oxidation, conventional treatment (coagulation, sedimentation, filtration), and the
proprietary high rate clarification processes Actiflo and AquaDAF. Processes that were
considered for further investigation for T&O removal include: advanced oxidation (AO) with UV
and hydrogen peroxide; granular activated carbon (GAC); and, ozone.
The primary objective of the pilot study was to identify which processes would be capable of
consistently meeting the treatment and operation goals of the Town (including all three
significant events). The ineffective processes could be ruled out, and the successful processes
could then be compared using detailed information collected during the pilot study. Includes tables.
| Edition : | Vol. - No. |
| Number of Pages : | 8 |
| Published : | 06/01/2007 |
