Content area
Full text
Water treatment plant upgrades system with new microfiltration treatment, PLC control systems, electrical, instrumentation
The Town of Whitecourt's Water Treatment Plant (WTP) was originally commissioned in 1980 as a conventional treatment system to provide a capacity of approximately 6 megalitres (ML) /day. Its treatment process included rapid mixing and coagulation, a solids contact clarifier, three dual media rapid sand filters, post chlorination, and fluoridation.
In late 2002, the Town of Whitecourt selected Stantec Consulting Ltd. to perform a detailed audit of the WTP, which subsequently identified concerns related to:
* WTP's capacity of approximately 6 ML/day being unable to meet the Town's current and future potable water demands
* Insufficient total clarifier detention time, mixing and flocculation, and recirculation rates, resulting in non-filterable turbidity carry over to the rapid sand filters at flows greater than 6 ML/day
* Insufficient chlorine contact time, primarily due to a lack of circulation through the adjacent potable water reservoir
* With raw water Giardia concentrations regularly exceeding 100 cysts/ 100 L, requiring a Giardia reduction credit greater than 5.0-Log (based on Alberta Environment's 1996 standards and guidelines), the WTP's 2.5-Log Giardia reduction credit was detenriined to be insufficient
Following the detailed audit, Stantec was further commissioned to determine how the WTP could be cost effectively upgraded as it had reached its capacity and did not meet current standards for contact time and Giardia reduction. As a result, the Town of Whitecourt became the first in Alberta, Canada to install microfiltration pressure membranes.
The WTP upgrade became a two-stage, multiyear project spanning from 2002 to 2009. Stage 1 involved baffling the adjacent potable water reservoir and construction of a new distribution pump house to take advantage of the new baffling arrangement. In addition, Pall Corporation Microza MF pressure membranes were installed in parallel with the existing conventional treatment process, providing the redundancy required for the Stage 2 upgrades to proceed.
Since commissioning, in 2005, the Pall Corporation pressure membrane system has performed exceptionally well and has been granted a 4.0-Log Giardia and Cryptosporidium reduction credit from Alberta Environment and tripled the WTP output without expanding the plant's footprint.
Stage 2 consisted of pre-treatment upgrades involving the conversion of the existing filter chambers and re-carbonation channel to provide three...