Environmental Science & Engineering - www.esemag.com - March 2004
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Advanced filtration system at Lake Louise WWTP is a Canadian first
The Lake Louise Wastewater
Treatment Plant in Banff National Park,
Alberta, is designed to treat an annual
average flow of 4 million litres per day.
Prior to the latest plant upgrade, the treatment
process included medium mechanical screening,
extended aeration activated sludge, secondary
clarification, and secondary effluent
disinfection, using in-channel ultraviolet (UV)
radiation. The treated effluent is discharged to
the adjacent Bow River.
In 2002, Associated Engineering’s Calgary
office wastewater team, led by George
McGeachie, completed design of an upgrade of
the Lake Louise Wastewater Treatment Plant
for Public Works and Government Services
Canada.
The upgrade was a challenging project. It
incorporates a new tertiary filtration system,
which is the first of its kind to be installed in a Canadian
wastewater treatment plant. The system consists of a new
submersible propeller flow, low lift pump station fitted
with variable frequency speed controls. This pump station
delivers the secondary effluent to the two new tertiary filters.
The filtered effluent is piped to flow by gravity to the
existing UV disinfection system. The filters are each
designed to handle an average flow of 4 million litres per
day and a peak flow of 8 million litres per day. They are
AquaDisk Cloth Media Filters, each fitted with four disks
housed within stainless steel tanks. The AquaDisk cloth
media filter is a complete system for continuously removing
particulates from a flow to the filter tanks, where the
filtration occurs. Associated Engineering received the filters
and controls as a complete package shipped to site.
Once anchored in place, powered, and piped into the treatment
system, the filters were started up and commissioned
in the same day, including operator training.
Components of the upgrade include the following:
The plant process has been updated with an activated
sludge, biological nutrient removal (BNR) process retrofit
and a tertiary filtration system, between the existing secondary
clarifiers and the UV disinfection process.
The two existing oxidation ditch bioreactors have been
retrofitted with internal reinforced concrete baffle walls to
create anoxic, anaerobic, anoxic, and aerobic zones in
series, part of the BNR process.
The existing jet aeration system was modified to use the
original jet pumps, for mixing only, in the first anoxic and
anaerobic zones. New submersible propeller mixers were
installed in the second anoxic zone. A de-nitrification recycle
system was provided using submersible pumps installed
in the aerobic zones to pump back to the second anoxic
zones. New fine bubble aeration was installed in the aerated
zones.
The original alum storage and metering system will continue
to be used to trim the BNR process to achieve the
required removal of phosphorous, if and when required.
Contact: Associated Engineering at mahl@ae.ca.
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