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Providing
Innovative Solutions
for Our Clients
since 1965
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Projects -
Slow Sand Filtration
Dayton & Knight Ltd. has designed
numerous slow sand filtration plants to reduce the risk of waterborne
giardiasis and cryptosporidiosis.
These include:Responsibility for the pilot scale program and
evaluation of water treatment at 100 Mile House. |
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Laboratory & Operations Room |
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Dayton & Knight Ltd. has completed
the detailed design, construction supervision, start-up and support for a number
of First Nations Communities' water treatment facilities.
These include: |
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Moricetown,
Tache,
West Moberly,
Hagwilget and
Gitsegukla
First Nations.
To address issues associated with the presence of colour and organics,
the water treatment plants at
Tache
and
Gitsegukla (Kits Creek)
include chemical pretreatment (alum addition, flocculation and plate
settlers) and slow sand filtration.
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Gitsegukla (Kits Creek)
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Filter Gallery Enhanced SSF |
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Hagwilget (New Hazelton)
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Dayton & Knight Ltd. co-authored with Colorado
State University "The Manual of Design for Slow Sand
Filtration" for the American Water Works Association Research
Foundation.
  The manual provides an overview of the technology and
reviews the design, construction and operation to best achieve
desired production and performance.
Tache |
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Gitsegukla
- Water Treatment Plant
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Click on Photo Above to Enlarge
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The Gitsegukla water treatment plant is a
conventional filtration system and includes pre-treatment with
coagulation, flocculation, and sedimentation. Filtration
consists of two slow sand filters with provision for an
additional third filter; a disinfection system with sodium
hypochlorite injection; a secondary limestone contactor for pH
adjustment; and a clearwell tank. |
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The system was designed to remove turbidity,
colour, organics, Giardia, and other pathogenic organisms.
The project also includes a 10,000 m3 impoundment
to provide adequate storage to meet the demand during the Kits
Creek low-flow periods in winter.
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mixer, two hydraulic flocculation tanks with three chambers
each; a settling tank with plate settlers; a computer
controlled sludge valve and two lagoons for sludge disposal.
Aluminum sulphate is the chemical used as coagulant. |
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design output of 700 m3 per day with two filters at
maximum day demand; each filter has an area of
approximately 120 m2. A SCADA system monitors
and records the flows and levels in the treatment plant and
reports alarm conditions to the operators.
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The operations building includes a laboratory for water
analysis, allowing the operators to perform jar tests and pH,
temperature, and monitor the plant overall performance.
Dayton & Knight Ltd. has provided continuous technical
support, training, and advice to the Band Council and
operators.
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New Hazelton
- Water Treatment Plant, Hagwilget
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Click on Photo Above to Enlarge |
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An agreement was reached
between the District of New Hazelton, the Hagwilget Band
Council and INAC to construct a new water treatment plant in
2000. INAC provided 50% of the total project cost.
The water treatment plant was designed by Dayton & Knight Ltd.
to provide safe drinking water that meets INAC standards and
the Canadian Drinking Water Guidelines.
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The new water supply and
treatment systems consist of a new intake on Station Creek, a
new 200mm diameter watermain, a water treatment plant with
slow sand filtration followed by disinfection with sodium
hypochlorite and a clearwell tank and a new 1,600 m3
bolted steel storage reservoir. |
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Click on Photo Above to Enlarge |
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Click on Photo Above to Enlarge |
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Each slow sand filter has
an area of 150m2, giving the plant a maximum output
of 2,000m3 per day with two filters at maximum day
demand. Provision has been made for the addition of a
third slow sand filter. The system was designed to
remove turbidity, colour, Giardia and other pathogenic
organisms at 3-log level. |
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A SCADA system monitors
and records the flows, levels, turbidity, and reports alarm
conditions to the operators.. The plant includes a laboratory
for water analysis where the operators can monitor turbidity,
pH, temperature, chlorine residuals and perform coliform
tests. Dayton & Knight Ltd. has provided continuous technical
support and training to the District operators. |
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Click on Photo Above to Enlarge
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Tache
- Water Treatment Plant |
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Click on Photo Above to Enlarge
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The Stuart Lake surface source
is vulnerable to microbiological contaminants such as giardia and
cryptosporidium. In addition, total organic carbon (TOC) generally
exceeds 4-8 mg/L with the result that disinfection byproducts formed by
the reaction with chlorine exceeded the recommended limits for
trihalomethane (THM). |
Following one year
of pilot study, Dayton & Knight Ltd. undertook the design and
contract administration for the 688 m3/day water treatment
plant. The plant includes new raw water pumps in the lake, chemical
addition, hydraulic flocculation, plate settling, filtration and
disinfection. A limestone contact is used to reduce the corrosiveness of
the water.
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For more information about Dayton & Knight Ltd.'s
capabilities and experience on slow sand filtration please contact:
Sean
Brophy (sbrophy@dayton-knight.com)
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