Projects -
Outfall Systems
Dayton & Knight has designed and supervised construction of more outfall projects that any other
consultant in B.C.
A description of a few of our projects
are linked below:
City of Abbotsford
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J.A.M.E.S. WPCC Effluent Outfall
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Photo courtesy of Fraser River Pile and Dredge Ltd.
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Dayton & Knight Ltd. carried out the pre-design,
design and construction management of a 1200 mm internal diameter
HDPE outfall within the Fraser River from the City’s J.A.M.E.S.
Water Pollution Control Centre in Matsqui, BC.
Work included arranging and coordinating
sub-consultant services for sounder profiling and environmental
assessments of sensitive riparian areas. |
The project involved the construction of 1200
metres of 1200 mm diameter marine outfall together with a 73 metre
tapered steel diffuser section, which discharges at a 45o
angle, oriented in a downstream direction.
City of Campbell River
- Campbell River Outfall
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Lowering of Outfall |
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Dayton & Knight Ltd. carried out the pre-design, including
various environmental impact assessment work, followed by the design and
construction supervision of the 725 mm internal diameter steel outfall.
The outfall conveys
effluent discharge into the Discovery Passage from the Campbell River's
Wastewater Treatment facility (Norm Wood Environmental Centre) and is approximately 500 metre long with an additional 40 metre length of
diffuser. |
The outfall and diffuser are lined and coated with coal tar
enamel. The trenched section of outfall (near shore) is lagged with timber
to protect the coal tar enamel.
To provide additional ballast to resist
the relatively high currents in the area, the exposed section of outfall on the
seabed has a 150 mm thick shotcrete layer and the diffuser has a 175 mm thick
shotcrete layer. For additional protection to the shotcrete (from
the possibility of an anchor catching on the pipeline), rip-rap has been placed on
each side of the exposed section of outfall and diffuser.
The diffuser has
38-100 mm diameter diffuser ports and a hinged end port assembly at the offshore
end to allow diver access into the inside of the diffuser.
Regional District of Nanaimo
- French Creek Outfall
Dayton
& Knight Ltd. completed the pre-design, including various
environmental impact assessment work, followed by design and
construction supervision of the 500 mm internal High Density Polyethylene (HDPE) outfall.
 The outfall conveys secondary effluent to
discharge into the Strait of Georgia from the French Creek Sewage
Treatment Plant. The outfall is approximately 2075 m long with an
additional 78 m long steel diffuser section.
The
outfall is 550 mm nominal diameter HDPE series 45 to 100 pipe. The
inshore sector of 950 meters includes a pigging port and is buried to a ocean
depth of 15 meters below mean tide. The diffuser is at a depth of
62.5 meters below mean tide. The diffuser has 25-63 mm diameter
diffuser ports and a hinged end part assembly at the off shore end for
access and cleaning.
City of Chilliwack
- Extension of Sewage Effluent Outfall
  Dayton & Knight Ltd. carried out the pre-design and
construction management of a 1,002 m sewage outfall extension consisting of
1,200 m of steel pipe complete with 41 m diffuser section.
The work involved
extending the effluent discharge point to a more stable reach of the Fraser
River, as the previous location has experienced sedimentation buildup with
relatively poor dilution capability.
Input from various environmental and regulatory agencies was a
key component in the final selection of the final outfall location. The
pipeline materials were pre-ordered by the District of Chilliwack and occurred
during the low-water period of January and March. Sub-consultants for the
pre-design work were Hay & Co. and Golder Associated. Coast Testing
was retained for X-ray testing of welds during construction.
District of Summerland
- Deep Lake Outfall
 Dayton & Knight Ltd. completed the design and inspection services of the Deep
Lake Outfall into Okanagan Lake for the District of Summerland. The
project involved the construction of 525 metres of 600 mm diameter land outfall,
together with 310 metres of 600 mm diameter lake outfall and a 28 metre long
tapered diffuser section.
The outfall and diffuser were constructed from
fused DR26 high density polyethylene (HDPE) pipe. The outfall weighting
system was constructed from manhole sections held in place with nylon
rope and stainless steel strapping.
For optimal dispersion the diffuser was installed at a minimum depth
of 40 metres. To minimize environmental impacts during a section of
underwater trench excavation, a silt containment curtain was installed around
the trench.
City of Vernon
- Vernon Outfall
Launching
of Pipe Strings
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Dayton & Knight Ltd. carried out the design and contract
administration of a 750 mm diameter outfall into the Vernon arm of Okanagan Lake
as part of the Vernon Wastewater Management Plan.
The 750 mm diameter
outfall, which is coal tar enamel lined and yellow jacket coated, discharges
tertiary treated effluent 6,855 metres from the shore through a diffuser section
into 60 metres of water. |
The land section of the 750 mm pipeline is 460
metres long and includes a meter chamber with ancillary works.
Greater Vancouver Regional District
- Lulu
Island Outfall
Laying of Diffuser Section |
Dayton & Knight Ltd completed the design and construction
supervision of the 2100 mm diameter outfall from the Lulu Island Treatment Plant
into the Fraser River. The outfall is approximately 200 metres long, with
a 50 metre diffuser section. |
The outfall invert is approximately 8 metres under the river
bed to protect the pipe from predicted future bed lowering. The diffuser
section has 23-250 mm diameter diffusers with riser pipes that can be adjusted
to the future bed levels. Unique materials, construction and backfill
requirements were specified to protect the pipe risers during backfilling.
For further information on
our capabilities and experience in outfall design,
please contact
John Boyle
(jboyle@dayton-knight.com),
P.Eng.
or
Dennis
Harrington (dharrington@dayton-knight.com)
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