Blackburn Wastewater Treatment Plant Upgrade Study

Section 3.0 -Audit of Existing Facilities
mm wide channel equipped with a cornminutor. The wmminutor is operated
once per day manually, and three times per day automatically. For each of
these cycles, the comminutor is run for approximately 5 minutes.
3.1.3 Secondary Treatment
The screenedtmacerated wastewater flows by gravity to a series of two unlined
aerated lagoons. The primary lagoon (Lagoon 1) has a volume of
approximately 4,500 m3. The secondary lagoon (Lagoon 2) has a volume of
approximately 14,000 m3. The design mTs of the two lagoons are
approximately 5 days and 15 days, respectively. Both lagoons are equipped
with vertical tube coarse bubble aeration diffusers. The aerators are located in
the centre of Lagoon 1, and in the upstream half of Lagoon 2. The downstream
half of Lagoon 2 serves as a sludge settling zone. Air to the lagoons is
supplied by two 60 hp multistage centrifugal blowers. There is some evidence
of rising sludge and excessive surface foarn/scum in Lagoon 1, and abundant
surface algae growth on the downstream half of Lagoon 2.
3.1.4 Effluent Disposal
The plant is equipped with a chlorine contact tank and chlorination equipment.
However, the City has had an exemption from eMuent chlorination at the plant
since 1983. The outlet of the chlorine contact tank is equipped with a V-notch
weir and Miltronics ultrasonic level sensor, which serve as the principal flow
measuring device. Effluent from the plant flows through a 300 mm diameter
outfall pipe to the Fraser River, where it is discharged just below the river low
water mark.
3.1.5 Sludge Treatment
The plant is not equipped with sludge removal or handling equipment.
Temporary pumps and piping are used to transfer sludge from -Lagoon 1 to
Lagoon 2 during the spring break-up. Buildup of sludge has not been a
problem during 25 years of operation and consequently removal of sludge from
Lagoon 1 or 2 has not been required.
3.2 LANSDOWNE ROAD WASTEWATER TREATMENT PLANT
3.2.1 Outline
The Lansdowne Road WWTP is the City's main wastewater treatment facility
and treats wastewater from all sewered areas within the City with the exception