6
the end of the recirculation pipe in the Sedimentation Chamber by using a measuring cup.
The upper part of the end of the Recirculation Pipe is cut off as
shown in the drawing on the previous page. Adjust the Recirculation
Control Valve so that the water level in the pipe is between the
horizontal edge of the pipe end and the Indication Line.
If the recirculation rate has increased considerably since the last
maintenance, this could indicate a clogged aeration pipe.
(4) Cleaning Recirculation Air-lift Pump
Excessive biofilm build-up in the recirculation air-lift pump could
affect the recirculation rate. Remove the cap on the air-lift head,
clean inside the pipe with a pipe cleaning brush and water hose.
Backwash and Sludge Transfer
Excessive biofilm growth on the contact and filter media may cause partial clogging or short circuiting
and deteriorate the performance of the system. It is important to carry out a backwash operation and
sludge transfer at every maintenance visit.
Step 1.
Shut off the Effluent Air-lift Pump by turning the Effluent Control Valve (white valve)
clockwise until it won
’t turn any more.
Step 2.
Transfer the sludge on the bottom of the aeration chamber by turning the Recirculation
Control Valve (grey valve) to 70
– 80 and wait for one minute.
Step 3.
Reset the Recirculation Control Valve (grey valve) to the original position.
Step 4.
Aerate one side of the chamber by turning the Aeration Balance Control Valve (blue
valve) fully one way. Wait for one minute, and then turn the valve fully to the opposite
direction. Wait for another minute, and then reset the valve to the original position.
Step 5.
Repeat
Step 2
–
4
a few times.
Step 6.
Perform
Step 2
.
Step 7.
Reset the Recirculation Control Valve (grey valve) and the Effluent Control Valve (white
valve) to the original position. Make sure that the aeration is working properly.
Step 8.
Adjust the recirculation as described in
“(2) Adjusting Recirculation Rate” on page 5.
Step 9.
Poke the anaerobic filtration media with a thin pipe (PVC pipe 15mm or smaller diameter
pipe) gently and evenly throughout Anaerobic Filtration Chamber for degassing and
preventing short-circuiting.
Cleaning Aeration Pipes
The following symptoms indicate that the aeration pipes may be partially clogged and the pipes need
to be flushed or cleaned with a pipe brush.
Bubbles are not evenly distributed throughout the chamber even after adjusting the aeration
balance.
Recirculation rate has increased considerably although the recirculation valve setting has not
been changed.
(1) Flushing with Pressure Water
*This method must not be used unless an appropriate backflow prevention device is fitted to the tap.
Step 1.
Close the Recirculation Control Valve (grey valve) and the Effluent Control Valve (white
valve).
Step 2.
Turn off the blower.
Step 3.
Disconnect a barrel union.
Cap (Closure)
Air-lift Head
