Biological Operation - ProMinent DULCOMETER PH-501 Assembly And Operating Instructions Manual

3.6

BIOLOGICAL OPERATION

The following table presents target parameters required for a good operation of the STP.
Table 4: Biological system targets operational parameters
Parameter
MLSS (mg/L): Mixed
Liquor Suspended Solids
Temperature (°C)
pH
Aeration Tank, DO (mg/L)
Viscosity (mPa-s)
Aeration Tank to Anoxic
Tank Recirculation
Membrane Tank to
Aeration Tank
Recirculation
F:M (kg BOD/kg MLSS/d)
F:M (kg COD/kg MLSS/d)
SRT : sludge retention
time (days)
3.7 MEMBRANE OPERATION
This section outlines the operating conditions that are required for proper sewage treatment, and
longevity of the membranes.
Generally, the following points can be used to operate the MBR system properly:
The MBR system is designed to treat wastewater with specified influent characteristics.
Never operate the MBR tank below the minimum membrane submerged level. It is necessary
to maintain a minimum of 250 mm liquid level above the membrane modules to ensure they
are wet at all times and to allow for proper filtration.
Always supply the required amount of air for scouring to the membrane module.
Always filter sewage at or below design flow rate.
Periodically, relax the membranes by ending filtration while allowing the membrane aeration
scour to operate continuously and initiate backwash operation during membrane relaxation
(default relaxation mode preset in PLC - permeation continues for 9 min and stops for 1 min).
Always operate the MBR in accordance with the parameters listed in the supplier O&M Manual.
Clean the membranes in-place with a dilute chemical in accordance with the supplier O&M
Manual.
Recommended Range
10,000 8,000 – 15,000
15 - 35 10 – 35
6.8 - 8.5 6.0 – 9.0
1.0 – 8.0
Not applicable 0 – 300
400% 200 – 500%
400% 200 – 600%
0.1 0.03 – 0.2
0.15 0.05 – 0.3
> 15 12 – 50
Operation & Maintenance Manual
Sewage Treatment Plant
December 2018
Notes
Never operate the membranes if MLSS <
3,000 mg/l. Sludge wasting should be
undertaken as required to maintain target
MLSS
Avoid sudden changes in temperature.
Minimum operating temperature is 15 °C
Membrane module can handle a change in
pH. However it is recommended to keep pH
between 6.8 - 8.5
This can be maintained by adjusting the
volume of air supplied to the aeration tank
F:M = [Flow (m3/d) x BOD conc (mg/l)] /
[Process volume (m3) x MLSS conc (mg/l)]
F:M = [Flow (m3/d) x COD conc (mg/l)] /
[Process volume (m3) x MLSS conc (mg/l)]
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