NIRE-170-1-6
35
2. Operating Parameters
The performance of the
“NHP210 Series” varies depending on raw water quality and site
specific operating conditions.
In order to achieve stable “NHP210 Series” operation it is
recommended that various operating parameter values be monitored and recorded regularly.
The following operational parameter values should be recorded regularly.
(1)
Scouring air flow rate (blower air flow)
(2)
Diffusion pressure (blower discharge pressure)
(3)
Filtrate water flow rate
(4)
Trans-membrane pressure (TMP)
(5)
Liquid temperature in the membrane tank
(6)
DO (dissolved oxygen) concentration in the membrane tank
(7)
pH in the membrane tank
(8)
MLSS in the membrane tank
(9)
Raw water quality (BOD, COD, turbidity, T-N, T-P, etc.)
(10)
Filtrate water quality (BOD, COD, turbidity, T-N, T-P, TSS etc.)
(11)
Excess-sludge discharge rate
(12)
Sludge viscosity
(13)
Sludge filterability
Preferable recording frequencies are;
➢
Every five (5) minutes for on-line instruments
➢
Every day for off-line instruments and sludge properties
➢
Every week for water quality analysis
3. Basic Control Philosophy
Presented below is a generic MBR control philosophy narrative. Actual MBR system control
philosophy will be based on specific site operating conditions.
(1)
Suction pump
: The filtrate suction pump should be controlled to operate for intervals of
nine (9) minutes on and one (1) minute off. The filtrate suction pump motor should be
fitted with a VFD drive. A filtrate flow transmitter should be installed to provide a control
signal to the suction pump VFD. The suction pump should be stopped if the liquid level in
the membrane tank drops to a predetermined low liquid level. If, at any time, the air
supply to the membrane module or RAS (return activated sludge) is interrupted the
suction pump should be stopped. Do not operate the filtrate suction pump on low
membrane tank level or high TMP. Once the air supply has been restored the membrane
tank and good RAS circulation is observed, delay activation of the suction pump for one