Profile of facilities

MBRMembrane Bio-Reactor System

The MBR is a sewage treatment process that combines a biological treatment (activated sludge process) with a membrane filtration. Microorganisms remove and decompose some pollutants from the sewage then the membranes separate microbes and other particles from treated water. MBR provides a small footprint and the use of membranes results in a high effluent quality.

MBR Units
MBR typically uses microfiltration (MF) membranes. Comparison between the Conventional System and MBR Functions of MBR Membranes Energy-Saving Operation of the MBR System

At Water Plaza Kitakyushu, some technologies for energy-saving and low-cost operation of MBR are applied.

Reduction of Aeration Volume
  • Reduce air flow rate of blowers that is the most energy consuming equipment in the MBR system.
  • Two membrane modules are stacked in a vertical formation.Scouring air for keeping membrane surface clean is supplied only from the bottom membrane modules.
  • By applying fine bubble diffusers for air scouring, high oxygen transfer efficiency is achieved.
  • Excess air supply is prevented by adjusting the flow rate of aeration depending on residual NH4-N concentration in the aerobic tank.
Reduction of Power Requirement for FiltrationGravity by water level difference is applied for filtration instead of pumping. Reduction of Chemical Consumption and Sludge ProductionMembrane-type UCT configuration which biologically removes organic pollutants, nitrogen and phosphorus simultaneously, reduces coagulant consumption and excess sludge production.
MBR Membrane Units
  No.1-1Train No.1-2Train No.2Train
Configuration Submerged Flat Sheet Membrane Submerged Flat Sheet Membrane Submerged Hollow Fiber Membrane
Pore Size 0.1μm 0.08μm 0.1μm
Membrane Material PVDF* PVDF* PVDF*
Membrane Area 800m²unit
（400m²/deck×2）		 280m²/unit 300m²unit
（25m²/module×12）
Number of Units 1 unit 3 units 3 units
Side View
Features
  • Fibrous screenings does not easily tangle and attach to the membrane.
  • Low filtration pressure.
  • Sturdy membrane fixation by using laser welding
  • Fibrous screenings does not easily tangle and attach to the membrane.
  • Low filtration pressure.
  • Fine bubble air diffuser with high oxygen dissolving efficiency
  • Easy backwashing.
  • Large membrane area in per unit volume.
*PVDF:Polyvinylidene fluoride