How is membrane filtration technology used in wastewater treatment?
Membrane technology used for removing solids in wastewater treatment is usually based on ultrafiltration or microfiltration. The membranes can be introduced into the biological wastewater treatment process either as:
- a separate unit operation downstream of the biological step, or
- integrated into a biological process.
If the membranes are added as a separate unit operation, they are often referred to as a 'polishing' step and are usually based on the hollow fibre membrane configuration.
Watch the following video which explains the difference between the 'integrated' and the 'separate' membrane technologies for wastewater treatment.
Alternatively, membranes are integrated with the biological step either as a membrane bioreactor (MBR) or a membrane aerated biofilm reactor (MABR). In the case of the MABR, the membrane is not used for filtration but for diffusing air or oxygen into the bioreactor in the molecular, or 'bubbleless', form. So an MABR employs the membrane as a high-efficiency diffuser, rather than for solids–liquid separation as for the MBR.
If these membranes are used for polishing after an activated sludge process, how much space would it require for a 15-20 MGD plant?
Secondary clarifier effluent turbidity around 3-4 NTU.
This would have to be determined based on the specifications of the membrane technology concerned. Judd Water & Wastewater could provide this service, but one imagines that there are many others who would do the same.
We want to avoid conventional biological treatment replacing with ceremic membrane for municipal sewerage treatment.Is it possible.
Probably not. Membrane filtration would only remove the suspended matter, and would foul significantly if challenged with raw sewage.