The Moving Bed Biofilm Reactor process refers to the operation of activated sludge tanks in various configurations in a combination of:
The term ‘Membrane Bioreactor’ (MBR) is generally used to define wastewater treatment processes where a perm-selective membrane e.g. microfiltration or ultra filtration is integrated with a biological process – a suspended growth bioreactor. MBRs differ from ‘polishing’ processes where the membrane is employed as a discrete tertiary treatment step with no return of the active biomass to the biological process.
All commercial MBR processes available today use the membrane as a filter, rejecting the solid materials which are developed by the biological process, resulting in a clarified and disinfected product effluent.
A membrane bio reactor is essentially a version of the Conventional Activated Sludge (CAS) system. While the CAS process uses a secondary clarifier or settlement tank for solid/liquid separation, an MBR uses a membrane for this function. This provides a number of advantages relating to process control and product water quality.
As opposed to the conventional activated sludge process in which wastewater treatment takes place in various, linearly arranged tanks, the SBR process (Sequencing Batch Reactor) occurs sequentially in the same tank. The resulting typical process step sequence is as follows:
Due to the batch charging of the tanks, continuous wastewater treatment demands that an SBR plant consists of various SBRs and/or of a buffer tank.
The upflow anaerobic sludge blanket reactor (UASB) is a single tank process. Wastewater enters the reactor from the bottom, and flows upward. A suspended sludge blanket filters and treats the wastewater as the wastewater flows through it.