Myth 1: Membrane pore size determines removal efficiency in submerged MBR applications.
Fact 1: Third party independent research (Gunder, et al. The Membrane Coupled Activated Sludge Process) confirms similar performance for microfiltration versus ultrafiltration membranes submerged in mixed liquor.
UF Hollow Fiber (H) vs. MF Flat Plate (P)
Coliform Data
University of Hawaii, Comparison Data
Myth 2: All membranes perform about the same in terms of flux and or permeability.
Fact 2: Membrane performance is a function of multiple parameters not just type or geometry. Some important parameters are given below, but there are several other factors to consider as well.
Myth 3: All MBR Systems are underloaded and do not operate at or near design capacity.
Fact 3: Many Enviroquip MBR Systems run at or above rated capacity during winter and spring seasons. Some plants, like Hyrum, Utah WWTP, are more than 60% utilized throughout the year.
Myth 4: Specifying average daily flow (ADF) and peak daily flow (PDF) is sufficient to characterize required capacity.
Fact 4: Establishing peak instantaneous flow (PIF) and durations is as important as ADF & PDF requirements. For example, at the McFarland Creek WWTP, instantaneous flux is much higher than average flux for most of the day between May 12 and May 19.
Myth 5: All membranes should have about the same service life.
Fact 5: Not all membranes have the same service life. Membrane life is not only a function of design and composition it is also determined by operating conditions. Some of the keys to long service life include; low TMP operation, reduced chemical exposure and equal air scouring.
Myth 6: Silt Density Index (SDI) values can increase over time degrading permeate quality.
Fact 6: Recent SDI results from a 0.5 MGD installation averaged less than 2.0. The plant is now in its 9th year of operation.
Source: http://www.Enviroquip.com
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