Friday, November 14, 2008

Mith and Fact in MBR

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.

Hyrum, UT WWTP Flow and Utilization Data

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.

Extensive Kubota membrane life data has been collected in the U.K. indicating membrane life on the order of 12.5 years. Other technologies may only last 3 to 4 years in some cases.


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

Research Project (In Europe)

AMEDEUS "Accelerate Membrane Development for Urban Sewage Purification"
Specific Targeted Research Project (Priority "Global Change and Ecosystems")
Duration: 01/10/2005 - 30/09/2008
Co-ordination: B. Lesjean, Berlin Centre of Competence for Water
(boris.lesjean(at)kompetenz-wasser.de)



EUROMBRA "Membrane bioreactor technology (MBR) with an EU perspective for advanced municipal wastewater treatment strategies for the 21st century"
Specific Targeted Research Project (Priority "Global Change and Ecosystems")
Duration: 01/10/2005 - 30/09/2008
Co-ordination: T. Leiknes, Norwegian University of Science and Technology
(torove.leiknes(at)ntnu.no)

MBR-TRAIN "Process optimisation and fouling control in membrane bioreactors for wastewater and drinking water treatment"
Marie Curie Host Fellowship for Early Stage Research Training
(Structuring the European Research Area; "Marie Curie Actions")
Duration: 01/01/2006 - 31/12/2009
Co-ordination: RWTH Aachen University, Department of Chemical Engineering
Contact: R. Hochstrat
(hochstrat(at)ivt.rwth-aachen.de)

PURATREAT
"New Energy Efficient approach to the operation of Membrane Bioreactors for Decentralised Wastewater Treatment"

Specific Targeted Research or Innovation Project (International Cooperation Action)
Duration: 01/01/2006 - 31/12/2008
Co-ordination: G. Schories, Technologie-Transfer-Zentrum Bremerhaven
(gschories(at)ttz-Bremerhaven.de)

Thursday, November 13, 2008

Manufacturer

The design of the reactor (including membrane, baffle and aerator locations) and the mode of operation of the membrane also appear as key parameters in the optimisation of the system. Several immersed MBR designs are currently proposed by the leading membrane suppliers such as GE-Zenon (Canada), X-Flow (The Netherlands), Siemens-Australia (Australia), Mitsubishi and Kubota (Japan). Kubota has the largest installation base of membrane bioreactors worldwide. In each case, the process proposed is very specific. Not only the membrane material and configuration used are different, but the operating conditions, cleaning protocols and reactor designs also change from a company to another. For example, the flat sheet membrane provided by Kubota does not require backwash operation, while hollow fibre membrane type from Zenon and Memcor (USFilter) have been especially designed to hydraulically backwash the membrane on a given frequency (around every 20 min).

Membrane and plant supplier links:

Research Group