The MBR Book: Principles and Applications of Membrane

Commercial technologies 175
(a) (b) (c)
Figure 4.14 Early Zenon modules: (a) the Moustic, (b) the ZeeWeed ® 145 and (c) the ZeeWeed ® 150
transverse feed flow was applied tube-side of the module. The manufacturing complexity
of the module prevented it from being commercialised, but the Moustic
represented an important stage in the development of the subsequent ZW series.
Following early trials with the Moustic, a reinforced HF membrane was developed
in 1991–1992. The early ZeeWeed ® membrane, providing 145 ft 2 (13.5 m 2 ) of
membrane area and thus named the ZeeWeed ® 145 (Fig. 4.14b), was an ultrafilter
with maximum 0.1 �m pore size, and comprised an inner reinforcing polyester
braid on which the membrane layer was cast. Bundles of fibres were potted at both
ends into permeating headers to make a prototype module, which was arranged
horizontally over an aeration assembly in the tank. Further testing led the development
team to move the two headers together and loop the fibre bundle over a raised
section of the PVC frame, allowing vertical bubble flow to better mechanically scour
the fibres. The ZeeWeed ® 145 was first commercially installed in 1993 for industrial
wastewater applications at Orlick Industries (Stoney Creek, Ontario, Canada) and
GM Sandusky. Module headers consisted of two pieces, one containing the potted
fibres and another completing the permeate cavity when both were bolted together.
Permeation occurred through both headers, and module aeration was continuous,
with aerators located between both headers within the module and on either side of
the module at the header level.
It was recognised that the looping of fibres over the PVC frame led to solids
build-up and abrasion at the top of the fibre bundle. The problem was substantially
ameliorated in the subsequent design, the ZeeWeed ® 150 (i.e. 150 ft 2 , 13.9 m 2
membrane area, Fig. 4.14c), which was the first self-supporting and stand-alone
immersed vertical HF module. The fibres in this module were potted at both ends,
with regular spacing between them to ensure better solids removal from the bundle.
Modules were custom-manufactured and could be interconnected in any number
depending on the application. Permeation occurred through both headers, and
module aeration was continuous. The aerators were bolted on to the bottom header
where they could introduce air directly into the base of the fibre bundle. The
ZeeWeed ® 150 was first tested in an MBR application at a land development site