Civil Engineering Reference
In-Depth Information
Reverse
Filtration
Permeate or
Gas
Permeate
Bleed and Backwash
Waste
Feed
Water
Cross-Flow
Reverse
Filtration
Permeate or
Gas
Permeate
Bleed and Backwash
Waste
Feed
Water
Direct Feed
Fig. 15-7.
Typical MF and UF process flow schematics
Memcor—USFilter
•
Pall
•
Zenon
•
Koch
•
The systems are capable of producing low-turbidity water with little or no pretreat-
ment. The state of California has approved MF as an alternative filtration technology
that satisfies the requirements of the Surface Water Treatment Rule.
Memcor—USFilter.
Memcor plants are in service producing drinking water at several
locations in the United States. Memcor is a continuous microfiltration system that is
capable of removing virtually all particles greater than 0.2
in size. A low-pressure
feed pump (30-35 psi) supplies feedwater to the membrane modules. Contaminants
in the feedwater build up on the outside of the hollow-fiber membrane surface and
clean filtrate flows down the inside. A driving force called the transmembrane pressure
difference (TMP) sets up across the membrane. The TMP increases as the contaminant
load increases, and at a set point a gas backwash is automatically initiated. Back-
washing is with compressed air from inside the hollow-fiber membranes. This pulse
of air dislodges contaminants from the outside membrane surface and the contaminants
