CMF - The Solution for High Solids Removal in Surface Water or Wastewater
The innovative design of Coiled Membrane Filter (CMF) resourcefully generates a secondary flow called Dean Flow. Because of that, CMF has higher shear force and more efficient mass transfer compared to the conventional Straight Membrane Filter (SMF) under the same feed flow rate. These advantages prevent foulants from building up on the membrane surface.
The chart on the right shows a good example. By allowing particles in the processed fluid to settle on the membrane surfaces (halting the operation for two days between Week 1 and Week 2), the test data indicates there is more than a 20% difference in flux rate. Note, both filters showed a significant drop of flux at the onset of Week 2. However, the flux of the CMF was able to resume and follow its original curve after several hours into the operation. By comparison, the SMF had no improvement and remained gap-down in the curve.
High concentration of colloidal solids (suspended sub-micron solids) are commonly encountered in surface water treatment as well as in industrial wastewater treatments, such as pH adjustment and processes involving coagulants/flocculants.
Depending on application needs, the CMF employs either tubular membrane filters (TMF) or hollow fibers with large
lumen diameter (1.5 mm) in the system to achieve an effective filtration of high concentrations of solids (up to 5% by weight) from water. Common applications include:
Pre-filtration with coagulants for SWRO and BWRO
Cooling tower blowdown water
Heavy metal removal
Semiconductor and photovoltaic wastes
Fluoride and high solids removal
Tumbler deburring slurries
Food processing water
Depending on the process requirement, the CMF can be integrated into a system with chemical pretreatment for a large-scale bulk stream process. Since the CMF is effective to hand high solids, it can also function as an independent unit for a small-scale application. The diagrams below illustrate both process arrangements.