Membrane Surgery -- A Cure For MBR

A small Vermont town is registering significant cost savings and improved efficiency after replacing original wastewater-treatment membranes with high-performing Layne POREFLON Membrane Bioreactors (MBRs). First settled nearly 230 years ago and now home to some 1,500 residents, the Town of Cabot installed an MBR plant in 2001 to eliminate residential septic tank discharges into the headwaters of the Winooski River.

The original membranes -- the leading MBR sold in recent years -- met operational expectations and lifespan projections for the first 9 years. When the first replacement membranes were needed in 2010, the Town, through system operators Utility Partners, opted for used membrane cartridges from the manufacturer at $1,300 each, compared to new ones at $5,700 each. However, within the first two years of operation after installation of the used membranes, the fibers began to pull out of the potting, resulting in increased turbidity. Meanwhile, the manufacturer stopped making the original membranes that fit Cabot's small system, which serves about 100 customers. While new cartridges in the old style were available for a limited time, future replacements would not be possible, according to Jim Brimblecombe, Project Manager at Utility Partners.