New Logic Research manufactures a membrane-based leachate treatment system unlike any other. Conventional spiral reverse osmosis (RO) membranes were developed over 50 years ago. Due to the risk of scaling and fouling, these systems have significant limitations. Spiral membranes require extensive pre-treatment to “clean” the water before it can be processed. New Logic’s “VSEP” (Vibratory Shear Enhanced Process) membrane was designed to overcome these limitations enabling treatment of difficult leachate without pretreatment.
In 1987, New Logic developed the VSEP with a wide channel between the membranes to handle high suspended solids without plugging. We also engineered a resonating drive system that moves the membrane back and forth in an oscillating motion reversing direction 50 times per second. This creates very high shear rates at the membrane surface, preventing scaling and fouling. Using polymeric membranes, pressure forces water to go in the reverse direction – hence the term reverse osmosis. As salt concentration increases, higher pressure is required to maintain this reverse flow. The VSEP system is limited only by the pressure needed to overcome osmotic pressure.
In developed regions, landfills often discharge to municipal sewers where the leachate is diluted with town wastewater and discharged after treatment. However, municipal sewage treatment plants (POTW) are increasingly unwilling to accept this waste. In some cases, towns have refused landfill leachate entirely, leaving landfill operators struggling for alternatives. The EPA is also now developing discharge regulations due to the presence of fluorinated polymers (PFAS). When this rule is adopted, it will make sewer discharge of leachate not possible.
Among wastewater treatment options, VSEP is uniquely suited for landfill leachate because it avoids the drawbacks of other technologies. Unlike digesters, VSEP removes nearly all pollutants from the effluent and can make drinking water quality. Unlike spiral membrane systems, VSEP does not require pretreatment and its only limitation is the osmotic pressure. Unlike evaporation, VSEP offers low operating costs. VSEP is less expensive than hauling, evaporation, biological, or any other method that can be used to treat leachate. For these reasons, VSEP has been installed at more than 25 landfills worldwide.
VSEP produces filtrate that can be discharged to rivers or used for dust control. There is a concentrate stream that is left that contains nearly all of the solids and pollutants. In most cases, this concentrate can be put back into the landfill. As long as the VSEP is removing more water from the landfill than is arriving, the water balance is safe and hydraulic pressure on the landfill cell is reduced so there is no risk of failure.
VSEP systems are fully automated and can be configured with remote access for easy operation. Because pretreatment is not required, the system takes up a small space and does not require chemical addition. The cost of operating a VSEP system is often less than the cost of hauling leachate to the POTW. For more details about how VSEP is used for leachate,
Read our article on Leachate Management
Maintaining a Careful Balance
In addition to removing excess water from the landfill, a VSEP RO membrane system provides an economical solution that can reduce operating costs for landfills considering hauling or evaporation.