Nut Shell Filters (NSF) are utilized as tertiary water treatment systems, and are the final step for appications which require very low oil and solids in water effluent levels. NSF Systems typically follow downstream from water treatment equipment like deoiler hydrocyclones and / or IGF systems.
eProcess NSF’s are deep bed downflow filters which utilize specially graded and ground pecan shells and / or walnut shells as the filter medium. Produced water enters the top of the vessel and is forced through the shell media where the oil and solids are removed, and the clean water exits the bottom of the vessel.
The media is periodically vented, scrubbed, and the effluent stream purged to ensure an ongoing continuous cycle. The NSF media is preferentially water wet and this reduces the tendency of the media to become coated and fouled with oil and fine solids.
- Treatment to very low levels of oil and solids in water (<5 ppm and <5 micron)
- Low media attrition rate of around 10% per year
- Onshore oilfield produced water applications
- Collection of produced water from multiple streams
- Proven and robust tertiary water treatment method
- Multiple media vessels are often used (i.e. 3 X 50% or 2 X 100%) – alternating between water treatment and media cleaning
- NSF’s typically separate up to 98% of all solids 5 microns and greater and discharge less than 10 ppm oil in effluent at inlet concentrations of less than 200 ppm
- For inlet oil concentrations below 100 ppm separation performance is 98% of all solids 2 microns and greater and less than 5ppm oil in effluent
- Design flux rates in the 13 to 15 US gpm/ft2 range