PowerClean™ Nutshell filter

PowerClean™ is the most effective, quickest regenerating nutshell filter media system available. The technology is proven in removing 98% of suspended solids and free oil droplets above five micron from produced water or any water source. The system is equally effective for the treatment of suspended solids, oily residues, ash and metallic hydroxides from industrial liquid generated by metal working, power generating, municipal, chemical or petrochemical industries.

Hydrocarbons and suspended solids removal.


PowerClean nutshell filters are a simple, automated system designed to eliminate filter plugging problems without the use of air or gas for particulate removal thanks to a quick media cleaning cycle that generates minimal volumes of backwash wastewater for disposal. Through a rapid fluidization process featuring a powerful shearing action, the contaminants are stripped from the media with very little backwash water and the filter is quickly returned to service.

Pecan or walnut shell media offers the advantage of better resistance to fluid fouling than other media. Because it is not affected by heavy oil surges, the media is easily cleaned in only 12 minutes and rarely needs replenishing — normally only 5% of the media require replacement per year. This media process also eliminates the need for chemicals during filtration.

How PowerClean Nutshell Filter works?

During the downflow filtration cycle, the feed water passes through the walnut shell media which effectively removes free oil and suspended solids. Once the maximum differential pressure across the bed has been achieved, the filtration service gives way to the cleaning cycle which consists of five simple steps performed via a computerized sequence: fluidization, discharge, settling, purge, and return to filtration. The media cleanup process, which does not require a separate water source, reverses the flow direction as it is enhanced by a modified centrifugal pump that creates high shear on the media surface. Next, the fluidized nutshell media is transferred to an external housing containing a robust wedge-wire assembly for superior scrubbing action. The screen allows the retained oil and particulates to be discharged but prevents the media to pass through as it is recirculated back into the filter vessel through a special nozzle that helps with fluidization and thorough cleaning of the media bed for a duration of 12 minutes in a closed-loop circuit. Finally, after a quick moment that allows the media to settle, PowerClean is ready to be turned back to filtration mode.

Veolia’s PowerClean is available in standard sizes that have been pre-engineered for quick turn-around and economical pricing. While we offer standard designs, we can also tailor any of our products to your specific needs. We will thoroughly review your specifications or help you write them for your application, and provide a filter system that delivers the performance to meet your stringent standards.

Feature and benefits

  • Nutshell media used along with patented fluidized bed process
  • 98% removal of suspended solids and free oil
  • Media cleaned in only 12 minutes
  • The media only requires a 5% replacement per year
  • No chemicals, air or gas are required for contaminant removal or media cleaning
  • Reclaims more oil
  • Upstream flow interrupted for only sixty seconds
  • Less maintenance than other filters thanks to patented design that eliminates plugging problems
  • Design flux rate of 12.5 to 15.0 gpm/sq.ft allows for smaller and fewer filters for specific applications
  • Uses less floor space than other type of filters


Produced water treatment for oil and gas exploration.
Technologies, services and process expertise to meet environmental requirements, remove contaminants and transform wastewater into a resource.


A combination of digital tools and Veolia expertise that make all your water processes smarter, safer and more sustainable.
Bundling high performance specialty chemicals, innovative dosing and controlling equipment with related expert support.


The high performance and simplicity of Veolia’s PowerClean® nutshell filters result in lower costs and easy operation. These nutshell filters are unparalleled in removing suspended solids and hydrocarbons from produced water or any water source.


Albert Low

Vice President, Sales - Veolia Water Technologies Inc.

Contact Albert through his LinkedIn account


FAQ about PowerClean™ Nutshell filter

How reliable are walnut shell filters?

Walnut shell filtration is a very proven technology on the market.  The walnut shell media offers the advantage of better resistance to fluid fouling than other media. Because it is not affected by heavy oil surges, the media is easily cleaned in only 12 minutes and rarely needs replenishing. This media process also eliminates the need for chemicals during filtration.

How frequently should walnut shell media filters be replaced?

Because our PowerClean nutshell media is used along with patented fluidized bed process, the media only requires a 3%-5% refilling per year due to media attrition and the media will reliably last for 10 or more years.

Where is nutshell filtration typically used?

Nutshell filtration is typically installed as a treatment step to reuse oilfield produced water for steam generation or as a polisher before reinjection into a well. Nutshell filters also applied to tertiary refinery wastewater, steel mill direct spray and caster water, quench water in ethylene cracking plants, copper concentrate decant and cooling water. Under normal conditions, PowerClean nutshell filters are capable of operating with oil content of up to 100 mg/L and can reliably deliver concentrations at 3-5 mg/L or lower.