Whittier™ PowerClean Nutshell Filters

Fine Oil and Suspended Solids Removal

PowerClean® filters are among some of the most advanced nutshell filtration technologies available in the market.


With superior design and long filtration runs, PowerClean filters are proven in removing 98% of all suspended solids and insoluble hydrocarbon particles above five microns.

PowerClean is a simple, automatic 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 particles and the filter is quickly returned to service.

  • Exceptional effluent quality.
  • Short media cleaning cycle interrupts filtration service for only 60 seconds.
  • No need for air scour, stand-by filters, or additional backwash water storage tanks..
  • Optimal protection against oil surge and upset conditions.
  • 100% black walnut media selected for its unmatched durability, oil affinity and coalescing surface properties.
  • High loading capacity and flux rate design (12.5 to 15 gpm/sq.ft.) provides greater throughput and more efficient footprint than other conventional filtration methods.


Features and Benefits

Power Clean Media

  • Cleans better and can be adjusted to different application requirements.
  • Nutshell media used along with patented fluidized bed process.
  • The media only requires a 5% replacement per year.
  • Reclaims more oil.
  • Removes 98% of all filterable contaminants.


Low System Costs

  • Designed flux rate of 12.5 to 15.0 gpm/sq. ft. allows for smaller and fewer filter requirements for specific applications.
  • Uses less floor space than other types of filters.
  • The positive retention of the media within the vessel eliminates media loss and disposal problems.
  • Separate pumps for feed and fluidization removes the necessity of having to size one pump at the flow rate for fluidization which is generally 3-4 times that of the feed rate and then adjusting it down to meet the specifications for filtration. Our process eliminates the severe energy penalty on the system that is found with single pump filters. One-pump systems subject an expensive pump to continual wear of the fluidization and feed pump operations. The Power Clean System allows for minimal use of the fluidization pump (only 10 minutes per cleaning cycle), allowing use of a more economically priced pump for feed purposes.
  • Utilizes unfiltered water for media clean-up, eliminating the need for high volumes of "clean" water storage.


Less Chance of Problems

  • The media is not "force set" after clean up, eliminating the potential for damage and plugging of the bottom screen. The Power Clean System screen is actually cleaned during every regeneration cycle before the media settles back down. Other filter systems do not have this feature.
  • No gas or air scour is required, thus reducing corrosion and environmental problems.
  • Fluid quality is independent of outside interactions because no chemicals are used in the Power Clean System filtration process.


Additional Advantages

High Performance Plus Simplicity

The Power Clean System upgrade, because of its unique design, gives a "like new" condition to the media after every backwash, yet does it in a simple operation. This results in a very simple control panel, a small amount of external piping and a minimal amount of startup and operator training. In the final analysis, the "Way" you "Clean" the filter is the "Key To Success" in fluid filtration technology. However, it must be done in an easy, understandable manner, compatible with normal unsupervised operations.



The Power Clean System design can be used to convert a "high rate" sand filter to a "high performance" filter. This conversion will increase the throughput by 60% and decrease the backwash volume by 90%, using the existing vessel. This will reduce supervision and operating costs and, at the same time, allowing oil recovery from the backwash water.



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.

PowerClean is also applied to purify 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 is capable of operating with oil content of up to 50 parts per million (ppm) and can reliably deliver concentrations below 2 ppm.

  • Produced Water De-oiling
  • Metalworking De-oiling



During the downflow filtration cycle, the raw water passes through the black 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 slurry of nutshells and water are pumped into 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.



During the filtration cycle of the Power Clean Filter System, the inlet feed fluid passes through valve "A" and enters the top of the vessel. The fluid is forced through the media where the solids and oil are removed.

The clean filtered fluid exits through valve "E". The vent valve "F" remains open during filtration to continuously remove any gas and oil from the top of the vessel. The filtration step terminates in one of three (3) ways:

  • Time lapses (24 hours maximum).
  • Differential pressure (14 psig) or
  • Manually.



Any of these methods will start the media cleanup cycle.

Media Clean Up


The first step closes the "E" and "F" valve. After 10 seconds valve "A" closes and valve "B" opens and the top pump is turned on. The fluid in the vessel passes through the fluidization pump, the scrubber assembly and back into the vessel through the fluidization nozzle. The fluid is jetted though the nozzle and into the media bed, creating a homogenous mixture of water, solids, hydrocarbons and media. This mixture is then circulated through the fluidization pump causing a shearing action that strips the oil and contaminants from the media. The entire bed fluidizes in a few seconds.



Once the bed is fluidized, valve "C" opens, allowing the dirty water to pass through the scrubber screen and into the discharge line. This water is replaced with inlet water through valve "B" and up through the bottom screen. The combination of inlet water and internal agitation cleans the bottom screen. The water-media mixture continues to pass through the fluidization pump, down the outside of the scrubber screen and returns to the vessel. Dirty water passes through the screen in the discharge line and through valve "C".

This process lasts for the amount of time (normally 10 minutes) set on the PLC located in the control box. After the contamination level in the vessel has been reduced by approximately seventy-five percent (75%), the discharge is complete and valve "C" closes. Ten (10) seconds later the pump is turned off. This final step cleans the separator system.



The next step in regeneration is a delay cycle, which allows the media particles to settle. The fluidization pump is turned off, allowing the media to sink by gravity. This takes approximately one (1) minute. Thirty (30) seconds into the delay time, valve "A" will open, valve "B" will close and the fluidization pump will come on for four (4) seconds to clear the media from the scrubber assembly. During the last thirty (30) seconds the media will settle by gravity for the completion of this cycle.



The last step in the media fluidization cycle is purging the lines and setting the bed. It is necessary to compress the bed to its filtering configuration and to remove the dirty fluid and heavy contaminants that remain in the bottom of the vessel. Valve "D" opens allowing the influent to be cleaned while passing through the media bed and forcing all contaminants out into the discharge waste tank.


5.Filtration - 2nd cycle

After regeneration has been completed the unit is ready to return to the filtration cycle. This is done by opening valves "E" and "F" and closing valve "D".



  • Texas Registered Professional Engineer
  • Water treating and injection facility design
  • Water quality and corrosion control programs and monitoring
  • Material selection and procurement of equipment
  • Quality control of procured equipment prior to shipment
  • Onsite construction supervision


On-site Testing

Power Clean mobile units are available for on-site testing. Trailer mounted pilot units can be easily connected to your water system, providing the necessary flow rate for optimal test results for your application. Our technicians are qualified to set-up the test filter, demonstrate its operation and let you perform the test yourself. You will see immediately, just how simple our system is to operate.


Less Maintenance than Other Filters

  • Simple, automatic design.
  • Patented design to eliminate plugging problems.
  • No chemicals, air or gas is required for contaminant removal or media cleaning.