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Defender® Regenerative Media Filters Benefits

Exceptional water filtration along with significant water and energy savings compared to traditional sand filtration.

​The Defender® media filter significantly eliminates the amount of backwash water associated with sand filter operation. Instead of backwashing, the Defender filter is programmed to automatically “bump” to regenerate the fine-grade perlite media for a fresh start. Eventually the filter will become saturated with trapped dirt and will require a quick and easy media discharge and replacement. Depending on bather load, the life cycle of the media averages around every four weeks.

Backwash Water Consumption​ ​ ​

​Filter Type
 
 
Filter Area
(sq ft)
 
Backwash Rate
(gpm/sq ft)
Backwash Volume
(gal)
​Annual Volume
(gal)
​Sand
(4) 4884SHFFG-6
​126.8​11.8
​9510 gal
3x / week
​1,483,560
​Defender Media Filter
(1) SP-49-48-1548
​1211​1.2
​1230 gal
1x / 4 weeks
​14,760
​​Annual Water & Waste Savings:
1,468,800 gallons


Energy & Chemicals Savings

The dramatic reduction of backwash waste directly translates to savings in make-up water along with the chemicals and fuel for re-heating. Consider the cost of chemically treating 1.4 million gallons and the BTU’s required to heat this volume from 50 degrees (10 °C) to 80 degrees Fahrenheit (27 °C).

It is also important to note that the improved water quality generated by the Defender® filter's ability to remove finer particles will also save on general chemical consumption.

Estimated annual savings ranges from $42,000 to $52,000 depending on local fuel costs for oil, gas or electricity. Based on the backwash water consumption of a typical waterpark attraction with a 2000 GPM (454m3 /hr) recirculation rate.

 

Construction Savings

More savings are derived from the smaller construction footprint for the Defender® filter.

This results in as little as one-fourth to one-sixth of the space required by an equivalently sized sand system, saving installation and rigging time. The lesser operating weight of the Defender filter reduces the extent to which the floor slab must be engineered. With building costs at an estimated $75 to $150 per square foot, selecting a Defender filter could generate construction savings in the tens of thousands of dollars.

 

Additional Construction Benefits:

  • No backwash holding tank
  • Small waste line to sewer
  • Local backwash to waste flow rate restrictions are no longer an issue
  • Operating weight may be as little as 10% of a similar sized sand filter

Power Savings

Defender® media filters reduce head loss (vs. sand) to save motor horsepower operational cost.

Starting differential pressures for a high-rate sand filter, depending on the media, could range from 4 to 6 psi (27.6 kpa to 41.4 kpa). In contrast, the starting differential of the Defender filter is approximately 1 psi (6.9 kpa).

Converting this to head represents savings of nearly 12 feet (3.65m) total dynamic head, or TDH, which translates to horsepower and energy savings. In most cases, the pump motor required for Defender filter recirculation is smaller than a sand filter. Utilizing a 25hp motor instead of a 30hp unit would result in electricity savings of $3,000 per year.

In waterparks with multiple attractions, the savings would be much more.

Defender Filter's Deliver Huge Energy Savings
This graph illustrates the actual operating pressures of High Rate Sand Filters compared to Defender Regenerative Media Filters.

The RED line represents the fluctuations in PSI for High Rate Sand Filters throughout one complete filter cycle (3 days). The BLUE line indicates the PSI differential for Defender Filters over a similar cycle (21 days).

As a result of the “Bump” cycle, the Defender filter operates at a dramatically lower head pressure and vastly reduces energy costs. The GREEN shaded area represents the level of lower head requirements which translates directly to dollars saved. “Defender Media Filters Deliver Huge Energy Savings”.


A High Rate Sand Filter, designed at 12 GPM/SF will typically start with a 5 PSI pressure differential, when clean. A pressure differential increase of 10-12 PSI occurs every 3 days, requiring backwashing.

A Defender® Filter, designed at 1.3 GPM/SF, will typically start with a 1 PSI pressure differential with new media. Daily pressure differential increase will be 0.25 PSI after bumping. A typical 21 day cycle has yielded a 5.5 PSI pressure differential increase.

All data is provided by Great Wolf Resorts based on actual results of filter systems they operate at various facilities in North America.

Water Quality

The Defender filter will remove particles down to 1 micron. With the growing concerns about waterborne illnesses (WBI) such as cryptosporidiosis, the smaller the particle removal the better. The Defender filter is especially effective on pools with heavy bather loads because of the increased filter area and dirt holding capacity.

Defender filter's will also retard the increase in turbidity. A major contributor to turbidity in pool water is the treatment chemicals, especially sodium hypochlorite. The improved filtration, along with the reduction of make-up water, cuts the chemical requirements and the associated turbidity buildup.

Findings from a recent study by the University of North Carolina on cryptosporidium and particle removal from swimming pool water indicate:

  • Precoat Filtration with both DE and perlite outperformed cartridge and sand filtration by a wide margin
  • Single pass testing resulted in crypto removal of 99.9% using perlite media
  • When testing 1-micron microsphere removal, perlite performed at 56.5% versus 20.2% for sand

nbsales@evoqua.com Defender® Regenerative Media Filters Benefits