What is a Water Recycling/Closed Loop system?

A Water Recycling System, or rather, a Closed Looped System for an abrasive waterjet cutting machine is a system that recycles the cutting water from the waterjet cutting process providing for zero discharge of wastewater. These systems are contained separately and can be installed/deinstalled from existing waterjet system very easily and at anytime. They consist of sediment catching weir tanks, filters, de-ionisation vessels, and organism killing devices that purify the water before returning it to the high pressure pump for reuse in the cutting process. These systems also include a 1 or more pumps to circulate the water and require a chiller to reduce the water temperature as the process of cutting creates an enormous amount of friction and thus, heat. However they DO NOT remove abrasive settled into your machines catch tank they merely recycle the water. A separate abrasive removal (CLICK HERE TO READ ALL ABOUT ABRASIVE REMOVAL SYSTEMS) method is required to keep your catch tank clean and/or prevent abrasive dig-outs.

Calypso WRS Closed Loop System

A closed loop system is likely offered as an option with a new waterjet system but precautions should be taken before considering if a closed loop system is right for you as there are many other options much cheaper. A typical closed loop system new will run about  25-30K in addition to your machine purchase price. Although a closed loop system may be recommended by the sales rep in conjunction with a new waterjet system,it should be noted that there are many other methods that can improve water quality and pressure to acceptable levels for far less of an initial investment AND less maintenance and operating costs. Also it is important to note that these systems can be installed and de-installed very quickly and simply on any machine as they are stand-alone units only requiring a few hose connections, however once installed they must be turned  on and operable in order to provide sufficient water flow to your waterjets pump.

When is it needed?

A Water Recycling / Closed Loop system is rarely required equipment for any shop, however there are certain factors that can make a Water Recycling System a necessary or preferred accessory. Several of these factors include:  

  • Local law dictates 0 water discharge for manufactrueres in your area
  • Materials you are cutting create a hazardous waste stream (i.e. Burrelium etc)
  • Incoming water quality is so poor that normal pre-treatment systems are ineffective.
  • Lack of access to running water or a drain.
  • Septic Systems that can easily be overwhelmed with 3 Gallons+ per minute of discharge water

When is it NOT needed?

If your contemplating using a Closed Loop system to save on water costs you are very likely to find that the operating costs of the system grossly outweigh the savings of less water used. Simply put if your considering a closed loop system for one of the following reasons you're likely headed down the wrong path:

  1. Save $$$ on water usage

  2. Simply to boost the water pressure (Boost pumps are available for a few hundred dollars)

  3. Improving Pump Seal life if it is at or exceeds 500 Hours
  4. Avoiding the simpler water treatment systems commonly available (Filtration, Water Softener, Etc).

What are the benefits?

A Closed Loop / Water Recycling System for an Abrasive Waterjet Cutting System provides several benefits to the waterjet user including:

  1. Provides the best possible water to your high pressure pump greatly increasing seal life to 1000 hours or more.

  2. Reduces water consumption to near ZERO (Oversplash and evaporation are the only water losses).

  3. Increases/Boosts incoming water pressure.

  4. Eliminates the need to run/plumb water supplies and drains (however machine must be topped off daily to provide for water losses due to evaporation).

What are the costs of adding a Closed Loop System?

As mentioned previously water recycling systems cost on average approximately 25-30K including the chiller.  They consume electricity and have consumables that need to be replaced including Filters and Resin Bags (Deionization Media) or tanks. They also require periodic maintenance and cleaning to remove sediment captured in the weir tank system and cleaning of the cooling coils/filters on the included chiller.  All told these costs add up to about $7 per operating hour of the typical closed loop water recycling system. This is in addition to the $30-$35 P/Hour it takes to run your waterjet cutting system alone.

If you are purchasing a closed loop system WITH your very first waterjet, you should strongly consider delaying the decision as cost/operating costs are very high considering other options available. Hold off on including the water recycling system until you have been assured that a closed loop system is indeed right for you.

Any other options to increase my water purity?
Absolutely. If you are not handcuffed by local regulations preventing water discharge (90% of North America is not) then several other methods should ALWAYS be considered first.

  1. Test Your Water - See if you even need a system in place to improve your waters quality most water jet pump manufacturers provide a free water testing service and all will provide water quality specifications your water should meet.

  2. Filter Your Incoming Water - Filter your water to remove any sediment or sand that can damage your pump seals and HP valves.  A basic Consumer (Home Style) Water filtration system available from your local hardware store is all that should be required.

  3. Soften the Blow - A Water Softener will most likely solve over 70% of water hardness/treatment issues. A simple water softener can be purchased locally and a typical residential style unit can be more than effective  or you may elect to contract these services from a water treatment company like Culligan.

  4. Reverse Osmosis Water Treatment Systems* - Reverse Osmosis water is very clean and pure and is great quality water for a waterjet but does nothing to recycle the water being used. Also a very large RO System is required to supply the .5 - 2 gallons p/minute the typical waterjet intensifier pump will require for operation and an enormous amount of waste water is created from the RO system (2-3X the amount of water produced).  Further these systems take an enormous amount of additional floorspace and although popular in years past, are rarely offered as a solution for water treatment on waterjet cutting systems today.


Closed Loop Water Recycling Systems can indeed be necessary in some waterjet applications, but are not required in most. Other filtration options should always be considered first as they are less money, less maintenance and quite frankly, less headaches than a closed loop water recycling system. If better water quality is needed there are other methods of water purifying that are much easier and just as effective then the closed loop systems. You shouldn’t consider a closed loop waterjet filtration system unless you absolutely need it, and if you do, you will know very quickly.

If you would like to discuss in more detail with one of our experts on how a Waterjet Cutting Closed Loop System can work for your application, or if you would like to discuss adding the capability of Waterjet to your shop just contact the experts at Southern Fabricating Machinery Sales today! Call us directly at 813-444-4555 or visit us on the web at WWW.SOUTHERNFABSALES.COM

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