Interoffice Memorandum



Mark Cupkovic
Director of Operations


Emir Kajoshi
(Water Treatment Staff)


July 17, 2003


Conservatory Water Treatment


Until recently, using chemicals to control scale and hardness has been the only option. Many operating engineers and pesticide applicators have been trying other alternatives for years, and I can include my own research as well that, until now, nothing has proven to work to phase out the dangerous chemicals still in use as the primary source of control of many plants.

Today’s alternative non-chemical water treatment systems utilize electrostatic technology (Electrostatic Rod) with which we are experimenting ourselves in the Conservatory boiler plant. The rod, as you know, was installed in the condensate tank of the plant last year and was in operation throughout the 2002/2003 heating season. This tank holds condensate return and make-up water (for any lost steam/condensate in process) and is the main and only source of water supply to the two 300 Hp Cleaver Brooks low-pressure steam boilers.

The rod, as we know, is based on a simple principle of charging particles in the water in such a way that they repel each other, thus preventing them from sticking to each other and collecting on surrounding surfaces (tubes, walls, etc.), and actually dissolving any existing scale over a period of time. Chemicals pretty much do the same by creating a film around the surfaces to prevent scale formation.

The following are my observations and facts based on one full heating season with the rod application in the above mentioned boiler plant:

  • Significant reduction in scale control chemicals

  • Elimination of hardness control chemicals.

  • 50% Reduction of oxygen control chemicals

  • Significant reduction of boiler blow-down procedure, which reduced both usage and loss of the above mentioned chemicals.

  • Both boilers had substantially less scaling then in previous years when the annual cleaning and maintenance was performed.

Mark, I also would like to emphasize, based on my resources and experience, that there is no such thing as 100% chemicalfree water treatment, at least not for all systems yet. As per the specs of the Chemfree Water Systems and other resources I gathered, the electrostatic rod can be used as a replacement for most water softeners to control hardness and significantly reduce the amount of other chemicals (in our case Nitrate based scale and oxygen control Chemidual 200).

My conclusions, based on the above, is that, aside from energy savings, elimination of hardness and reduction in the need for scale control chemicals in our plant, there is a significant savings in the cost of chemicals and associated equipment indeed. Down-time/replacement/repair of costly equipment is reduced as well. Failure of the tubes due to scale build-up and the resultant temperature rise across the heat exchange surface will be greatly reduced in proportion to the reduction in scale formation.


I would like to have at least one more rod installed at the next most important location, the Museum Boiler Plant (steam system as the Conservatory plant), where I think it would help us tremendously to control scale and save the equipment there as well.



View More Case Studies