According to the Association of State Drinking Water Administrators, 45 states have adopted or planned legislation, regulations or policies requiring drinking water system components to conform to NSF/ANSI Standard 61. Therefore, companies that plan to sell process media (activated carbon, ion exchange, sand, etc.) to drinking water municipalities must have the media certified to NSF/ANSI Standard 61 by an ANSI-accredited certification agency. Acceptable ANSI-accredited certification agencies include the Water Quality Association (WQA), NSF International (NSF), Underwriters Laboratories, the International Association of Plumbing Mechanical Officials and the Canadian Standards Association.
The process has been working very well for municipalities because they know that the certified media has been tested to ensure it passes the extraction protocol specified in NSF/ANSI Standard 61. Passing the extraction protocol demonstrates that the media does not add contaminants back into the drinking water above allowable levels. The scope of standard 61 includes several types of media that reduce dissolved or suspended materials present in drinking water, such as ion exchange, adsorption, oxidation and filtration.
Many process media can be regenerated (ion exchange) or reactivated (activated carbon), put back into service, and used again and again to remove dissolved or suspended contaminants. Everyone is familiar with a residential cation exchange water softener that is regenerated on site with sodium chloride. These systems typically regenerate at least once per week. Similar to residential water softeners, municipalities also regenerate process media so that they can use the media over an extended time before it is replaced with “virgin” media.
Municipalities regenerate the media one of two ways: at the treatment facility (similar to consumers and water softeners) or off site at a regeneration plant. A question has recently been raised concerning offsite regeneration. When the media is regenerated off site, does it retain its ANSI-accredited certification? This is an important question because municipalities are required to use media that is certified to standard 61 by an ANSI-accredited certification agency. If the media that has been regenerated off site is no longer certified, then the media could not be put back into service by the municipality.
Certification agencies’ responses to the question are that the media is no longer certified to standard 61 because they have no way to review the offsite regeneration process to ensure the regenerated media would still pass the requirements of NSF/ANSI 61. Municipalities are not happy with this response because they cannot afford to purchase virgin media every time their media becomes exhausted. In addition, manufacturers of regenerable media don’t like the response because their products can no longer compete with throwaway media in the marketplace.
The WQA presented this issue to its Gold Seal Product Certification Public Health Review Board for discussion and review. The Public Health Review Board’s responsibilities include the review and formal ratification of all Gold Seal Certification Policies related to objectivity, impartiality and public health protection before they are enacted into official program policies of the WQA.
The WQA’s Gold Seal Certification staff, along with the Public Health Review Board, developed a procedure for certifying media that is regenerated off site and presented the procedure to the NSF Joint Committee for Drinking Water Additives on Nov. 27, 2006. The procedure states the following:
Maintaining certification of media that is regenerated off site shall be classified into two categories.
The WQA has spent considerable time and effort developing its procedures for certification of regenerable media, but revising the NSF/ANSI 61 will take several months to complete. The WQA anticipates that a task force will be established to resolve the issue.
Will the regeneration process always strip off all the contaminants that have been picked up while the media was treating the drinking water? This is one of the WQA’s biggest concerns. The WQA has performed numerous tests of media that has been exhausted/regenerated and found that the exhausted/regenerated media extracts less contaminants than the virgin media when tested in accordance to NSF/ANSI 61, Section 7. This question can be answered easily if the media is always treating the same water source by testing the media after the regeneration process, but when media treating different water sources is combined during regeneration, the question becomes difficult to answer.
The industry needs to develop a procedure for certifying regenerable process media that is accepted by the regulatory community and ensures consumer safety.