By David Krupinski, CWS-VI
More work needs to be done on single barrier systems for many to feel comfortable recommending and installing such products due to the risks they carry.
Recent media coverage about contamination events and potential vulnerability to terrorist attacks have resulted in heightened concerns about pathogens in our water supplies. Coupled with newer research showing that private wells often contain microorganisms that can cause illness, these events have led consumers to seek alternatives to ensure that they and their families minimize exposure. While some have turned to bottled water, others are interested in purchasing water treatment devices for protection.
There are a number of alternative technologies that have been used for years to disinfect water for use in the home, from simple chlorinators to ozonation machines to UV systems. Recent innovations have resulted in systems that don’t rely on these traditional methods, instead utilizing barrier filtration to physically exclude microorganisms to prevent waterborne illness.
Barrier filtration has recently received accolades as an improved method for protection against waterborne pathogens like viruses, bacteria and cysts. Why? There are several reasons. The primary advantage is that barrier filtration provides physical removal of pathogens rather than just inactivation. That means there are no inactive ‘bugs’ floating in water processed through the barrier method. Nor are there concerns about turbidity and its ability to hamper the process as it can with other methods. And certain barrier systems can operate completely independent of an electrical supply so they will continue to protect users in the event of a power outage, which is a common cause of boil alert notices.
While the barrier method may seem to be the best possible solution for water supplies with potential pathogen problems, barrier systems vary in their construction, certification, performance and maintenance requirements. Multibarrier systems have been available for several years and use multiple stages of filtration to ensure failsafe protection from pathogens in the influent and from backward contamination from the systems’ dispensing devices. The recent introduction of single barrier ‘purifier’ systems raises ethical concerns about true long-term protection and the ability of such systems to continue to remove pathogens in the event there is a breach in their single barrier.
Advantages of multibarrier
The beauty of a multibarrier system lies in its redundancy. Its multiple stages ensure proper pathogen removal even in the event a microorganism happens to find a way through one barrier. Additionally, protection as close to the dispensing device as possible ensures safeguards are as close to the consumer’s glass as they can be; it also prevents retrograde contamination from compromising the system.
To prove this approach is the most appropriate for consumer use, one multibarrier system underwent extensive testing using the U.S. EPA Guide Standard and Protocol for Testing Microbiological Water Purifiers as a guideline. A strict interpretation of that Standard by NSF International resulted in NSF P-231, the microbiological purifier protocol that sets the benchmark against which all systems developed since its introduction will be judged.
The multibarrier purifier being tested exhibited unparalleled pathogen removal, far exceeding the requirements set forth by NSF P-231 and the EPA Guide Standard, but the two companies working jointly to develop the device were not satisfied with only one source of performance data. So they also approached Underwriters Laboratories and BioVir Laboratories about performing their own tests according to the EPA Guide Standard. The device also exceeded removal requirements set forth by the standards during testing provided by the other organizations. To further verify the results, the manufacturers enlisted the Water Quality Association to review all test procedures and findings. The WQA ruled all procedures and results were satisfactory and exceeded the EPA Guide Standard.
Still not satisfied that the tests could accurately simulate real-life conditions under which the systems would be applied, the companies placed their devices on water supplies with known contamination for two years. After the test period, the specialty microbiological filters were removed from the systems and allowed to incubate for a period of 30 days to simulate (within reason) the worst possible conditions the filters might experience: contaminated water and inactivity within the filters themselves.
After incubation, the filters were tested by BioVir Laboratories for pathogen grow-through. BioVir found no grow-through. They were also put into a testing operation and spiked with pathogens to determine if field exposure and a stagnation period compromised the filters. Testing revealed pathogen removal performance consistent with brand new filters.
In yet another challenge, the multibarrier system was subjected to additional testing to verify that its pathogen removal performance exceeded the treated water volume amount listed in the consumer literature. By challenging the system with pathogens according to a schedule dictated by the test protocol, BioVir proved the system can provide outstanding removal for many times the original volume claimed. The testing was halted after the system had produced 3,500 gallons of biopure (microbiologically purified) water—approximately seven years of drinking water for an average family of four. To be conservative, the developers chose to only allow claims up to 2,000 gallons to guarantee the water quality and allow a safety factor.
It is presumed that due to the vast amount of time and expense associated with such testing, the single barrier system has not undergone similar testing to verify that it will last for the full life claimed, in some cases more than 100,000 gallons. The multibarrier system is the only one that has actually been tested for the full life claimed.
Medical grade filters: the key to multibarrier
What makes the multibarrier system so effective are the medical grade microbiological filters that were chosen as the primary pathogen barriers. Technology used to purify pharmaceuticals during the manufacturing process as well as to remove contaminants from donated blood prior to providing it to hospital patients formed the basis for the specialty bacteria and virus filters incorporated into the new multibarrier system. In important medical applications like those mentioned, there is no room for error or failure. The product developers felt the same was true when making claims of pathogen removal from drinking water and they selected filters that had proven to be consistent and reliable in performance under the most challenging circumstances.
Owners of POE systems can now use a handheld integrity tester to determine if their systems are performing properly, but there’s always the chance that a user could find out their system is not working after they have already ingested the water. That’s why employing a failsafe, multibarrier solution is a much better alternative.
POU versus POE
Some debate seems to center around the need for whole-house water purification. But lack of widespread market acceptance of POE purifier devices indicates that consumers are not terribly interested in high purity water for general use and relegated the devices to specialty applications. There really is no need for such high quality water for flushing toilets, or watering the lawn.
Even at the high efficiencies under which the POE purifier device operates, the system wastes a substantial amount of water during the year due to the fact that it produces such a large volume. Assuming an average household of four uses approximately 75 gallons per person per day, annual water consumption totals more than 100,000 gallons. Even at only three percent waste, the POE system would waste more than 3,000 gallons per year, 100 percent more than a multibarrier POU system.
POE purification also suffers from other pitfalls since it is located so far away from multiple dispensing points. Since there is no chemical residual, if distribution lines are not kept adequately disinfected or are not properly disinfected during the system installation, there is an opportunity for pathogens to grow and be distributed throughout the plumbing system. Thus the argument for incorporating purification at the point of use and as close to the dispensing faucet as possible. And since a POE barrier device has to periodically clean itself, it cannot provide an uninterrupted supply of purified water, 24 hours a day.
Additionally, the claim that the POE purifier requires no electricity “to filter the water” is a bit misleading. The same can be said of many water treatment processes that rely on chemistry and physics to address water concerns, such as ion exchange, deionization and reverse osmosis. Electricity is not required for the process itself, but for other functions necessary to ensure high water quality and system longevity. If power is not available for the system to be able to switch to cleaning mode, barrier integrity and water quality may be compromised. The same is not true for the multibarrier system, which requires neither electricity nor battery power for any of its functions.
Additional contaminant removal
Another advantage of multibarrier purification is its ability to reduce a variety of other contaminants that the POE purifier can’t handle. Pesticides, herbicides, lead, nitrates, fertilizers, chromium, arsenic, hardness and a host of other substances are easily filtered using the multibarrier approach for the ultimate in premium water quality.
These additional capabilities render a multibarrier device more suitable for commercial applications where microbiological water purity, coupled with additional contaminant removal is required. Laboratories, pharmacies, dental practices and others benefit from biopure water that also minimizes scale buildup and fouling of their precision instruments.
Concerns about system integrity and true-life testing make single barrier, POE purifiers a risky proposition. As of the date of this writing, no POE system has passed NSF P231, the protocol developed by NSF to test systems to the U.S. EPA Guide Standard. And no POE system or its components have been extensively used in highly critical medical applications where failure is not an option.
While the POE approach may be suitable for some specialty applications where disinfection of all incoming water is necessary, more work needs to be done to ensure protection against possible system breakdowns. On the contrary, a multibarrier system’s field-proven capabilities, true-life testing, third-party certifications and redundant filter mechanisms provide the ultimate in assurance that the systems will perform as claimed.
Multibarrier purifiers’ ability to remove a significant amount of other troublesome contaminants and their ability to operate independent of any power source makes them even more attractive. As consumers and business owners continue to investigate ways to protect themselves from bacteria, viruses, protozoa and the variety of non-living contaminants that can be found in water supplies, the multibarrier approach will continue to provide the most reliable, effective and economical solution.
About the author
David Krupinski is Manager of residential markets for Kinetico Incorporated. He has been an industry member for more than 12 years and has worked extensively with all areas of product development, marketing and sales and is a Certified Water Specialist, Level VI. He can be reached at (440) 564-9111, ext. 289 or via e-mail at [email protected]