By Thomas Palkon
Introduction
When people hear that the Water Quality Association (WQA) operates a drinking water laboratory they always ask, “Can you test my water and let me know what’s in it?” They are always surprised when we say no!
Different facilities
There are a variety of laboratories specifically designed to analyze drinking water and waste water samples. These are typically defined as analytical labs. They offer a variety of U. S. Environmental Protection Agency (U.S. EPA) accepted test methods and scans that can be performed on drinking water samples to detect and analyze metals (lead, mercury, etc.), organics (pesticides, herbicides, etc.), radionuclides (radium, radon, etc.) and microorganisms. Analytical laboratories are prevalent in the U.S. and Canada, offering tests at very competitive prices to consumers, regulators, municipalities and product performance labs.
The second type of testing facility that is commonly used in the drinking water treatment industry is a product performance laboratory. Much less prevalent when compared to the large number of analytical labs spread throughout North America, product performance labs are specifically designed and engineered to test drinking water treatment units (water softeners, filters, RO’s, distillers, UV systems, etc.) and drinking water additives (water treatment chemicals, media, faucets, pipe, water meters, plumbing products, etc.). Product performance laboratories normally test product(s) to specific industry standards that have been developed to ensure consumer safety. The results of the testing are typically used for product certifications.
Standards
Drinking water treatment units and drinking water additives products are normally tested to NSF/ANSI standards. Developed under the American National Standards Institute Process (ANSI), they typically are drafted from the input of three groups of interest: manufacturers, regulators and consumers. The NSF/ANSI standards developed for drinking water applications typically contain three categories of testing procedures: materials safety/extraction, contaminant reduction and structural integrity. Depending on the product type, one, two or all of the testing categories must be performed on the product for it to become certified.
Material safety/extraction
The material safety/extraction test is required for all product types. It is performed to ensure that the product’s materials of formulation will not add harmful contaminants into the drinking water. This industry designs products intended to make drinking water cleaner, better tasting, safer, clearer, etc. Manufacturers definitely do not want their products to add contaminants into the water that would make it less safe, dirtier or worse tasting.
Depending on the type of product, there are a variety of testing protocols used for the extraction tests but they all contain the same principles. First, reasonably aggressive water is used to soak the product. Second, the water remains in the product for a certain period of time (normally to represent sitting overnight). Finally, the water is collected and analyzed to determine if the product’s material formulations added contaminants into the water above safe levels for consumption.
Although the test appears very simplistic, each step must be carefully performed to prevent contamination or errors by the lab. Prior to soaking, water preparation is necessary and analysts must begin with the correct high purity water that meets the requirements of the standard(s). They also must ensure that the high purity chemicals used to make up the extraction water are added in the correct quantities. During the soaking and sample collection process the chemist has to be sure to use containers, glassware and environmentally controlled rooms that prevent the possibility of false contamination of the samples.
After the samples have been collected, they are transferred (and preserved if necessary) to specific bottles and sent to the analytical lab to determine what, if anything, has extracted from the product. Photo 2 shows part of the Water Quality Association’s extraction room, specifically designed to reduce the chance of contamination.
During extraction tests, numerous water samples are collected to determine if the product meets the requirements of the test standard. All the extraction water samples and blanks must be bottled correctly (preserved if necessary), kept at appropriate temperatures and sent to an analytical laboratory. Most performance labs also maintain an analytical laboratory because of the large volume of samples generated during performance tests.
Contaminant reduction
Contaminant reduction testing is performed on all complete drinking water treatment systems that intend to be certified for performance capabilities. Again, depending on the system type (water softener, water filter [POE and POU], RO, UV or distiller) a specific standard has been developed to challenge the system with reasonably aggressive challenge water that has a high potential to leach contaminants from a product. This type of laboratory water is more aggressive than that typically used in households but not as aggressive as RO/DI (reagent grade water.
Water softeners are tested in accordance to the NSF/ANSI 44 standard for performance claims. They are required to pass the following performance tests:
- Hardness capacity. Water softeners are tested to ensure that the hardness capacity per salt setting stated in the literature is accurate. For example, if a softener is capable of removing 16,000 grains of hardness at a three-pound salt setting, the laboratory will verify the claim by testing the system using the following influent characteristics: 18-22 grain-per-gallon hard water; 6.5-8.5 pH; 400-600 mg/L TDS; less than one NTU turbidity; less than 85.5 mg/L sodium and less than 0.1 mg/L iron at 55-75°F.
- Softening performance. Water softeners are tested to ensure that they are capable of providing soft water at the manufacturers’ maximum rated service flow.
- Rinse effectiveness. This test ensures that after the system has been regenerated, all of the chlorides from the brine have been rinsed from the system before it is placed back into service.
- Pressure drop. Water softeners are tested to ensure that the unit will not create a drop in pressure above 15 psig when the system is operating at its rated service flow.
- Brine accuracy. Brine systems are tested to ensure that the correct amount of brine is being made and delivered to the system during the regeneration process.
Water softening testing is extremely labor intense. Labs, and the manufacturers they serve, have had a difficult time developing ways to automate each of the required tests. Because of the quick exhaustion curves, the best use well-trained technicians who completely understand how the manufacturer’s valve operates, how water softeners function and the requirements of the standard instead of completely automating the testing process.
Water filters (POU and POE) are tested in accordance to the NSF/ANSI 42 (covers aesthetic claims) and NSF/ANSI 53 standards (covers health claims) for performance. Aesthetic claims are characteristics of water, which affect its taste, odor, color and appearance but which do not (in themselves) pose any adverse health effects. Health claims are any substance or condition that may have an adverse effect on human health. Although the NSF/ANSI 42 and 53 standards contain a variety of claims and test procedures for making inorganic, organic and mechanical filtration claims, filters are only required to pass one performance claim test for certification. This has caused some confusion throughout the industry because many people thought that if a manufacturer’s product passed the NSF/ANSI 42 or 53 standard(s) the system had passed all the tests listed in each standard. Requiring clear language in the product literature that differentiates tested claims, certified claims and any other claim made by the manufacturer has rectified this issue.
Water filters are tested to a set capacity, specified by the manufacturer. Because filter capacities vary anywhere from 20 gallons to over one million gallons, a lab that has automated its filter test benches can set reasonable fees. Each bench is capable of automatically filling or emptying the challenge water with the correct test water so that the technician only needs to add the correct quantity of stock solutions. The automated test benches are also capable of taking samples (automatically) so that the samples can be collected at the precise time during the test even if that time is at 2:00 a.m.
Reverse osmosis (RO) systems are tested in accordance to the NSF/ANSI 58 Standard. This standard, along with the distillation Standard (NSF/ANSI 62), differs from the filtration standards because the system is not tested for its entire life or capacity. RO membranes typically last three to five years; therefore, it would be impractical to test RO systems for their entire life. Because life testing is impractical, the NSF/ANSI 58 Standard challenges RO systems for seven days, utilizing a test procedure that provides worst-case usage patterns so that the system will not perform as well during the testing as it would during normal use in the home.
During the seven-day test, the units are challenged 24 hours per day. Samples must be taken every six hours for the RO test; therefore, automatic sampling devices keep labor costs to a minimum. Automated test benches fill and drain challenge tanks along with take samples at the required times as outlined in NSF/ANSI 58, without the need to have numerous staff members available around the clock. Such automations allow testing to be conducted in complete compliance with the standard with far less labor expense.
Large numbers of water samples are collected during each of the performance tests. Each must be bottled correctly, preserved if necessary, kept at the appropriate temperature and sent to the analytical laboratory to determine if the products have passed the testing protocols; i.e., removed the contaminants from the challenge water below the allowable level.
Structural integrity
The final category of testing is structural integrity. Systems and components that operate under pressure are subject to structural integrity testing, developed to ensure that products will not break under normal operation and ‘water hammer’. Water hammer can be defined as the shock wave or series of waves caused by the resistance of inertia to an abrupt change of water flow through a water piping system, producing an instantaneous pressure many times greater than the normal pressure.
Products need to be structurally sound to prevent household flooding. Typically, products are tested in accordance with a hydrostatic pressure test (holding a required amount of pressure for 15 minutes) and a cycle pressure test (to simulate water hammer). These tests are designed to simulate 15 years of normal water use and water hammer; the tests typically destroy the water treatment and plumbing products. When designing a structural integrity test bench, the performance lab must use components that will not wear down or break under these high-pressure tests.
The newest automated structural integrity test bench has meant the pressure rise and decay times can be easily controlled, monitored and recorded. The test bench has also been designed to handle pressures exceeding 1,000 psig to prevent it from breaking down during the testing. This high-pressure design of the structural integrity bench allows the lab to perform a wide variety of structural integrity tests for all types of manufacturers.
Conclusion
As the water treatment industry continues to grow and develop new products to solve problem water or to meet the U.S. EPA’s ever-lower MCLs, product performance laboratories must keep up with the increased demand for testing.
About the author
Thomas P. Palkon, CWS-VI, is the Director of Product Certification for the Water Quality Association’s Gold Seal Certification Program. He has worked with product certification, laboratory and facility assessment programs for over eight years. Palkon earned a BS in biology from the University of Illinois at Urbana-Champaign and an MBA from Keller University. He can be contacted by phone at (630) 505-0160 ext 523 or via email: [email protected].
About the WQA Product Performance Lab
The WQA has taken great strides automating test benches in order to maintain a state-of-the-art laboratory and to meet clients’ timelines for completing tests. The large number of samples that are collected by the Product Performance Laboratory keeps WQA’s in-house analytical laboratory extremely busy. Palkon advises those seeking to have a water sample analyzed to use one of the many analytical labs, but if you need to have a product tested to the NSF/ANSI standards check out the Water Quality Association’s state-of-the-art facility.