There are several North American government agencies and organizations that interact to protect the health and safety of the public and the environment while simultaneously serving the best interests of water treatment facilities. Most water treatment facilities recognize that environmental protection is not only the responsibility of government agencies and organizations. In fact, most municipalities use the governmental regulations as guidelines to establish and maintain their own basic standards as “Best Practices” for water safety. A prime example of this is the story of Ferrate Treatment Technologies LLC (FTT), which partnered with SEEPEX Inc., a manufacturer of the only NSF certified progressive cavity metering pump on the market to build a commercial device that represents a fundamental breakthrough in the water disinfection industry. As a critical component of a water treatment system process, disinfection chemical metering pumps often come under the microscope because they meter chemicals that could be potentially harmful if not handled properly, but did you know that chemical metering pumps are not required to be NSF certified in disinfection systems? Deciding what type of pump technology to install for water and wastewater treatment applications can be a daunting task. Many objectives come into consideration, mainly meeting the various governmental laws and regulations affecting the drinking water processes.
The US Environmental Protection Agency (USEPA) is a government agency that has been granted by Congress the responsibility of maintaining and enforcing water pollution prevention under a variety of environmental laws. The USEPA has sanctioned other organizations like NSF International (NSF) that have common interests and goals to help with this cause. The USEPA and the NSF Water Division share a similar mission to protect human health and the environment by enforcing precautions that are critical to maintaining and improving the United States’ water quality. NSF is a global independent public health and environmental organization that provides standards development, product certification, testing, auditing, education and risk management services to the public. NSF is accredited by the American National Standards Institute (ANSI) to develop American National Standards for the safety of all materials and products that treat or come in contact with drinking water, such as plumbing components, water treatment chemicals and drinking water filters. ANSI is a private non-profit organization that oversees the development of standards by representatives of other standards organizations for products, services, processes, systems, and personnel in the United States. In 1990, the USEPA replaced its own drinking water product advisory program with NSF/ANSI standards. The NSF mark on any product affiliated with drinking water treatment processes means that the product complies with all standard requirements and ensures water industry stakeholders that the product will not create adverse effects on the health of those consuming the drinking water or on the environment. NSF product certification is valued by consumers, manufacturers, drinking water, and public health officials along with regulatory agencies worldwide.
NSF/ANSI 61 Standard, titled “Drinking Water System Components- Health Effects”, sets health effects criteria for water system components. It is intended to minimize any negative effects on the health and safety of the public and the environment. Currently 48 US States require NSF/ANSI Standard 61 compliance of any product that is manufactured, sold or distributed for water treatment and comes into contact with drinking water. Drinking water system components fall into two categories of regulation. Centralized water treatment plants and water distributions systems up through the water meter are typically regulated by state drinking water agencies. Water distribution systems downstream of the water meter or inside a building are typically regulated by state or local pumping codes. While all major model plumbing codes require the use of NSF/ANSI 61 Standard certified products, the specific requirements for those product types can be found in state or local plumbing codes.
Types of products requiring NSF certification include; protective barrier materials like paints or coatings, joining and sealing materials such as adhesives, mechanical devices, water meters or valves, plumbing and piping related devices, and non-metallic potable water materials. This is essentially every component of a water treatment system. Interestingly however, the USEPA’s Safe Drinking Water Act (passed by Congress in 1974 to ensure public water systems provide drinking water safe for human consumption) guidelines for drinking water treatment plants do not require NSF compliance for all mechanical chemical feeders. This is because feeders do not come in contact with finished drinking water or post treated water in the distribution system. Metering pumps are used as feeders primarily to convey and deliver precise dosage of chemicals to the pretreatment process during the drinking water treatment process. NSF 61 Section 8 further provides a guidance of “high rate feeders”, a category metering pumps fall into, and states a minimum ratio allowance calculated on the basis of an area of the wetted surfaces to a specific volume of water treated. This allows the exemption by a waiver allowance of appropriate Diluted Surface Area ratio calculation meeting a specific threshold level. Metering pumps qualify for exemption with the DSA ratio calculated per a design’s flow rate for a specific plant flow throughput. However as stated previously, many facilities require all parts of their treatment systems including their metering pumps to be constructed of NSF certified components as part of their own “Best Practices” regardless of this omission.
Ferrate Treatment Technologies, LLC (FTT) is one such company utilizing “Best Practices”. Based in Orlando Florida, the company was founded to invent, develop, and commercialize innovative water and wastewater treatment technologies based on its proprietary iron chemistry platform. FTT manufactures an innovative water treatment system called “The Ferrator®” which produces ferrate, a water treatment chemical generated onsite at water treatment facilities that is extremely powerful, environmentally friendly, and will not create disinfection byproducts. Ferrate is synthesized in a temperature-controlled reaction using commercial-grade chemical feedstocks: 50% sodium hydroxide, 13% sodium hypochlorite (Bleach), and 40% ferric chloride. When dosed into water as a liquid, ferrate acts simultaneously as a disinfectant, oxidant, and coagulant, and will readily destroy all microorganisms; inactivate micro constituents such as EDCs (endocrine disrupting chemicals) and PPCPs (pharmaceuticals and personal care products); oxidize organics and color and odor-causing compounds; coagulate suspended material, and co-precipitate metals. In order to place their innovation in municipalities requiring total NSF compliance, it was essentially mandatory that every component of FTT’s water treatment innovation be in compliance with NSF/ANSI 61 standards, including the chemical metering pumps.
Craig Alig is an Environmental Engineer and Chief Operating Officer of FTT and was tasked with choosing a pump technology that was not only NSF/ANSI 61 Standard certified, but that was also capable of reliably and precisely metering and blending the variety of feedstock chemicals needed to produce ferrate. There are several types of hose and diaphragm pumps on the market certified to the NSF standard, but Alig found that these pump types were not able to meet their requirements for consistent blending, steady flow, and corrosion resistance. The initial design of FTT’s water treatment innovation included diaphragm pumps as the main pumping elements. However, pulsation and blending issues soon proved to be a problem. The diaphragm pumps were complex and prone to breakdowns. Vapor lock and valve leaks required expensive and time consuming repair kits.
FTT decided to remove three diaphragm pumps and replace them with progressive cavity pumps (PCP), which provided better blending and flow control. The unique design of a PCP offered several advantages over other positive displacement pumps. This is due to the simple principle of the pumping element which employs a metal rotor and a rubber stator. The rotor rotates inside of the stator, forming two cavities at the suction end of the stator. One cavity closes as the other opens and the cavities progress from one end of the stator to the other. The result is continuous flow streams with relatively low pulsation which means accurate metering results and a better ratio of blending chemicals, as opposed to over or under feeding with a diaphragm pump. Another major benefit is that the sealing line between the rotor and stator acts like a valve, therefore no flow control valve is needed. Additionally, the compression fit between the rotor and stator prevents siphoning and back flow, a concern in water treatment. This results in tighter control, less residual byproduct, and less chemical usage over time. The PCP design was more compact, with lower maintenance and personnel requirements, and lower operating costs. No pulsation dampeners were needed. Other benefits included low shear rates, run-dry and overpressure protection, and no vapor lock. The PCPs also had components made of specialized materials just for chemical processing that will resist wear and hold up in caustic environments.
But there was still the issue of proper certification in finding a progressive cavity pump technology that worked well for their water treatment innovation. Despite chemical feeders not being required to be NSF certified, many of FTT’s potential water treatment innovation end users refused to include in their facility a system that was not entirely composed of NSF certified products. The general consensus was that if a treatment chemical is generated on site, no equipment used in the generation process could be in contact with a chemical to be applied to drinking water unless the equipment has been tested and certified as meeting the specifications of NSF/ANSI Standard 61. The reasoning is that if the equipment that came in contact with the water needed to be NSF/ANSI 61 Standard certified why wouldn’t there be the same expectations of the equipment that handled the chemicals (which also require NSF certification) that are injected into the water? This was a matter of public safety, environmental safety, and liability that was basically up to the end user.
At FTT’s request, one progressive cavity pump manufacturer, SEEPEX Inc. in Enon, OH answered the need for NSF/ANSI 61 Standard certified progressive cavity metering pumps when previously there had been no other certified progressive cavity pump options. The whole process of certification took nearly 4 years. In order for the progressive cavity metering pumps to become certified, physical audits of the manufacturing facility took place and will continue on a yearly basis ensuring verification of proper labeling and record keeping, quality assurance, and sample collecting for subsequent testing. Certification also required pump and component material formulation and ingredient disclosure. Pump part suppliers were also investigated. Testing of the pumps with the actual chemicals used in treatment processes as well as testing on the actual pumped materials for toxicity, leaching and contamination was required. Alig explains why the certification of the chemical metering PCPs FTT’s water treatment innovation utilized is important, “Ferrate is a treatment chemical generated onsite at the point of use by our water treatment innovation. Everything in our water treatment innovation that is touched by product that goes into the water that someone drinks must be covered with NSF certification to ensure we are not adding anything toxic. If we used a non-certified pump, we are taking a risk that could potentially cause our system to exceed NSF certification specifications of the end product. FTT uses a PCP as a chemical mixing device within our water treatment innovation because it does not exacerbate the formation of foam during the chemical reaction which synthesizes ferrate. We use the dosing PCPs to deliver ferrate to its point of use primarily because of its low maintenance when the wetted components of the pump are exposed to ferrate over time. ”