Water Conditioning & Purification Magazine

Solar-powered treatment system

Wednesday, April 15th, 2020

Puronics Water Systems, Inc. introduces its line of residential solar-powered systems. The new power option allows homeowners to choose a greener method for water treatment and not worry about power outages. The solar-powered feature is available on any unit using an iGen® control valve, including Bacteriostatic and Chlorostatic® water softener and filter systems. The solar power is stored in a rechargeable and replaceable battery pack, and the solar panel can be mounted up to 18 feet (5.4 meters) from the unit.
(844) 787-6642

Swingbolt vessels

Wednesday, April 15th, 2020

Delta Pure Filtration’s SBV Series multi-round swingbolt vessels are economical solutions for industrial liquid filtration applications. All vessels come with welded support/mounting legs. Heavy-duty, self-centering swingbolts with single O-ring seals provide secure cartridge access. Sizes are available that hold from four to 102 cartridges in standard 10-, 20-, 30- and 40-inch (25.4-, 50.8-, 76.2- and 101.6-cm) lengths. Flow capacities are determined by type of cartridge utilized and process conditions. Vessels are designed and fabricated in accordance with ASME vessel code (U or UM Stamp). With all 304 or 316 stainless steel construction and various O-ring materials available, the SBV Series vessels are compatible with a wide range of fluids. The type of cartridges that can be used include: wound, melt blown, pleated, carbon, resin-bonded, stainless steel and others. In addition, universal mounting allows for installation of DOE, 222/Fin and 222/Cap cartridge configurations. Pressure gauges and transmitters are available with other accessories. Duplex and packaged systems are also available.

Solenoid valves

Wednesday, April 15th, 2020

Emerson introduces expanded options available on its ASCO lead-free, brass solenoid valve line to enable original equipment manufacturers (OEM) and contractors to comply with US Safe Drinking Water Act (SDWA), Section 1417. Series 210 model will now be available with both normally open and normally closed constructions. An optional Next Generation electronically enhanced coil will offer customers lower power consumption and voltage-ranging options for both AC and DC constructions. It also boosts the pressure ratings on DC constructions to match AC pressure ratings. In addition, 1.25-, 1.5- and 2-inch (31.7-, 38.1- and 50.8-mm) pipe sizes have been added. The lead-free brass versions of the Series 262 and 263 models will be available with the Next Generation electronically enhanced solenoid coil.

Multi-diaphragm metering pump

Wednesday, April 15th, 2020

Blue-White Industries’ Chem-Pro® CD3 multi-diaphragm metering pump is designed as a solution for pumping gas-forming chemicals, such as peracetic acid and sodium hypochlorite. The CD3 Dual Diaphragm Hyperlink Drive technology pumps chemicals continuously, is self-priming and will not vapor-lock. The patented, ultra-durable diaphragm design will last the life of the pump, which makes it highly reliable and requires zero maintenance. The energy-efficient, brushless DC variable-speed motor helps achieve a large turn-down ratio for extreme accuracy. With a flow range of 0.05 to 53 gph (0.2 to 200 L/h), leak detection, simple installation and setup, and fittings for multiple configuration included, this pump is just what is needed to precisely inject chemicals into a system. Units are CE, ETL and NEMA 4X. Blue-White is an ISO 9001:2015-compliant manufacturer.

Experts Weigh in on Waterborne Coronavirus Transmission

Wednesday, April 15th, 2020

By Kelly A. Reynolds, MSPH, PhD

At the time of this writing, a global effort in social distancing is underway to minimize the spread of SARS-CoV-19 (the virus) and COVID-19 (the disease). Restaurants, bars and other businesses where people congregate are encouraged or mandated to close, while only essential services remain open. With water being a foundational element of good health and nutrition, water treatment and purification should be considered as essential services and remain in operation. Therefore, protection of water treatment professionals must be considered relative to the potential spread of highly infectious viruses via the waterborne route.

Expert insights
Recently the Water Research Foundation (WRF) assembled a panel of experts to discuss the potential for waterborne transmission of coronaviruses. The panel included representatives from the water and wastewater treatment industries, the Centers for Disease Control and Prevention (CDC) and academia. The webcast, available at the WRF website, focused on the latest research on CoV-19 and was attended by over 4,000 participants from 30 countries.1

Highlights from the March session included discussions on the potential spread of CoV-19 via the fecal-oral route, opening up the possibility for transmission routes to include water, wastewater and food. While person-to-person contact appears to be the primary route of transmission, more research is needed on the potential for other routes to be involved. Coronaviruses are known to be shed in stools of infected individuals in high concentrations.

Questions such as the survival times and disinfection efficacy of standard water and wastewater treatment works are also being considered. Speakers pointed participants to an updated guidance from the World Health Organization (WHO), specifically targeting water and sanitation practitioners and providers.2 WRF also announced a follow-up communication planned on April 16 from 3:30-5:00 p.m. EDT.

COVID-19 origins
COVID-19 originally emerged from Wuhan, China, linked to large seafood and live-animal markets. On January 21, the first case was identified in the US and was determined to be exported from China following recent travel to the region. Since then, the infection has been identified as a global pandemic and cases have been reported in all 50 US states.
Scientists are scrambling to characterize important traits of the virus that may lead to mitigation of its spread.

Coronaviruses are not new. In fact, CoV-19 is the seventh known human strain. We are, however, still evaluating if this newly mutated strain has the same characteristics as other coronaviruses or the more extensively studied influenza viruses. While COVID-19 exhibits some similarity to the flu, there are also critical differences, in particular, the presence of CoV-19 viruses in the feces of some infected individuals.3,4 Fecal shedding has been observed with other coronavirus illnesses, such as SARS and MERS, but the CoV-19 virus does not appear to be as deadly as its genetic relatives.

We know that the CoV-19 can be transmitted from aerosols and also from direct contact with mucus membranes of the mouth, nose or eyes. Symptoms include fever, cough and shortness of breath and the estimated incubation time may range from two to 14 days. Infected individuals may exhibit no symptoms at all or the illness may range from mild to severe and even deadly. Deaths are usually due to advanced pneumonia and respiratory or multi-system organ failure.

The immunocompromised and elderly are most at risk for more severe adverse outcomes.

Water management options
Despite communications from multiple sectors, including government officials, health agencies and media outlets, consumers flocked to grocery stores to stock up on bottled water, citing fear about the safety of drinking water supplies. To date, data indicate that the municipal drinking-water supply is safe and that standard treatment protocols, such as filtration and disinfection, are effective against the coronavirus. Coronavirus is known to be more sensitive to disinfectants than other waterborne microbes, including our water quality indicator monitoring standard, E. coli. This includes common disinfectants such as chlorine, UVC light, chlorine dioxide, paracetic and peroxyacetic acids and quaternary ammonium compounds.

While there is a chance that CoV-19 can persist for long periods of time (perhaps hours to days or longer) in water, wastewater and septic tank effluent, properly functioning systems are considered low-risk scenarios. CoV-19 has not been detected in drinking water or treated wastewaters. As with any waterborne pathogen, however, maintenance of proper treatment levels, including chlorine residuals, is important to ensure water safety. Free chlorine dosed to achieve residuals of 0.2 to 0.5 mg/L have been found to readily inactivate other coronaviruses and are likely to be effective against the current pandemic strain.

Given that outbreaks from other fecal pathogens have occurred due to lack of proper drinking or wastewater treatment, POU devices offer additional assurances to consumers that effective treatments are maintained to reduce exposures. For more information on community mitigation practices, the CDC provides a guidance on standard infection control practices targeting hand hygiene, surface disinfection and wastewater, drinking water and recreational water treatment.5

Worker safety
Although properly treated water sources are expected to be low risk, worker exposures to untreated waste waters or filters with potentially concentrated hazards may be a valid concern. Contaminated wastewater that is not properly collected and treated has been associated with a number of drinking-water outbreaks in the US. Protective measures and effective practices are in place for wastewater treatment and worker protection, and should be diligently adhered to.
There is no evidence that water and wastewater treatment and service workers need additional protection beyond current practices; however, now is a good time to provide a refresher and instill renewed compliance with current recommendations. CDC and OSHA guidelines are available for workers handling hazardous, infectious wastes and have been updated with coronavirus specific information.6

Basic hygiene practices for workers include7:
• Wash hands with soap and water immediately after handling human waste or sewage.
• Avoid touching face, mouth, eyes, nose or open sores and cuts while handling human waste or sewage.
• After handling human waste or sewage, wash your hands with soap and water before eating or drinking.
• After handling human waste or sewage, wash your hands with soap and water before and after using the toilet.
• Before eating, removed soiled work clothes and eat in designated areas away from human waste and sewage-handling activities.
• Do not smoke or chew tobacco or gum while handling human waste or sewage.
• Keep open sores, cuts and wounds covered with clean, dry bandages.
• Gently flush eyes with safe water if human waste or sewage contacts eyes.
• Use waterproof gloves to prevent cuts and contact with human waste or sewage.
• Wear rubber boots at the worksite and during transport of human waste or sewage.
• Remove rubber boots and work clothes before leaving worksite.
• Clean contaminated work clothing daily with 0.05-percent chlorine solution (one part household bleach to 100 parts water).

Preparedness over fearfulness
Participants from the WRF webcast urged individuals and communities to “replace fear with preparedness,” recognizing that panic and fear may cause unintended adverse health consequences in the future. As individuals we can support common prevention measures (such as to avoid touching areas of your face with unwashed hands), practice social distancing (some studies are suggesting up to 12 feet) and stay home when ill.

The coronavirus pandemic reveals a level of uncertainty related to public-health response that has never been seen before. Details are changing daily, if not hourly. We are being inundated with information and in some cases, misinformation. The CDC website is frequently updated with information from new research and monitoring information and is a primary source for the most current information on COVID-19 (www.cdc.gov/COVID19).

(1) Coronavirus Research Update. The Water Research Foundation. https://www.waterrf.org/event/coronavirus-research-update. Accessed March 21, 2020.
(2) Water, sanitation, hygiene and waste management for COVID-19. https://www.who.int/publications-detail/water-sanitation-hygiene-and-waste-management-for-covid-19. Accessed March 21, 2020.
(3) Yeo C, Kaushal S, Yeo D. Enteric involvement of coronaviruses: is faecal–oral transmission of SARS-CoV-2 possible? Lancet Gastroenterol Hepatol. 2020;5(4):335-337. doi:10.1016/S2468-1253(20)30048-0
(4) Zhang W, Du RH, Li B, et al. Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes. Emerg Microbes Infect. 2020;9(1):386-389. doi:10.1080/22221751.2020.1729071
(5) Municipal Water and COVID-19. https://www.cdc.gov/coronavirus/2019-ncov/php/water.html. Accessed March 21, 2020.
(6) Safety and Health Topics | COVID-19–Control and Prevention. Occupational Safety and Health Administration. https://www.osha.gov/SLTC/covid-19/controlprevention.html#solidwaste. Accessed March 21, 2020.
(7) Guidance for Reducing Health Risks to Workers Handling Human Waste or Sewage | Global Water, Sanitation and Hygiene | Healthy Water. CDC. https://www.cdc.gov/healthywater/global/sanitation/workers_handlingwaste.html. Accessed March 21, 2020.

About the author
Dr. Kelly A. Reynolds is a University of Arizona Professor at the College of Public Health; Chair of Community, Environment and Policy; Program Director of Environmental Health Sciences and Director of Environment, Exposure Science and Risk Assessment Center (ESRAC). She holds a Master of Science Degree in public health (MSPH) from the University of South Florida and a doctorate in microbiology from the University of Arizona. Reynolds is WC&P’s Public Health Editor and a former member of the Technical Review Committee. She can be reached via email at reynolds@u.arizona.edu

RO Systems and Lead Reduction

Wednesday, April 15th, 2020

By Rick Andrew

In January, this column reported on an update to the requirements in NSF/ANSI 53 for the lead reduction claim. Essentially, the Joint Committee on Drinking Water Treatment Units revised the pass/fail criteria for lead reduction from 10 μg/L to five μg/L in the effluent (filtered) water. This change was precipitated by regulatory developments regarding lead in drinking water. In March 2019, Health Canada lowered the national regulatory maximum allowable concentration of lead in drinking water from 10 ppb to five ppb.

The European Union has also proposed a revision to its Drinking Water Directive to lower lead concentrations to five ppb. The World Health Organization and other public health organizations have concluded there is no safe level of lead and that even low concentrations can cause adverse health effects, especially for infants and children. Several states are seeking to reduce regulatory levels for lead in drinking water to five μg/L.

Revisions to NSF/ANSI 58
Basically, the same change made to NSF/ANSI 53 has also been made to NSF/ANSI 58. The Joint Committee on Drinking Water Treatment Units revised the pass/fail criteria for lead reduction in NSF/ANSI 58 from 10 μg/L to five μg/L in the effluent (RO) water.

The influent challenge (raw water) concentration of lead remains at 150 μg/L, which means that under the new standard a higher treatment efficiency for lead is required (see Figure 1). Aside from the change in the requirement for lead reduction, the test protocol remains unchanged. This protocol continues to be a seven-day test of two test units with any pre- and post-filters removed or bypassed such that the efficiency of the RO membrane is being evaluated.

The test units are operated under a variety of conditions over the seven days, designed to evaluate real-world, end-use scenarios, including a two-day stagnation period in which no product water is withdrawn from the test units. There are 13 sample points during the test in which a sample of the influent challenge and a sample of the effluent water from each test unit is collected and analyzed for lead concentration. The average effluent sample lead concentration, as well as 90 percent of the individual effluent water samples, must meet the requirement of a maximum of five μg/L lead.

Considerations regarding the change
As this change was being proposed and evaluated by the joint committee, the impacts of the change were being evaluated. Test results were reviewed to determine whether previously tested RO systems had reduced the lead challenge to the proposed new level of five μg/L or lower. This review determined that most of the previously tested RO systems did indeed meet the proposed new criteria for lead reduction, making the impact of such a change a relatively minor one. This review of data and conclusion of minor impact on the industry provided reassurance to the joint committee that making this change would be beneficial in terms of public health and not disruptive for RO system manufacturers.

Cooperation among stakeholders
The NSF Joint Committee on Drinking Water Treatment Units is comprised of 28 voting members and 80 observers who offer input and expertise during the standard development process. Its activities are facilitated by NSF’s standards development group. The joint committee follows the American National Standards Institute (ANSI) process, which is designed to ensure openness, balance, consensus and due process for all stakeholders. These stakeholders represent the interests of consumers, water industry manufacturers and state and federal health and environmental agencies in the US and Canada. They come together through the ANSI consensus process to cooperate, provide expertise and work in the interest of protection of public health, while taking into account technological and manufacturing capabilities. Their cooperation is critical to the success of the standards development process.

The revised standard was also ratified by NSF’s Council of Public Health Consultants, which includes representatives from the US EPA, Health Canada and the US Centers for Disease Control and Prevention (CDC). This ratification is a last step for all standards developed by the joint committee to provide ultimate assurance that the standard is protective of public health. The result of this cooperation, in this particular case, is a standard which is more protective of public health, while causing minimal disruption for the manufacturers producing RO systems that conform to the standard.

About the author
Rick Andrew is NSF’s Director of Global Business Development–Water Systems. Previously, he served as General Manager of NSF’s Drinking Water Treatment Units (POU/POE), ERS (Protocols) and Biosafety Cabinetry Programs. Andrew has a Bachelor’s Degree in chemistry and an MBA from the University of Michigan. He can be reached at (800) NSF-MARK or email: Andrew@nsf.org

‘By Far the Best Years of My Life’

Wednesday, April 15th, 2020

By Donna Kreutz

The Rio Grande Valley at the southern tip of Texas is an ideal location for a thriving water treatment business. “We’re at the end of the line of the Rio Grande River; the municipal water is high in TDS and sediment relative to many areas of the United States. This is a very good market,” said Tyler Stenseng, General Manager and President of Culligan Water of the Rio Grande Valley. “Very few individuals in our market drink tap water because of the high TDS content and chloramines/chlorine.”

“Our primary water source is from surface-water reservoirs fed by the Rio Grande River. The water is relatively brackish, with high TDS and a natural metallic taste. That combined with chloramines and chlorine does not lend itself to tasting good out of the tap. Even carbon filters do not do enough to improve the taste. You really need to use an RO system, buy bottled water or buy from vending stations that use RO. Water softeners are very much needed in our market as well, as most municipalities have water hardness levels in excess of 15 gpg, which can be very disruptive to people’s homes or to local business operations.”

This family-owned Culligan business has prospered in the small town of San Benito, (population about 25,000) since the late 1960s. “That’s when Colonel B.E. Hanson, my father’s uncle, bought and consolidated the existing Cameron County Culligan franchises into one franchise at the San Benito location.” Stenseng’s father, Winslow (Win), acquired the company in 1975, when Hanson was ready to retire. It now serves four counties with a population of 1.3 million people.
“Win and his uncle worked out a deal for the Culligan dealership and early in 1975, Win and his new bride, Susan, drove 1,500 miles south from Minnesota to turn the page on their next chapter in business and in life. Back then, south Texas was like the Wild West. There wasn’t a lot going on. My dad didn’t mind—he’s a big outdoorsman, passionate about hunting and fishing, which he can do here year round. My mom had more of a challenge, missing family and being so far away from their Midwest roots.”

Young Tyler worked in the family business every summer through high school and college. “I did a wide variety of office work along with salt and bottled water delivery, plant labor and assisting with service and installation calls when needed,” he said. “Not long after graduating from St. Olaf College in 2003, I came home to work in the business and go back to school at a local University of Texas campus to get my MBA. During school, I mainly helped with the finance, accounting and human resources functions of the business.”

But the son wasn’t ready to jump into the water business full-time. “When I finished my master’s program, I felt the need to challenge myself and try working elsewhere, since basically the only work experience that I had was in the family Culligan business.” Through networking, he was able to get hired by a property casualty insurance brokerage in Des Moines, Iowa as a financial analyst working with clients of captive insurance companies. “It was a rewarding position. I developed many new skills and got to travel around the Caribbean and Canada. But after about three years in the position, I began to get that itch that my dad had so many years earlier: to be my own boss and go back into the Culligan business,” he said.

“When I came on board again, we had a very minimal web presence and a good amount of redundancies in our operation. I have been working with our team to refine our digital presence, eliminate redundancies and waste in our operations, and use technology to help us perform more efficiently and effectively. I’ve now been working here going on 10 years and these have been (by far) the best years of my life. It has been a blessing to work alongside my parents and to learn from my father. The business is co-owned by me and my father. My mother is involved in several finance functions of our business, while my wife, Krystal, helps us with our digital and print marketing.”

No doubt the water treatment business is deep in his blood. “It’s part of who I am now. During this time, I met my wife. We now have a four-year-old daughter and a two-year-old son that hopefully (someday) will want to be involved in the business. That’s a long way away but I hope to get them involved in little things—projects they can do when they get a bit older with office tasks—and see where their interest is.”

Over the years, this Culligan company has kept its familial character with employees who stay for decades. “We have four 30+ year employees, seven 25+ year employees, a couple of 20- to 25-year employees and about six 10+ year employees. We do have relatives: a brother and sister, even a husband and wife. My parents created that familial culture within our business, have offered competitive pay and benefits, and have always aimed to treat our employees with respect. I am trying my best now to retain our familial culture, while encouraging and challenging everyone to keep improving their performance and help the company grow,” Stenseng said. “It can be a challenge to treat your employees with compassion after they make big mistakes that cost the company money or open the company up to excess liability but we try to be as fair as possible when determining consequences.”

One pillar of that long-term employee retention is a commitment to training. “I’m a Class III Water Treatment Specialist in Texas and a WQA Master Water Specialist. I am a firm believer in continuing education and challenging oneself to attain the highest certifications possible within your field. All of our service and installation technicians have gone through our in-house training program and are licensed by the Texas Commission on Environmental Quality as water treatment specialists of varying levels (I, II & III). We are proud to have, by far, the highest number of Texas-licensed water treatment specialists in the Rio Grande Valley and firmly believe in the value of licensing and education for all of our staff.

We also have sent many of our service and installation technicians to Culligan International equipment training schools in Illinois. We have one employee who is an IBWA-certified plant operator and is FSPCA-certified to operate our bottled water plant. We try to replicate situations in our shop when possible so we have hands-on training, working on equipment right here.

Environmentally Friendly Water Reuse for Industrial Water Treatment Applications

Wednesday, April 15th, 2020

By Lior Eshed

Water scarcity and population growth create increasing pressure on natural water sources and require the development of new, sustainable water sources. As technologies gradually improve, reusing effluent from municipal wastewater plants is becoming more popular as an alternative renewable source and wastewater reuse is proving to be an effective sustainable method for ensuring a drought-proof, safe, reliable, locally controlled water supply.

Aerial view of a sewage treatment plant

The conventional water reuse process (and more so the RO part of it) hasn’t changed much over the years. It normally includes two to three stages operating at continuous and fixed hydraulic conditions and is accompanied by continuous chloramine dosing to protect membranes from biofouling. Chloramine should be carefully dosed and monitored in order to avoid overdose, because if the dosage values are too high it may end up as free chlorine, a stronger oxidizing agent than chloramine that can oxidize RO membrane surfaces very quickly. In addition, chloramine dosage is associated with the production of DBPs such as N-Nitrosodimethylamine (NDMA), trihalomethane (THM) and haloacetic acids (HAA), all of which are organic contaminants. NDMA is even suspected as carcinogenic and is therefore limited to a value as low as 10 ng/L. Another drawback of chloramine usage is its negative impact on the UV Transmittance (UVT) value of the RO permeate. UVT is a measure of the amount of UV light that passes through a water sample compared to the amount of light that passes through a pure-water sample. In other words, it is a measure of the water’s purity level. Higher UVT value translates to higher energy and chemical demand in the subsequent ultraviolet/advanced oxidation process (UV/AOP) stage. Operation without chloramine results in energy savings of 30-40 percent, as well as savings on the equipment size (CAPEX) and chemical demand (OPEX).
Demonstration facilities, such as one that recently operated in the Pismo Beach Wastewater Treatment Plant (WWTP) in California (as part of Central Coast Blue, a regional recycled water project) have proven that chloramine-free, indirect potable reuse can be both cost effective and highly efficient. The demo facility, which operated from October 2018 until September 2019, leveraged a technology where the water source was the secondary effluent of a municipal wastewater plant. This technology enabled higher recovery and flux without chloramine dosage, while avoiding the formation of DBPs and reduction of permeate UVT value.
The unit operated with an average flux of 16.5 gallons per ft2 of membrane/day (GFD) (28 L/hr/m2), which is 50-percent higher than the standard design of 11 GFD (18-19 LMH). Specific flux was 0.12 GFD/psi, which is about 25-percent higher than most well-operated wastewater reuse facilities, operating at the same recovery, with specific flux of 0.09-0.1 GFD/psi. The unit operated at 86-percent recovery in a single RO stage. No chloramine was dosed, meaning no DBPs (such as NDMA) were formed.
Chloramine-free operation generated permeate with a UVT value of about 100 percent, thereby saving 30-40 percent on capital expenditure (CAPEX) and operational expenditure (OPEX) in the final stage of UV/AOP. The overall cost of water from this process was 14-28 percent lower than a similar standard fully advanced treatment (FAT) water reuse process.

Oil production at sea

Wastewater reuse for industrial applications
The main industrial sectors that are utilizing wastewater reuse are power plants, food and beverage industries, chemical manufacturing, hydraulic fracking, oil and gas, and petrochemicals. Industrial cooling towers have long been seen as an ideal repository for wastewater, because of the large volumes of water necessary for the evaporative cooling process.
What are the main factors driving the need for better and more advanced industrial water reuse technologies? In most cases, these are water scarcity and the ability to reduce costs by maximizing water recovery, as well as increased awareness of corporate social responsibility (CSR). Some industries, however, are still hesitant to adopt reuse solutions on a wider scale. Industrial users typically think of water management issues at their facility from two perspectives: securing water supplies for operations (including supply and discharge) and complying with quality standards for wastewater discharge.
On the one hand, putting in place a smart reuse management plan helps facilities reduce their freshwater demand and generated wastewater volume, minimize subsequent discharge permits, reduce the costs of freshwater acquisition and effluent treatment and, in some cases, even provide recycling opportunities for certain industrial byproducts. On the flip side, properly managed reuse requires knowledge, financial investment and, understandably, modification of current operations for both direct and indirect potable reuse applications. Weighing the pros against the cons, implementing a reuse management plan often proves to be the most sustainable, resource-efficient, cost-effective and environmentally conscious alternative.
Evolving regulation supports more rapid reuse market growth and encouragement at a legislative level and is also a key factor contributing to market readiness. Therefore, despite minimal push-back, all predictions indicate a much broader adoption of water-reuse management plans in industrial facilities across the globe.

The Dukovany nuclear power plant in the Czech Republic

Water reuse in the power sector
Electricity utilities are challenged by a competitive use of water in water-scarce regions and therefore need to rely on alternative water sources. Water-use applications in electricity utilities include cooling tower make-up, boiler feed, sanitation and irrigation of landscape. The day-to-day operation of a thermoelectric power plant, for example, is especially water-intensive and requires a large quantity of freshwater to sustain its ongoing activities.
To address this pressing need for water in such large-scale quantities without exhausting freshwater supplies or competing with municipalities over local water resources, reused municipal wastewater can offer a feasible alternative water supply for the power sector. Degraded or non-traditional water supplies are constantly being considered by the power sector to offset water consumption. Although reclaimed wastewater appears an obvious choice due to geographic accessibility and unlimited availability, only 60 of 5,000 power plants across 16 states in the US currently use municipal reclaimed water.
One of these rare examples for a reuse-centric plant is Palo Verde Generating Station in Arizona, the largest power generator in the US with a total output of 4,030 net MW, which meets the electricity needs of approximately four million people around the clock (source: WateReuse, https://watereuse.org/wp-content/uploads/2015/10/S3B2_WRA-FLagstaff-Industrial-Water-Reuse-2015hd.pdf)). Because of its desert location, Palo Verde is the only nuclear power facility that uses 100-percent reclaimed water for cooling. The facility is a 409-K-m3/day tertiary treatment plant that reclaims treated secondary effluent from local valley cities and, unlike other nuclear plants, it maintains zero-discharge, meaning no wastewater is released to rivers, streams or oceans.

Modern urban wastewater treatment plant

The Koyambedu case study
The Chennai area has very challenging water circumstances, due to heavy industrial activity in the area and highly polluted water sources in the city’s vicinity. To tackle this issue, a major industry player has recently completed the erection phase of the tertiary treatment reverse osmosis (TTRO) plant for Chennai Metropolitan Water Supply & Sewage Board (CMWSSB) at the facility’s location in Koyembedu, City of Chennai, province of Tamil Nadu, India. The TTRO plant, which includes a capacity of 45K m3/day, was initially executed in 2018, in order to produce non-potable-use water (NPU) for industrial use. The NPU product helps to relieve some of the extensive water demand generated by the industrial activity in the area and allows a larger portion of the local potable water sources to be allocated for municipal use.
CMWSSB was in need of a partner to design, build and operate (DBO) the plant at Koyambedu, including supplying and laying of pipeline transmission for conveying product water to various industries situated at Irungattukottai, Sriperumbudur and Oragadam. Leveraging technologies, including gravity sand filters, ultrafiltration (UF) and reuse RO treatment, the plant is equipped to successfully treat the intensely poor quality of the sewage treatment plant effluent. Additionally, the DBO project was a key priority for local authorities seeking to improve the difficult water conditions in the area. It even included a 15-year O&M period, funded by the Jawaharlal Nehru National Urban Renewal Mission (JNNURM), the Government of India (GOI) and the Tamil Nadu Investment Promotion Program (TNIPP).

Images source: Shutterstock

As more regions around the world face increasing water crises, it will be paramount for more local governments and authorities to get involved. The technologies outlined in this article will go far to advance progress for all entities to offset the dire consequences of having done little until crises occur.

About the author
Lior Eshed graduated from Technion Israel Institute of Technology with B.Sc. and M.Sc. Degrees in environmental engineering. He started at IDE Technologies in 2015 as a process engineer focused primarily on advanced reuse technologies R&D. Eshed is in charge of IDE new products development and has several water treatment patents. Previously, he was an R&D manager at Emefcy (now Fluence), a startup that develops membrane-aerated biofilm reactors and microbial fuel cells.

About the company
IDE Technologies specializes in the development, engineering, construction and operation of desalination and industrial water treatment plants. They provide small to large cost-effective desalination solutions and have an especially well-proven track record in large-scale membrane and thermal desalination, including some of the largest plants worldwide. IDE has proven experience in providing plants that deliver reliable, sustainable and economical solutions across industries.

Diagnosing Organic Issues Related to Larger RO Operations

Wednesday, April 15th, 2020

By Matthew Wirth

Reverse osmosis (RO) machines have unique problems and diagnosis is often an educated guess. Sometimes the problems are obvious, but sometimes the problems are multifaceted with more than a singular issue. The key to this is the term educated. Troubleshooting requires understanding how RO works; the pressure system, the membrane elements and hydraulic requirements. With an understanding of how and what ROs do, one can extrapolate from available data the causes of malfunction. In this article, we will look at a general description of an RO system, membrane crossflow and discuss how organics can quickly derail the RO machine’s functionality.

Equipment and diagnostic instrument needs
In addition to the pump and membranes, larger ROs need monitoring equipment. Without flowrate data, TDS monitoring, pressure conditions and pH, it is difficult to figure out the causes of reduced performance and physical failure. The following are things to consider:

The pump
• The pump must produce the pressure required to meet the operating specification of the membrane elements. This is found on the manufacturer’s specifications for a specific membrane element.
— Substituting membranes requiring hydraulics outside the performance curve of the pump will affect performance and cause operational issues. One example is the thread to 8”x 40” elements with 400 ft2 of membrane surface. Prior to 400 ft2, the common ft2 for an eight-inch element was 365 ft2 of membrane. An advantage to the 400s is increased permeate (more product water) or lower flux rate and pressure at the system’s given flow. This means the system does less work to create the needed permeate. This is all good if the machine has the ability to accept the change. Say the RO machine has a VFD (variable frequency drive) and the RPM can be adjusted to slow the motor. If the machine is less sophisticated, the pump may not deliver the flow and pressure required to manage greater flux and still meet the concentrate flows for necessary crossflow. Match the membrane elements with the capability of the RO machine.

• Membranes have crossflow requirements, pressure specifications and feed-water quality specifications (see Image C).
— Working outside the parameters of these operational conditions is not recommended. (Some examples: If you over-flux a membrane element, it can be damaged and produce poor water. Using a water source with chlorine/chloramine levels outside a manufacturer’s recommendations can (and likely will) result in damage to the membrane. Running recoveries too high for the element can result in telescoping the windings and compromise the element [see Image X].)

Image X. Telescoping membrane element

TDS monitors—conductivity monitor
• Knowing the feedwater TDS and the permeate TDS shows the operating performance of the system. Realize that ppm of TDS is often a calculated measurement based on the water conductivity. Many larger ROs use conductivity to monitor water quality. A rule of thumb is to divide the ppm value by 0.64 to convert to a conductivity value approximation.

Pressure gauges
• The pump inlet feed pressure and pump outlet pressures and ΔP (change in pressure) are paramount to the operation of the system.
• The RO high-pressure pump boosts the inlet feed pressure, therefore the high-pressure pump requires a minimum and maximum pressure to operate optimally. One needs to know the feed-line pressure to operate and log the performance of the machine.
— Most larger RO machines have low feed-water pressure safety shut-offs to protect the high-pressure RO pump. Be aware that some machines come back online once the pressure returns and others alarm and/or shut down until they are manually restarted.
• To operate the high-pressure system pump and set the system recovery, one must know the pressure delivered by this pump.
• The ΔP is the difference in pressure between the system pressure and the permeate pressure.
— The ΔP for a single membrane is 12 psi and 50 psi for an array (see Image C).
— Increased ΔP is one of the first indicators of organic fouling and other issues. If the pressures are out of balance, something is likely plugged or there is a compromised interior seal and/or membrane pocket.

Flowrate indicators
• Hydraulic dynamic flowrates are indicators of RO performance.
— Systems without flow indicators are difficult to troubleshoot and operate. The permeate and concentrate flows show the system’s performance. In addition, they are indicators of system flow imbalance. Without knowing these values, diagnosing problems is difficult at best.

RO system design related to crossflow and flux rate
A complete water analysis is the first and most important part of an RO system design. If there are seasonal variations (which are common for surface sources) or varying sources (which are common with municipal supplies), get all the pertinent water quality data. Size to worst-case data to ensure year-round system functionality. Note: The usable source data is the current source data; test results from years past are not usable.

Part of any RO system is appropriate pretreatment. The quality of the water feeding the RO determines if it will function correctly. An RO with a clean, low TDS water source can function more aggressively than with questionable high TDS water. Design the pretreatment to produce the RO feed-water parameters and ensure that it operates uninterrupted during peak use. Check that the source pressure and the ΔP across the pretreatment do not affect the performance of the RO pump. The RO pump needs a specific flow and pressure. The pretreatment system cannot be a choke point that robs water and pressure from the RO pump. It is highly recommended that the source-water feed to the RO is not on a line that loses water pressure when other upstream systems call for water.

The RO system requires a steady pressure and flow. If the pretreatment is chemical and the source water is hard, the application may require tertiary treatment downstream. One example of tertiary treatment is a permeate polisher, which is a water softener designed to work in water that has low conductivity and low pH. Softening permeate is common on large systems fed with hard water. The water hardness and subsequent scaling issue are managed with chemical pretreatment. In many cases with large RO machines, it is not cost effective or practical to soften the water before the RO because of the scale of water use and the size of the equipment.

Carefully read the operational specification for the membrane elements and consider both the flux and crossflow requirements. Consider that a reduced rate of permeate water flow for a given area of membrane element reduces the collection of foulants at the membrane surface. Flux rates (flow per square foot of membrane over time) for surface water supplies should range from eight to 14 GFD (gallons per square foot of membrane area per day) and 14 to 18 GFD for well water.1

RO recovery rate should be conservative. Example: A normal 8”x 40” (8040) membrane element has 365 square feet of membrane rolled around the permeate tube. A flux rate of 10 gallons per day per ft2 equals 3,650 gallons in 24 hours. Many 8040 membrane elements are rated at two to three times that output, but that is a maximum. A conservative percent recovery of the feed water minimizes the concentration of foulants.

Image A. Contaminants moving properly in the crossflow (bulk flow)

In challenging water, maximize the crossflow velocity in the elements. Crossflow creates the tortuous path across the membrane surface to keep foulants up and off the membrane and allow water to pass through to the permeate side of the element. The concentrate percentage flow determines the crossflow: in larger systems, this is 50 to 30 percent of the total feed rate. In addition, a conservative design maximizes the crossflow velocity of the feed and concentrate streams. A higher crossflow velocity reduces the concentration of mineral salts, organics and foulants at the membrane surface by increasing their diffusion back into the crossflow feed stream above and along the membrane surface (see Image A). Inadequate crossflow allows contaminants to settle on top of the membrane surface and block its production (see Image B).

Image B. Contaminants lodged on the surface of the membrane

The membrane element must match the desired recovery rate for the temperature, pump feed pressure, feed-water conductivity and available upstream feed flow and pressure. An RO pump boosts the feed pressure to the desired system needs. If feed pressure and flow drop below the specifications for the pump, either the system will alarm or the pump may be damaged. Example: A low-energy membrane works at a pump feed pressure of 100 psi, but this membrane will not function well in a system with pump feed pressures of 250 psi. In waters with low temperature, consider low-temperature elements. Match the membrane element to the water and the machine.

Osmotic pressure and transmembrane pressure
The water’s conductivity and/or TDS dictate osmotic pressure and thus the transmembrane pressure requirement to make RO water. Osmotic pressure is the pressure required to prevent the flow of water across a semi-permeable membrane separating two solutions having different ionic strengths: the permeate and concentrate. For RO systems, it is this osmotic pressure that has to be overcome in order to produce permeate. The rule of thumb is for every 100 ppm of TDS difference between feed and permeate, one psi of osmotic pressure exists.2

Increasing the water temperature makes it less viscous (thinner), making it easier for the water to pass through the membrane. A 10°F-increase in feed-water temperature will decrease the feed-pump pressure requirement by 15 percent. Be aware that both the conductivity and the temperature of the feed will affect the performance of a membrane element. In reviewing the element specifications, note that there is a change in water condition stated for the performance of a membrane. Example: Average salt rejection after 24 hours operation. Individual flowrate may vary +25% / -15%.2 Testing conditions: 2,000 ppm NaCl solution at 225 psi (1,551 kPa) operating pressure, 77°F (25°C), pH 7.5 and 15% recovery.3

Image D. Biofilm dripping from an eight-inch membrane element

Delta P (ΔP)
There needs to be pressure differential between a permeate side of the membrane element and the feed-water side. It is a pressure differential that creates RO and allows the system to overcome transmembrane pressures and desired permeate flow. Without a ΔP, an RO system would not work. Problems arise when the pressure differential is too high. The published ΔP (maximum pressure drop) for an 8040 membrane (see Image C) is 12 psi and the recommended ΔP for an array is 50 psi.3

Image E. Biofilm on the end cap of an eight-inch membrane housing

Organic (bio) fouling
All RO membranes are subject to organic fouling. Even with careful sanitary care and consideration when loading new membranes, the system may become contaminated and the result is a slimy, smelly organic loading on the membranes and in the array housings. In Image D, there is actually biological material dripping from the end of the membrane element. In Image E, notice the slime buildup on the end cap of the array housing. In both of these cases, the RO machine was experiencing increased pressure differential across the membrane elements. This was the indication that the system was experiencing biological fouling. The correction for this problem is either to replace the membranes after fully sanitizing the system or conducting a clean-in-place (CIP) procedure.

Image F. Dirty CIP high pH solution

There are two parts to CIP for RO systems. One includes a low pH acid cleaning to remove calcification and other mineral deposits. To remove organics from an RO system using CIP, the system is flushed with a high pH solution to clear the organic matter. The order in which the low or high pH is run depends on the baseline issue of concern. If the system is loaded with organics, it becomes difficult for a low pH solution to cut through the biofilm and attack the mineral deposits. If this is the case, perform the high pH CIP first to remove the biofilm and expose the mineral deposits to the low pH acid CIP stage.

There is a saying concerning system cleaning: keep it hot, keep it strong and keep it moving. CIP solutions recirculate through the system at a given rate based on the CIP instructions for the chemical used. There are multiple CIP solutions and instructions for cleaning RO systems and membrane elements. The best practice is to follow the instructions to the letter. In cases of extreme fouling, it may become necessary to dump the CIP solution several times during the process (see image F). Note that some larger production RO systems are not able to receive CIP. If the site wishes to reuse the existing membranes, there are companies that clean elements offsite and this is an option if the installation can be down while the membranes are cleaned. FYI: If membranes go out for cleaning, they have a finite shelf-life. Check with the company that did the cleaning for the recommendations on membrane element storage after the cleaning procedure.
If the system has experienced increased pressure differential across the membranes and/or a housing, it is often due to organics. A quick way to diagnose if there is an organic issue due to biofouling is just safely shut the system down, release all the energy from the system, ensure that all the power is locked out and pull off one of the end caps on the array housing. If there is a distinct putrid odor and/or signs of slime buildup in the walls of the array, the end cap or membrane element, then action is required. RO systems of any kind or size will not function optimally in the presence of biofilm within the system.
Be aware that organic fouling is an issue with RO systems. While it is common, it is often overlooked. Considering the biological control is removed from the water prior to the water seeing the membranes, it is actually not surprising that organics can get a foothold within a system and grow. Presuming the system should not have an organic issue is an incorrect assumption.

Image C, courtesy of Suez Water. All other images, courtesy of Pargreen.


  1. Troubleshooting Your RO, Hydranautics (A Division of Nitto Denko Corp.), Informational Document, January 23, 2001.
  2. Reverse Osmosis Chemistry, Manchester, 2018, Retrieved March 6, 2020. http://reverseosmosischemicals.com/reverse-osmosis-guides/reverse-osmosis-glossary-terms/osmotic-pressure-reverse-osmosis-systems
  3. Suez AG Series Fact Sheet. Retrieved March 6, 2020. http://www.gemembranes.com/ge-osmonics-ag-ro-water-membranes.pdf

About the author
Matthew Wirth is an Industrial Water Specialist with 40 years of experience working with large process systems, including RO, IEx, process filtration and media filtration. He is the General Manager of Water at Pargreen Sales Engineering in Chicago, IL. Wirth received his engineering training at the South Dakota School of Mines and Technology in Rapid City, SD and earned a Bachelor’s Degree from Concordia University in St. Paul, MN. He can be reached via email, mwirth@pargreen.com or phone (630) 628-1330.

About the company
Since 1966, Pargreen, Inc has been supplying advanced filtration solutions to a variety of industries worldwide. Pargreen Process Technologies & Water Technologies Systems provide IEx, separation and filtration for a variety of manufacturing processes. Visit the website for more information: www.pargreen.com


Wednesday, April 15th, 2020

IAPMO’s Hansen promoted, Carrier hired
The International Association of Plumbing and Mechanical Officials (IAPMO) has promoted Dain Hansen to Executive VP of Government Relations, in recognition of his vital work in Washington, DC and across the globe. Since joining The IAPMO Group in 2010, he has overseen an expansion of the association’s influence among government policymakers, both in the US and abroad, including (notably) India, Southeast Asia and the Middle East. Hansen manages IAPMO’s global policy interests before foreign governments, the US Congress, the White House, federal and state regulatory agencies, and state legislatures. He also helps manage International Water, Sanitation and Hygiene Foundation (IWSH), the IAPMO Group’s charitable arm. In this role, Hansen made great strides in developing IWSH into a well-recognized and highly regarded philanthropic entity in the water sector. He has organized and participated in Community Plumbing Challenge projects, bringing clean water and safe sanitation to people who lack them in Nepal, India, South Africa, Indonesia and the Navajo Nation in the US. Hansen will continue his important role with the IWSH team.
IAPMO has hired Jerry Carrier as Senior VP of Uniform Evaluation Services (UES) and the Institute of Building Technology (IBT). He will oversee UES operations and the building products test lab in this newly created position at the IAPMO Group World Headquarters in Ontario, CA. A graduate of the University of Virginia with a Bachelor’s Degree in architecture, Carrier joined Glen-Gery Corp. in 1989 as a design advisor. He was promoted to Director of Technical Services in 2001 and Director of Research and Development in 2008. He brings more than 15 years’ experience in strategic and technical/business leadership, in addition to his 30-plus years of providing design, detailing and installation advice to owners, architects, engineers, contractors and masons to ensure code compliance, durability and performance.

Congressional members honored by WQA
US Senator Thom Tillis (R-NC) has been named a WQA Congressional Champion Award honoree for co-sponsoring per- and polyfluoroalkyl substance (PFAS) legislation, including a new law directing a nationwide survey of PFAS contamination. The award was presented during the annual WQA Fly-In. Tillis has been one of the main Republican supporters of PFAS legislation over the past two years, co-sponsoring several WQA-endorsed bills. One of those, the PFAS Detection Act, which became law last year, directs the US Geological Survey to conduct a nationwide survey of PFAS contamination in water sources, including private wells. Tillis also has signed onto a letter calling on the US EPA to set a maximum contaminant level for both PFOA and PFOS, two of the ‘forever’ chemicals known collectively as PFAS. US Representative Paul Tonko (D-NY) was honored with the WQA Congressional Champion Award for his support of water-related legislation, particularly legislation to combat per- and polyfluoroalkyl substance (PFAS) contamination. As Chairman of the House Energy and Commerce Subcommittee on Environment and Climate Change, Tonko has led committee debates and amendments for numerous PFAS bills, including several that WQA has endorsed. He has co-sponsored several bills to combat PFAS contamination, including one that would require the US EPA to publish a maximum contaminant level for total PFAS.

Bayley appointed at Pure Water Group
Phil Bayley joined the Pure Water Group in March as Senior Sales Engineer. He will be part of the EDI support team. Bayley brings more than a decade of direct experience in EDI technologies. He can be contacted via email, p.bayley@purewatergroup.com or EDIsupport@purewatergroup.com.

Long-time Culligan Man mourned
In February, lifetime Culligan Man Charles ‘Chuck’ Hurst died in Reno, NV. An active California water treatment dealer, he graduated from Paso Robles High, attended Fresno State University and earned his degree in industrial technology from Cal Poly, San Luis Obispo. In 1972, Hurst assumed a management position in the family-owned Culligan business founded by his father, Fred. One of Hurst’s immediate successes was the establishment of a bottled-water division to complement their soft-water services. In 1985, he and his wife (Jeri) took over ownership of the business (which consisted of two dealerships: Santa Maria and Paso Robles) then in 2012, sold the business to his son Justin and his wife Becky. Hurst is fondly remembered as an integral part of the Culligan organization, serving on the Dealer Advisory Committee as one of the original founders of CDANA (Culligan Dealers Association of North America), as well as a vociferous opponent to California SB1006. He was also a founding member of the California Bottled Water Association. He is survived by his wife; his children, Justin (Becky) Hurst and Nick Kioski (Emalee); sister Vicky Jeff-coach and five grandchildren. The family requests donations to the Lewy Body Dementia Association or the Michael J Fox Foundation, in lieu of flowers.

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