Water and the Plight of Women in Ethiopia


Renowned Ethiopian artist Aida Muluneh has taken a series of striking images to depict the harsh life of many women in rural areas of Ethiopia–especially their daily efforts to obtain clean water for their families.

Aida Muluneh’s  Water Life series, which was commissioned by the charity WaterAid, is on display at London’s Somerset House beginning in late September of 2019. Muluneh shot some of the photos in a studio while others were staged in the extreme landscape of one of the hottest and driest places on earth, Ethiopia’s northern Afar region.

“We cannot refute that it is mainly women who bear responsibility for collecting water, a burden that has great consequences for our future and the development of our nation,” Muluneh said. The jerry cans are tied to a rope to reflect the shackles of carrying water.

Almost 40% of Ethiopians do not have clean water close to their homes, compared to the global average of 10%, according to Water Aid.



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More symbolically complex, this shot focuses on girls and how the lack of water and bathrooms in schools affects their education. “The fact that most girls don’t attend school when they are menstruating is a major hindrance on the progress of women in our society,” Muluneh says.

In this piece, the moon represents a woman’s monthly cycle The red wings illustrate her freedom and strength but also the fact that she cannot achieve her full potential because she is shackled by the natural occurrence of menstruation.

“In a sense, it is like a caged bird that cannot fly but is grounded. The striped floor is symbolic of the road to destiny in which our path to success is in front of us but we must take the step forward,” Muluneh says.

More images from the Water Life Series can be seen on the BBC website.





The much celebrated and much hated Waters of the United States rule, aka WOTUS, appears to be dead. The Trump EPA along with the Army Corps of Engineers have, after a prolonged effort, finally killed it. The 2015 addition to the Clean Water Act was controversial from its inception because it lies on the sensitive line between individual rights and common good.  The ownership of water is really the same issue as the apparently unsolvable questions like gun ownership, abortion, and vaccination. It asks the question does water belong to everyone or to the individual who owns the land where it is found at the moment. In other words, can the farmer whose drainage stream is pictured above dump his leftover fertilizer or the refuse from his hog lot into the tiny stream on his property without concern for where it will eventually end up? Repeal of the Waters of the United States rule says essentially that no one can tell him what he can or can’t put into “his own stream.”



The Dr. Seuss classic story of McElligot’s Pool should have laid to rest any question about the connectedness of all water. Apparently not. 

Our feeling is that we’re all in this together. We need strict rules on water protection, even when these rules are an inconvenience to home builders, factory managers, and farmers. The Nixon-Era Clean Water Act has brought us a long way since the Cuyahoga River caught fire. It’s sad to see years of environmental progress reversed for the sake of political expediency.

Lead Pipes That Tainted Newark’s Water Are Found Across US

A drinking water crisis in New Jersey is bringing new attention to an old problem: Millions of homes across the U.S. get their water through lead pipes.

by David Porter and Mike Catalini

Pure Water Gazette Editor’s Note: This AP article is the best we’ve seen on the massive lead pipe problem that American water systems are facing. We’ve added a couple of pictures. We ask you to read this article carefully. It is sobering.

NEWARK, N.J. (AP) — A drinking water crisis in New Jersey’s biggest city is bringing new attention to an old problem: Millions of homes across the U.S. get their water through pipes made of toxic lead, which can leach out and poison children if the water isn’t treated with the right mix of chemicals.

Replacing those lead pipes is a daunting task for cities and public water systems because of the expense involved — and the difficulty of even finding out where all those pipes are. Only a handful of states have put together an inventory of the buried pipes, which connect homes to water mains and are often on private property.leadwaterpipe

Do you feel good about drinking water that came to your home through this pipe?

But after drinking water emergencies in Washington, D.C.; Flint, Michigan; and now Newark, some experts are calling again for a rethinking of the theory that treating the pipes with anti-corrosive agents is enough to keep the public out of danger. Instead, the lead lines should be replaced, they say.

“It’s hard to come up with an argument against it,” Manny Teodoro, a public policy researcher at Texas A&M, told New Jersey lawmakers this week. “Look, lead service line replacement is expensive, but it’s also removing poison from the bodies of ourselves and our children. It’s difficult to think of many things that are more important.”

Done correctly, chemical treatment should be enough to keep water in line with federal regulations, according to Peg Gallos, executive director of the Association of Environmental Authorities, a group representing water utilities. But in cases where the chemicals fail, pipe replacement becomes an option, she said.

People in about 15,000 households in Newark were told to drink only bottled water last month after the Environmental Protection Agency warned that the city’s efforts to control lead contamination weren’t working. Since then, residents in the largely poor, mostly black and Hispanic city have had to line up in summer heat for cases of free water distributed by government agencies.

The crisis has unfolded over several years, with city officials insisting until recently that everything was under control.

Numerous city schools switched to bottled water because of lead contamination in 2016. Tests in 2017 found that 1 in 10 Newark homes had nearly twice as much lead in their water as allowed by the federal government. The state Department of Environmental Protection issued a warning to the city and public health advocacy groups complained, but Mayor Ras Baraka defended the safety of the city’s water by sending residents a brochure condemning what he said were “outrageously false” claims about lead contamination.

Later, consultants concluded that the city’s corrosion control treatment for one of its main water supplies wasn’t working. New chemicals were introduced this spring, but it will be months before their effectiveness can be accurately gauged. The city handed out filters beginning last fall, but then the EPA warned that they might not working.

Newark’s water crisis shares some similarities to the ones in Flint and Washington, D.C.

Flint’s lead levels spiked in 2014 after the city switched its water source from Lake Huron, which was being treated with the anti-corrosive orthophosphate, to the Flint River, which was not treated. Washington’s high levels between 2000 and 2003 resulted from the city’s switching anti-corrosion chemicals from chlorine to chloramine.


Lead Pipe from Newark

Experts estimate there could be as many as 10 million lead service lines nationwide but only five states require inventories or maps of their locations, according to the Association of State Drinking Water Administrators. A handful of other states have set up voluntary reporting.

That leaves dozens of states with incomplete knowledge of where and how much of the toxic plumbing they have.

“The biggest problem we face is we don’t know where these lead pipes are,” said Marc Edwards, an environmental engineering professor at Virginia Tech University. “In Flint, ultimately we had to dig up every single yard to find out what pipe was there because the records were so bad.”

Newark is now racing to try and replace all of its roughly 18,000 lead service lines, with the help of a county-backed, $120 million loan.

While cost is a factor — in Newark, it will cost about $10,000 per home to replace the pipes — so is the diffuse nature of water utilities. Teodoro estimated there are about 50,000 water systems in the U.S., many of them small systems. And in many cases the location of pipes isn’t even written down, Mary-Anna Holden, a commissioner on New Jersey’s Board of Public Utilities, told lawmakers recently.

“I asked the superintendent ‘Where’s the map of the system?’ He’s pointing to his head. Like his grandfather and great-grandfather had started the water system so he knew where every valve was,” Holden said.

The most common source of lead in water comes from pipes, faucets and fixtures, rather than from water sources, according to the Environmental Protection Agency. Congress banned the use of lead in water pipes in 1986, citing lead’s harmful effects on children’s nervous systems. In 1991, federal regulators began requiring water systems to monitor lead levels in drinking water and established a limit of 15 parts per billion.

Since the Flint water crisis, some states have gone farther. Michigan last year lowered its threshold to 12 parts per billion. Experts say no amount of lead is safe for children.

Kim Gaddy, 55, works as an environmental justice advocate for Clean Water Action. She’s a renter in Newark and had her lead service lines replaced by the city shortly before the two positive lead tests led to the city handing out bottled water.

She says she thinks it’s time for state and federal officials to require replacing lead service lines, no matter what the cost might be.

“My message would be let’s protect the health of (residents) and provide them with safe, affordable drinking water from the taps,” Gaddy said.

Lead service lines are a menace to public health. Millions of such pipes still feed Americans’ homes.

A Bloomberg Editorial

Sept. 9, 2019

Once more an American city faces a lead crisis, with thousands of residents unable to drink from their taps. Lines for bottled water have stretched into the hundreds. Politicians are scrambling to overhaul the water system — and fast. This time it’s happening in New Jersey’s largest city, Newark.

Like the fiasco in Flint, Michigan, the Newark lead crisis had its own unique causes, including mismanagement and political infighting. But the two debacles have one crucial thing in common: pipes. Specifically the lead pipes installed decades ago, by the millions all over the country, to connect mains to houses and businesses. Pipes that can shed invisible molecules of metal when water passes through.


These pipes, known as service lines, were made from lead until well into the 1980s (even though lead’s dangers have been known for centuries). When the government banned lead from new pipes in 1986, it did nothing about the hundreds of miles of pipe still underground. At least 6 million such pipes (and likely many more) are still in use, serving households in almost one-third of the country’s water districts.

Lead is a neurotoxin. Its effects on the brain are well-known: learning disabilities, behavioral problems, anxiety and depression. It can also trigger heart, liver and kidney disease. Growing children are especially vulnerable. There is no safe level of exposure.

Right now, the standard practice is to treat water with anti-corrosion chemicals before sending it to households. Sometimes this works, but not always — as Newark shows. The city’s long-established corrosion control practice appears to have stopped working after the city made an unrelated tweak to the water supply. As is often the case, nobody saw it coming. As long as there’s lead in the pipes, the risk remains.

Why not just replace the pipes? That’s what Newark is doing — albeit belatedly — and what more than half a dozen other cities have done. The National Drinking Water Advisory Council recommends this approach. Granted, full replacement is costly and complicated, not least because most service lines are partly privately owned. But success in cities such as Lansing, Michigan, and Madison, Wisconsin, has shown that the legal and financial obstacles are surmountable. The state of Minnesota recently found that every dollar invested in lead-pipe replacement would yield $10 in savings.

Other cities have adopted more modest policies, such as replacing lines to day-care centers or requiring service lines be replaced when properties change hands. Whatever the approach, states can help by requiring home sellers to disclose the existence of lead service lines, for example — much like federal law requires sellers to disclose lead paint. States should also be more aggressive in tracking and publicizing the location of lines, and lay the legal groundwork to help communities fund replacement efforts. The federal government should provide grants to defray some of the cost.

It would be money well spent. Researchers at New York University say lead poisoning costs the U.S. $51 billion annually. And remediation works: Plans to phase out lead have proved to be spectacular public-health successes, though they were met with grumbles at the time.

In ancient times, people drank from lead vessels because they didn’t know any better. There’s no longer any excuse.

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Global Warming: Rising Sea Levels Threaten Egypt’s Alexandria


Flooding is now commonplace in Alexandria, and it continues to get worse.

Alexander the Great established the city more than 2,000 years ago. In that time, it has survived invasions, fires and earthquakes. But, Alexandria now faces severe flooding from rising waters blamed on climate change.

Alexandria is Egypt’s second largest city, with more than 5 million people. It is also an important port and home to about 40 percent of Egypt’s industrial activity. The city is surrounded on three sides by the Mediterranean Sea and sits next to a lake. Officials have built concrete barriers in the sea in an effort to reduce the force of waves. A severe storm in 2015 flooded large parts of the city. At least six people were killed in the flooding, which also caused the collapse of many homes.

In the late 1940s and 50s, Alexandria was a popular place for writers and artists from Egypt and other countries. Today, more than 60 kilometers of waterfront make Alexandria a top summer vacation spot. However, many of the city’s most famous beaches are already showing signs of damage.

The United Nations has warned that worldwide sea levels could rise by 0.98 meters by 2100, with “serious implications for coastal cities, deltas and low-lying states.”

Egypt’s Ministry of Water Resources and Irrigation said the sea level rose by an average of 1.8 millimeters each year until 1993. Over the next 20 years, it rose by 2.1 millimeters a year. Since 2012, however, the rate became 3.2 millimeters each year.

Measurements show that the land on which Alexandria is built is also sinking at about the same rate. This is expected to increase the risk of dangerous flooding.

A 2018 research study predicted that up to 734 square kilometers of the Nile Delta could be under water by 2050. People living in low-lying areas are already experiencing problems.

A 52-year-old resident of the Shatby neighborhood, Abu Randa, said he has repaired his three-story home twice since the 2015 floods. “We know it is risky. We know that the entire area will be underwater, but we have no alternative,” he told The Associated Press.

Sayed Khalil is a 67-year-old fisherman living in the el-Max neighborhood, where hundreds of people were forced to leave their homes after the flooding in 2015. He said homes have flooded with seawater every winter in recent years. “It is hard to imagine that el-Max will be here in a few decades,” Khalil said. “All these houses might vanish. The area you see now will be an underwater museum.”

The government built sea defenses to protect the neighborhood, but people who live there say it has not made a big difference. “Every year the waves are much stronger than the previous year,” said Abdel-Nabi el-Sayad, a 39-year-old fisherman. “We did not see any improvement. They just forced people to leave.”

Some of the city’s archaeological treasures are also threatened. Among them is the citadel of Qaitbay, a fortress built in the Middle Ages on the ruins of the ancient Pharos lighthouse in the central harbor.

Ashour Abdel-Karim is head of Egypt’s General Authority for Shores Protection. He said the citadel is especially at risk. Powerful waves continue to push against the structure’s foundation. Officials were forced to build a long line of concrete sea barriers that can be seen from the downtown waterfront area known as the Corniche.

The Egyptian government has put aside more than $120 million for the barriers and other protective measures along the shore, Abdel-Karim said. He added that without barriers, parts of the Corniche and other buildings near the shore would be damaged. If that happens, he said, repairs could cost nearly $25 billion.

Article Source: VOA Learning English.

How Much PFAS Is A Lot?

Posted September 2nd, 2019



Tiny toxins: Measuring the “Forever Chemicals”

The reporting thresholds for the group of chemicals lumped under the PFAS label are minute.

Writer Martin Wisckol explains that using current California standards:

If PFOA is found in 14 parts per trillion, the water agency must notify the cities served by that well for the first round of testing, recently completed. For PFOS, the trigger is 13 parts per trillion. Those thresholds are dubbed “notification levels.”

For the next round of quarterly testing, the notification levels are being lowered to 5.1 parts per trillion for PFOA and 6.5 for PFOS.

In an Olympic-sized swimming pool, one part per trillion amounts to four grains of sugar.

In 67 trips to the moon, it would equal 1 inch.

If the combined total of PFOA and PFOS in a well is 70 parts per trillion or more — an amount known as the “response level” — the state recommends that the well be taken out of service, and the Environmental Protection Agency recommends that consumers be informed. A new state law kicking in next year will require customer notification.

What’s totally unknown is if the California standard is overly cautious or lax, since no federal standard for the contaminants has been set.

Although the chemicals have been around for decades, regular testing for them is recent.

California only this year began ordering testing for the chemicals, and a state law requiring that customers be notified about the presence of those chemicals won’t kick in until next year.

PFAS have been called “forever chemicals” because they resist breaking down in nature.

“PFAS is the climate change of toxic chemicals,” said Andria Ventura, toxics program manager for the advocacy group Clean Water Action. “They never go away. Virtually all Americans have them in their blood. Babies are born with them. They’re some of the scariest things I’ve worked on.”




Plastics Found in Rainwater

Posted August 24th, 2019

Scientists discover it’s “raining plastic” from metro Denver to high in Rocky Mountain National Park

U.S. Geological Study research in Colorado finds “plastic is everywhere”

by Bruce Finley


Scientists testing rainwater around metro Denver and high in the Front Range mountains found microscopic bits of colored plastic in more than 90% of their samples — adding to growing evidence that plastics have contaminated the planet far more deeply than people can see.

This research led by U.S. Geological Survey research chemist Greg Wetherbee is raising questions about the possible impact on people and ecosystems. It’s unclear, for example, whether metro Denver drinking water treatment plants remove these tiny plastic fibers and shards.

“People might be seeing a lot of plastic in the oceans, on the ground, at the supermarket. But there is more plastic in the environment than meets the eye,” Wetherbee said in an interview Thursday. “Plastic is everywhere. It is in the rain and snow.”

The findings are summarized in a federal research report titled “It Is Raining Plastic” that was published in July after passing a four-stage, peer-review process. It’s based on analysis of 300 rainwater samples collected weekly in 2017 at six urban sites in the Denver-Boulder area and two in the mountains, including a seemingly isolated site in Rocky Mountain National Park.

Lab analysis using microscopes found water from the Colorado collection sites contaminated with blue, red, silver, purple and green fragments from the breakdown of larger pieces of plastic.

There are no limits in place, or standards, for this type of pollution, and federal scientists suggested the “microplastics” come from clothing through laundry drier vents, household materials such as tarps, and packaging that degrades, releasing bits that blow in the wind and wash into water — and presumably are evaporated into the atmosphere.

USGS scientists found more plastic particles in water samples drawn from the urban sites — which followed a line from the National Jewish Hospital in east Denver through downtown to Arvada, the Rocky Flats National Wildlife Refuge, the University of Colorado’s Boulder campus and Boulder Canyon.

But Wetherbee and his team also found frequent plastics contamination in water samples drawn at a mountain site near Nederland and at a relatively isolated Loch Vale site at an elevation of 10,364 feet above sea level beneath towering peaks in Rocky Mountain National Park — a watershed that scientists have monitored for more than 20 years for chemical contamination from wind and rain.

The scientists concluded that plastics contamination of water “is ubiquitous and not just an urban condition,” the report said.

These results fit into recent research by European scientists who detected plastics contamination of water in the Arctic. A Utah State University scientist has been conducting studies focused on pollutants inside U.S. national parks.

Plastics fragments often are so small that they slip through water-cleaning filters and spread into rivers and oceans.

After revelations that many U.S. personal care products including soaps and toothpastes contained plastic “micro-beads” for scouring, Congressional lawmakers in 2015 began trying to prevent companies from making those projects in the United States. A phase-out was to begin in 2017. Several states, including California and New Jersey, passed laws requiring a total phase-out of micro-bead products by 2020. These are but one source of plastics pollution. Oceans around the world contain floating heaps of plastics, and larger pieces splinter over time into tiny bits.

The fragments detected in Colorado water are considerably smaller, scientists said. The consequences for human health and ecosystems are largely un-studied.

“An emerging contaminant issue”

Drinking water impacts are “a good question,” said Denver-based USGS research hydrologist William Battaglin, founder of the Consortium for Research and Education on Emerging Contaminants, a group of metro water professionals and scientists who meet regularly to discuss water pollutants that remain mostly uncontrolled.

“This is an emerging contaminant issue. It is something we should be aware of,” Battaglin said. “It is another impact of human society on the landscape that we were unaware of until recently.”

When Wetherbee began his research, he was looking for nitrogen pollution of water as part of a four-decade National Atmospheric Deposition Program that began with investigations of acid rain and broadened in 1978 to encompass other pollutants that spread from people into the natural environment.

Water samples were sent to a central lab in Wisconsin. Wetherbee asked to have filters sent back after testing. He wanted to see whether they’d caught heavy metals from possible industrial sources in Denver.

“I thought I’d better look at these things just to see what is on them. Then the data will make more sense.” He photographed each filter to preserve a record.

“I started to notice there were these pieces of plastic. Was it that surprising to see these plastics in the urban environment? Then, when I saw them in Rocky Mountain National Park, it started to be very surprising.”

Depending on funding, future USGS research in Denver, where the agency’s national water quality lab is located, will focus on measuring how much microplastic is spreading around the planet.

“Second, it is up to the ecological community to find out what the effects on ecosystems might be,” Wetherbee said. “It might not matter as much as we might suspect. It may be something we really need to worry about.”

At Denver Water on Thursday, utility officials familiar with the federal findings said they didn’t know whether microplastics are present in drinking water but would monitor research and adjust treatment processes accordingly.

“Denver Water is fortunate to have watersheds that are in great health, consisting of more remote mountain sites that provide us with high-quality snow runoff. Denver’s drinking supply does not come from the metro Denver area that the USGS study sampled,” utility spokesman Travis Thompson said in an emailed response to queries from The Denver Post.

“As Denver Water’s scientists learn more about emerging issues like this, we use that to inform monitoring programs, management of our watersheds and treatment processes to ensure Denver’s tap water always meets or goes above and beyond the strict federal regulations and water quality standards.”

Source: Denver Post

Pure Water Gazette Fair Use Statement

Washing Cars



Car wash products have never been our favorites.

We believe that the best place to wash a car isn’t at home but in a professional car wash establishment. Commercial car wash locations are set up to furnish water for spot free rinses at a reasonable cost, to recycle water,  and to get rid of the wastewater in a much more environmentally friendly way than you can at your home. At home, the soap, chemicals, and wastewater end up in the worst place you could put them–in the storm drain.

Nevertheless, home car washing is extremely popular, and there are probably worse things people could do with their time than washing their cars.

We sell a garden hose filter with a softening cartridge that has been very popular. It isn’t perfect, but if you use it according to instructions it will do a fair job of knocking down  the hardness minerals (calcium and magnesium) that cause spots on cars.  This helps in many cases but in others not so much, because the softening process (whether it’s done by our tiny cartridge or by a full-fledged home water softener) doesn’t always solve the problem.  Softening removes the hardness (calcium and magnesium) from the water, but it adds an equal amount of sodium, which also can cause spotting.  So, washing with softened water helps, but you often still have to wipe away the spots caused by the sodium.

The only way to get a real spot free wash is with low mineral water and the only practical ways to produce this are with deionization (DI) or reverse osmosis (RO), or with a combination of the two.

Softening “exchanges” ions–salt for calcium and magnesium–but DI removes all of the minerals. DI makes water that’s perfect for a spot-free car wash, but it has the drawback of being very expensive. Softener resin can be regenerated at home, but DI resin can’t, and it doesn’t last long. The small garden hose car wash “filters” that come and go (Mr. Clean, for example) are DI units. They work well, but cost is so high that it would almost make more sense to trade in your car for a new one when it gets dirty. There are lots of larger refillable DI home car wash units on the internet now that allow you to buy resin in bulk to cut the cost. Buying in bulk is better than buying small individual cartridges, but any way you do it, DI costs a lot and continually changing the resin is no fun.

Reverse Osmosis removes about 95% of the minerals in water–both hardness minerals and sodium–not by exchanging but by straining them out. RO is what car wash establishments use to get “spot free” water, and it is the most economical way to do it at home.



RO is a slow process, so a storage tank is needed. In the simple home RO car wash setup shown above, the small RO unit might need half a day or more to put enough water into the storage tank to wash a car.  (But, what’s time to an RO unit?)  The low-mineral RO water is then sprayed onto the car using the small “demand” pump. If only the final rinse is done with RO water, a small tankful of water is plenty.

Although there is an initial investment, RO is the most economical source of spot-free rinse water.  The simple unit shown above, without the tank (any plastic tank, including a strong garbage can will work) costs only about $350 for the essential parts–the RO unit and the pump.  Upkeep is small.

This simple system can be enhanced with items like a float shutoff to make filling automatic, larger tanks and larger pumps.  The small “countertop” RO unit will make as much water as you want if you give it the time.

This simple system, of course, does not have to be used for car washing. It works well for small greenhouses, aquariums, and more–any venue in which a small amount of top quality water is needed.

RO water is a lot like rainwater, so having the system shown above is like having a rain barrel but not having to wait for it to rain.


Whole House Reverse Osmosis

The most common reason for buying a whole house reverse osmosis unit for a residential well is to treat water with such  high salt content that it is otherwise essentially unusable. RO is the only practical way for residential users to remove large amounts of minerals like sodium and chloride from well water.

For most other problem contaminants with wells, like hardness, iron, and manganese, there are easier ways than reverse osmosis, and some contaminants, like arsenic and nitrates, which are removed well by RO, are most often addressed as drinking water but not whole house treatment problems.

Before and After Test Results for a Whole House RO Unit

Below is a chart showing  before treatment and after treatment results from  National Test Labs tests made by one of our customers. The high TDS (Total Dissolved Solids)  water is treated with a sediment filter, a water softener (to protect the reverse osmosis unit), then with a Watts R12 1200 GPD RO unit. This water is typical of what  whole house residential reverse osmosis is used for–bringing the TDS count down to a level where the water is usable for household purposes. I’ve selected a few items from the tests that illustrate typical RO performance on high TDS well water.

Contaminant or Characteristic



% Reduction


0.352 ppm

0.007 ppm



12.5 ppm

0.7 ppm



761 ppm

15 ppm



260 ppm

0 ppm





NA (See comment below.)


2400 ppm

84 ppm



310 ppm

17 ppm



3.6 ppm

0 ppm



2.2 ppm

0.6 ppm



960 ppm

0 ppm



A whole house reverse osmosis system consists of a lot more than the reverse osmosis unit itself.  In most cases the water will need pretreatent for sediment, hardness, iron, and manganese to protect the RO membrane(s).

Most large RO units produce water into a non-pressurized tank, so a pump will be needed to send the water to the home. RO lowers the pH of the water (see test results above), so a neutralizing filter is usually added after the RO unit to to protect the home’s pipes and appliances from acidic water. An ultraviolet unit is usually added as the final stage to assure that the water is microbiologically safe.

You can normally expect the cost of pre-treatment, storage, delivery to the home, and post-treatment to be as much as the cost of the RO unit itself.

Whole house RO units are not trouble free. They require some attention, especially if pre-treatment equipment is used. One issue that people often overlook is that a lot of wastewater is generated and this has to be disposed of. Expect at least half the water that goes into the unit to come out as reject water, or brine, so if your family uses 300 gallons of water per day, you will have at least 300 gallons of reject water to get rid of. Disposal in rural environments can often be arranged so that septic systems are not overwhelmed. The homeowner who sent us his test results catches the RO brine in large holding tanks and blends it with rainwater to produce water suitable for irrigation.


Above is a 2200 gallon per day Watts R4X40 reverse osmosis unit.  We offer Watts units that produce 600, 1200, 2200, 4400, and 6600 gallons per day. The unit shown includes low pressure cutoff to protect the unit if inlet pressure falls too low, pump to send pressurized water to the membrane, flow meters to measure both the permeate (product water) and brine (reject water) as they leave the membrane, a TDS meter to give instant TDS readings for both the untreated water and the permeate, and a manual control to allow part of the brine to be recycled for treatment.







Total Dissolved Solids: A Matter of More Than Just Good Taste


The following discussion of Total Dissolved Solids views TDS mainly from the municipal water supplier’s point of view. 

Everyone wants good-tasting water, but most water treatment plants (WTPs) are hostages to the composition of their local source water supplies. One of the components involved in taste is total dissolved solids (TDS), which can affect both the acceptability of finished water taste and its likelihood to corrode or clog pipes and fixtures. Here’s how to quantify the problem and what to do about it if it is excessive.

TDS: Good, Bad, Or Indifferent?

Water chemistry can be a complex subject based on the qualities of the source water and the objective of where it needs to be. TDS includes all conductive ions in a solution – both positively charged ions and negatively charged anions – able to pass through a 2-micron filter. TDS presents itself in multiple forms – e.g., magnesium, calcium, sodium, potassium, sulfates, chlorides, nitrates, etc. These components’ effects on drinking water treatment depend on the degree of their presence (measured in mg/L or ppm) and their impact on water aesthetics (taste and clarity). For example, TDS at elevated levels can be a concern in terms of excessive mineral deposits on water treatment and water distribution infrastructure. In and of itself, however, TDS is not considered to be a health hazard and is only regulated as a secondary drinking water standard. The U.S. EPA Guideline for TDS is 500 ppm.

Aside from the potential for corrosion, another practical matter of TDS concern for water treatment providers is the aesthetics of taste. An often-cited guideline, resulting from a study reported by William Bruvold and Henry J. Ongerth in the April 1969 AWWA Journal, classifies the correlation between TDS and taste-test results as follows:

The Luck Of The Draw

To a degree, water utilities are victims of their source water’s geography. For example, in the U.S. the Ohio, Mississippi, and Missouri river drainages all have naturally higher levels of TDS. But TDS levels can also vary within a water source based on seasonal conditions, weather events, and other external causes. These might include soil contamination, stormwater-induced runoff (urban or agricultural), or point-source pollution from sewage treatment or industrial plants.

Of the many dissolved solids potentially found in water, calcium and magnesium – in proper amounts – are key ingredients in a great-tasting glass of water. (By comparison, TDS levels in bottled mineral water typically range from 350 to 600 ppm.) Too much of a good thing, however, can lead to a metallic, bitter, or salty taste and to mineral deposits on water distribution infrastructure and consumer faucets. Other TDS salts, minerals, or organic components can also introduce undesirable tastes, especially at higher levels. While many of the ions that make up TDS are not considered health hazards, some naturally occurring toxic ions such as lead, arsenic, and cadmium can be included in TDS sample readings.

Measuring TDS Accurately

Using the behavior of electricity as a means of reflecting water chemistry is a common thread in water quality testing. For TDS detection and measurement, changes in conductivity are used to identify higher or lower concentrations of TDS in surface water. Readings can vary with gentle springtime rains that dilute TDS levels in the water or by heavy summer downpours that raise conductivity as a result of sudden heavy runoff from mineral-rich soils.

Because WTPs can be affected by water sources coming from miles away from the plant intakes, hand-held portable instruments provide a convenient means of taking accurate and reliable readings at remote locations in addition to the plant intake.

Some extremely compact instruments even include the ability to interface with smartphone apps, enabling users to collect, view, and transmit field readings easily. Readings can be completed in as little as 10 to 20 seconds, with conductivity and TDS resolution of 0.1 for measurements of 1 to 99 ppm and repeatability of + one count for readings < 1,000 ppm.

Be sure to calibrate all TDS instrumentation using the appropriate standard solutions traceable to the National Institute of Standards and Technology (NIST) and having appropriate conductivity/ppm values.

Figures 1 and 2. Compact handheld instruments and smartphone applications make the capture and management of TDS data easier, wherever readings are required.

TDS: What To Do Once You Identify It

Depending on the nature of the solids and dissolved solids in the source water, there are a variety of methods for removing them. The following chart shows the relative performance levels of various filtering media in removing particles and dissolved solids.

Reverse Osmosis.  Reverse osmosis (RO) is the most complete and reliable solution for removing salts and other TDS from drinking water. While it does a good job of removing all particles as well as undesirable dissolved solids, it can be very expensive. Unfortunately, it will remove all of the calcium and magnesium that can give drinking water its taste, so RO-water is often filtered back through a mineral bed of calcium and magnesium to restore those elements.

Nanofiltration. Because nanofiltration can remove some salts (divalent ions), it can be used to reduce levels of TDS and soften water.

Ultrafiltration.  While ultrafiltration will remove larger particles, in order for it to have an impact on TDS removal, dissolved substances first need to be captured through coagulation with alum or iron salts or through activated carbon adsorption.

Source: Water Online, July 15, 2019

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