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Conventional Water Treatment Can Be a Disaster for Small Communities
Joan Thompson posted on October 19, 2016 | 3330 views

With an enormous expanse of lakes and rivers, it’s hard to believe that Canada would have any major issues supplying clean water to its residents—but unfortunately, this is the case.

For decades, First Nations communities in Canada have consistently dealt with mismatched water treatment systems, and the consequences have been disastrous.

A water treatment plant on a First Nations community where bacterial biofilms used to clog the filtration membranes. (Image courtesy of the Safe Drinking Water Foundation.)
A water treatment plant on a First Nations community where bacterial biofilms used to clog the filtration membranes. (Image courtesy of the Safe Drinking Water Foundation.)

Hans Peterson is the former head of the Saskatchewan Research Council’s Water Quality Team and technical advisor of the Safe Drinking Water Foundation. When it comes to broken-down water treatment plants and frustrated utility operators, he has seen it all.

Now retired in Stanley Mission, Sask., Peterson spoke with ENGINEERING.com about some of the nightmares these water treatment operators have had to deal with, including:

  • Water in the treatment plant with nutrient levels so high that biofilms grow on the membrane filtration equipment and clog it.
  • Sand filters that have to be constantly backwashed in order to keep the plant operating and providing water.
  • A community without a water treatment plant at all, but with well water with sporadically high levels of arsenic. The operator’s job was to mix and match the water between four wells in order to bring the concentrations of arsenic below government regulations.

The water in some of these communities has since improved, but access to clean water is truly a dire problem for First Nations communities across Canada. Figures from 2015 state that there is a total of 162 drinking water advisories across 118 First Nation communities.

How could this be the case? There are a number of reasons why First Nations have been left behind in the provision of access to clean drinking water. A very prominent one is that these communities have been assigned water treatment plants without enough source water tests to determine whether or not the chosen water treatment technology is appropriate.

Why are these treatment plants chosen in the first place? Two reasons: they are typically cheaper and they utilize conventional water treatment methods that have been around for decades or more.

 

The Tried-And-True Methods for Treating Water

EPA Defines ‘Conventional’ Treatment

Civil engineers likely remember being taught the “typical” water treatment process during their undergraduate degree, where the beginning stages are coagulation, flocculation and sedimentation, followed by filtration and disinfection.

As defined by the U.S. Environmental Protection Agency (EPA), coagulation is the addition of chemicals that cause colloids in the raw water to floc together (flocculation) into larger precipitates. Colloids are miniscule particles—between 1 nm and 1 µm—that need to undergo this process, or else they are far too small to remove effectively through sedimentation and filtration. The addition of positively charged coagulant chemicals destabilizes the negative charges that keep the colloidal particles apart.

When people think of the “tried-and-true” method of water treatment, they often think of technologies that date back to the ‘50s and ‘60s, the age when building water treatment infrastructure was at an all-time high. However, coagulation and flocculation actually go back much farther; illustrations on the wall of the tomb of Amenophis II and Ramses II from 1500 B.C. show Egyptians using the chemical alum to clarify their water.

Raw water being treated with ferric chloride coagulant. (Image courtesy of Ecologix Environmental Systems.)
Raw water being treated with ferric chloride coagulant. (Image courtesy of Ecologix Environmental Systems.)

The coagulant chemicals used today vary from the alum used by the ancient Egyptians to iron sulphates and organic polymers. The exact type and dosage vary significantly based on the source water, but the overall process of coagulation and flocculation as a pre-treatment is widely used today, especially in small utilities.


Another Conventional Water Treatment Process: Manganese Greensand

Manganese greensand is also considered a typical treatment method.

Manganese greensand is frequently used in utility plants to treat iron, manganese and trace amounts of hydrogen sulfide. These compounds tend to be excessively high in groundwater sources and while they are not necessarily harmful to health, it is still vital that they are removed during treatment. High levels of manganese and iron will damage plumbing fixtures, give water an unpleasant taste and color and provide nutrients to certain strains of bacteria.

In a manganese greensand filtration system, coagulation and flocculation are usually not part of the picture. Instead, the manganese greensand filtration unit is typically preceded by aeration and chlorination (or another type of oxidant addition) and then there may be pH adjustment of the water.

Manganese greensand was first used in U.S. drinking water treatment plants in the 1950s. The sand itself is composed of glauconite, a mineral deposited onto the eastern shores of the U.S. and treated with manganese oxides. It is because of this that it has the nickname “New Jersey greensand.”

Glauconite minerals from a deposit in Ohio. The formation of the mineral glauconite occurs in anoxic marine environments and is often found in coastal areas. (Image courtesy of James Cheschire.)
Glauconite minerals from a deposit in Ohio. The formation of the mineral glauconite occurs in anoxic marine environments and is often found in coastal areas. (Image courtesy of James Cheschire.)

The ion exchange properties of the sand were discovered in the early 20th century, when it was used as a slow-release fertilizer for soils. As a water treatment process, manganese greensand has a proven effectiveness and is relatively inexpensive to deploy, making it one of the most popular processes ever implemented.

 

Moving Forward: Cases Where the Old Methods Have Failed

If you were going to have your house painted and you had to choose between hiring a senior with 25 years of painting experience under his belt and a teenager who hasn’t been in the business very long, you would probably pick the former option.

This kind of thinking has plagued the water treatment industry for years. Conventional treatment methods have had a long record of success—and as a result, there are more people who are trained to operate them, more options for company suppliers, more overall knowledge.

We need to talk more, however, about case studies in which these treatment methods have utterly failed, wasting millions of dollars and further complicating the community’s access to clean drinking water.


Saddle Lake Cree Nation, Alta.: Coagulation and Ultra-Filtration

“If you have a really poor-quality water source, coagulation and filtration is not going to cut it,” said Peterson. For example, look at Saddle Lake Cree Nation, Alta., (Saddle Lake) a First Nations community in which the utility served around 7,000 people. The source water was a lake that was so contaminated, the operators had to treat the water with CAD$15,000 worth of chemicals every month.
Saddle Lake is the source water for the Saddle Lake Cree Nation utility. The water is so thick with blue-green algae it washes ashore in mats. (Image courtesy of the Safe Drinking Water Foundation.)
Saddle Lake is the source water for the Saddle Lake Cree Nation utility. The water is so thick with blue-green algae it washes ashore in mats. (Image courtesy of the Safe Drinking Water Foundation.)
Approximately one month’s supply of chemicals for the water treatment plant at Saddle Lake. (Image courtesy of the Safe Drinking Water Foundation.)
Approximately one month’s supply of chemicals for the water treatment plant at Saddle Lake. (Image courtesy of the Safe Drinking Water Foundation.)

These chemicals were part of the overall treatment process, which used advanced coagulation followed by ultrafiltration. When the treatment plant was first built in 1982, the cost of chemicals was just $1,000 per year. This jumped to $200,000 in 2006 after some major plant alterations and it still wasn’t enough to treat the water adequately.

The capital costs of the water treatment plant itself turned out to be a waste since there was no way to optimize the treatment process.

“At Saddle Lake, a full-scale plant was built that ended up producing water with 12 mg/L of dissolved organic carbon. When combined with chlorine, this produced trihalomethanes way above 200 µg/L, [the upper limit is 100 µg/L]. The level of aluminum in the tap water was also ten times higher than Health Canada’s operational guidelines. So, tens of millions of dollars, just wasted,” said Peterson.

Despite all the chemicals, bioavailable and dissolved organic compounds were still leaving the water treatment plant, which in turn caused loss of chlorine residuals. The operators were left in a difficult situation where they had to increase the chlorine dose, creating harmful disinfection by-products (trihalomethanes). Surveys conducted in the First Nations community found that almost half of the population was seeing a doctor about gastrointestinal illnesses.

At the time, industry experts agreed that the water produced at Saddle Lake was some of the worst in the country. The community was under a boil-water advisory for years. The treatment performance was so bad that the plant needed a complete overhaul.

Why didn’t advanced coagulation and ultrafiltration work in Saddle Lake? Peterson’s theory is that it was because the source water had an extremely high level of dissolved organic carbon (DOC).

“In natural water sources, there are two types of organics; you have fat-loving, or lipophilic, and water-loving, hydrophilic, organics,” Peterson explained. “With coagulation, you can only pull out the lipophilic organics.”

As Peterson states, the lipophilic organics get tied up with the coagulant and the particles formed can be removed by ultra-filtration. At Saddle Lake, it is likely that both lipophilic and hydrophilic organics were present in equal amounts because 25 mg/L of DOC was reduced to 12 mg/L.

It’s considered an extremely high level of organic matter when water contains 25 mg/L of DOC. According to Peterson, when coagulation was first developed as a water treatment practice for large cities, it was never intended to treat such poor-quality water sources. Large urban areas often have the option to extract from large water bodies or groundwater sources that are relatively pure, whereas rural areas need to draw water from whatever source is nearby.

“City water is way better; for instance, Calgary [Alta.] has 1 mg/L of DOC. If you want to treat that type of water, coagulation isn’t half bad,” said Peterson. “But when you have water that is ten times poorer than the average city, you have to think differently.”

When Peterson talked about his experience with the disastrous water quality at Saddle Lake, he was only just getting started. He has actually seen more than one case of coagulation-filtration water treatment processes not working for similar reasons; poor quality water with too little pilot data to decide on the best treatment method.

It is not only for the pre-treatment of coagulation. Peterson has seen other traditional treatment methods that have utterly failed because the source water had far too many contaminants.

 

George Gordon First Nation, Sask.: Manganese Greensand

George Gordon First Nation (George Gordon), unlike Saddle Lake, extracted its water from underground wells. However, the water was equally poor and difficult to treat.

“Some of the well-water in Saskatchewan is extremely poor in quality. At 100 or 200 m below ground, the water is brackish and high in ions because the area used to be an inland sea,” Peterson explained. “As a result, we have contaminants such as methane and hydrogen sulfide gases, ammonium, iron and manganese. Arsenic levels in the source water were as also high, reaching 80 µg/L.”

For years, the utility at George Gordon used manganese greensand to treat these contaminants, thinking it would be a simple process. Clearly, it did not pan out that way. “There was just no end of trouble,” said Peterson. “They used to have five manganese greensand filters treating the water and each of them had to be backwashed twice a day.”

Peterson explains the necessary process for regenerating manganese greensand filtration.

“The manganese greensand filtrations units are activated by adding potassium permanganate and then they are left overnight. Then, you dump the water to waste and you rinse the filter and start again. After regeneration, this process is supposed to run for six months; at George Gordon, it was only effective for four hours,” said Peterson.

Before the water treatment upgrade at George Gordon, the water utility operator had easily one of the worst jobs in the country. Faced with the responsibility of providing clean water to the community, he would have to repeatedly backwash the failing filters. According to Peterson, he would work late most nights.

The utility at George Gordon used to have a manganese greensand filter that was followed by chlorination and then distributed. It was found, however, that the treated water still had high levels of manganese, ammonium and arsenic, so a reverse-osmosis (RO) membrane treatment step was implemented in 2001. This just caused more problems.

Residual nutrients such as metals and ammonium created an environment for bacteria to settle and thrive on the concentrated side of the RO membranes. In other words, they became “biologically fouled.”

Foul is right. A clogged RO membrane is cut open at George Gordon First Nation. (Image courtesy of the Safe Water Drinking Foundation.)
Foul is right. A clogged RO membrane is cut open at George Gordon First Nation. (Image courtesy of the Safe Water Drinking Foundation.)
Fouling membranes at First Nations water treatment plants with which Peterson has worked. (Image courtesy of the Safe Drinking Water Foundation.)
Fouling membranes at First Nations water treatment plants with which Peterson has worked. (Image courtesy of the Safe Drinking Water Foundation.)

RO membranes are filtration units with the smallest pore size, filtering particles at just 1 nm in width. With bacterial activity producing biofilms, one can only imagine how frequently they would get clogged.

“RO membranes are terribly difficult to clean and when you do so, you often destroy the integrity of the membranes. And they are very expensive to replace,” said Peterson. The yearly cost to replace the membranes reached $54,000 as the membranes were replaced every eight months.

Peterson recalled a conversation he had with the chemical engineer working for the distributor of the potassium permanganate used to activate the manganese greensand. After seeing the water quality data from the First Nation community, the engineer agreed with Peterson: “This process was just never intended to work on such poor-quality water.”

Just like coagulation and flocculation, the manganese greensand technology was first developed to address low to moderate levels of contaminants like manganese. These source waters also did not have high levels of nutrients such as ammonia to interfere with the manganese greensand process.

“At places like George Gordon, you have a lot more chemicals in the water—and when you try to battle those chemicals by adding more chemicals, it just doesn’t cut it,” said Peterson.

Peterson stresses the need for sufficient pilot testing before designing and building a full-scale plant. As an example, he discussed his experience with Yellow Quill First Nation (Yellow Quill), a community that had almost never seen clean water.

It was here that Peterson began the highlight of his career. At the Yellow Quill utility, he developed the Integrated Biological Reverse Osmosis Membrane (IBROM) system. This alternative water treatment technology has had a great deal of success, but the invention required a 22-month-long pilot and the testing of a wide variety of water treatment approaches.

 

Biological Filtration: So Far, Successful

A study from the Water Resource Foundation surveyed water industry professionals about their experience with and perceptions of biological water treatment. The survey found that utility workers and regulatory professionals are typically hesitant to accept its practice—and the most prominent reasons for this are the insufficient full-scale experience and lack of unified understanding.

Perhaps Peterson’s technology will change this. Between 2002 and 2004, he developed a biological treatment process that has had enormous success in First Nations communities that have to rely on poor-quality water sources. The first community to benefit was Yellow Quill First Nation.

Located about 186 miles (300 km) northeast of Saskatoon, Sask., Yellow Quill has had one of the longest boil-water advisories in Canada, put in place in 1995. One reason is that the raw water source was a lagoon that had comparatively bad quality to larger cities.
Yellow Quill extracted water from Pipestone Creek, which received waste water from an upstream community. On the right, it is compared to the South Saskatchewan River, Saskatoon, Sask.’s water supply. (Image courtesy of the Safe Drinking Water Foundation.)
Yellow Quill extracted water from Pipestone Creek, which received waste water from an upstream community. On the right, it is compared to the South Saskatchewan River, Saskatoon, Sask.’s water supply. (Image courtesy of the Safe Drinking Water Foundation.)

Before IBROM, the local utility was treating the water with coagulation, along with upflow clarification and downflow granular filtration. Since the water quality was so poor, however, the treatment process was unable to remove the dissolved contaminants. Peterson states that when the treated water reservoir was cleaned at Yellow Quill, a layer of black ooze was present at the bottom.

The community was fed up.  After years of boil-water advisories, four community members filed a class-action lawsuit against the federal government for inadequately addressing their poor-quality tap water. It’s unfortunate that drastic legal action had to be taken, but it paid off, as government officials responded by providing funds for a research project to examine Yellow Quill’s water.

One of the first decisions made was to change from the surface water supply to a groundwater source. While this raw water was not receiving waste, it was still given the official label of untreatable since it still had a high level of contaminants. Over a period of 22 months, a number of conventional treatment technologies, such as manganese greensand, and advanced treatment technologies, such as biological filtration and ozone, were tested.

This is where IBROM was developed—and from the way Peterson describes it, the process actually seems fairly simple.
A flow diagram of the IBROM process as implemented at Yellow Quill First Nation. (Image courtesy of the Safe Drinking Water Foundation.)
A flow diagram of the IBROM process as implemented at Yellow Quill First Nation. (Image courtesy of the Safe Drinking Water Foundation.)

“The well pump pushes the water through a series of biofilters, then a booster pump picks up the water and runs it through the RO membranes, the water is then pH-adjusted, chlorinated and sent to treated water reservoirs,” Peterson explained. “That’s it.”

Peterson states that one of the biggest advantages IBROM has to offer is its ability to treat contaminants without excessive backwashing and chemical applications.

“For example, we actually deal with ten times as much iron biologically as anybody can do through chemical or physical oxidation, so we only need to backwash at a fraction of the rate done before,” said Peterson.

The full-scale IBROM implementation finally lifted the nine-year boil-water advisory at Yellow Quill. Residents were initially skeptical about the safety of their water, but tests from the water treatment plant have assured its cleanliness.

The IBROM process is currently operational in 15 First Nations communities, including Saddle Lake, George Gordon and Yellow Quill. Two additional First Nations communities will introduce IBROM plants before the end of 2016.

Biological treatment has proven advantages, but as with all water treatment systems, its effectiveness does still largely depend on the source water quality, staff training, overall environment and plant set-up. One of the biggest drawbacks is that that biological filtration doesn’t have the historical proven success that conventional treatment has had.

Davis Cole is a senior civil engineer at H. Davis Cole and Associates. He is currently working at the water treatment utility in St. Joseph, La., where the treatment process is manganese greensand combined with aeration tanks. He understands the challenges that come with implementing alternative water treatment methods.

“Advanced technologies like biofilters combined with RO membranes are very exciting,” Cole explained. “The unfortunate reality of implementing this type of technology in rural communities is the lack of properly educated and trained operators that can operate and maintain complex treatment systems.”

“Generally speaking, payment for operators is low due to the small customer base and corresponding low revenues,” Cole continued. “There is little incentive for more qualified people to pursue a career in water treatment in these rural areas.”

In Peterson’s experience of implementing IBROM, it has actually made the operator’s job easier.

“I find that water operators grow at least a foot once they start working with the IBROM,” said Peterson. “At George Gordon, the operator’s job literally went from being a backwasher to a staff member who now had the opportunity of advancing his career. He can sit and ponder, read, discuss technologies with other operators.”

 

A Bittersweet Success

Before IBROM, Saddle Lake, George Gordon and Yellow Quill were, unfortunately, just the tip of the iceberg when it comes to water quality issues in Canadian First Nations communities. First Nations in Canada, as well as rural villages and towns globally are facing unprecedented challenges trying to get better tap water into their communities. This problem, according to experts such as Peterson, is systemic.

“The decision-making process when the government chooses which company and system for a First Nations community is quite often based on the lowest-cost bid,” Peterson explained. “This is typically the cheapest option possible—cheap parts, cheap processes—and the result is just a mess. The approval of unproven water treatment processes has turned some First Nations communities into guinea pigs for sometimes hare-brained schemes. This has already resulted in non-working water processes that within a few years have had to be replaced, on the federal government’s tab.”

Choosing simplistic treatment systems without the proper source water checks is a problem in the U.S. as well as Canada.

“Quite often, smaller communities are ‘prescribed’ conventional treatment technologies with little or no source water testing or assessment.  I don’t understand how this is acceptable practice,” said Cole. “The tests are relatively inexpensive and by gathering simple data, many potential design mistakes can be avoided.”

As someone who is fairly vocal about water quality issues, Peterson urges utility operators and public health representatives to speak openly about their struggles.

“We need to talk openly about technical issues, try to address technical issues,” said Peterson. “Unfortunately, staff need to answer to the politicians—and they want no bad news about water. I think talking about water issues should be the best news ever.”

To learn more about Peterson’s work, you can visit the Safe Drinking Water Foundation website, or the Safe Drinking Water Team website.

 

Engineers, We Want to Hear From You:

  • Small utilities are assigned conventional treatment technologies (eg. coagulation and flocculation, manganese greensand), without a proper assessment of their source water. Are there any civil engineers with similar frustrations? What other challenges arise when choosing the right treatment approach?
  • Surveys show that regulatory officials and utility workers are hesitant to implement biological treatment technologies since it is an alternative treatment approach that is relatively new. Has anyone ever encountered specific challenges with biological water treatment that they think should be addressed? What problems arise with implementing them in small communities?

More on Water

RE: Story Discussion: Conventional or biological water treatment?

  • Reply by member: TheEngineer | Reply to thread

    ENGINEERING.com Joan Thompson's article on water treatment approaches has been published at:

    Conventional Water Treatment Can Be a Disaster for Small Communities
    http://www.engineering.com/DesignerEdge/water/Arti...

    Quote:

    With an enormous expanse of lakes and rivers, it’s hard to believe that Canada would have any major issues supplying clean water to its residents—but unfortunately, this is the case.
    For decades, First Nations communities in Canada have consistently dealt with mismatched water treatment systems, and the consequences have been disastrous....

    Engineers, we want to hear from you:

    - Small utilities are assigned conventional treatment technologies (eg. coagulation and flocculation, manganese greensand), without a proper assessment of their source water. Are there any civil engineers with similar frustrations? What other challenges arise when choosing the right treatment approach?

    - Surveys show that regulatory officials and utility workers are hesitant to implement biological treatment technologies since it is an alternative treatment approach that is relatively new. Has anyone ever encountered specific challenges with biological water treatment that they think should be addressed? What problems arise with implementing them in small communities?

  • Reply by member: QualityTime | Reply to thread

    A lot of the treatment methods that are selected to be used in small remote towns or villages are selected by engineering companies who don't have the depth of experience that is required. I call them package plant engineers. They think they know water treatment but they do not

    In small remote towns or villages they do not have the expertise to run plants or to maintain them. There is too much electronics. In the old days we did not electronics just wire, pulleys and floats. In remote communities we should go back to their use. Everyone understands wire, pulleys and floats. It is also unrealistic to expect finished water quality to be as good as what is expected in a city. That type of quality costs money. Certain standards should relaxed.