Researchers Work to Solve Clean Water Problems
Mother Earth has no shortage of environmental problems, but the fight for clean water may dominate environmental issues of the 21st century. Consider this fact: The World Health Organization (WHO) estimates that approximately one-sixth of humanity lacks access to any form of safe and improved water supply within 1 kilometer of their homes. That’s more than a billion people, roughly three times the population of the United States, who must walk more than half a mile to find water that is clean enough to drink or bathe in.
This barrier is killing people, mostly children, because they are forced to consume and use unsafe water. According to the WHO, waterborne diseases, primarily diarrhea and malaria, account for more than two million deaths worldwide every year.
Although most deaths occur to children under five who live in rural and semi-urban areas of developing countries, disease caused by consumption of or contact with unsanitary water is not limited to the underdeveloped nations of Asia, Africa and South America. Unsafe water supply causes endemic and epidemic disease in all countries. The problem leads not only to disease and death but also economic hardship for individuals and entire communities.
In recent years, several international organizations have responded to this problem. WHO and the International Water Association have developed an international framework for the provision of safe drinking water. Described in WHO Guidelines for Drinking-water Quality and the Bonn Charter for Safe Drinking Water, the framework led to a United Nations Millennium Development Goal to reduce by half the proportion of the world’s population who is unable to reach or afford safe drinking water by 2015.
Researchers and students at the University of Arkansas are contributing to the United Nations’ goal. Three distinct, yet not entirely disparate, research projects will improve water quality and ensure that more people have access to safe water. The projects vary in scale and impact, but all three will improve and perhaps save lives.
The Zaragoza Project: “I Realized I Didn’t Have Any Specific Skills”
Thomas Soerens never let go of youthful idealism. Years ago, more than a decade before he earned a doctorate in civil engineering, Soerens joined Shelter Now International, a relief organization that sent him to Mexico and Pakistan. While working at an Afghan refugee camp in Peshawar, Pakistan, he had a moment of clarity about his future.
“I realized I didn’t have any specific skills,” said Soerens, now an associate professor of civil engineering. “So I decided to go be an engineer.”
He returned to the United States, picked up a bachelor’s degree in civil engineering, and went back overseas, this time to the Republic of Maldives, an island nation in the Indian Ocean. Soerens worked there for two years as a water and sanitation engineer before returning to school and eventually becoming an engineering professor.
Two years ago, a friend who works with missionaries in South America told Soerens that children in rural villages near Leticia, Colombia, were dying from waterborne diseases. The friend asked Soerens to see what he could do to help the villagers. In December 2004, Soerens visited several tiny villages on the Amazon River where Colombia, Peru and Brazil intersect.
He discovered the indigenous people in the villages did not have access to clean water.
There were a few wells, but they had dried up or were contaminated. For most of the year, villagers relied on rainwater for drinking and bathing. A few industrious residents had constructed crude catchment systems to exploit what nature provided. During the short dry season, people used untreated water from ponds and the Amazon.
Soerens also confirmed that parasites and bacteria in the water had caused illness and death. Sadly, most villagers did not understand the connection between use of bacteria-laden water and illness or death.
Soerens returned to Fayetteville with a plan. He challenged students in his senior-level design class.
“I told my students what it was like there,” Soerens said, “and asked them to come up with a system that people could use and maintain.”
The students gathered scrap materials from the Engineering Research Center and devised a system that included plastic plumbing pipes, large plastic tanks and two kinds of filters. The system collected rainwater from the roof of the research center and funneled it into one tank on top of a wooden platform. Water from that tank flowed through plastic pipes to filters inside the two other tanks. The students built and tested a slow-sand filter and a biosand filter.
Both systems removed bacteria from the water, but the biosand system, a filter that keeps sand wet and forms a biologically active layer to help treat bacteria, worked better and produced water clean enough to drink. After construction, Soerens observed the system further and noticed that it filtered water slowly, so he modified it and added an extra tank for storing the water after it had been processed by the filter tank.
In June, Soerens returned to South America and, with help from several locals, built the filtration system at a church in Zaragoza, a small village in Colombia. Since then, villagers have used the system to obtain clean water. Soerens communicates with local officials and residents and recently confirmed that the system is working well. He said the villagers like it and requested more storage capacity to get them through dry months.
Through a foundation in Arkansas, Soerens is trying to raise money to build additional filtration systems in and around Zaragoza. The mayor of Leticia and governor of Amazonas, a Colombian state, have offered to help build systems at schools in other villages if the Zaragoza system continues to work well.
Without offending the indigenous population’s cultural sensibilities, Soerens also wants to provide education about the importance of clean water, sanitation and hygiene.
“The priority is prevention of illness and death,” he said. “For this to happen, the local people must take ownership of the system culturally and develop a reputation of being responsible for it.”
Developed Nations: Poor Land Management and the Effects of Urbanization
Results of membrane filter tests on creek water demonstrated that the biosand filter, at bottom, removed all fecal coliform bacteria in all tests. The picture at top shows creek water without filtration. The middle picture shows the results of a slow-sand filter.
Poor understanding of the connection between unsafe water and disease may seem like a problem affecting only developing nations. But, when it comes to laws, policies and behavior that affect water quality, developed nations aren’t much better.
In the United States and much of the developed world, population growth and urbanization have degraded water quality. To most people, this cause-and-effect relationship is not apparent, especially for those who don’t consider the source of their treated water. In short, urbanization equals profound land-use change, which damages streams, rivers and lakes.
Development is particularly traumatic because removal of trees and vegetation to construct roads and buildings increases runoff, which leads to flooding, erosion and sediment washed into streams, rivers and lakes. As areas continue to develop, impervious surface — roads, buildings and parking lots — replaces pervious surface — pastures and woodlands. This means rainwater that used to soak into the soil — which processes nutrients such as nitrogen and phosphorous — now flows through a series of artificial conveyances until it reaches a stream.
Too often, agricultural operations and poor land-management practices compound the problem. Farmers use more nitrogen and phosphorous — organic elements that are essential constituents for plant life but, in excess, can accelerate eutrophication, which leads to a reduction in dissolved oxygen in water. Runoff carries these nutrients into streams and rivers.
Furthermore, agricultural and domestic use of herbicides and pesticides contributes to poor water quality in streams, rivers and lakes. Not surprisingly, the influx of nutrients and chemicals makes water-treatment processes much more difficult and expensive.
Beaver Lake Watershed Decision Support System
Even in upland areas, urbanization and land-use change damage streams, rivers and lakes anddegrade water quality.
This satellite photograph shows concentrations of sediment, chlorophyll and organic carbon in Beaver Lake. Researchers can use satellite images to indirectly predict nutrient content in the lake water.
Sumit Sen, former graduate student in the departmentof agricultural and biological engineering, collects a water sample from Beaver Lake on the same day that a satellite takes a photograph of the lake. Researchers compare actual water quality samples with predictions based on satellite images.
Northwest Arkansas, one of the fastest growing urban areas in the United States, is not immune to the above problems. In fact, the area might be viewed as a classic example of the effect of population growth and urbanization on water quality.
In the 1960s, the Army Corps of Engineers dammed the White River near Eureka Springs, and Beaver Lake was born. Today, Beaver Lake is the primary source of drinking water for approximately 300,000 people in a four-county area and generates millions of dollars annually in tourism revenue for the state of Arkansas. It also produces electricity for the nation’s power grid.
The lake is clean, but the environmental consequences of rapid growth are threatening its water quality. Widespread development and agricultural operations within the lake’s watershed have caused erosion in streams and rivers and increased transport of sediment and nutrients. The situation has caught the attention of many stakeholders because the lake is so vital to the health of the local economy.
Five years ago, Indrajeet Chaubey and his colleagues in the department of biological and agricultural engineering received funding from the Arkansas Natural Resources Commission (formerly the Arkansas Soil and Water Conservation Commission) to develop a comprehensive, geographic – information – systems – based program for the management of Beaver Lake’s watershed. The first step toward creating the program involved conquering a mountain of historical data from many water-quality reports and projects sponsored by various governmental agencies and environmental organizations. Chaubey said some of these reports were in paper format only or otherwise unavailable to the general public.
After many months of work, the researchers synthesized the historical information, which helped them accurately assess water quality and identify knowledge gaps, and created a general database of all watershed and water-quality information. They then linked the database to GIS-based information about the watershed. The researchers combined this information with their own water-quality samples taken from virtually every nook and cranny on the lake. The combination of all data comprises their final product, the Beaver Lake Watershed Decision Support System.
The system allows researchers to develop mathematical models that explain environmental processes in upland areas, streams and rivers, and the lake itself. The models show how the land is changing and how that change contributes sediment, nutrients, pesticides and other water-quality constituents to Beaver Lake. For example, the models indicate that the urban area around Fayetteville and Springdale contributes pollution to the streams and rivers that feed Beaver Lake, but agricultural areas along the west, middle and main forks of the White River also are high impact areas.
In addition to identifying low- and high-impact areas, the models can predict the environmental consequences of developing a particular piece of property and land-management changes.
“You can provide different scenarios,” says Chaubey. “If I change the land here, how will it affect the lake? If you take the amount of animal manure that farmers apply and cut that in half, how much will that potentially reduce the amount of phosphorous getting into the lake?”
Chaubey says publication of the database via the Internet will ensure that watershed water-quality information is accessible and free to the public.
Recently, Chaubey has relied on satellite photographs of Northwest Arkansas to predict sediment loads and nutrient content in the lake. The new technology reduces expense because his team can gather water-quality information without traveling to many locations on the lake. The photographs also provide near real-time results, rather than having to wait a week for lab analyses of pollutant concentrations in actual water samples.
Although reading the photos is tricky, the process works because certain constituents — sediment, chlorophyll and organic carbon — in the water interact with light, and nitrogen and phosphorous attach to sediment. Also, high concentrations of chlorophyll mean there must be a source of energy, which indicates the presence of nitrogen and phosphorous.
“If you see high concentrations of chlorophyll,” Chaubey says, “chances are there are high amounts of nitrogen and phosphorous present. If they weren’t, algae would not be growing.”
He knows algae are present because his researchers continue to draw water samples at the exact locations captured in the photographs. They compare lab results from the samples to predictions based on the photographs. So far, their predictions of the concentration of nutrient levels at various locations on Beaver Lake, based on images provided by satellite photography, have been 98 percent accurate.
“Satellite photography provides several advantages,” Chaubey says. “We can monitor the entire lake, not just one area where you take a water sample. We can do this with much less expense than having to process hundreds of thousands of water samples through the traditional lab process. Until now, we’ve had very limited capability to monitor what is happening on a real-time or near real-time basis.”
Chaubey says Beaver Water District, the public entity charged with treating water from the lake and providing it to most Northwest Arkansans, will be able to use this technology to overlay snapshots that will help them identify water-quality trends in the lake over time.
Supersaturated Dissolved Oxygen Injector
The injector shoots a stream of water “supersaturated” with dissolved oxygen.
The portable Supersaturated Dissolved Oxygen Injector at use in a lake.
Ecologists and ecological engineers like Chaubey understand that many times the best environmental policy, other than mitigating damage at the source, is to step back and let Mother Nature do her thing. For example, when excess nutrients and other organic waste reach a body of water, the cheapest, most effective and efficient method of treating them is bioremediation, the process by which naturally occurring microorganisms (bacteria) digest organic matter through their respiration cycle.
This process occurs in many lagoons and ponds on farms. On a larger scale, engineers at municipal waste water treatment facilities monitor the health of water bodies to facilitate the proper environment for this natural process to occur. One of the problems they encounter is insufficient oxygen in water, which reduces the rate at which bacteria can eat waste. When this happens — when waste-water becomes anaerobic — bioremediation slows down and the public complains because odor is an undesirable byproduct of insufficient oxygen.
“One of the things we’re facing in Northwest Arkansas and all around the country is that when population becomes more urbanized and cities grow out to what traditionally had been rural areas, people find themselves living close to these huge waste lagoons that used to be out in the middle of nowhere,” says Scott Osborn. “So now people live next to the lagoons, the wind blows, it stinks, they complain, they’ve got political power, and you’ve got to do something about it.”
Traditionally, landowners and waste water treatment engineers have introduced oxygen, which is a gas, into the water to make it aerobic, speed up the biological process and eliminate the odor. Various technologies accomplish this, but none are terribly efficient because they apply oxygen directly to water. With these systems, oxygen bubbles quickly rise to the surface, and much of the gas escapes before it absorbs into the water.
Osborn and Marty Matlock pondered this problem and created a system that more efficiently applies oxygen to water. Their patent-pending invention, the Supersaturated Dissolved Oxygen Injector, shoots a stream of water saturated with dissolved oxygen directly into a body of water that needs treatment. Because gas cannot escape from the carrier stream, the system reduces energy expenses. Water-treatment operators do not have to churn larger bodies of water to mix gas and prevent it from escaping.
“It’s like mixing your coffee with liquid creamer instead of powder,” Osborn says. “With liquid, you stir it once and it’s mixed. With powder, you have stir and stir to get it mixed in. A lot of energy, particularly at waste water treatment plants, is spent on getting that mixing done. With our system, the energy savings is that this is simply a stream of water mixed in with other water.”
The simple device collects a water sample from a creek, pond or lake that needs dissolved oxygen. The water is directed through pumps and then into a chamber where the gas is introduced. Liquid water containing dissolved gas then comes out of the chamber. The system can strategically inject supersaturated water at any depth without significantly disturbing a water column. In other words, with long hoses, the device can pump oxygen into the bottom of lakes where there is insufficient oxygen during the summer without affecting areas that do not need additional oxygen.
The device is completely scalable. Osborn says they can build systems to fit in cupboards for in-home use, large, portable units that could deliver 200 gallons of water per minute or even gigantic, permanently installed units for waste water treatment facilities. The smaller systems are portable and, along with a generator, may be taken to remote locations that may not have a source of electricity.
Osborn is chief technology officer for BlueInGreen, LLC, a start-up company and entrepreneurial partnership between the inventors, the university and Virtual Incubation Company, a local, private company. BlueInGreen will build, sell, assemble and install the Supersaturated Dissolved Oxygen Injector and other similar systems. Osborn says they hope to sell the first oxygenator this year.
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Thomas Soerens is an associate professor of civil engineering.
Indrajeet Chaubey, Scott Osborn and Marty Matlock are professors of biological and agricultural engineering, with joint appointments in the Dale Bumpers College of Agricultural, Food and Life Sciences, the Division of Agriculture and the College of Engineering.