A company uses the tools of nature to restore polluted lakes and rivers
When a young electronics engineer running a computer design and electron ballistics consulting firm in the late 1960s decided to venture into a lake cleaning business, it was one of the most unusual career decisions.
That was the time when the United States discovered that hundreds of its water bodies were polluted and scores of students started joining courses in lake restoration. The techniques they were taught were all conventional. These included dredging, nutrient diversion and weed harvesting. But Robert L. Laing thought of introducing newer approaches that imitate natural processes and minimize the use of harmful chemicals.
Why did Laing shift from electronics to water pollution? While developing a high voltage thermionic energy converter, which converts heat to electricity. Laing, stumbled upon a process to solve water pollution problems. "So it was natural to move on to the next step: water pollution control," he explained, during a recent visit to India.
He started his career in 1958 as an aerospace systems design engineer with General Dynamics, Fort Worth, where he designed the bombing/navigation test computer for the B-58 Hustler airplane. Unfazed by criticism, he founded CLEAN-FLO Laboratories, Inc. in 1970, two years before the U.S. Environmental Protection Agency (EPA) began. But business was hard to come by initially. CLEAN-FLO's methods were difficult to accept for the scientific community at that time, though it does endorse them now. "Although there was a lot of money in lake cleaning business then, it was tough for us because what we did was not taught in schools," said Laing. Moreover, big money went to consultants and professors who worked for civil engineering companies and municipalities that built bridges and highways. Lake cleaning was the second priority.
Business volume and clients rose gradually and the company, to date, has treated more than 2,000 water bodies in and outside the U.S. In 1987, it started expanding its international business. Three-fifths of its business now comes from abroad. "It was much easier to be accepted outside the United States because of what the consultants knew in the U.S., what they were programmed to do like dredging, nutrient diversion, etc." Laing said. Today CLEAN-FLO has projects running in India, Japan, Korea, Taiwan, the Philippines, Malaysia, France, the United Kingdom and Sri Lanka.
CLEAN-FLO's non-toxic lake, river and reservoir restoration process employs a combination of mechanical, microbial and non-toxic chemical methods developed over the years by the company: the continuous laminar flow inversion/oxygenation system; CLEAN-FLO lake cleanser, a nontoxic phosphate precipitant; Lake Care, non-toxic water clarifier; Sky Blue Lake Dye; and microbes to feed on organic sediments, oils, pesticides, human sewage, phosphorus and nitrogen.
All water bodies restore themselves using natural processes. In cool climates, lakes turn over twice a year due to temperature variations while in the tropics, hurricanes, typhoons, and other adverse weather conditions turn lakes over multiple times a year. This natural inversion has a lot to offer. CLEAN-FLO duplicates these "Spring and Fall" turnover and accelerates it to keep up with today's pollutants.
When the lake runs out of oxygen at the bottom, there is a massive release of phosphorus and nitrogen that breed weeds and algae, from the bottom sediment. Exposure to sunlight and oxygen in the atmosphere kills disease bacteria and toxic gases accumulated at the bottom are released. Putting oxygenated surface water on the bottom of lakes binds phosphorus and nitrogen to inorganic sediments like clay. This reduces the content of these two compounds in water by up to 97 percent and neutralizes acids so that the lake can begin its recovery.
Equipment is set up on the shore and at the bottom of the water body. The entire lake is artificially filled with oxygen starting from the bottom. Oxygenation kills anaerobic bacteria which live in the absence of oxygen, and are the source of toxic hydrogen sulfide, sulfuric acid, and ammonia gas. The sulfate in sulfuric acid already in the lake is absorbed by microbes, plants and aquatic animals. Low-oxygen microbes convert nitric acid to inert nitrogen gas. Carbon in the sediment is used as an energy source, so carbon dioxide is another end-product.
A diffuser, which blows oxygen, is set up at the bottom. Oxygen bubbles, while moving upward, drag bottom water to the surface. This initiates a flow called continuous laminar flow inversion. This releases toxic carbon dioxide and nitrogen gas. The bacteria are also weakened and killed when exposed to ultraviolet rays in sunlight. Reduction in phosphorus/nitrogen starved the bacteria.
The key to the process is a special formulation, termed C-FLO by the company. Beneficial microbes, that feed on organic sediment, ooze, and peat at the bottom, are introduced. These microbes convert this muck into carbon dioxide and water. C-FLO also adds organisms that are natural food for aquatic insects.
C-FLO multiplies as it (feeds) on muck, and insects grow and multiply as they feed on C-FLO. Fish then feed on insects and grow rapidly. This results in deepening of the pond makes a better environment for fish and makes it difficult for weeds to grow. Cattails and lilies gradually disappear. The microbial culture is generally added after three weeks of installing the aeration equipment, once the bottom water is suitable for its survival. Natural enzymes are used to speed up the work of the bacteria. Natural chemicals such as calcium tie up phosphates so the weeds and algae cannot grow. Sky-blue Lake Dye may be added to shade the weeds and algae from sunlight and impart artificial color to the surface.
The initial dominance of these beneficial microbes in the lake environment gives way to natural competition between organisms that regains a healthy balance. "The conventional method of dredging the muck can deepen a lake, making it more difficult for submerged vegetation to grow, but does nothing for water quality, algae and fish," Laing said.
Nutrient diversion involves channeling of all possible sources of sewage into a single zone where it is treated and then redirected into the water body. The process reduces pollutants in the lake by 5 to 35 percent but does nothing for the organic sediments at the bottom. The problem with nutrient diversion is non-point source pollutants, which cannot be avoided. One cannot stop people from throwing flowers into the river, and when it rains water comes in from the watershed, Laing said. "That is one of the primary reasons for poor performance of earlier methods. As you cannot stop pollutants from entering the river, they should be treated internally and worked into the food web so that they become food for fish or biodegrade, and convert to carbon dioxide," he explained.
Weed harvesting removes weeds, but if it is done without improving water quality, there is an algae bloom, because nutrients are there in the lake and they have to go someplace. Wet landing is another conventional method. Take, for example, a stream flowing into a lake. It is kept shallow and weeds are planted that absorb phosphorus and nitrogen before the water enters the lake. Again that does not take care of nonpoint sources.
Working with French engineers in 1992, CLEAN-FLO restored the Helpe Minuere river in Fourmies, France, for which the city won two prestigious environmental awards front the French Government. There was a 19-kilometer stretch of the river in an industrial region with no fish or insects for 43 kilometers. Feng-Shang drinking water reservoir with hundreds of pig farms upstream was restored in Taiwan. Other notable projects include Silver Springs Lake in Wisconsin, Lake Yononnolka in North Carolina, Lake Weston in Florida, Upper Marlboro Lakes in Maryland, Sweeney Lake in Minnesota, St. James Park near Buckingham Palace in London, and Olympic Park in Seoul.
But do rivers pose a difficult task to treat? No. A lake, that has inflow and an outflow, is a slow-moving river, Laing said. What is looked at is the volume of water and parameters like the content of phosphorus, nitrogen, and ammonia, and biological and chemical oxygen demands (BOD and COD, which are measures of oxygen consumed in the decomposition of various organic matter). The bottom of a river does not flow; the surface flows and going downwards, it is a parabolic curve - zero water speed at the bottom and as you go up, the velocity increases. The lake process is duplicated in a river. The speed of moving water does not hamper the treatment process. Inside a polluted town, if a river is shallow, it will restore itself through the same process.
CLEAN-FLO operates in India through its representative based in Mumbai, who hires Indian labor to install the equipment. He supervises the installation of the equipment, imported from the U.S., and its maintenance, which is done every three months - some filters need replacement. "We have some installations operating for the last 20 years. For the first few projects in any country, we send one of our supervisors over," Laing said.
No human intervention is required to operate the equipment. Once started, they run all day. In five to six years, a few parts in the air compressor, and in 7-10 years, bearings may wear out. Turning off the equipment for five days results in an algae bloom. It requires minimal maintenance -annual maintenance costs typically range between 10 and 20 percent of the equipment cost.
Two finished projects in India are the Kachrali Lake cleaning project in'Inane, Maharashtra, and a few lagoons for the Leela Group of Hotels in Goa, which was done about three years ago. "We installed CLEAN-FLO aerators in the lagoons in late 1996 and they have been functioning well since then. There has been a marked improvement in the clarity of water as well as adequate oxygen levels," said Col. U .C. Thakur, general manager (projects) of the Leela Group. "We would definitely be using CLEAN-FLO treatment system, for water treatment in any of our future projects," he said.
Laing said although hyacinth seeds are present in the four-hectare Kachrali Lake, where CLEAN-FLO systems were installed in January 1999, they won't germinate due to lack of nutrients inside water. But the results for the lake could have been better had CLEAN-FLO taken up the responsibility of post-installation management, he said. The lake does not have the water transparency that meets CLEAN-FLO's standards as some substances not recommended by the company were added to the lake afterwards, he said. The company is eyeing several other Indian projects that include the Yamuna River near Delhi, which has extremely high levels of fecal and other pathogenic bacteria; Dal Lake in Srinagar; Kerala Inland Waterwavs; Rabindra Sager Lake in Kolkata; Powai Lake in Mumbai; Hebel Lake in Bangalore, that is totally covered with hyacinth; and a polluted reservoir in Chennai.
The time required for installation depends on the size of the project. The Kachrali Lake project took about ten weeks in all- three weeks to put the equipment together, five weeks shipping time and a week or two for installation. Periodic assessment and monitoring are done. The company relies on its database of 31 years of case reports. When a fresh query is entered, the computer replies with options for any particular project.
The cost is not at all high, according to Laing, and the larger the waterbody, the cheaper it is. The cost is one-tenth the cost incurred in dredging or nutrient diversion. "For a single typical small river, conventional methods of treatment could require around $100 million whereas our process could cost about $20 million," Laing said. For a small lake, it could be roughly $10-15,000 per hectare.
He said there have been several proposals made over the years for cleaning the Yamuna River, but nothing has been done. "We can do it [clean the Yamuna] and I promise you it will be a small fraction of any other thing that is being proposed. But it might still be expensive," he said. The World Bank has agreed to fund projects in India that would use the CLEAN-FLO process, he said. But nothing concrete has been finalized yet.
The major problem associated with CLEAN-FLO systems is improper maintenance by the customers when they take charge after installation. As a result, the water quality goes down gradually and the company is blamed. Change of staff is another serious problem. "New staff does not understand CLEAN-FLO systems and turns them off. When the algae bloom occurs within a week, they do not relate that to the equipment. And this happens even in the United States," Laing added.