A company uses the tools of nature to restore polluted lakes and rivers
When a young electronics engineer running a computer designand electron ballistics consulting firm in the late 1960s decided to ventureinto a lake cleaning business, it was one of the most unusual career decisions.
That was the time when the United States discovered thathundreds of its water bodies were polluted and scores of students startedjoining courses in lake restoration. The techniques they were taught were allconventional. These included dredging, nutrient diversion and weed harvesting.But Robert L. Laing thought of introducing newer approaches that imitate naturalprocesses and minimize use of harmful chemicals.
Why did Laing shift from electronics to water pollution?While developing a high voltage thermionic energy converter, which converts heatto electricity. Laing, stumbled upon a process to solve water pollution problems.”So it was natural to move on to the next step: water pollutioncontrol,” he explained, during a recent visit to India.
He started his career in 1958 as an aerospace systems designengineer with General Dynamics, Fort Worth, where he designed thebombing/navigation test computer for the B-58 Hustler airplane. Unfazed bycriticism, he founded CLEAN-FLO Laboratories, Inc. in 1970, two years before theU.S. Environmental Protection Agency (EPA) began. But business was hard to comeby initially. CLEAN-FLO’s methods were difficult to accept for the scientific community at that time, though it does endorse them now. “Although therewas 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 a 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. In1987, it started expanding its international business. Three-fifths of itsbusiness now comes from abroad. “It was much easier to be accepted outsidethe United States because of what the consultants knew in the U.S., what theywere programmed to do like dredging, nutrient diversion, et cetera,” Laingsaid. Today CLEAN-FLO has projects running in India, Japan, Korea, Taiwan, thePhilippines, 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/oxygenationsystem; CLEAN-FLO lake cleanser, a nontoxic phosphate precipitant; Lake Care, anon-toxic water clarifier; Sky Blue Lake Dye; and microbes to feed on organicsediment, oils, pesticides, human sewage, phosphorus and nitrogen.
All water bodies restore themselves using natural processes. In coolclimates, lakes turn over twice a year due to temperature variations while inthe tropics, hurricanes, typhoons and other adverse weather conditions turnlakes over multiple times a year. This natural inversion has a lot to offer.CLEAN-FLO duplicates these “Spring and Fall” turnover and acceleratesit 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 andtoxic gases accumulated at the bottom are released. Putting oxygenated surfacewater on the bottom of lakes binds phosphorus and nitrogen to inorganicsediments like clay. This reduces the content of these two compounds in water byup 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. Theentire lake is artificially filled with oxygen starting from the bottom.Oxygenation kills anaerobic bacteria which live inthe absence of oxygen, and are the source of toxic hydrogen sulphide, sulphuricacid and ammonia gas. The sulphate in sulphuric acid already in the lake isabsorbed by microbes, plants and aquatic animals. Low-oxygen microbes convertnitric acid to inert nitrogen gas. Carbon in the sediment is used as an energysource, 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. Thisinitiates a flow called continuous laminar flow inversion. This releases toxiccarbon dioxide and nitrogen gas. The bacteria are also weakened and killed whenexposed to ultraviolet rays in sunlight. Reduction in phosphorus/nitrogenstarves the bacteria.
The key to the process is a special formulation, termed C-FLOby the company. Beneficial microbes, that feed on organic sediment, ooze andpeat at the bottom, arc introduced. These microbes convert this muck into carbondioxide and water. C-FLO also adds organisms that are natural food for aquaticinsects.
C-FLO multiplies as it (feeds) on muck, and insects grow andmultiply as they feed on C-FLO. Fish then feed on insects and grow rapidly. Thisresults in deepening of the pond, makes a better environment for fish and makesit 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 ascalcium tie up phosphates so the weeds and algae cannot grow. Sky-blue Lake Dyemay be added to shade the weeds and algae from sunlight and impart artificialcolor to the surface.
The initial dominance of these beneficial microbes in thelake environment gives way to natural competition between organisms that regainsa healthy balance. “The conventional method of dredging the muck candeepen a lake, making it more difficult for submerged vegetation to grow, butdoes nothing for water quality, algae and fish,” Laing said.
Nutrient diversion involves channeling of all possiblesources of sewage into a single zone where it is treated and then redirectedinto 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.T he problemwith nutrient diversion is non-point source pollutants, which cannot be avoided.One cannot stop people from throwing flowers into the river, and when it rainswater comes in from the watershed, Laing said. “That is one of the primaryreasons for poor performance of earlier methods. As you cannot stop pollutantsfrom entering the river, they should be treated internally and worked into thefood web so that they become food for fish or biodegrade, and convert to carbondioxide,” he explained.
Weed harvesting removes weeds, but if it is done withoutimproving water quality, there is algae bloom, because nutrients are there inthe lake and they have to go some place. Wetlanding is another conventionalmethod. Take, for example, a stream flowing into a lake. It is kept shallow andweeds are planted that absorb phosphorus and nitrogen before the water entersthe 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 theriver in an industrial region with no fish or insects for 43 kilometers. TheFeng-Shang drinking water reservoir with hundreds of pig farms upstream wasrestored in Taiwan. Other notable projects include Silver Springs Lake inWisconsin, Lake Yononnolka in North Carolina, Lake Weston in Florida, Upper Marlboro Lakes in Maryland, Sweeney Lake in Minnesota, St. James Park nearBuckingham 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 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 nothamper the treatment process. Inside a polluted town, if a river is shallow, itwill restore itself through the same process.
CLEAN-FLO operates in India through its representative basedin Mumbai, who hires Indian labor to install the equipment. He supervises theinstallation of the equipment, imported from the U.S., and its maintenance,which is done every three months – some filters need replacement. “We havesome installations operating for the last 20 years. For the first few projectsin 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 aircompressor, and in 7-10 years, bearings may wear out. Turning off the equipmentfor five days results in an algae bloom. It requires minimal maintenance -annualmaintenance costs typically range between 10 and 20 percent of the equipmentcost.
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 inthe lagoons in late 1996 and they have been functioning well since then. Therehas 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 ofpost-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 inSrinagar; Kerala Inland Waterwavs; Rabindra Sager Lake in Kolkata; Powai Lake inMumbai; Hebel Lake in Bangalore, that is totally covered with hyacinth; and apolluted 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 is done. The company relies on its data base 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 ornutrient diversion. “For a single typical small river, conventional methodsof treatment could require around $100 million whereas our process could costabout $20 million,” Laing said. For a small lake, it could be roughly$25,000 per hectare.
He said there have been several proposals made over the years for cleaningthe Yamuna River, but nothing has been done. “We can do it [clean theYamuna] and I promise you it will be a small fraction of any other thing that isbeing proposed. But it might still be expensive,” he said. The World Bankhas agreed to fund projects in India that would use the CLEAN-FLO process, hesaid. But nothing concrete has been finalized yet.
The major problem associated with CLEAN-FLO systems is improper maintenanceby 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.