LAKE AERATION SYSTEM OF NAINITAL, INDIA
A story from Dennis Williams


Lake Nainital is located near the borders of China and Nepal, Nainital (Tal means lake in Hindi) is east and slightly north of Delhi about 300 KM or about 9 hours of the harrowing experience they refer to as driving. This was the culmination of three years of planning. The aeration system for this very sick lake was finally about to be installed and we were on our way to do it.

We cleared the airport about 1:30 a.m., piled our stuff into a rather “safari” looking Toyota and headed for the lake.

At night is when th e trucks in India take to the road in mass because their engines run cooler; and also there are way fewer cars, pedestrians, oxcarts, tractors, rickshaws, horse drawn wagons, water buffalo, cows, dogs, monkeys, homebuilts, buses, bicycles, motorcycles, and other vehicles that simply defy description.

It was 2 in the morning and we were still within the suburban limits of Delhi on a divided four lane highway when all the trucks in the slow lane and then the “fast” lane came to a decided halt. Even though it was two in the morning it was still most of a hundred degrees and what seemed like at least 250% humidity. Our driver Sanji got out, surveyed the scene and then disappeared for a moment. When he returned the truck in front of us pulled forward about ten feet and we immediately followed. Sanji disappeared again.



This time when he returned the truck pulled up another five feet; just enough to expose a missing concrete barrier. A space appeared between it and the truck just big enough for the Toyota to squeeze through. Zip, and there we were on the other side of the divided road headed directly into the lights of oncoming traffic. Fortunately, this was India so no one was really surprised or even particularly cared about our chosen position on the road; oncoming traffic just simply moved over out of our way. After about three quarters of a mile another barrier was miraculously missing and voila, only partially airborne, we were back on our own side of the road. We never did see the cow or whatever it was “sticking up” the traffic. This actually turned out to be one of the saner, even verging on boring moments we experienced being driven around in India. Actually, I considered it a miracle that we only hit one pedestrian the whole trip. (The particular gentleman was actually quite embarrassed for being “horn deaf”).

The Himalayas are not preceded by rolling hills and then foothills. They shoot right straight up from the flat level plains. In the course of 25 feet you have gone from level to a rather formidable grade. The road switchbacks up the face for nearly 30 kilometers, all the while the view looks out over the hazy plains. Finally after a 7,000 ft climb the road takes a turn to the right and a mere 50 feet further is the lake. With the exception of the entrance the lake is surrounded by more higher, steep mountains.


Because the lake is virtually perched on the side of a cliff there is a phenomenon where the clouds drifting over the plains suddenly bump into the mountains. The tops of the clouds continue to drift over the lake. When this happens it amounts to a dense fog on the lake for a refreshingly cool minute or two. The cloud passes and the sun returns. The locals say “the cloud kisses the lake”.

When we finally arrived at Nainital it was ten in the morning. One of the obvious things we noticed was that the amount of litter along the road, in the town, in and around the lake was truly phenomenal. It was the way of the land: open it and simply drop it.
The lake itself had been, until recently, receiving all of the city’s sewage. The considerable monsoon runoff from the roofs and roads still runs unchecked into the lake.
Before the British came the roads were unpaved. The water entering the lake, which was then an azure blue, now a kind of pea green, was naturally filtered before entering the lake.
I was informed that the town’s wastewater had been diverted from the lake. I was glad to receive this news and really wanted to not know just exactly what they were doing with it.
Still, each morning the lake surface would be floating with litter. Sometimes the newly installed aeration disks would form it into giant rings until the daily breeze would gently disperse it to where it could assume its part in the ever growing mass of disgusting flotsam accumulating along the lake’s edge. Fortunately this situation was, by the time I left, “miraculously remedied”. But, I digress…

When we began the installation of the aeration system at Nainital there was very little dissolved oxygen in this lake with more than 90 feet of depth. The oxygen bearing epilimniom was only the top 2 meters and the thermocline occupied perhaps only one more at most. Below that was 75 feet of truly anoxic water with BOD’s exceeding 35 mg/l and nutrients through the roof.

Before actually placing the aerator disks we first dispatched buoys to mark the locations. I was on a high spot on the trail between the two installations chatting on the walkie talkie with Matt who was out in the boat placing said buoys. I was having a difficult enough time communicating on those cheap chatter boxes when the temple bells a few feet away started in with their “bong, bong, bong, bong…”. This was a regular occurrence lasting sometimes several minutes to a quarter hour or more. Amid this I became aware of someone right behind me who proceeded to sit down. The chills really didn’t go up my spine until my peripheral vision caught him taking out what appeared to be a really big snake.

He then commenced to serenade me on his “snake charmer horn”. By this time I had pretty much given up on the walkie talkie conversation with Matt. Once I had composed myself I gave the snake charmer some rupees and took his picture. The next day we caught up with him in the Tibetan market. I had translators with me so we struck up a conversation and before it was over he let me try playing his horn.

I left with a whole new respect for his abilities. He could really play. I must admit that I never saw the snake move and I couldn’t even be totally sure it wasn’t rubber. None the less, how many folks do you know who travel home from India saying they played the snake charmers horn?

By the time we had installed most of the aerator disk modules the thermocline had completely disappeared and the remaining top oxygen was mixed, diluted and subsequently devoured by the huge oxygen demand waiting in the rest of the lake. The resulting zero dissolved oxygen anywhere in the water column did cause a few concerns at first.
It was six in the morning. The temple bells across the lake had been bonging for a half an hour or so and I had my earplugs in. Believe me, nobody in India does anything quietly. I was just conscious enough to discern a banging on the door and make out a voice saying “fish kill, fish kill”.

Well, missed my shower that morning. We hurried down to the lake to find dozens of people lined up and pointing out in the lake.

Sure enough there was a dead fish floating and a bunch more up on the surface gasping for air. Someone had grabbed one of the 12 kg monsters called Brigand or Big head, perhaps to eat. He was being soundly beaten by another for killing a supposed sacred fish.
We thought there might be a riot so we took a hasty leave of the whole situation. The press soon ran stories of hundreds of dead smelly fish floating on a stinking lake and distressing residents. This is actually pretty close to right. The aerators were in fact bringing anoxic water directly up from the lake’s sludge ridden bottom that had an aroma that let’s just say was bad enough to defy any description in polite company. We were secretly hoping the town’s folk didn’t show up with some Indian version of torches and pitchforks in the middle of the night.

Just when things seemed darkest we received two important redeeming morsels of information from Dr. Sharma, the official university limnologist (Lake Scientist). First, that for the first time in a great many years the ORP had gone from negative to positive; that very morning. This was the sign we were looking for, we were actually making a difference. Secondly, the fish that had died were undesirable zooplankton strainers, and were no longer legal to stock in India. The remainder were slated to be netted and removed. There was a full on press conference at the city hall. However, this time the press got it right and people started to receive true information. The crisis was diffused and the dramatic improvements in the lake since have rendered it forgiven and/or forgotten.

Nainital is kidney shaped. An ancient landslide divided the lake into two distinct deep basins with a shallow area in between. These basins on each end of the lake are respectively called Malital and Talital. There is a separate compressor house and installation of aerator disks on each end of the lake.
The entire system consists of thirty 100’ LTC aeration disks from Air diffusion Systems in Gurnee Il. There are two 30 HP Kaeser rotary screw compressors supplying the air. They are equipped with refrigeration and dryers to prepare the airflow to receive the ozone.

Each installation has the capability to inject 54 grams per hour of ozone. This is mainly for maintenance of the orifices in the aeration tube.

The ozone equipment was supplied by Clearwater Tech and the ozone pumps to inject the ozone to a 40 PSI air flow were provided by Ozone Solutions.

Launch of an ADS disk module.

Flow meters
The most amazing not to mention serendipitous part of this whole adventure is that at the very same time we were installing the aeration system to restore the lake, there was a full on movement to Clean Up Nainital coming to fruition. The drive was being spearheaded by a Dutch Australian named Remco waiving hat at left. He engaged the ministers (city leaders) as well as the schools.

Together they sponsored a poster contest for the students in the schools. The theme was what the lake means to them, how to clean up the lake, the town and beyond. There were over six hundred entries. The students took pledges home for their parents to sign promising they would not litter.

City Hall realized that if you want people to deposit litter you must give them a place to throw it; so they provided trash cans. This entire town of 70,000 people turned out with brooms and rakes, dust pans and wheel barrows. The oarsmen used the paddleboats to collected virtual mountains of litter and garbage.

The entire population literally cleaned the town from one end to the other. In the three weeks I was there the town morphed from a virtual dump to a completely changed place not only in terms of cleanliness but a whole new found sense of community pride.

Sept. 18, 2007 was the day designated as “Clean Up Nainital Day”. There was a tent with space for dignitaries and guests. School let out so every school kid in town and many of their parents participated. The press was out in force. It was a major event.

There was a PA system that resembled something out of M.A.S.H. From it came a seemingly endless series of speeches given by mayors, government ministers and a stream of other dignitaries and officials I couldn’t begin to name. It was very hot in the sun and everyone secretly wished for a cloud to “kiss the lake”.
From there all were invited to come and celebrate the dedication of the aeration project at the nearest compressor house.

There were high commissioners and city ministers in abundance. The Hindu priest blew his conch. There were flowers on the flow meters and a special concrete and marble monument outside with all the information engraved in Hindi. They also served these neat little “oranges”. They are balls of sweetened cous cous with chunks of green pistachio nuts for stems.

One month after official startup there was over 8.2 mg/l of dissolved oxygen on the surface and over 6.7 mg/l on the bottom; right down in the mud. The Secchi depth had increased to over three meters and the bottom was now visible around the shoreline. The odors went away and the lake did not turned its usual seasonal shade of black but rather a rich emerald green. Daphnia culture was being introduced to further reduce the algae and enhance the zooplankton levels. Soon they will begin re-introducing desirable species of fish.

The residents are happy, the ministers are pleased, the local press is giving good reports and the project is receiving coverage on both state and national TV.

It was an honor and a privilege to have been part of this amazing endeavor.

SPECIAL THANKS TO:
- "Happy" Randhawa
- Dr. Anil Sharma
- Baljeet
- Moga
- Babu
- Anand

And the rest of the new friends who made this trip a success.

This shot was taken within six months of start-up. The lake has begun to change back to its original azure blue color.