Bubbles could help clean Lake Apopka

WEST ORANGE — Although Lake Apopka has improved since its worst point decades ago, the process has been gradual, with local advocates such as Friends of Lake Apopka leading efforts to restore the largest body of water in Orange County for its important ecological and anthropological benefits.

But a Japanese designer, Santoshi Anzai, has created a technology that could expedite that process, through a simple process that diffuses bubbles into seabeds and lake bottoms, which adds oxygen to help restore aquatic life. His staff has already met to discuss how the technology could benefit Lake Apopka.

In Anzai’s technology, a pump produces a water jet and a unique carbon-ceramic nozzle makes minuscule bubbles that shrink to nanometer size as they traverse water.

“There are traditionally six ways of making nanobubbles, which by and large means making bubbles into smaller bubbles or using a lot of energy to push bubbles out,” said Tony Humphreys, business development director for Anzai Machine Customised Service. “Ours is an entirely different system. Our diffusers work by osmosis. The gas goes into a diffuser with no single exit point. It actually diffuses through the material. We don’t need to pump liquid through our diffuser. We pump liquid over the outside of the diffuser.”

A small factory run by Anzai Kantetsu invented the technology, which is simpler and less expensive than other micro-bubble technologies. Nanobubbles remain in the water for a significant time because they are smaller and too light to rise to the surface, even after the nozzle is removed, and about 90% of the bubbles will osmose — double the rate of some micro-bubble technologies, Humphreys said.

“Ours works off the energy of a lightbulb, with just 29 psi,” he said. “We’re working on one that can work on just water power. The other difference is … we can put gas into larger diffuser heads and then increase pickup area of the liquid, which means the viscosity of the liquids we can handle (is) thicker.”

For Lake Apopka, Anzai MCS would have a large system firing oxygen into the lake bottom, if talks with local environmental experts and tests on smaller areas of the lake match the company’s research, Humphreys said.

“We want to get to the objectives of the community, which are to clean the whole thing up,” he said. “We’re very excited about the environmental aspects of it.”

Santoshi Anzai stands behind the technology and even uses it in his personal fish tank, where ordinary air pumped in has not only removed the need to clean the tank for two years but allowed freshwater and saltwater species to co-habitate, Humphreys said.

Moreover, a 2011 experiment at Nippon-maru Memorial Park in Yokohama, Japan, tested the device with propeller-shaped stirrers and a bubble-defusing nozzle. The device fit in a truck and was easy to place in the water without heavy machinery. Three divers installed it 10 meters below the surface within a half-day. Although the top of the water looked clean, the bottom was covered in sludge and showed few signs of aquatic life.

“Normally, bubbles rise to the surface, but most aquatic life is at the bottom,” Santoshi Anzai said. “Nanobubbles shrink on their own and are picked up by currents, which carry them to the seabed, where they mix into the sludge. Nanobubbles can supply oxygen to organisms at the bottom of the sea.”

Bubbles usually stay in the system for three to five hours but sometimes can last three months, Humphreys said.

Experiments in 2013 at Hakkeijima Sea Paradise near Tokyo Bay in Yokohama also featured a water body with thick sludge at its bottom. Within six months, there were shrimp species near the bottom that could not survive in poor oxygen environments.

In January 2014, the experiment ended with drastic changes in aquatic life, including various types of fish and seaweed growths.

For Lake Apopka, the pollution from now-extinct farms has largely stopped, which means pumping nanobubbles into the bottom could have a permanent effect and renew the ecosystem.

“We introduce more oxygen, introduce other plankton that the fish will eat and then build up the fish in a cycle again,” Humphreys said. “It’s about trying to address the environmental balance naturally without chemicals.”

A small, short-term test would last six months, which would prompt a larger two-year test if successful, Humphreys said.

“Over two years, you’d look for the next level change,” he said. “At some point in there, you might feel confident enough that this is working and scale it around what time period may be there or the costs and budget.”

Because in-person meetings with local officials have not happened yet, Humphreys was uncertain of those costs for the area. But this much is certain: As climate change worsens and oxygen levels in water bodies are depleted, ecosystems gradually worsen until most aquatic life dies out. With nanobubbles, bodies like Lake Apopka and perhaps even oceans could find new life.

Contact Zak Kerr at [email protected].