A technology to help stagnant waters ‘breathe’ again

JStories ー The primary issues we have a tendency to think about after we hear the time period “international warming” are melting glaciers and rising sea ranges. Nonetheless, international warming can be a significant explanation for water air pollution. As water temperatures rise, phytoplankton multiply. This causes irregular development in organisms reminiscent of blue-green algae and reduces the quantity of oxygen within the water. Fish and different algae suffocate whereas foul odors and poisonous substances unfold, destroying the aquatic surroundings.

In recent times, international warming has triggered a series response of worsening water high quality and deteriorating ecosystems. This has been noticed in oceans, rivers and lakes not simply in Japan, however world wide. The presence of blue-green algae has even been confirmed in Russia’s Lake Baikal, considered one of many world’s clearest lakes.

One technique to halt this deterioration in water high quality and restore aquatic environments is a man-made course of known as “Lake Biwa deep respiratory.” It mimics a pure phenomenon in Lake Biwa, Japan’s largest freshwater lake, situated simply northeast of Kyoto. Through the winter, chilly air and wind trigger the chilly water close to the floor of Lake Biwa to combine with the hotter water on the backside, naturally equalizing oxygen ranges and water temperature. This purification phenomenon is named “full turnover” or “lake overturn” in English, however may happen within the ocean as a consequence of wave motion attributable to giant storms.

Previously, one methodology to advertise full overturn and revitalize stagnant water has been to blow air into the water. Nonetheless, it’s costly and the massive dimension of the gear required makes it unsuitable for rivers and different shallow our bodies of water. Chemical compounds may also be used for fast outcomes, however there are issues over long-term residual results on water high quality and ecosystems.

“This know-how improves water high quality all through all the water column, from the floor to the underside, by transferring water with water itself, and with out utilizing chemical brokers,” says Terai.

The fee to put in the Jet Streamer in a dam is 50 million to 100 million yen, however that is simply round one-third that of typical units. Resulting from its hole construction, floating rubbish gained’t get trapped within the gadget, lowering the necessity for upkeep. It’s primarily constructed from fiber-reinforced plastic, which mixes low weight with excessive energy and sturdiness. As soon as put in the system stays operational for over 10 years.

For the reason that Jet Streamer is smaller and lighter than typical units, it’s straightforward to relocate or take away and may also be put in in shallow areas reminiscent of rivers. This makes it appropriate for short-term seasonal initiatives, reminiscent of throughout summer season months when water high quality tends to deteriorate. The corporate additionally sells ultrasonic units and ozone mills, in addition to non-obligatory extras that provide versatile options for various conditions, together with blue-green algae circumstances, water depths, and ranging terrain.

In keeping with Terai, the corporate’s Jet Streamer has already been put in in varied areas, from Akita Prefecture in Japan’s north to Okinawa Prefecture within the south. It has been used for jellyfish management at sea, coping with purple tide and blue tide algae blooms, in dams, lakes and marshes, in fish farms, and for water high quality enchancment at crops. Inquiries have additionally been obtained from abroad, together with Olympic venues and international locations in Asia.

In 2024, the corporate partnered with Nagasaki Prefecture on demonstration experiments to regulate purple tides utilizing the Jet Streamer, whereas full-scale operational use of the gadget within the prefecture is scheduled for this summer season. Pink tide has triggered widespread harm in Nagasaki, together with the lack of round 530,000 farmed fish at an estimated value of 1.5 billion yen. Due to this, the native fisheries business has excessive hopes for the know-how.

The corporate can be engaged on a tool that makes use of air as a substitute of water; or, because it places it, “transferring air with air.” This was collectively developed with the Tokyo Metropolitan Sewerage Service Corp. and is already being utilized in sewer building.

“We’re ‘circulation specialists,’” says Terai. Our mission is to fire up stagnant issues and revitalize them.” 

Nagasaki Prefecture is especially vulnerable to stagnant water, surrounded as it’s with mountains, sea and plenty of bays. The native economic system has additionally stagnated in recent times, with the prefecture affected by a shrinking inhabitants compounded by what was Japan’s third-highest outward migration in 2023.

“Water, air, the economic system… all of them trigger issues after they stagnate,” says Terai. “We need to make them circulation, make them transfer, and revitalize. There are numerous locations in Japan and abroad that want our know-how.”

In the end, he says, his firm’s purpose is to not solely revitalize Nagasaki’s surroundings, however its economic system, too.

Translated by Tony McNicol

Prime photograph: Photograph courtesy of Ebismarine (Collage by JStories)

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