Water Regeneration - The Trajectory of Water Purification Technology from the 1990s to the 2020s

Water Regeneration - The Trajectory of Water Purification Technology from the 1990s to the 2020s

As humanity has developed, we have used, polluted, and then advanced technologies to purify water. In modern times, it is essential to purify water while minimizing environmental impact and building a sustainable society. This document introduces the evolution of water purification technologies from the 1990s to the 2020s and the innovations that support them.

The water purification technology developed by the Ministry of International Trade and Industry's Industrial Technology Institute and Shimane University's Brackish Water Research Center leverages natural food chains. To prevent water pollution caused by excessive nutrients, this method utilizes natural food chains to balance the nutrients in water bodies. In Lake Nakaumi, Shimane Prefecture, this technology has been implemented as part of a fishery restoration project, regulating plankton growth and restoring water clarity through predator control.

Ehime Industrial Technology Center has developed a new water purification technology that utilizes microorganisms used in fermented foods, such as yeast, lactic acid bacteria, and Bacillus subtilis. Unlike conventional wastewater treatment, this method uses naturally derived microorganisms to reduce sludge and eliminate odors. In a demonstration experiment at the Yawatahama Kamaboko Cooperative's fish fertilizer production facility, sludge was reduced by 70–80%, significantly lowering costs. This technology offers a low-cost, environmentally friendly alternative for future water treatment.

Membrane separation technology has also evolved for advanced water treatment. By combining reverse osmosis (RO) membranes, ultrafiltration (UF) membranes, and nanofiltration (NF) membranes, over 90% of heavy metals, nitrogen compounds, and organic pollutants can be removed, achieving water quality below regulatory thresholds. In 1997, a purification plant in Kariya City, Aichi Prefecture, processed 10,000 tons of wastewater per day. In 2015, a seawater desalination plant was established in Kumamoto Prefecture, supplying 10,000 tons of drinking water daily. By the 2020s, Yokohama City had increased its drinking water production to 30,000 tons per day, significantly improving cost efficiency.

Shimane Ecotech Corporation has developed a biofilter technology aimed at improving water quality in rural areas. Many rural regions lack adequate household wastewater treatment, but this technology prevents pollution expansion. Additionally, it is used for environmental education with community involvement, making it a valuable contribution to sustainable society.

Hitachi Zosen Corporation has developed a next-generation biofilter technology to improve water quality in Lake Biwa. As Japan's largest lake and a critical water source for the Kansai region, Lake Biwa faces severe water quality deterioration due to eutrophication. The introduction of biofilters, along with reducing chemical fertilizer use, has helped restore water quality while preserving the lake's ecosystem. This technology is expected to be applied to other lakes and wetlands.

The progress of these water purification technologies is crucial for our future. Various methods have been developed, including approaches that harness natural forces, microbial treatments, and advanced membrane technologies, all aimed at sustainable water resource management. Further advancements in these technologies will be necessary to ensure a cleaner water environment for future generations.

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Related Information
- Research at Shimane University's Faculty of Bioresource Sciences: Details on water purification using food chains in brackish water areas.
- Research at Ehime Industrial Technology Center: Study on water purification technology using fermentation microorganisms (official materials not confirmed).
- "Ise Bay Environmental Conservation Comprehensive Survey Manual" by Mie Prefecture: Details on advanced water treatment using reverse osmosis and ultrafiltration membranes.
- Shimane Ecotech Corporation's Initiatives: Biofilter technology specializing in household wastewater treatment (official materials not confirmed).
- Research by Hitachi Zosen: Biofilter technology for improving water quality in Lake Biwa (official materials not confirmed).