[Wonders of the World] Kumamoto - The Truth of Groundwater Cities💧
Kumamoto City has 100% groundwater, which is rare in the world. It is the only city in Japan with a population of over 500,000 and is extremely rare in the world 👇
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* * 【 Kumamoto Groundwater System 】 * *
✅ * * Water Source * *: Groundwater and Underground Water in the Aso Mountains
✅ * * Filtration period * *: Natural filtration over about 20 years
✅ * * Water quality * *: Natural soft water (hardness 60-80mg / L)
✅ * * Features * *: Natural mineral water from faucet
This is truly a blessing of nature that we can be proud of in the world.
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* * However...Scientific facts you need to know] * *
Because it's groundwater, there's a risk of soil derived molecular level impurities.
⚠️ * * Nitrate nitrogen (NO3-) * *
・ Source: Agriculture (fertilizer), livestock industry
Molecular size: about 1nm
・ Feature: Completely soluble in water, cannot be removed by normal filtration
・ Challenges in Kumamoto: Continuous Influx from Agricultural Areas
⚠️ * * PFAS (Organic Fluorine Compounds) * *
・ Source: Industrial products, fire extinguishers, etc.
Molecular size: 0.5 nm
・ Feature: A global problem as "eternal chemicals"
・ Actual situation in Kumamoto: Exceeding the provisional target value was detected from the well water in the city in 2023 (announced by Kumamoto Prefecture)
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* * [Limits of municipal water treatment] * *
Water treatment in Kumamoto City is properly implemented based on laws and regulations, but there are physical limitations:
・ Sedimentation / Filtration: Remove only large particles
・ Chlorine disinfection: Removal of bacteria and viruses
・ Molecular level: Impurities in nm units
This is not limited to Kumamoto City, but is a common technical limitation nationwide.
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* * [Solution: Molecular level removal by RO membrane] * *
・ RO membrane pore size: 0.1 nm
Nitrate nitrogen: 1 nm → physically blocked
PFAS: 0.5nm → Physically blocked
・ Water molecule: 0.3nm → can pass through
Due to the physical laws of molecular size, only impurities can be reliably removed.
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* * [Important Supplement] * *
✓ Kumamoto city tap water meets the water quality standards
✓ This post is not intended to criticize Kumamoto City
✓ It is a proposal to add science and technology to the world-class groundwater system
The blessings of nature + the power of science = true safety and security
Save and look back 🔖
This post is for sharing knowledge on water quality science
With respect to Kumamoto City
※ Source: Kumamoto City Water and Sewerage Bureau, Ministry of the Environment, Kumamoto Prefecture Survey Data
# kumamoto The Groundwater City Rare in the world. # PFAS Nitrate nitrogen