Water Purification Technology Progress - From 1997 to the 2020s

Water Purification Technology Progress - From 1997 to the 2020s

### Beginnings in the 1990s
In 1997, a groundbreaking purification plant utilizing membrane separation technology (membrane technology) began operations in Kariya City, Aichi Prefecture. This plant could process up to 10000 tons of industrial wastewater daily, efficiently removing over 90% of contaminants, including heavy metals (lead, cadmium), nitrogen compounds, and organic pollutants. Post-treatment, the concentration of heavy metals in the discharged water was reduced to below the standard value of 0.01 ppm, significantly contributing to the ecological recovery of the Yahagi River. The project was realized with approximately 5 billion yen in subsidies from the local government, and its construction cost totaled around 20 billion yen.

### What is Membrane Separation Technology?
Membrane separation technology involves using ultra-fine membranes to selectively separate and remove contaminants. Commonly used membranes include reverse osmosis (RO), ultrafiltration (UF), and nanofiltration (NF), each capable of removing specific contaminants. For instance, RO membranes have ultra-fine pores (0.0001 microns) and are highly effective at removing salts and heavy metal ions, making them ideal for seawater desalination and advanced water treatment. Key features of membrane technology include:
- **High Purification Efficiency**: Effectively removes hazardous substances and microorganisms.
- **Environmental Friendliness**: Requires minimal chemical usage.
- **Versatility**: Applicable to industrial wastewater, domestic wastewater, and seawater desalination.

Although reducing operational costs was a challenge, advancements in membrane durability and energy efficiency in the 2000s led to increased adoption.

### Developments in the 2000s
In the 2000s, membrane separation technology became more widespread nationwide. In 2005, a new purification facility in Fuji City, Shizuoka Prefecture, processed up to 12000 tons of wastewater daily, achieving over 95% removal efficiency for nitrogen compounds and phosphates. In Yokkaichi City, Mie Prefecture, specialized membranes were introduced to efficiently remove benzene and toluene from petrochemical industrial wastewater. By 2008, Japan's total annual treatment capacity exceeded 10 million tons, supported by government-led environmental policies. This period also saw the development of energy-efficient membrane systems, further reducing costs and improving efficiency.

### Global Expansion and Innovation in the 2010s
In the 2010s, membrane separation technology expanded beyond Japan. In 2013, a large purification facility utilizing Japanese technology was completed in Jakarta, Indonesia, with a daily capacity of 30000 tons of domestic wastewater. Within Japan, the durability of membranes improved, extending their average lifespan to 7 years and reducing annual maintenance costs by 20%. In 2015, a seawater desalination plant in Kumamoto Prefecture began operation, supplying up to 10000 tons of drinking water daily. This facility boasted a high desalination rate of 99.5%, contributing significantly to local water resource security.

### Current Status and Prospects in the 2020s
In the 2020s, a new facility in Fuji City achieved a daily processing capacity of 15000 tons, reducing heavy metals (lead, arsenic) concentrations to below 0.001 ppm. Additionally, Yokohama City, Kanagawa Prefecture, launched a seawater desalination facility capable of producing 30000 tons of drinking water daily, with a production cost of 0.5 yen per liter. Membrane separation technology is also adopted in water-scarce regions in the Middle East and Africa, addressing global water resource challenges.

Since its inception in the 1990s, membrane separation technology has evolved into a foundational technology for sustainable societies. Its importance continues to grow, particularly in addressing water resource challenges exacerbated by climate change and population growth.