LocationsUNDP-Japan partnership turns wastewater into opportunity through Johkasou technology, building climate resilience across communities
June 27, 2025
Many regions struggle with water scarcity as consumption exceeds freshwater reserves. This is particularly acute in Karakalpakstan, Uzbekistan, where declining precipitation and rising temperatures intensify water stress. Uzbekistan's growing population and economic expansion further widen the supply-demand gap, posing a critical challenge for sustainable development.
These water challenges have far-reaching consequences beyond supply shortages. In Karakalpakstan's arid plains, water scarcity and the Aral Sea's disappearance have left communities struggling with basic sanitation needs. Across rural Uzbekistan, conventional sewage systems are often absent, forcing families, schools, and healthcare facilities to rely on outdated septic systems that pose serious health and environmental risks. To address this challenge, the United Nations Development Programme (UNDP), in partnership with the Government of Japan, Uzbekistan's Ministry of Agriculture, and Jokargy Kenes (Parliament of Karakalpakstan), is piloting an innovative solution: the compact Japanese Johkasou wastewater treatment system.
From left: Mr. Anas Qarman (UNDP Deputy Resident Representative), Mr. Hatori Takashi (Ambassador of Japan to Uzbekistan), and Mr. Alisher Shukurov (Deputy Minister of Agriculture) during the launch in Tashkent of the project supporting self-reliance through climate-resilient agriculture in the Aral Sea region.
What Is Johkasou?
Originally developed in Japan in late 1940s, the Johkasou system was designed to tackle public health crises caused by inadequate sanitation. Unlike traditional septic systems, which rely on soil filtration, the Johkasou system uses tanks to separate solids from liquids, break down waste without oxygen, and disinfect it.
Inside view of the Johkasou wastewater treatment system showing the compact tank design with internal piping that efficiently separates and treats wastewater for safe reuse.
The result is a compact, energy-efficient, and highly effective system that separates and cleans wastewater, making it safe to reuse or release for watering gardens and plots. Ideal for places where conventional systems fall short, Johkasou offers much flexibility.
In March 2025, with funding of $96,000 from the Government of Japan, UNDP and Uzbekistan’s Ministry of Agriculture as well as Jokargy Kenes introduced Johkasou systems at three key public institutions in Karakalpakstan. Each site—a rehabilitation center, a kindergarten, and a specialized school—was carefully selected to demonstrate how decentralized wastewater treatment can meet urgent sanitation needs in health, education, and care settings.
Clean Water for Healing
Rehabilitation center in Nukus district
At the Center for Rehabilitation of Persons with Disabilities in Nukus district, the Johkasou system has transformed daily operations. Serving around 3,500 patients annually—including the only prosthetic care unit in the region—the center now has a reliable source of clean water that is also used for agriculture on its grounds. The ability to reuse water enabled the cultivation of fruit and vegetable crops—a particularly valuable solution in a region facing acute water shortages. These homegrown harvests now help provide fresh, nutritious meals for the patients, making the system not only a technical upgrade but a direct contribution to their care and well-being.
Zhenisbay Tursynbekov, facility manager at the center, enthusiastically talks about the new opportunities: “With the installation of the system, we started growing tomatoes, cucumbers, pumpkins, and fruit crops. There are no problems with irrigation – the treated water allows us to efficiently use every drop. We no longer worry about the harvest.”
In addition, the expansion of green areas and planting of trees around the facility has created a more vibrant, calming environment. This growing ecosystem not only improves the local climate but also has a positive impact on the mental health of patients, offering a more peaceful and healing space during their rehabilitation.
Rehabilitation center officials with Akiko Fujii, UNDP Resident Representative, during the launch of the Johkasou system in Nukus district
“Reliable access to clean water is vital for quality patient care. The Johkasou system has improved the center’s working conditions and opened new opportunities for the institution’s self-sufficiency,"concludes the center’s director.
Safer Classrooms for Young Learners
At Kindergarten No. 13 in Nukus, a smaller Johkasou unit ensures that children and staff have access to safe sanitation facilities. In a setting where poor water quality previously heightened health risks, the system now plays a key role in keeping the youngest community members safe and healthy. Beyond hygiene, the presence of the system has become a valuable educational tool—helping children understand where water comes from, why it must be used wisely, and how small actions can make a big difference.
Teachers lead outdoor activities like watering garden beds, watching plants grow, and playing games that show how water is reused. These fun lessons help children learn to value water and care for the environment from an early age.
“Now our children can play and learn in a cleaner, healthier environment,”shared Tursinay Ilyasova, kindergarten teacher.
Supporting Inclusive Education
At the State School for Children with Scoliosis in Khodjeyli district, a new Johkasou unit has improved hygiene and comfort for students with special needs. Managed by the Ministry of Preschool and School Education, the school now has a reliable water treatment system that supports both care and inclusion.
The system also encourages students and staff to use water wisely. Children are learning its value and how to avoid waste—an important lesson in a water-scarce region.
As one parent said, "It’s a relief to know our children are in a clean, safe place and learning to respect nature too."
A Measurable Impact
Since their installation in March 2025, these systems have treated over 16,400 cubic meters of wastewater—enough to irrigate 12–13 hectares of land per year using recycled water. This not only improves sanitation and public health but also opens new possibilities for water reuse in agriculture, which is critical to water-scarce regions.
Demonstration of the Johkasou system at the rehabilitation center
More than just infrastructure, these installations represent a shift toward sustainable, community-driven water solutions. Cleaner facilities and safer environments are just the beginning.
For many families, economic relief is just as important. The Johkasou system lifts a heavy burden—freeing residents from expensive wells construction. That means more money stays in the household, supporting daily needs, education, and well-being. It’s a solution that doesn’t just clean water—it strengthens communities.
Apart from significantly reduced water bills, Johkasou eliminated the risk of waterborne infections, and ensured plants thrived with nutrient-rich treated water. Johkasou didn’t just solve a problem—it redefined how water is used: smartly and safely.
Why It Matters
The benefits of the Johkasou system go beyond clean water. They help:
- Protect public health, especially in schools and healthcare institutions
- Prevent groundwater pollution, vital in regions where well water is the only option
- Reduce long-term costs, thanks to minimal maintenance and the potential for water reuse
- Operate efficiently with very low energy use, requiring only a small pump to function
Looking Ahead
Following the UN General Assembly resolution of May 18, 2021, which designated the Aral Sea region as a zone of ecological innovations and technologies, international partners have intensified transformation efforts. This landmark resolution, initiated by President Shavkat Mirziyoyev and co-sponsored by Japan, established a framework for multilateral cooperation.
Building on this foundation, Karakalpakstan demonstrates how innovation addresses complex environmental challenges. Facing climate change, Uzbekistan's growing population, and environmental degradation, the region requires integrated solutions. The technologies piloted here offer scalable models for nationwide implementation across Uzbekistan.
This collaborative approach reflects Japan's commitment to climate-resilient development and human security, aligning with UNDP's mandate to protect vulnerable communities. The partnership leverages Japan's technological expertise to enhance regional resilience and improve livelihoods.
