A new wastewater treatment initiative backed by the government of Japan and implemented by the United Nations Development Programme (UNDP) is offering practical solutions to one of Uzbekistan’s most pressing environmental challenges: water scarcity in the Aral Sea region.
As climate change, population growth, and the drying of the Aral Sea continue to strain water resources in Karakalpakstan, many communities remain dependent on outdated septic systems that pose health and environmental risks. In response, UNDP, in cooperation with Uzbekistan’s Ministry of Agriculture and the Jokargy Kenes (Supreme Council of Karakalpakstan), has launched a pilot project introducing Japanese Johkasou wastewater treatment systems in three public institutions.
With $96,000 in funding from the government of Japan, the Johkasou systems were installed in March 2025 at a rehabilitation center, a kindergarten, and a specialized school. The systems are designed to operate independently from centralized sewer networks, treating wastewater on-site and making it safe for reuse.
Originally developed in Japan in the late 1940s to improve public health, Johkasou systems use a tank-based method to separate solids, treat liquid waste anaerobically, and disinfect the water. The compact technology is well suited to rural and remote areas where traditional sanitation infrastructure is lacking.
At the Center for Rehabilitation of Persons with Disabilities in Nukus district, which serves over 3,500 patients annually, the new system has significantly improved daily operations. Treated water is now used for irrigation, allowing staff and patients to cultivate vegetables and fruits on-site. The resulting harvest contributes to patient nutrition while reducing reliance on external supplies.
“With the installation of the system, we started growing tomatoes, cucumbers, pumpkins, and fruit crops,” said Zhenisbay Tursynbekov, the facility’s manager. “There are no problems with irrigation—the treated water allows us to efficiently use every drop.”
The system has also supported the expansion of green spaces around the center, creating a more therapeutic environment for rehabilitation.
At Kindergarten No. 13 in Nukus, the system has replaced an aging sanitation setup, improving hygiene and safety for young children. Teachers have incorporated water-saving and gardening activities into the curriculum, helping students learn the importance of conservation from an early age.
In the Khodjeyli district, the State School for Children with Scoliosis now provides a cleaner and more accessible environment for students with special needs. Supported by the Ministry of Preschool and School Education, the system contributes to improved health conditions while promoting inclusive learning.
Since installation, the Johkasou systems have treated more than 16,400 cubic meters of wastewater—enough to irrigate up to 13 hectares annually. Beyond improved sanitation, the reuse of treated water has helped reduce household expenses by lowering the need for costly wells and decreasing water bills. The nutrient-rich water also supports crop growth while mitigating the risk of waterborne diseases.
The initiative reflects broader efforts to promote ecological innovation in the Aral Sea region, following the 2021 UN resolution that designated the area as a zone of environmental innovation and technology. The resolution was co-sponsored by Japan and championed by President Shavkat Mirziyoyev.
By demonstrating how compact, low-cost technology can provide safe sanitation and support climate resilience, the pilot aims to serve as a model for expansion across water-scarce regions in Uzbekistan.
UNDP representatives say the results so far are promising and underline the potential for scaling up similar systems in other rural communities, schools, and health facilities.
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