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Advanced domestic wastewater treatment tanks (Johkasou)


The need to reduce the impacts of deteriorating quality of public waters (particularly enclosed water bodies, etc.) as a result of climate change, in areas that may face declining sanitation conditions. Particularly applicable in response to the need to mitigate impacts in regions where water pollution is occurring due to urban population growth associated with economic growth, or due to rapid industrial development.

Organisation providing the technology:

Large johkasou systems can process between 1 and 1,000 m3 daily. Effluent has a BOD of 20 mg/L.

  • Improvement of sanitation by proper treatment of domestic wastewater, etc.
  • Creation of employment for installation, operation and maintenance of the systems.
Working principles:
  • Limiting the deterioration of water quality in enclosed water bodies due to the effects of climate change, etc.
  • Prevention of deterioration of sanitation conditions and reduction of disease risk due to climate change, etc.
  • Improved wastewater treatment capacity to handle extreme events
Succes factors and requirements:

For johkasou, factors affecting the installation potential and post-installation effectiveness include national and regional legislation/regulations relating to water quality, economic support/incentive programs, and institutional capacity for proper maintenance, etc.For example, the following issues affect efforts to improve the water environment in Indonesia:

  • Weak environmental protection standards relating to wastewater BOD water quality.
  • Inadequate systems of inspections and administrative guidance relating to water quality and wastewater.
  • No certification or installation subsidy/incentive programs for wastewater treatment equipment.
  • The area classification of onsite versus offsite treatment is not formulated in regional cities.
  • No mechanisms are in place for routine maintenance and sludge removal.
Countries where implemented:
Further information:
Content organisation:
Technology owners:
  • Kubota Corporation
  • Kubota Johkasou Systems Corporation