Johkasou: Japan’s Advanced On-site Wastewater Treatment

  • To meet the water treatment needs in the Middle East, 4ELEMENTS has committed itself to offering optimal water treatment solutions by utilizing all the technologies, and expertise available.


  • 4ELEMENTS now unveils a package incorporating Japan’s advanced water treatment engineering expertise which has been refined through many years of experience in building water treatment plants.


  •  Customers, who are dedicated to building environmentally friendly communities and lifestyles for befitting the 21st century, choose Johkasou.


Tank for Purifying

Johkasou is a sophisticated treatment system that uses anaerobic, aerobic and disinfectant processes to render blackwater (that bears human excreta) and/or greywater (from kitchens and sinks) relatively harmless and clean. Johkasou system was introduced in Japan in 1911 and developed rapidly in 1960s to meet the high demand for clean water.


Difference between Septic Tank and Johkasou

In many countries, septic tanks as anaerobic digesters are still built for domestic wastewater treatment. Johkasou uses Japan’s original method, which combines aerobic, anaerobic, filtration, and disinfection treatments

  • Johkasou devices are mass produced under strict Japanese production guidelines
  • Industry leading manufacturing techniques
  • World leading quality assurance
  • Japanese quality control
  • Made in ISO certified factory




Johkasou Line-Up

Kubota now unveils a package incorporating its advanced water treatment engineering expertise, which has been refined through many years of experience in building water treatment plants. Optimal water treatment solutions are available in locations and in sizes customers require. Kubota’s “plant package” is sure to serve as the key concept of combined wastewater treatment tanks.



Small and Medium Johkasou


This wastewater treatment tank is designed for individual homes and vacation homes to small-scale stores and flats. It is a standard product.


KZ series

  • 1.0~2.0 m3/day
  • Moving bed contact aeration circulation method

HCZ series

  • 2.8~10.0 m3/day
  • Sedimentation-separation anaerobic filter moving bed process




Large Johkasou



For various uses, including large-scale plants, public facilities and apartment buildings. It is custom-made according to the facility’s demands.


MBBR type

  • 10 m3/day~
  • Peak-cut flow solid-liquid separation anaerobic filter moving bed media filter process & Flow equalization type moving bed media filter process

MBR type

  • 5 m3/day~
  • Membrane bioreactor process


Tertiary Treatment



Optional advanced treatment for Johkasou system and the effluent improvement for existing STP. The final treatment for effluent polishing to remove remained SS and BOD from the secondary treatment. By adopting high performance carrier media, compactness has been achieved and the workability has been greatly improved.


HCAT series

  • 2.8 m3/day~above
  • Any STP systems can be attached for effluent polish
  • Tertiary treatment

Kubota Johkasou System Around the World

The Treated Effluent from Johkasou is Usable as Reclaimed Water




Installation and Maintenance of Johkasou





Reclaimed Water