Cascade Raceways

  • Continuous design optimization since 2010 by A4F for cost effective microalgae production considering energetic costs, productivity enhancement and weather specific conditions, such as high rainfall or sand storms.
  • This improved cascade raceway, deployed in 2014 in the scope of BIOFAT FP7 project, comprises two parallel-sloped ramps with opposite inclination. After this photosynthetic flow path, the culture flows into a covered tank and pumped back to the first sloped ramp.
  • Typical industrial production modules are 3.000 to 4.000 m2.
  • The CRW tank has the capacity to store the entire culture volume, which enables this type of raceway to be operated outdoors during high precipitation seasons with better culture management. The CRW ramps slope and pump specifications were designed to operate with a reduced film thickness, 3 to 8 cm, which allows an increase in volumetric productivity and a decrease in harvesting costs due to the lower total volume of the culture, when compared with a conventional raceway design, with water columns between 20 and 30 cm.
  • The CRW special configuration enables it to be operate trough the tank and also bypassing the tank, reducing considerably its energetic requirements.
  • Ideal for microalgae that grow in selective media and to every weather conditions.
  • Recommended for intensive microalgae production projects.


  • Lower ratio volume/area
    • Lower amount of water, and inorganic nutrients required =>reduction of operation costs
    • Higher microalgae concentration => Better culture conditions and quality =>higher annual productivity
  • Easier CO2 control and lower O2 build-up – better cultivation conditions =>lower OPEX and higher annual productivity
  • Culture continuously flows through a pipe =>Higher mixing efficiency and ability to control contaminants and optimized culture management
  • Storage capacity: capacity to protect the culture from extreme environmental conditions =>Higher annual productivity and optimized culture management
  • Adjustable film thickness between 3 cm and 8 cm =>optimized culture management