Raceway ponds are an innovative and affordable type of algaculture system that takes advantage of natural sunlight. It takes a lot of engineering to build an effective raceway. The design needs to be based on your algae culture’s target viscosity along with changes to the water volume over time. These ponds are made to keep water flowing continuously rather than standing still. To that end, raceways are designed as passages or looped circuits that resemble a racetrack—or a waterslide, if the slide were level. Smooth curves are required at the ends of the tracks to create turbulence that mixes the water, thus exposing algae to sunlight, air and nutrients. This is why precise engineering is so important: An algae raceway’s curves can make or break the system’s growth rate.
To build a raceway, you will need to pay strict attention to depth. Too shallow, and evaporation will hamper your efforts to speed your algae’s growth rate. Too deep, and the water may not mix properly, stunting algae growth. Determining the proper depth means taking into account the needs of the specific species you plan to produce. You’ll also need an impermeable liner. Concrete has been used to create raceways, but this risks water loss through cracks. For a truly permanent and impermeable raceway liner, consider a flexible liner over concrete—something like AquaArmor from BTL Liners. Circulation and mixing equipment are additional key components that raceways require. Circulation must happen whenever light is applied, be it from artificial or natural sources. Because circulation is so crucial, many raceway operators will keep backup equipment on hand to keep water flowing in the event of an equipment failure. Last of all, raceways will have a specialized harvesting area comprised of settling tanks or other harvesting facilities. This is where the algae and water will go at the end of the growth cycle so that the algae can effectively be separated out. As you explore raceways, you will discover that there are dozens of different designs, each customized to the needs of certain algae and to the available space to build the facility.