New device to harvest microalgae
Microalgae are cultivated for human and animal nutrition, cosmetics, pharmaceuticals, biofuels and wastewater treatment. However, the energy used in conventional harvesting methods makes up approximately 30 % of total biomass production costs. The EU-funded 'High algal recovery using a Salsnes Water to Algae Treatment (SWAT) filter technology' (OPERATION SWAT) project aimed to design a universal harvesting technology that would yield 95 % recovery at 40 % lower costs. Three small technology companies each contributed apparatus or know-how to the project. Researchers began by studying particle size and other characteristics of seven commercial microalgae species to help identify the correct filters. They also investigated 20 different flocculating agents to improve the filtration. Two prototype systems were designed and installed in different microalgal production facilities. After modifications, the final prototype — which operated continuously — could remove 97 % of suspended solids and used significantly less power than conventional methods. The companies involved in OPERATION SWAT are in the process of bringing the novel algal harvesting system to market. They expect sales to begin by the end of 2014.
Microalgae, algal recovery, harvesting method, wastewater treatment, filter technology