A method for preparing and selecting a polymeric flocculant for use in harvesting microalgae

A method for preparing and selecting a polymeric flocculant for use in harvesting microalgae, the method comprising:

• (i) preparing a plurality of different polymers;
• (ii) introducing an amount of each polymer into a separate suspension comprising microalgae;
• (iii) repeating step (ii) at least once by varying the amount of each polymer so as to provide a series of separate suspensions comprising different polymers in different amounts;
• (iv) measuring optical density of each suspension in the series;
• (v) calculating a flocculation efficiency for each suspension in the series;
• (vi) generating a flocculation efficiency dose-response curve for each polymer at each amount;
• and
• (vii) selecting a polymeric flocculant.

An apparatus for flocculating an aqueous suspension of particles using one or more polymers, the apparatus comprising:

• a plurality of vessels for containing one or more monomers, a photoinitiator, water and a deoxygenation system;
• a mixing vessel for mixing the one or more monomers, the photoinitiator, the water and the deoxygenation system to form a mixture;
• a polymerisation vessel for producing an aqueous solution of a polymer;
• and
• a UV light source for irradiating the polymerisation vessel;
• wherein the plurality of vessels are in fluid communication with the mixing vessel, and the mixing vessel is in fluid communication with the polymerisation vessel.