Microalgae dewatering is a challenge for industrial-scale processing of microalgae. There is no superior method of the concentration process and although centrifugation has been successfully applied for algae production systems, but it is both time- and energy-consuming and requires expensive equipment.
The harvesting process involves the concentration of dilute microalgae suspensions, typically 0.03% (open ponds) to 0.3% (closed photo bioreactors) total suspended solids (TSS) into a slurry or paste with concentrations of 2%–30% TSS. The concentration obtained in the harvesting steps is crucial to the overall process as it influences the subsequent drying process.
The concentration process is a major obstruction to industrial-scale processing of microalgae. With our phytoharvester(patent pending) it is now possible to obtain a desired microalgae concentration by a one or two step harvesting process. The primary phytoharvester step forms a slurry of up to 2% TSS (20kg/m3) followed by a secondary dewatering step of your choice that produces an algae paste of 15%–25% TSS. The phytoharvester can be adjusted to any separator or centrifuge which work under different centrifugation conditions.
This phytoharvester pre-concentrates algae suspensions from typical open ponds (0.03% to 0,1%TSS) or from closed PBR (0,1-0,5%TSS) like our phytobag before any separator or flocculation process proceeds. This step 1 process of algae dewatering drastically reduce the costs and energy demands (see Energy consumption). The average power consumption is 0.32 kWh/m3 feed flow. The air scour design minimizes power consumption and eliminates sludging, avoiding localized dewatering of the algae sludge. Particles > 0,1 µm are removed. The system can also be used to recycle the algae-free effluent, to pre-treat the production water and to minimize contamination. Requirements for cleaning and maintenance are minimized.
Modules are available in a variety of sizes. The largest single units are integrated in one 20`open-top container and can concentrate up to 2700 m3/day. They are customized to the corresponding algae-production system.