Algae Harvesting

Our Separation Solutions for Algae Harvesting

Algae Harvesting – Special Requirements for Microalgae

Microalgae are single-celled organisms that place special demands on separation technology during algae harvesting. Their small size and the low solids concentration in the feed stream require the use of separators to ensure efficient dewatering. The diversity of microalgae species offers enormous potential for various applications, such as the sustainable use of marine resources and renewable energy.

Separators are used in particular for solids concentrations below 5 vol%, producing an algae concentrate with a solids content of 10–15 wt%. The recovery rate of insoluble components is close to 100 wt%.

Small and medium-sized plants in particular benefit from the single-stage process: low investment costs, low operating costs, and robust, service-friendly technology make the Flottweg Separator a high-performance and sustainable solution for companies seeking to process microalgae in an economical and forward-looking manner.

Algae Harvesting with the Flottweg Separator

The algae suspension flows from the photobioreactor directly into the Flottweg Separator. Then the distributor gently accelerates the suspension to full speed. Due to the high centrifugal force of up to 12,000 g, the separator dewaters the algae suspension producing an algae concentrate with creamy consistency. Thus making the algae concentrate ideal for further processing.

From Suspension to Concentrate: Precision Algae Separation

Algae Harvesting with the Flottweg Sedicanter®

For solid concentrations above 5 vol.%, the Flottweg Sedicanter® is ideally suited. It enables efficient, gentle, and continuous cell harvesting, particularly for solid contents ranging from 10 to 50 wt.%.

The overall process consists of two stages: First, the algal suspension grows in the fermenter or photobioreactor and is then thickened using pre-concentration methods such as flotation or membrane filtration. This removes excess water, significantly reducing the energy requirements in the subsequent separation step.

In phase two, the actual cell harvest and dewatering take place in the Flottweg Sedicanter®. The preconcentrated algae suspension is processed continuously and gently, resulting in a high-quality algae concentrate with a creamy consistency and a dry matter content of approximately 25 to 35%. The cell structure is preserved, creating optimal conditions for further processing.

The fully automated, continuous process ensures sustainable and economical algae harvesting with minimal energy and water consumption. Thanks to its scalable process control, the Flottweg Sedicanter is ideally suited for industrial applications and the predictable production of algae biomass.

Efficient Two-Stage Algae Harvesting with the Flottweg Sedicanter®

Macroalgae, particularly brown algae (kelp), are a valuable natural resource containing substances such as polysaccharides, proteins, vitamins, and minerals. They are widely used in the food and pharmaceutical industries, particularly for the extraction of alginate and other substances such as fucoidan.

Since brown algae are often mixed with sand and solids, their processing places high demands on separation technology. This is where the Flottweg Decanter comes in. After harvesting, the algae are mechanically pretreated and homogenized. During centrifugation, the Flottweg decanter ensures reliable separation of solids and liquid—even with high solids content and abrasive components.

The result is a dry, coarse-grained algae paste with approximately 30% dry matter, which is ideally suited for downstream processes such as alginate extraction. In the subsequent processing, the alginate is initially in liquid form and is separated as a solid through precipitation. It is then mechanically dewatered, e.g., using a belt press or a decanter. Both methods enable an effective reduction of the water content and optimally prepare the product for further processing. The continuous use of Flottweg Decanters enables efficient, sustainable processing. By-products can be further utilized and contribute to resource conservation.