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Updated: Jun 20, 2026
07:34
Biogas Purification through the use of a Microalgae-Bacterial System in Semi-Industrial High Rate Algal Ponds
Published on: March 22, 2024
Improved algal harvesting using suspended air flotation.
Patrick E Wiley1, Kristine J Brenneman, Arne E Jacobson
1Willits Wastewater Treatment Facility, 111 East Commercial Street, Willits, CA 95490, USA. pwiley@willitscity.com
Summary
This study found suspended air flotation (SAF) is a more efficient method for harvesting algae from wastewater than dissolved air flotation (DAF). SAF requires less energy and reduces solids content in effluent, lowering costs for wastewater treatment and algal product manufacturing.
Area of Science:
- Environmental Science
- Biotechnology
- Chemical Engineering
Background:
- Algal harvesting from liquid media is energy-intensive and costly.
- Algae, primarily Chlorella and Scenedesmus, constitute a significant portion (approx. 80%) of solids in wastewater oxidation ponds.
- Efficient algal harvesting is crucial for wastewater treatment and the cost-effective production of algal-based products.
Purpose of the Study:
- To characterize algae in wastewater oxidation ponds.
- To identify a more efficient algal harvesting technique compared to existing methods.
- To evaluate suspended air flotation (SAF) as a potential solution.
Main Methods:
- Analysis of oxidation pond wastewater composition.
- Characterization of algal species (Chlorella and Scenedesmus).
- Comparative performance evaluation of suspended air flotation (SAF) and dissolved air flotation (DAF) based on air:solids ratio, energy requirements, and loading rates.
Main Results:
- Algae comprised approximately 80% of the solids in the studied wastewater.
- Suspended air flotation (SAF) demonstrated a lower air:solids (A/S) ratio compared to dissolved air flotation (DAF).
- SAF exhibited lower energy requirements and higher loading rates than DAF (P < 0.001).
Conclusions:
- Suspended air flotation (SAF) offers a more efficient and cost-effective method for harvesting algae from wastewater.
- Implementing SAF can reduce solids content in wastewater effluent, benefiting treatment plants.
- SAF can potentially lower manufacturing costs for algal-based products like fuel, fertilizer, and fish food.
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