Algae production in wastewater

Where: Slovenia  
Bioeconomy theme: Aquatic/water systems, Food/ agriculture, Forestry/natural habitats, Bioenergy, Biomaterials

Algae are by nature excellent organisms for recycling and reusing the nutrients and energy, as they can produce biomass while cleaning the wastewater. Algae biomass can be used for animal feed, biofuels, biomaterials, organic fertilisers, and soil amendments to improve the soil quality. Valuable compounds for (phyto)pharmacy and cosmetics can be extracted as well. Bio-stimulants and bio-pesticides from algae have already been shown to be very effective in agriculture. Algae can also be used for food (Spirulina, Chlorella) if the wastewater is pre-treated or comes from a side-stream of food production or processing.

What does “Algae production in wastewater” aim to achieve:

The beauty of algae ponds is that they can be added to the existing technological process without changing the original system. Their biomass can be used for additional value streams, while the treated wastewater usually complies with the demands for environmental release. In the case of biogas plants, algae can be used for stabilisation of liquid anaerobic digestate, which is problematic to manage because it is very dilute. Algal systems enable concentration of nutrients and organic matter into biomass, while treated water can be utilised for irrigation. Algae also recycle CO2, effectively use excess heat, and reduce the odour of digestate. In sewage treatment plants, algal systems can replace secondary and tertiary water treatment, and instead of sludge, valuable biomass is produced.
Algae ponds are easily operated and can fit nicely into the rural landscape.