Production of algal biomass in coastal lagoons

Søren Laurentius Nielsen

Department of Environmental, Social and Spatial Change

Roskilde University, Denmark

Purpose:

• To assess the feasibility of algal biomass production in a low-tech, local setting

• Focus on pollution mitigation– Nutrients (coastal eutrophication)

– CO2

• Bioenergy and production of high-value products a secondary priority

Lolland

Onsevig lagoons

N retention in algal biomass

P retention in algal biomass

Glucose content in biomass (g/g DM)

Efficiency of ethanol conversion (67 hrs)

CH4 yield in fermentation (300 hrs) (Nm3/ha)

75 % 42 % 0,1378 ± 0,0090 10,73 ± 2,88 % 10860 ± 2360

Results from Onsevig lagoons

• Significant nutrient retention in biomass – but room for improvement

• Low ethanol conversion efficiency – needs more work

• Methane yield from fermentation of biomass residues comparabel with or larger than the yield from corn

Søllested

Could we grow algae inmunicipal waste water?

Yes – with microalgae(Chlorella vulgaris)

The set-up

Harvesting

Growth curves

Doubling time 3.5 days

Production – over 300 hrs.

Dry matter 3.01 g l-1 Ethanol 0.0146 ± 0.0005 g g-1 dry matter 0.0439 g l-1 CH4 330 ± 50 ml g-1 dry matter ~ 1 l l-1

Results from Søllested

• Production of microalgal biomass is feasible in municipal waste water

• CO2 – addition from district heating enhances growth

• Good potentials

• Much further work needed concerning best practise and best use of biomass

The future

• An Algal Innovation Center has just opened on Lolland

• We are developing proposals for European Union funding– FP7– COST

• We invite interested collaborators!• We are interested in biofuels, high-value

products and pollution mitigation

Visions – off shore algal production