Production of algal biomass in coastal lagoons Søren Laurentius Nielsen Department of...

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