Domestication and proliferation of algae cultures for boosting efficiency of waste-water treatment through symbiosis

András J. Kovács, Zsolt Méhes, Imre Tolner, László Tolner

Abstract

Native algae strains have been domesticated and stimulated in activated sludge wastewater treatment operations. The term of domestication indicates that we did not add any selected algae to the wastewater, but made use of species existing in the system. The term of proliferation indicates a stimulation of the biological oxidation process by provision of CO2 with the air stream and illumination of the reactor. The idea of domestication of algae present in communal wastewater systems was demonstrated. Stimulation of the system with domesticated algae community did improve efficiency of the treatment process. Removal of organic components in terms of reduction of chemical and biological oxidation demands (dissolved COD, BOD) as well as nitrogen and phosphorous contents was superior to extent of removal in conventional activated sludge system. We did conclude that conventional systems lack available light and carbon resources for these microorganisms. Upon providing these, symbiotic operation can contribute to reducing greenhouse gas emissions and increase of the rate of pollutants removal kinetics.  Symbiotic operation increased the production of biomass expressed in terms of total suspended solids. Biodiesel potential of the filterable biomass was in the range of 8-18%. Because of technical difficulties in manipulation of the excess sludge other than biodiesel synthesis processing scheme has been recommended for economically viable processing.

Keywords

algae, wastewater, biodiesel.