Abstract The presented technology is aimed on the one hand at purifying the effluents from fermented sludge to the quality enabling their discharge to a river, and on the other hand at ensuring the production of high concentrations of algae biomass. The produced algae biomass will be used as a substrate in the process of methane fermentation. The main factor which minimizes the possibility of introducing crude effluents into photobioreactors is a high content of organic compounds and the suspension. The removal of these contaminants from wastewater will proceed with both physical methods via floatation and biological methods with the use of a biofilm. It is expected that biogenes will be effectively removed from effluents through the growing biomass of microalgae.