Landfill leachate treatment: a new photobioreactor technology

The landfill leachates represent a major environmental problem and their treatments present big challenges. Many technologies have been developed but the quest for the best treatment technology is still ongoing. The microalgae treatment technology has been gaining momentum due to their advantages. In this thesis, a pilot treatment plant with an innovative configuration and a new photobioreactor of attached biomass was tested and its startup monitored. Three photobioreactor diameters were tested. The assembling process was phased and diverse operational problems occurred, leading to complex analysis of the results obtained. The COD, BOD, total N, NH4-N, NO2-N, NO3-N, PO4-P, Fe, DO, pH and temperature have been analyzed in the various treatment components to access the treatment efficiency of each component and of the whole system. The overall efficiency proved to be low, attaining the COD and the NH4-N mean removal rates of 6.4% and 19.1% respectively, and no difference was observed between the different photobioreactors. The biofilm formation inside the photobioreactors was studied by optical and microbiological methods and results showed that complex dynamics of the microbial communities occurred. The dominant microalga present in the photobioreactors, Chlorella sp., was isolated for further characterization.