The photocatalytic degradation of two environmentally relevant organic compounds and p-toluenesulfonic acid (PTSA)] was investigated using a novel cylindrical fluidized bed photoreactor (FBPR). Accumulated biodegradable organic acids, identified as intermediate reaction products, decreased after the removal of original pollutants. Measurements of the oxygen uptake rates with a mixed culture showed that all intermediate photooxidation products were much better biodegradable than the initial aromatic pollutants (4-CP, PTSA). The influence of HCO 3and Clon the degradation rate was also studied. For concentrations of 1 mM bicarbonate (HO • radical scavenger) and of 140 mM chloride (photoinhibitor), the photocatalytic degradation rate decreased by 50%. During the photocatalytic reaction process, hydrogen peroxide accumulated in solution up to 0.21 mM depending on the initial concentration of the organic compounds and the concentration of dissolved oxygen. The relative quantum efficiency increased up to a factor of 2.3 by dosing of additional H 2 O 2 .

A model is presented to simulate the biodegradation of easily and slowly hydrolyzable organic matter, as well as the generation of biogas and heat release. The model is based on fundamental relationships among physical/chemical, thermodynamical and microbial processes occurring in municipal landfills. Local, microbially-mediated degradation processes occurring in municipal landfills, are simulated in terms of the hydrolysis of solid organic matter, the formation of glucose and acetate as intermediary carbon substrates and the generation of the biogases CH4 and CO2. Thus, the overall decomposition of the organic matter has been assumed to follow four sequential biochemical reactions: hydrolysis, acidogenesis, acetogenesis and methanogenesis. In order to study the impact of environmental factors on the biological decomposition processes, pH, temperature and hydrogen changes have been integrated into the degradation model as inhibition terms.

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In this work, a mathematical description of a Microbial Electrolysis Cell (MEC) is proposed, taking into account the global mass balances of the different species in the system and considering that all the involved microorganisms are attached to the anodic biological film. Three main biological reactions are introduced, which were obtained from the solution of partial differential equations describing the spatial distribution of potential and substrate in the biofilm. The simulation of the model was carried out using numerical methods, and the results are discussed.