16 2 The influence of biogas flow rate (0, 0.3, 0.6 and 1.2 m 3 m -2 h -1 ) on the elemental and 17 macromolecular composition of the algal-bacterial biomass produced from biogas upgrading in a 18 180 L photobioreactor interconnected to a 2.5 L external bubbled absorption column was 19 investigated using diluted anaerobically digested vinasse as cultivation medium. The influence of 20 the external liquid recirculation/biogas ratio (0.5 < L/G < 67) on the removal of CO2 and H2S, 21and on the concentrations of O2 and N2 in the upgraded biogas was also evaluated. A L/G ratio of 22 10 was considered optimum to support CO2 and H2S removals of 80% and 100%, respectively, at 23 all biogas flow rates tested. Biomass productivity increased at increasing biogas flow rate, with a 24 maximum of 12±1 g m -2 d -1 at 1.2 m 3 m -2 h -1 , while the C, N and P biomass content remained 25 constant at 49±2%, 9±0% and 1±0%, respectively, over the 175 days of experimentation.

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Design and configuration for wetlands treating greywater are usually based on literature data obtained from domestic wastewater operating wetlands. It is very important to determine proper criteria for design and configuration to provide efficiency and minimum maintenance, avoiding bad odour and clogging amongst others, ensuring the acceptance of householders. The aim of this work was to design a wetland system treating greywater for a household and determine whether the chosen criteria were appropriate. Some of the criteria taken into consideration for design and configuration were: quantitative and qualitative characteristics, desired removal of biochemical oxygen demand (BOD) and suspended solids (TSS), substrate and ornamental aspect of the system. The system was composed of a grease trap (kitchen), sedimentation tank, a horizontal flow constructed wetland (HF-CW), intermittent feeding system, and a vertical flow constructed wetland (VF-CW). The results showed that the suggested design and configuration were in accordance with the expected efficiency. Being a compact system, it was susceptible to peak flows, temporarily deteriorating the performance of the HF-CW. The hybrid system, however, showed to cope well with influent fluctuations. The overall performance of the system shows that the removal of turbidity, TSS, COD and BOD were over 88%, reaching 95% removal for both BOD and turbidity.

In Advanced oxidation processes (AOPs) radicals are considered to play an important role. Organic contaminations can in AOPs generally be converted to carbon dioxide, water, etc. The most important limitation to the application of AOPs, however, is their high costs, especially when complete mineralisation of the pollutants is pursued. The costs can be reduced by using the oxidant more efficiently, which can be achieved by introducing selectivity. Kinetic and mechanistic data are the basic requirements for optimization of the process. In this work, the influence of several different parameters (temperature, pH, UV irradiation and carbonate concentration) on the kinetics of the degradation ofortho -chlorophenol and para-chlorophenol by ozone was investigated. The pH is the most important parameter. Strongly related to the pH is the degree of ionisation of the phenol, which might be of importance since the shift from a slow to a fast reaction occurs at a higher pH in the case of para-chlorophenol as compared to the case with the more acidic ortho-chlorophenol. A strong indication for a radical mechanism is found in the decrease of the reaction rate in the presence of carbonate, a well known radical scavenger. A further indication is seen in the first step of the reaction, which is dechlorination of the aromatic compound.

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