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Photochemical activation routes are gaining the attention of the scientific community since they can offer an alternative to the tradi-tional chemical industry that mainly utilizes thermochemical activation of molecules. Photoreactions are fast and selective, which would potentially reduce the downstream costs significantly if the process is optimized properly. With the transition towards green chemistry, the traditional batch photoreactor operation is becoming abundant in this field. Process intensification efforts led to microand mesostructured flow photoreactors. In this work, we are reviewing structured photoreactors by elaborating on the bottleneck of this field: the development of an efficient scale-up strategy. In line with this, microand mesostructured bench-scale photoreactors were evaluated based on a new benchmark called photochemical space time yield (mol.day(-1).kW(-1)), which takes into account the energy efficiency of the photoreactors. It was manifested that along with the selection of the photoreactor dimensions and an appropriate light source, optimization of the process conditions, such as the residence time and the concentration of the photoactive molecule is also crucial for an efficient photoreactor operation. In this paper, we are aiming to give a comprehensive understanding for scale-up strategies by benchmarking selected photoreactors and by discussing transport phenomena in several other photoreactors.

The removal of 99% of metals is possible with standard physicochemical wastewater treatment systems. As a consequence of stricter legislation with regard to metal concentrations in industrial waste water, companies use ion exchangers to remove the residual metals. These ion exchangers are expensive and sometimes do not meet targeted metal concentrations in case of complex wastewater streams, e.g. wastewater containing both a high concentration in metals and organic matter. In this case, the best practice is to use an activated carbon filter to avoid fouling of the resin used in the ion exchanger. Companies are, therefore, on the lookout for alternative, cheaper, and more efficient technologies. At the same time pyrolysis allows transforming organic residue streams into valuable products. In this study this innovative research path will be further explored. Activated biochar will be produced by pyrolysis of biomass residue streams. In the next step, this activated biochar will be used to test its use in the removal of the remaining metals in real wastewater samples of different companies. A techno-economic analysis (TEA) will be performed which consists of four different steps (1) market analysis, (2) mass and energy balance, (3) economic analysis, and (4) sensitivity analysis. It allows verifying whether the process is economically feasible from an early phase. Moreover, a TEA assists in identifying the parameters that should be focused on to increase the chances of market success. This implies that the technical and economic calculations are directly linked. Using the technical analysis and the TEA, we will identify which biomass residue sources are most interesting to produce an activated carbon with a high quality that can be used for wastewater treatment. We closely collaborate with the industrial stakeholders (i.e. waste processing companies, manure processing companies, water treatment companies and technology suppliers) and Flemish government to identify the main problems and find solutions to overcome theremaining barriers.

ispartof: Aquaconsoil location:Barcelona, Spain date:16 Apr - 19 Apr 2013 status: published