Degradation of carbamazepine (CBZ), a widely detected recalcitrant pharmaceutical in sewage treatment plant (STP) effluent, has been studied in the present work using combination of hydrodynamic cavitation (HC) and advanced oxidation processes (AOPs). Due to its recalcitrant nature, it cannot be removed effectively by the conventional wastewater treatment plants (WWTPs) which make CBZ a pharmaceutical of very high environmental relevance and impact as well as stressing the need for developing new treatment schemes. In the present study, the effect of inlet pressure (3-5bar) and operating pH (3-11) on the extent of degradation have been initially studied with an objective of maximizing the degradation using HC alone. The established optimum conditions as pressure of 4bar and pH of 4 resulted in maximum degradation of CBZ as 38.7%. The combined approaches of HC with ultraviolet irradiation (HC+UV), hydrogen peroxide (HC+HO), ozone (HC+O) as well as combination of HC, HO and O (HC+HO+O) have been investigated under optimized pressure and operating pH. It was observed that a significant increase in the extent of degradation is obtained for the combined operations of HC+HO+O, HC+O, HC+HO, and HC+UV with the actual extent of degradation being 100%, 91.4%, 58.3% and 52.9% respectively. Kinetic analysis revealed that degradation of CBZ fitted into first order kinetics model for all the approaches. The processes were also compared on the basis of cavitational yield and also in terms of total treatment cost. Overall, it has been demonstrated that combined process of HC, HO and O can be effectively used for treatment of wastewater containing CBZ.

Solar thermal technology promises to be a significant component of the future renewable energy mix. As the most mature solar thermal technology, parabolic trough concentrators (PTC) are the focus of considerable research. Conventional PTC use evacuated receivers, which contribute 30% of the solar field cost, not including significant failure (55% due to broken glass envelopes and 29% due to loss of vacuum arising due to failure of glass to metal seal). We report a non-evacuated receiver with a modular design for easier assembly and superior thermal performance for a PTC made of reflective strips of mirrored glass with a rim angle of 60 . The receiver performance is estimated using our own ray-tracing software and computational fluid dynamics (CFD) simulations using a model that we have validated with our own experimental rig. Critical parameters like the width of the mirror strip, the emissivity of solar selective coating, insulation material, and reflectivity of optical cavity walls have been analyzed in this study. A scaled-up model of the proposed novel receiver with a heat transfer fluid conduit diameter of 70 mm has been simulated to compare the performance with the commercial SCHOTT PTR ® 70.