This study evaluated the photocatalytic activity of polyaniline (PANI)-capped titanium dioxide and zinc oxide (TiO/ZnO) hybrid, for the degradation of P-Cresol. The hybrid was synthesized by precipitating ZnO on the surface of commercial TiO. An "in situ" chemical oxidative polymerization method was used to prepare the PANI capped hybrid (TiO/ZnO/PANI). The photocatalysts were characterized by powder X-ray diffraction (XRD), a Brunauer Emmett Teller (BET) analyzer, Fourier-transform infrared (FTIR) and photoluminescence spectroscopies, high resolution-transmission electron microscopy (HR-TEM) and thermogravimetric analysis (TGA). During photodegradation under ultraviolet (UV) irradiation, ZnO, TiO, TiO/ZnO hybrid and TiO/ZnO/PANI composite had P-Cresol removal of 43%, 50%, 61% and 99%, respectively. The higher activity of the TiO/ZnO hybrid as compared to TiO and ZnO was attributed to a reduced electron-hole pair recombination. The recombination was further significantly reduced upon introduction of PANI; hence, the highest activity observed with TiO/ZnO/PANI. The initial reaction rate constant for TiO/ZnO/PANI (0.9679 min) was more than twice compared to that for TiO/ZnO hybrid (0.1259 min). A synergistic effect between PANI and TiO/ZnO resulted in a highly efficient charge separation caused by the transfer of photogenerated holes from the hybrid to highest occupied molecular orbitals (HOMO) of PANI. The best TiO/ZnO/PANI (PANI to TiO/ZnO) ratio observed was 0.5:2 for the photodegradation of P-Cresol. Total organic carbon (TOC) analysis indicated a 97.4% mineralization of P-Cresol with PANI/TiO/ZnO.

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The green economy (GE) has increasingly gained international focus, with new strategies aimed at restructuring the economy in an environmentally friendly manner. A study was carried out to analyse existing and potential green jobs and identify green qualifications and skills necessary for the development of the GE. The study was done within the context of the role of local governments in the adoption of green economy strategies in the wastewater treatment sector, in selected local governments across the northern provinces of South Africa. A descriptive survey method with qualitative and quantitative approaches was employed for data collection from twenty-four wastewater treatment plants in eleven local municipalities. The concept of the GE was foreign to several employees, who could not identify green jobs within most sectors of the economy. Only13.5% of the employees of the surveyed plants were involved in directly green jobs. A further 36% were in green-related jobs while the remaining 50.5% were involved in non-green jobs. Barriers to the creation of green jobs and implementation of green practices were the shortage of employees with green and conventional wastewater treatment skills, and lack of training in green skills. Several opportunities for green jobs creation exist, such as the implementation of renewable energy, re-use of treated effluent, and processing of waste sludge into compost. To spur GE growth and create green jobs, the creation of awareness, development of skills and implementation of green technologies should be intensified.

Anaerobic digestion (AD) can remove the high organic load of molasses wastewater (MWW), but is ineffective in removing the characteristic dark brown colour caused by biorecalcitrant melanoidin. Ultraviolet (UV) photodegradation, can mineralise the biorecalcitrants leading to complete colour removal, but with a high-energy input and low organic load removal. This study investigated the plausibility of integrating the two processes for organic load and colour reductions. Desk scale AD and photodegradation processes were carried out in batch reactors. A hybrid photocatalyst consisting of titanium dioxide (TiO 2 ) and zinc oxide (ZnO) was used for photocatalytic degradation. Biodegradation at thermophilic conditions in the bioreactor achieved high total organic carbon (TOC) and chemical oxygen demand (COD) reductions of 80 and 90%, respectively, but with an increased colour intensity. Contrastingly, UV photodegradation achieved a high colour reduction of 92% with an insignificant 6% TOC reduction, after 30 min of irradiation. During photodegradation, the mineralisation of the biorecalcitrant organic compounds led to the colour disappearance. The energy required for the TOC reduction was 40-fold higher than that required for the colour reduction in the same irradiation period, suggesting that the UV process was only suitable for colour reduction. Therefore, there is a possible synergy when the two processes are integrated, with AD preceding UV, where AD removes the high COD/TOC while UV removes the recalcitrant colour at a reduced cost.