Advanced oxidation process (AOP) such as photocatalysis is seen as a potential future technology to offer clean water for various human needs. Through this process, different organic pollutants and recalcitrant chemicals are effectively removed from both water and wastewater. Some of the AOPs, such as ozonation (O3), catalysis by iron ions, electrodes, metal oxides, UV/Fenton, UV/hydrogen peroxide (H2O2), etc., generate harmful intermediates which restrict their full-scale implementation. Alternatively, irradiation techniques such as photocatalysis are a viable option and have been shown to treat wastewater contaminated with hazardous chemicals, organic dyes, pesticides, antibiotics, viruses, bacteria, protozoa, etc., without producing toxic levels of byproducts. This chapter reviews emerging aspects of photocatalysis for the treatment of various recalcitrant pollutants with a special emphasis on polyethylene degradation. It summarizes the source, types, mechanism, and parameters of wastewater treatment using photocatalytic activity. Polyethylene is well known as a serious cause of threats to human health and environment. Polyethylene, polystyrene, plastic film, and polypropylene degradation have been shown to occur via photocatalysis. This could be achieved using TiO2, ZnO, and doped and undoped metal oxides as photocatalysts. Also, photocatalytic degradation is compared with microbial techniques for polyethylene degradation along with brief reports on novel photobioreactors, a combination of microbial and photocatalytic reactors in the degradation of polyethylene.