HYBRID ADVANCED OXIDATION PROCESSES FOR THE DEGRADATION OF PHARMACEUTICAL AND PERSONAL CARE PRODUCTS IN WASTEWATER

Abstract

The presence of pharmaceutical and personals care products (PPCPs) in the environment is a matter of great concern owing to their potentially harmful effects on the environment and human life. The concentration of these PPCPs in the aquatic ecosystems is low. However, continuous intake of these persistent organic pollutants (POPs) in aquatic life is a serious concern. These micropollutants are non-biodegradable and refractory to microorganisms used in biological treatment systems, and their derivatives are more toxic than the parent compounds. The primary sources of micropollutants are pharmaceutical manufacturing plants, hospital effluents, livestock, and agriculture. Among all PPCPs, antibiotics are of overwhelming concern because of their increase in the production and consumption rate and possible risks associated with the growth of microbes resistant to antibiotics. Therefore, research on the removal of PPCPs in wastewater has gained attention among the scientific community. Various conventional wastewater treatment processes such as coagulation, adsorption, and biological treatment have been applied for the removal of PPCPs. However, these methods have their limitations in secondary waste generation and low degradation/mineralization efficiency. Therefore, advanced and efficient technologies are required to treat these persistent environmental toxic compounds. Many researchers have used advanced oxidation processes (AOPs) in the last few decades to treat PPCPs. The hydroxyl radicals (•OH) and other reactive oxygen species (ROS) such as singlet oxygen (1O2), H2O2, triplet oxygen (3O2), superoxide radicals ions (O2•−), etc. produced during AOPs are very reactive and non-selective, which can virtually degrade the most recalcitrant pollutants with a high degradation rate constant of the order of 106-109 L mol−1s−1. Hydroxyl radicals (•OH) can be produced along with other oxidants using a light source, i.e., ultraviolet (UV) light, or through photocatalysts such as titanium dioxide or the electrode or the sound wave.