Per capita average annual freshwater availability is gradually reduced due to increasing
population, urbanization and affluent lifestyles. Hence, management of wastewater
is of great concern. The wastewater from different industries can be treated by various conventional
treatment methods but these conventional treatment technologies seem to be ineffective
for the complete removal of pollutants especially refractory organic compounds that
are not readily biodegradable in nature. Detergents, detergent additives, sequestering agents
like EDTA, Pesticides, Polycyclic aromatic hydrocarbons, etc. are some of the recalcitrant
organic compounds found in the wastewater. One of the treatment technologies for the removal
of recalcitrant organic compounds is Advanced Oxidation Process (AOP). The production
of hydroxyl free radical is the main mechanism for the AOP. AOP is a promising
technology for the treatment of refractory organic compounds due to its low oxidation selectivity
and high reactivity of the radical. Hydrogen peroxide (H2O2), Ozonation, Ultra-violet
(UV) radiation, H2O2/UV process and Fenton’s reaction are extensively used for the removal
of refractory organic compounds thus reducing Chemical Oxygen Demand (COD), Total
Organic Carbon (TOC), phenolic compounds, dyes etc. to great extent. From the studies, we
found that Fenton’s reagents appear to be most economically practical AOP systems for almost
all industries with respect to high pollutant removal efficiency and it is also economical.
From the energy point of view, the ozone based process proves to be more efficient but
it is costlier than the Fenton’s process.
Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations
