Wastewater mineralization using advanced oxidation process

Abstract

ab s t r ac tWater scarcity and environmental considerations are leading to the search for alternatives for industrial and urban wastewater reclamation. The objective of this research study was to examine the potential of recycling wastewater as an alternative or complementary technique for biological treatment. The degradation of organic matter from strained sewage and secondary treated sewage was studied using the advanced oxidation process (AOP) with hydrogen peroxide as an oxidant and iron oxide-based nanocatalysts. This process may be used when contaminants are resistant or toxic to conventional biological treatments. It also may be used as a complementary technique for polishing treated water. AOP, which involves the in situ generation of extremely strong oxidants such as hydroxyl radicals in aqueous solution, has recently appeared as a remarkable technique for accelerating the oxidation and degradation of a broad range of organic matter in wastewater. The final products of this process are carbon dioxide, water and inorganic salts. The oxidation of an organic compound by AOP is catalyzed by using transition metal oxides such as iron oxides. Another alternative for removing organic pollutants from aqueous streams is adsorption on activated carbon. The AOP process may be used on loaded active carbon or other adsorbents for cold regeneration, followed by successive repeated recycling of the adsorbent. It was shown that organic matter is efficiently destroyed by the Fenton-like reaction using FeOOH in the presence of hydrogen peroxide. The strong effect of nanocatalyst and hydrogen peroxide concentrations on reaction rate is demonstrated. The kinetic reaction was evaluated, and the reaction rate coefficient k was calculated. The optimal pH for destroying the organic matter was found to be around 2.7. Moreover, the results show high efficiency catalytic recovery of used activated carbon after treatment of filtered raw or secondary treated sewage, enabling the inexpensive reuse of the adsorbent.

Solar photocatalytic treatment of phenolic wastewaters: influence of chlorides, sulphates, aeration, liquid volume and solar light intensity

“…The results suggest that photocatalytic process with solar light irradiation is a feasible technique for phenol removal. The use of solar light could be an excellent alternative since this natural source of energy could reduce the costs for the treatment of phenolic wastewaters [22][23][24][25].…”

Recovery, regeneration and sustainable management of spent adsorbents from wastewater treatment streams: A review

“…Subsequently, regeneration using AOP with H2O2 is performed where the MTBE concentration is reduced from 0.9-1.5mg/L to ≤0.1 mg/L within 2 to 3 days. In another work, Bach et al (2009) used room temperature AOP for the regeneration of GAC using hydrogen peroxide (oxidant) and iron oxide (nanocatalysts). The regenerated samples show a negligible reduction in adsorption even after four cycles of regeneration.…”

Nanoporous Copper Doped Aluminium Pillared Montmorillonite for Dye‐containing Wastewater Treatment

“…From this point of view, we have been interested in enhancing the decolorization efficiency of the Alpill-MMT by doping with copper (II) in the present study because the copper (II) could not only act as catalyst in advanced oxidation processes (AOPs) (Lahtinen et al, 2005;Yang et al, 2007;Punniyamurthy and Rout, 2008;Wang et al, 2009;Wang et al, 2013), but also antibacterial agent (Majzlik et al, 2011;Yu-Hao et al, 2011). The AOPs are one of the most attractive and effective methods for wastewater treatment because the AOPs have the ability to generate the highly reactive hydroxyl radicals (HO ), in which they can attack a wide variety of organic contaminants in wastewater, resulting in decolorization, degradation and mineralization to CO 2 and H 2 O (Al-Kdas et al, 2004;Bach et al, 2009;Grrido-Ramirez et al, 2010). In addition, the copper (II) was selected as dopant in this work because it was claimed to have greater catalytic activity for AOPs than iron catalysts in some researches (Tomul, 2011;Zhou et al, 2011).…”