Trace Organic Compound Removal from Wastewater Reverse-Osmosis Concentrate by Advanced Oxidation Processes with UV/O3/H2O2.

Hadas Mamane,Yaal Lester,Aviv Kaplan,Dror Avisar

doi:10.3390/ma13122785

Abstract

Advanced technologies, such as reverse osmosis (RO), allow the reuse of treated wastewater for direct or indirect potable use. However, even highly efficient RO systems produce ~10–15% highly contaminated concentrate as a byproduct. This wastewater RO concentrate (WWROC) is very rich in metal ions, nutrients, and hard-to-degrade trace organic compounds (TOrCs), such as pharmaceuticals, plasticizers, flame retardants, and detergents, which must be treated before disposal. WWROC could be up to 10 times more concentrated than secondary effluent. We examined the efficiency of several advanced oxidation processes (AOPs) on TOrC removal from a two-stage WWROC matrix in a pilot wastewater-treatment facility. WWROC ozonation or UV irradiation, with H2O2 addition, demonstrated efficient removal of TOrCs, varying between 21% and over 99% degradation, and indicating that radical oxidation (by HO·) is the dominant mechanism. However, AOPs are not sufficient to fully treat the WWROC, and thus, additional procedures are required to decrease metal ion and nutrient concentrations. Further biological treatment post-AOP is also highly important, to eliminate the degradable organic molecules obtained from the AOP.

Highlights

More than 2 billion people live under high water stress, which is expected to increase due to effects of climate change and global warming [1]
Desalination technologies such as reverse osmosis (RO) or nanofiltration are attractive for wastewater reclamation and reuse [4]
The efficiency of advanced oxidation processes (AOPs) for the degradation of trace organic compounds (TOrCs) in two-stage wastewater RO concentrate (WWROC) was demonstrated by comparing UV and ozone, with and without H2 O2

Summary

Introduction

More than 2 billion people live under high water stress, which is expected to increase due to effects of climate change and global warming [1]. Water reuse is the best economic and environmental solution, and possibly the only viable one, for the increase in urban water consumption and depletion of water sources [3]. There is a need for advanced treatment of wastewater that generates high-quality potable water. Today, desalination technologies such as reverse osmosis (RO) or nanofiltration are attractive for wastewater reclamation and reuse [4]. RO of wastewater (subsequent to biological treatment) can produce high-quality reclaimed water [5,6,7,8,9] by rejecting contaminants such as metal ions, nitrates, viruses, pharmaceuticals, and pesticide residues. Various combinations of bioreactors followed by RO processes demonstrate recovery of 80–90% of the water [10,11,12], while the remaining

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Conclusion