Simultaneous Removal of MTBE and Benzene from Contaminated Groundwater Using Ultraviolet-Based Ozone and Hydrogen Peroxide

Bassam S Tawabini

doi:10.1155/2014/452356

Abstract

Efficiency of ultraviolet-ozone (UV/O3) and ultraviolet-hydrogen peroxide (UV/H2O2) processes was investigated for simultaneous removal of methyl tertiary butyl ether (MTBE) and benzene from contaminated ground water. The photoreactor employed housed 15-watt low pressure (LP) and 150-watt medium pressure (MP) mercury UV lamps. Oxidation of contaminants was studied at two different levels of ozone and hydrogen peroxide. Brackish groundwater samples were spiked with MTBE and benzene up to a concentration of 500 μg L−1. Removal potential was evaluated at different parameters such as UV type and intensity and peroxide and ozone dosages, as well as contact time. Results indicated that no removal of the contaminants was attained when treated with hydrogen peroxide or ozone alone. However, about 50% and 30% removal of MTBE were achieved in 30 minutes when irradiated with MP-UV and LP-UV lamps, respectively. On the other hand, UV/H2O2process was found to be superior in removal of MTBE (90% in 10 min.) and benzene (95% in 5 min.) compared to UV/O3process. Furthermore, removal of benzene was comparatively easier than MTBE in both approaches. It is hence concluded that higher UV intensities and elevated doses of H2O2accelerate simultaneous removal of MTBE and benzene from water.

Highlights

In oil producing countries, contamination of water resources is generally attributed to fuel additives and different fuel products
Contamination of water resources is generally attributed to fuel additives and different fuel products. These contaminants reach water bodies through different routes such as the process of transportation, mixing, refining, and filling operations. Fuel products such as benzene, toluene ethyl benzene, and xylenes (BTEX) and fuel additives such as methyl tert-butyl ether (MTBE) are among the organic pollutants commonly detected in water resources
Levels of chloride, bromide, and sulfate ions are on the higher side at 1220, 4.2, and 546 ppm, respectively. High levels of these anions were expected to compete with the target pollutants (MTBE and benzene) for the hydroxyl radicals [22,23,24,25]

Summary

Introduction

Contamination of water resources is generally attributed to fuel additives and different fuel products. These contaminants reach water bodies through different routes such as the process of transportation, mixing, refining, and filling operations. Fuel products such as benzene, toluene ethyl benzene, and xylenes (BTEX) and fuel additives such as methyl tert-butyl ether (MTBE) are among the organic pollutants commonly detected in water resources. Major causes of MTBE pollution are leakages in underground storage tanks and pipelines and accidental spills during refining processes. Toxicity analysis conducted on test animals has shown that direct exposure to MTBE, even for shorter periods of time, can cause nausea, vomiting, and sleepiness [3]

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