Investigation of Impact Factors on the Treatment of Oily Sludge using a Hybrid Ultrasonic and Fenton's Reaction Process

Ju Zhang,Lei Liu,Guangji Hu,Jianbing Li,Ronald W Thring

doi:10.11159/ijepr.2014.006

Abstract

In this study, a hybrid ultrasonic and Fenton's reaction process (US/Fenton) was applied for oily sludge treatment. The impacts of four different factors on the reduction of total petroleum hydrocarbons (TPH) in oily sludge were investigated. These include the initial sludge content, the molar ratio of hydrogen peroxide to iron (H2O2/Fe2+), the ultrasonic power, and the ultrasonic treatment duration. Taguchi experimental design method was used to arrange laboratory experiments. The results indicated that a TPH reduction rate of up to 88.1% was reached with an initial sludge content of 20 g/L, a H2O2/Fe 2+ molar ratio of 4:1, an ultrasonic treatment time of 5 min, and an ultrasonic power of 60 W. The initial oily sludge content and ultrasonic treatment duration were found to be the most significant factors affecting the US/Fenton treatment of oily sludge.

Highlights

As one of the major wastes generated in the petroleum industry, oily sludge is a complex mixture consisting of water, inorganic solid particles, and various petroleum hydrocarbons (PHCs)
The total petroleum hydrocarbons (TPH) reduction rate was in the range of 51.9% to 88.1%, 42.3% to 83.9%, and 36.0% to 81.3% for experiments with low, medium, and high initial sludge contents, respectively
Among all of the 27 experimental runs, the highest TPH reduction rate of 88.1% was observed for treatment L3, with an initial sludge content of 20 g/L, a molar ratio of H2O2/Fe2+ of 4:1, an ultrasonic treatment time of 5 min, and an ultrasonic power of 60W

Summary

Introduction

As one of the major wastes generated in the petroleum industry, oily sludge is a complex mixture consisting of water, inorganic solid particles, and various petroleum hydrocarbons (PHCs). It contains a large amount of heavy PHCs, such as longchain alkanes and alkenes, polycyclic aromatic hydrocarbons, asphaltenes, and resins [1, 2]. Among various technologies, advanced oxidation processes (AOPs) have been recognized potential treatment approaches to effectively degrade the recalcitrant compounds [3]. During AOP processes, a large amount of hydroxyl radicals (·OH) can be generated through various methods (e.g., ultrasonic irradiation, ultraviolet radiation, photo-catalysis, ozonation, and/or Fenton’s reaction) [4]. The Fenton’s reagents, usually hydrogen peroxide (H2O2) and ferrous (Fe2+)

Objectives

Methods

Results

Discussion

Conclusion