Impact of microwave treatment on dewaterability of sludge during Fenton oxidation

Abstract

The impact of microwave treatment on the dewaterability of sludge during Fenton oxidation treatment was studied. It was found that MW/Fenton could significantly improve the dewaterability of sludge and reduce reaction time. In this study, the effect of Fenton reagent influence factors, such as initial pH value, reaction time and concentration of H₂O₂ and Fe²⁺, was investigated to obtain the optimal operating conditions (pH 3, Fe²⁺ = 0.4 g L⁻¹, H₂O₂ = 6.0 g L⁻¹, t = 2.0 min and p = 648 W). In addition, the effect of temperature was also studied. Under the optimal operating conditions, the specific resistance to filtration (SRF) and moisture contents was 1.85 × 10⁹ s² g⁻¹ and 65.93%, respectively. Then the micro-morphological characteristics of sludge under the optimal condition were studied to further explore the responsible mechanisms of this advanced method on sludge dewatering. The results of particle size distribution of raw sludge and conditioned sludge confirmed MW/Fenton could effectively improve the dewaterability of sludge.

Keywords:

• Dewaterability
• Microwave–Fenton pretreatment
• Micro-morphological characteristics
• Specific resistance to filtration
• The moisture contents

Acknowledgements

This research was financially supported by the open fund of the National Science and Technology Pillar Program (2014BAL04B04), Natural Science Foundation of Hubei Province, China (NO. 2013CFB289; 2013CFB308) and Major Science and Technology Program for Water Pollution Control and Treatment (NO. 2009ZX07317-008-003).