Biodegradation of olive mills wastewater using thermophilic bacteria

Abstract

Biodegradation of olive mill wastewater (OMW) toxic constituents was investigated using thermophilic bacteria. Three types of thermophilic bacteria were isolated from olive mills solid waste (Jift) and tested their ability to detoxify OMW. These thermophiles, namely Bacillus polymaxa JT6, Bacillus Maceramns JT7 and Bacillus popilliae JT8, can grow on Zebar as a main carbon source. The optimal growths of thermophiles were obtained at temperature of 65°C and pH of 6.4. The growth of the three thermophiles on Zebar was descending with increasing Zebar concentration. Complete inhibition of thermophiles was observed when the total solid concentration of Zebar was above 20 g/L. This suggests the need for a pretreatment process for Zebar prior to the biological treatment or the use of diluted Zebar solution. Moreover, the growth rate of the thermophiles on Zebar solution of 8 mass% was described by Monod growth model.

Keywords:

• Thermophilic bacteria
• Olive mills wastewater
• Batch growth kinetics
• Biodegradation

Acknowledgments

The authors are grateful for the Higher Council of Science and Technology (HCST), Jordan, Al-Balqa University, Jordan, and Deutsche Forschungsgemeinschaft, DFG (The German Research Foundation), for funding the project. The technical support of Hashemite University, Jordan and Hamburg Technical University, Germany are greatly appreciated for their help in conducting parts of the experiments.