A Combined Bioprocess for Integrated Removal of Copper and Organic Pollutant from Copper-Containing Municipal Wastewater

Abstract

Heavy metal-containing wastewater is difficult to treat by most of the bioprocess due to its toxicity to microorganism in activated sludge. In this study, a combined bioprocess consisting of biosorption section that contained magnetite immobilized Pseudomonas putida 5-x cell as biosorbent followed by sequence batch reactor (SBR) was developed to treat Cu²⁺-containing municipal wastewater. The production techniques of Pseudomonas putida 5-x cell as biosorbent, such as optimal cell harvest period and cell pretreatment techniques were studied. Experimental results showed, considering both cell biomass and cell adsorption capacity to Cu²⁺, 36 h is the optimal harvest period in the course of culturing Pseudomonas putida 5-x cells as biosorbent, and 0.1–0.3 mol L⁻¹ HCl is an optimal cell pretreating eluant to improve Cu²⁺ adsorption capacity. The performances of the combined bioprocess for treating Cu²⁺ containing wastewater were assessed. Experimental results showed that after treatment by biosorption, the Cu²⁺ level in wastewater was reduced to level that did not inhibit COD removal efficiency of subsequent SBR activated sludge process, although it still affected the COD adsorption capacity of activated sludge. In terms of COD removal, the biosorption section was efficient for reducing Cu²⁺ concentration to provide biodegradable wastewater for subsequent SBR activated sludge process.

Keywords:

• Cell pretreatment
• COD removal
• COD adsorption capacity (CAC)
• Cu²⁺ adsorption
• Pseudomonas putida

Acknowledgments

This work was supported by the Hong Kong Research Grants Council Grant and Visiting Scholar Fund of State Key Laboratory for Pollution Control and Resource Management, Tongji University.