COD fractionation and toxicity of pulp and paper mill wastewaters in a tertiary process

Abstract

The chemical oxygen demand (COD) fractionation, as well as the acute toxicity and UMU genotoxicity of pulp and paper mill wastewater (PPMWW) were investigated to determine the COD compositions of PPMWW and to find the relationship between COD fractionation and toxicity. The fraction comprising non-biodegradable (inert) organic matter (X_I) was the main component in influent PPMWW, accounting for about 80% of the total COD. The acute toxicity of the influent was 0.08–0.16 mg Hg²⁺ L⁻¹ and the UMU genotoxicity was 0.6–0.8 μg 4-nitroquinoline-N-oxide L⁻¹. Both acute toxicity and genotoxicity were reduced in the biotreatment system. However, coagulation and Fenton oxidation were efficient in eliminating UMU genotoxicity. Total COD, acute toxicity, and genotoxicity showed significant correlation with each other (p < 0.01).

Keywords:

• Pulp and paper mill wastewater (PPMWW)
• COD fraction
• Acute toxicity
• Genotoxicity

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 21007010), Joint Funds of Chinese Transportation Ministry and Hunan Province for Science and Technology Development (No. 2010-353-343-290), and the Project of Transportation Department of Hunan Province (No. 200908, 201105). The authors would also thank Shira Glabman for revising the paper.