Microbial community distribution and genetic analysis in a sludge active treatment for a complex industrial wastewater: a study using microbiological and molecular analysis and principal component analysis

Abstract

Liquid industrial chemical wastes are often treated with complex and integrated chemical and biological processes to attain the required standard for water discharge into the environment. Such wastewaters are potentially dangerous and of unknown composition. Biological treatment represents the cheapest means of pollution abatement. In the present work, a microbiological and genetic analysis was performed for the biological pool of an industrial wastewater treatment plant located in Civita Castellana (Viterbo, Italy). This study focused on active sludge treatment and on the subsequent secondary sedimentation system. The parameters of the biological section (the sludge active plant) are normally constantly monitored, but the biological efficiency of the microbial community should be better evaluated to understand the dynamics of the microbial community and its relationship to the overall standard quality parameters that are usually monitored. For this study, Biolog community level physiological profiling (CLPP) on EcoPlates and PCR-amplified 16S rRNA denaturing gradient gel electrophoresis (DGGE) were used in comparison and combined as ecological techniques to characterize an anthropic closed ecosystem. Biolog CLPP provides the potential metabolic pattern and DGGE analyses helps to explain the structure and complexity of the microbial community. The results suggest that these techniques could be predictive and more useful when used together than alone. In addition, a principal component analysis (PCA) performed on the Biolog assay over time can relate principal components predictive wells to the biological and standard chemical analysis used to control and monitor the activity of this type of industrial wastewater treatment plant, providing a selection method for further DGGE community analysis.