Effective In situ Biological Treatment of Tannery Wastewater by Using a Novel Microbial Consortium BM-S-1

This study was carried out to indentify microbial populations in the industrial treatment of tannery wastewater using a microbial consortium and their specific roles during the treatment process. A novel microbial consortium enriched from the natural soils was successfully implemented to treat the tannery wastewater from leather manufacturing industries in Korea and China. The treatment process was composed of the six processes including buffering tank (B), primary aeration tank (PA), secondary aeration tank (SA), and sludge digestion tank (SD). The consortium was periodically added to B, PA, SA and SD. The water quality was monitored for COD, T-N, T-P and Chromium (Cr), etc. Microbial communities and some functions were monitored by pyrosequencing and quantitative real-time PCR techniques. The COD, T-N, T-P and Cr removal efficiencies reached 98%, 98%, 93% and 88%, respectively. Pyrosequencing data from different stages of the treatment processes revealed that the dominant phyla were similar in four different samples, while the proportions of them were shifted. The genus of Brachymonas within Proteobacteria was highly dominant in B (37.7%), SD (22.1%) and PA (17.3%), and this genus was known to associate with denitrifying process. This could be indicating an efficient removal of nitrogen and less production of sludge in the treatment system. The nitrous oxide reductase gene copies detected in B were also higher than those of PA, SA and SD in monitoring of real-time PCR. Augmentation of the mixed culture (BM-S-1) appeared to facilitate degradation of the tannery organic wastes and remove their malodor via the comprehensive metabolic activities of various microbes with little generation of sludge.