Treating Pollutants-receiving Ponds And Improving Water Quality In Rivers By Microbial Technology

The aim of this research was to treat pollutants-receiving ponds and to improve water quality by directly using cultured microorganisms. Following results were obtained:1. Before bacterial inoculation, the ponds yielded bad smell. After the inoculation, the smell had been gradually reduced and eventually disappeared after a four-month treatment and the water became much clearer compared to the original. The content of dissolved oxygen in the water was increased by 3.2 mg/L～4.0 mg/L, and transparency degree by 0.35 m～0.42 m. The contents of permanganate index and total nitrogen were reduced by 57.31%～62.57% and 41.80%～44.09%, respectively. This indicated that the inoculated microorganisms can significantly degrade input pollutants.2. 51 culturable medium-temperature bacteria were isolated by using cultivation method from the Taohuajiang River. The dominant bacterial groups were determined by 16S rDNA sequence analysis. The isolated microbes included y-Proteobacteria (45. 10%), β-Proteobacteria (27. 45%) and Firmicutes (23. 53%), most of which were closely related to genera Pseudomonas, Bacillus and Acinetobacter. Diversity analysis revealed that these microbial isolates fell into 24 different taxa with the Shannon diversity index of 3. 14. The total bacterial community was abundant in sampling site No. 26, 32, 33, 38 and 42 (about 10~5 cfu/mL), and much less abundant in sampling site No. 9, 14, 20, 31 and 35 (about 10~3 cfu/mL). With respect to the species of isolated microbes, generus Pseudomonas was distributed in each sampling sites; genera Bacillus, Acinetobacer and Aquaspirillum were distributed in most sewage discharges; while genera Micrococcus and Chromobacterium were present in deep clean water.3. Three strains which showed high activity were obtained by studying the capacity of degrading organic materials during the initial screening of isolated indigenous microbes from the Taohuajiang River. These were Pseudomonas stutzeri, Bacillus cereus and Acinetobacter junii, which were used to improve water quality. After treating with these bacteria for 8 days individually, the effenciencies in removing permanganate index and total nitrogen from the entrophicated water samples were 62.29% ～ 69.54% and 28.36% ～ 32.40%, respectively. The content of dissolved...