Project Commissioning Of Biofilter For Removaling Iron And Manganese And The Study On Diversity Of Manganese-oxidizing Bacteria

Groundwater is the main water supply source in northern of China, while theexistence of iron and manganese ions in groundwater Seriously affected the securityof water supply. Groundwater for Pine North water plant is a typical water qualitywith high iron, manganese and ammonia, and “spraying-driping-aerating andprimary biological filter” are used to achieve a good treatment effect.The production scale of the second stage is2×10⁴m³/d. The concentration ofiron in the raw water is10¹5mg/L, the concentration of manganese is about1.0mg/L, and the ammonia is0.8¹.2mg/L. since the11to20filter waslaunched in June2011, the effluent can be up to the standard of drinking water aftercommissioning, and the concentration of the effluent were TFe<0.2mg/L,Mn<0.05mg/L and NH₄⁺-N<0.3mg/L respectively. In order to study species andstructures of microrganism removing iron and manganese, the fifteenth filter wasused to research the structure changes of manganese-oxidizing bacteria at differenttime and different depth by Flat-panel separation、Clone and T-RFLP technique, andthe phylogenetic tree of manganese-oxidizing bacteria was established.Experimental results show that the dominant bacteria in the mature manganese sandbelong to β-Proteobacterium and-Proteobacterium. In addition, common bacteriasuch as Leptothrix, Gallionella and Pseudomonas using to remove iron andmanganese appeared in the different depth of filer layer. The terminal restrictionfragment lengths of these three bacteria were147bp,120bp and484bp respectivelyby software simulation（the specific primers were27F and1492R, and the forwardprimer was labelled with the fluorochrome6-FAM on the5′end; the enzymes wasMspI）.Through terminal restriction fragment length polymorphism analysis, themicrobial structure in the depth of60cm did not change obviously when the filterhas operated to30d and60d. But when the filter has operated for120d, Thediversity of community was low, but the number of the bacteria with terminalrestriction fragment length of the147bp increased significantly, from25%to60%.When the filter has operated for120, the flora structure changed unconspicuously inthe depth of20,40and80cm, while the community diversity deteriorated in thedepth of60cm. Howerver, corresponding to fragment whose length was147bp, thenumber of the bacteria increased from25%to60%, and became to be the dominantbacteria.Water plants mature manganese sand was inoculated into the MSVP medium toenrichment culture. After cultering for four generations, T-RFLP technique was used to analyse the fourth generation, and two predominant bacteria was found, whoseterminal restriction fragment length were484bp and147bp. The fourth generationbacteria were screened to get two pure bacteria Pseudomonas sp. and Sphingomonassp.