The Basic Research Of Using Microorganisms To Remove Zinc From Waste Water

Microbial treatment technology removing heavy mental from wastewater has become a new hotspot recently. It not only has the advantages of high speed and high selectivity but also do not create the second pollution. In this dissertation, the main content is the basic research of using sulfate reducing bacteria (SRB) to remove zinc from waste water. The serial experiments began from finding good mixed SRB population with high removal efficiency to enrichment, culturing and repeated domesticating. At last, two bacteria strains named yy4 and pxl-1 with strong removal capability were isolated. Then the author did some basic research work on the two bacteria. Through the method of molecule biology we know that the two strains belong to S.flexneri. The growth lines and the density of the two strains were also determined. At last, the mechanism of zinc removal was studied tentatively. The results of the research show us:1. The two strains named yy4 and px1-1 can remove the 120mg/L Zn²⁺ with high remove efficiency 96.75% and 95.12% separately under the condition of35°C, pH=7.2 in 48 hours.2. Through identification by the DNA technology, we know that the two strains belong to S.flexneri.3. Efficiency of zinc removal coincides with the amount of sulfide generated by SRB. With the improvement of the sulfide concentration, the efficiency will rise. ZnS was found in the solution of bacteria, which expressed that zinc removal can be realized by the SRB metabolized production.4. The change of redox potential (Eh) of bacteria solution also coincides with the change of amount of sulfide. If this technology can be applied in engineer project, we can estimate the efficiency of zinc removal through checking the change of Eh quickly and conveniently. Several factors affecting on the growth of SRB and the change of Eh were also researched.We have get bacteria strains in order to study deeply on how to get higher zinc removal efficiency. In addition, the elementary research on mechanism of zinc removal was done from macro-aspects. The results of this dissertation can provide reference for the future research on zinc removal by SRB.