Using microbiological leaching method to remove heavy metals from sludge

Abstract

Microbial leaching is one of the most effective methods to remove heavy metals from sludge. In the conducted researches, the sludge samples were processed with Thiobacillus ferrooxidans and Thiobacillus thiooxidans obtained via cultivation, extraction and purification processes. Heavy metals such as Pb, Cd, Cu and Ni were leached from sludge by Thiobacillus ferrooxidans and Thiobacillus thiooxidans within different substrate concentration and pH value conditions. It is defined that from the point of view of economy and efficiency the optimal concentration of FeSO4.7H2O and sulfur for bio-leaching process was 0.2 g. The leaching rates of heavy metals such as Pb, Cd, Cu and Ni of the same concentration were 74.72%, 81.54%, 70.46% and 77.35% respectively. However, no significant differences depending on the pH value among the leaching rates were defined, even for the pH value of 1.5. Along with the removal of heavy metals from sludge, the organic matter, N, P, K were also leached to some extent. The losing rate of phosphorus was the highest and reached 38.44%. However, the content of organic matter, N, P, K in the processed sludge were higher in comparison with level I of the National Soil Quality Standards of China. Ecological risk of heavy metals in sludge before and after leaching was assessed by Index of Geo-accumulation (Igeo) and comprehensive potential risk (RI). The results of research defined that the content of heavy metals in sludge meets the level of low ecological risk after leaching and their contents is lower in comparison with the National Agricultural Sludge Standard of China. Sludge leached by biological methods is possible to use for treatment for increasing soil fertility. 

Keywords

• pH value,sludge,microbiological leaching,substrate concentration,heavy metals

References

1. Babel, S., Dacera, D.M., 2006. Heavy metal removal from contaminated sludge for land application: A review. Waste Management 26(9): 988–1004.
2. Benmoussa, H., Tyagi, R.D., Campbell, P.G.C., 1998. Simultaneous sewage sludge digestion and metal leaching using an internal loop reactor: effect of suspended solids concentration. Water Research 32(8): 2373–2390.
3. Brown, M. J., Lester, J.N., 1979. Metal removal in activated sludge: the role of bacterial extracellular polymers. Water Research 13(9): 817–837.
4. Li, C., Zhou, L., Wang S., 2008.B ioleaching of heavy metals from municipal sludge by the co-inoculation of two acidophilic Thiobacillus. Acta Scientiae Circumstantiae 28(6): 1155–1160 [in Chinese].
5. Dai, L., Ren, J., Tao, L., Li, H., 2012. Effects of sewage sludge application on soil and physiological property of Triticum Aestivum. Agro-Environment Science 31(2): 362–368. [in Chinese].
6. Fournier, D., Lemieux, R., Couillard, D., 1998.Essential interactions between Thiobacillus ferrooxidansand heterotrophic microorganisms during a wastewater sludge bioleaching process. Environmental Pollution 101(2): 303–309.
7. González Benito, G., Osorio, G., Bonilla, D., 1995. Biological sulphur removal by thiobacillus thiooxidans in fine coal coming from a flotation washing plant. Coal Science and Technology 24: 1745–1748.
8. Hakanson, L. 1980. An ecological risk index for aquatic pollution control. A sedimentological approach. Water Research 14(8): 975–1001.

9. Hunsom, M., Pruksathorn, K., Damronglerd, S., Vergnes, H., Duverneuil, P., 2005. Electrochemical treatment of heavy metals (Cu2+, Cr6+, Ni2+) from industrial effluent and modeling of copper reduction. Water Research 39(4): 610–616.
10. Jakobsen, M.R., Fritt-Rasmussen, J., Nielsen, S., Ottosen, L.M. 2004. Electrodialytic removal of cadmium from wastewater sludge. Journal of Hazardous Materials 106(2–3): 127–132.
11. Kaminari, N.M.S., Schultz, D.R., Ponte, M.J.J.S., Ponte, H.A., Marino, C.E.B., Neto, A.C., 2007. Heavy metals recovery from industrial wastewater using Taguchi method. Chemical Engineering Journal 126(2–3): 139–146.
12. Lester, J.N., Sterritt, R.M., Kirk, P.W.W., 1983. Significance and behaviour of heavy metals in waste water treatment processes II. Sludge treatment and disposal. Science of The Total Environment 30: 45–83.
13. Liu, C., Shao, S.G., Fan, C.X., 2014. Pollution status and risk assessment of heavy metals in the sediment of the highly polluted confluence area of the Lake Chaohu. China Environmental Science 34(4): 1031–1037. [in Chinese]
14. Liu, J.Y., Sun, Y.Y., Xu, Y.B., 2009. Heavy metal characteristics in sewage sludge and its potential ecological risk assessment for agriculture implementing in Guangzhou. Acta Scientiae Circumstantiae 29(12): 2545–2556. [in Chinese]
15. Liu, Y.F., 2014. Experimental study on sludge drying and co-combustion with coal in pulverized coal power industrial boiler. McS Thesis, Zhejiang University, China. [in Chinese]
16. Lombardi, A.T., Garcia, Jr.O., 2002. Biological leaching of Mn, Al, Zn, Cu and Ti in an anaerobic sewage sludge effectuated by Thiobacillus ferrooxidans and its effect on metal partitioning. Water Research 36(13): 3193–3202.
17. Muller, G., 1969. Index of geoaccumulation in sediments of the Rhine River. Geojournal 2(3): 108–118.
18. Pansu, M., Gautheyrou, J., 2006. Handbook of Soil Analysis: Mineralogical, Organic and Inorganic Methods. Springer-Verlag Berlin Heidelberg. 993 p.
19. Pathak, A., Dastidar, M.G., Sreekrishnan, T.R., 2009a. Bioleaching of heavy metals from sewage sludge: A review. Journal of Environmental Management 90(8): 2343–2353.
20. Pathak, A., Dastidar, M.G., Sreekrishnan, T.R., 2009b. Bioleaching of heavy metals from sewage sludge by indigenous iron-oxidizing microorganisms using ammonium ferrous sulfate and ferrous sulfate as energy sources: A comparative study. Journal of Hazardous Materials 171(1–3): 273–278.
21. Peng, G., Tian, G., Liu, J., Bao, Q., Zang, L., 2011. Removal of heavy metals from sewage sludge with a combination of bioleaching and electrokinetic remediation technology. Desalination 271(1–3): 100–104.
22. Shen, L., Zhang, T.P., Jia, X.S., 2005. Removal of heavy metals contained in sewage sludges by using Thiobacillus ferrooxidans and Thiobacillus thiooxidans. Acta Scientiarum Naturalium Universitatis Sunyatseni 44(2): 111–116. [in Chinese]
23. Shen, R.Y., Luo, Y.M., Zhang, G.Y., Li, Z.G., Teng, Y. 2007. Effect of municipal sludge on the accumulation of organic pollutants in different plant-soil systems. Journal of Agro-Environment Science 26(2): 651–657. [in Chinese]
24. Shi, W., Liu, C., Ding, D., Lei, Z., Yang, Y., Feng, C., Zhang, Z., 2013. Immobilization of heavy metals in sewage sludge by using subcritical water technology. Bioresource Technology 137: 18–24.
25. Sreekrishnan, T.R., Tyagi, R.D., 1996. Comparative study of the cost of the heavy metals leaching from sewage sludge. Process Biochemistry 31(1): 31–41.
26. Tessier, A., Campbell, P.G.C., Bisson, M., 1979. Sequential extraction procedure for the speciation of particulate trace metals. Analytical Chemistry 51(7): 844–851.
27. Varela, P., Levican, G., Rivera, F., Jerez, C.A., 1998. Immunological strategy to monitor In situ the phosphate starvation state in Thiobacillus ferrooxidans. Applied and Environmental Microbiology 64(12): 4990–4993.
28. Wang, D.Q., 2004. Study on heavy metal removal from urban sewage sludge and utilization. PhD thesis, Chongqing University, Chongqing, China. [in Chinese]
29. Wang, H.R., Yu, P.P., Han, J.X., Zhao, B., Huang, B.C., Zhen, X.J., 2014. Survey of treatment technology of wasted water and sewage sludge in Zhejiang province. Energy Environmental Protection 28(3): 1–3. [in Chinese]
30. Yu, Y.J., Hu, L.K., Yang, Y., 2010. Pollution characteristics and ecological risk assessment of heavy metals in arable soils of typical river basin. Research of Environmental Science 23(12): 1523–1527. [in Chinese]
31. Zhou, S.G., Zhou, L.X., Huang, H.Z., 2002. Removal of heavy metals from sewage sludge by bioleaching. Acta Ecologica Sinica 22 (1): 125–133. [in Chinese]
32. Zhu, Y., Zeng, G., Zhang, P., Zhang, C., Ren, M., Zhang, J., Chen, M., 2013. Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge. Bioresource Technology 142: 530-534.