1. M. Erdem, Chromium recovery from chrome shaving generated in tanning process, J. Hazard. Mater., 129 (2006) 143–146.
  2. G. Zheng, L. Zhou, S. Wang, An acid-tolerant heterotrophic microorganism role in improving tannery sludge bioleaching conducted in successive multi-batch reaction systems, Environ. Sci. Technol., 43 (2009) 4151–4156.
  3. A. Esmaeili, A.M. Nia, R. Vazirinejad, Chromium (III) removal and recovery from tannery wastewater by precipitation process, Amer. J. Appl. Sci., 2 (2005) 1471–1473.
  4. J. Wang, S. Zhu, Y. Zhang, H. Zhao, M. Hu, C. Yang, W. Qin, G. Qiu, Bioleaching of low-grade copper sulfide ores by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, J. Cent South Univ., 21 (2014) 728–734.
  5. C. Elicker, P.J.S. Filho, K.R.L. Castagno, Electro remediation of heavy metals in sewage sludge, Braz. J. Chem. Eng., 31 (2014) 365–371.
  6. S. Ding, L. Dong, D. Pan, Chrome Adsorption characteristics of yue village soil fertilized with tannery sludge, J. Soc. Leath. Tech. Ch., 98 (2014) 163–166.
  7. J. Allue, A.M. Garces, J. Bech, J. Barcelo, C. Poschenrieder, Fractionation of chromium in tannery sludge-amended soil and its availability to fenugreek plants, J. Soil. Sediment., 14 (2014) 697–702.
  8. L. Alibardi, R. Cossu, Pre-treatment of tannery sludge for sustainable landfilling, Waste Manage., 52 (2016) 202–211.
  9. P. Kavouras, E. Pantazopoulou, S. Varitis, G. Vourlias, K. Chrissafis, G.P. Dimitrakopulos, M. Mitrakas, A.I. Zouboulis, T. Karakostas, A. Xenidis, Incineration of tannery sludge under oxic and anoxic conditions: Study of chromium speciation, J. Hazard. Mater., 283 (2015) 672–679.
  10. F.P. Camargo, P.S. Tonello, A.C.A. Dos Santos, I.C. Silveira Duarte, Removal of toxic metals from sewage sludge through chemical, physical, and biological treatments-a review, Water Air Soil Poll., 227 (2016).
  11. W. Zhang, L. Yang, A. Wang, C. Wang, J. Zhou, Advance of sludge producing, hazards and disposal methods, Adv. Mater. Res., 1033–1034 (2014) 369–377.
  12. S.O. Rastegar, S.M. Mousavi, S.A. Shojaosadati, Cr and Ni recovery during bioleaching of dewatered metal-plating sludge using Acidithiobacillus ferrooxidans, Bioresour. Technol., 167 (2014) 61–68.
  13. J. Zeng, M. Gou, Y. Tang, G. Li, Z. Sun, K. Kida, Effective bioleaching of chromium in tannery sludge with an enriched sulfur-oxidizing bacterial community, Bioresour. Technol., 218 (2016) 859–866.
  14. M.L.M. Rodrigues, K.C.S. Lopes, H.C. Leoncio, L.A.M. Silva, V.A. Leao, Bioleaching of fluoride-bearing secondary copper sulphides: Column experiments with Acidithiobacillus ferrooxidans, Chem. Eng. J., 284 (2016) 1279–1286.
  15. W. Gu, J. Bai, B. Dong, X. Zhuang, J. Zhao, C. Zhang, J. Wang, K. Shih, Catalytic effect of graphene in bioleaching copper from waste printed circuit boards by Acidithiobacillus ferrooxidans, Hydrometallurgy, 171 (2017) 172–178.
  16. H. Ma, J. Zhou, L. Hua, F. Cheng, L. Zhou, X. Qiao, Chromium recovery from tannery sludge by bioleaching and its reuse in tanning process, J. Clean. Prod., 142 (2017) 2752–2760.
  17. S.V. Prabhu, R. Baskar, Detoxification of electroplating sludge by bioleaching: process and kinetic aspects, Pol. J. Environ. Stud., 24 (2015) 1249–1257.
  18. L. Li, J. Gao, S. Zhu, Y. Li, R. Zhang, Study of bioleaching under different hydraulic retention time for enhancing the dewaterability of digestate, Appl. Microbiol. Biot., 99 (2015) 10735–10743.
  19. G. Zheng, M. Huo, L. Zhou, Extracellular Polymeric substances level determines the sludge dewaterability in bioleaching process, J. Environ. Eng., 142 (2016).
  20. J. Zhu, J. Zhang, Q. Li, T. Han, Y. Hu, X. Liu, W. Qin, L. Chai, G. Qiu, Bioleaching of heavy metals from contaminated alkaline sediment by auto- and heterotrophic bacteria in stirred tank reactor, T. Nonferr. Metal. Soc., 24 (2014) 2969–2975.
  21. G. Akinci, D.E. Guven, Bioleaching of heavy metals contaminated sediment by pure and mixed cultures of Acidithiobacillus spp., Desalination, 268 (2011) 221–226.
  22. A. Pathak, M.G. Dastidar, T.R. Sreekrishnan, Bioleaching of heavy metals from sewage sludge: A review, J. Environ. Manage., 90 (2009) 2343–2353.
  23. H. Hong, C. Su, U.U. Jadhav, Bioleaching of metals from steel slag by Acidithiobacillus thiooxidans culture supernatant, Chemosphere, 117 (2014) 652–657.
  24. H. Yang, S. Feng, Y. Xin, W. Wang, Community dynamics of attached and free cells and the effects of attached cells on chalcopyrite bioleaching by Acidithiobacillus sp., Bioresour. Technol., 154 (2014) 185–191.
  25. D. Fang, L. Zhou, Enhanced Cr bioleaching efficiency from tannery sludge with coinoculation of Acidithiobacillus thiooxidans TS6 and Brettanomyces B65 in an air-lift reactor, Chemosphere, 69 (2007) 303–310.
  26. W. Hu, G. Zheng, D. Fang, C. Cui, J. Liang, L. Zhou, Bioleached sludge composting drastically reducing ammonia volatilization as well as decreasing bulking agent dosage and improving compost quality: A case study, Waste Manage., 44 (2015) 55–62.
  27. A. Pathak, M.G. Dastidar, T.R. Sreekrishnan, 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, J. Hazard. Mater., 171 (2009) 273–278.
  28. F. Liu, L. Zhou, J. Zhou, X. Song, D. Wang, Improvement of sludge dewaterability and removal of sludge-borne metals by bioleaching at optimum pH, J. Hazard. Mater., 221 (2012) 170–177.
  29. Y. Wen, Q. Wang, C. Tang, Z. Chen, Bioleaching of heavy metals from sewage sludge by Acidithiobacillus thiooxidans - a comparative study, J. Soil. Sediment., 12 (2012) 900–908.
  30. Y. Wen, Y. Cheng, C. Tang, Z. Chen, Bioleaching of heavy metals from sewage sludge using indigenous iron-oxidizing microorganisms, J. Soil. Sediment., 13 (2013) 166–175.
  31. S. Chen, J. Lin, Enhancement of metal bioleaching from contaminated sediment using silver ion, J. Hazard. Mater., 161 (2009) 893–899.
  32. G. Zheng, L. Zhou, Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching, Water Res., 45 (2011) 5295–5301.
  33. M. Gan, Z. Song, J. Zhu, X. Liu, Efficient bioleaching of heavy metals from contaminated sediment in batch method coupled with the assistance of heterotrophic microorganisms, Environ. Earth Sci., 75 (2016).
  34. H. Li, M. Ye, Z. Li, Optimization of kinetics and operating parameters for the bioleaching of heavy metals from sewage sludge, using co-inoculation of two Acidithiobacillus species, Water Sci. Technol., 2 (2018) 390–403.
  35. APHA, Standard Methods for the Examination of Water and Wastewater, American Public Health Association, Washington, DC., 2005.
  36. S. Wang, G. Zheng, L. Zhou, Heterotrophic microorganism Rhodotorula mucilaginosa R30 improves tannery sludge bioleaching through elevating dissolved CO2 and extracellular polymeric substances levels in bioleach solution as well as scavenging toxic DOM to Acidithiobacillus species, Water Res., 44 (2010) 5423–5431.
  37. Y. Liao, L. Zhou, J. Liang, H. Xiong, Biosynthesis of schwertmannite by Acidithiobacillus ferrooxidans cell suspensions under different pH condition, Mater. Sci. Eng. C - Biomim. Supramol. Syst., 29 (2009) 211–215.
  38. L.X. Zhou, D. Fang, S.M. Wang, J. Wong, D.Z. Wang, Bioleaching of Cr from tannery sludge: The effects of initial acid addition and recycling of acidified bioleached sludge, Environ. Technol., 26 (2005) 277–284.
  39. Y. Wang, W. Li, A. Irini, C. Su, Removal of organic pollutants in tannery wastewater from wet-blue fur processing by integrated anoxic/oxic (A/O) and Fenton: Process optimization, Chem. Eng. J., 252 (2014) 22–29.
  40. P. Zhang, Y. Zhu, G. Zhang, S. Zou, G. Zeng, Z. Wu, Sewage sludge bioleaching by indigenous sulfur-oxidizing bacteria: Effects of ratio of substrate dosage to solid content, Bioresour. Technol., 100 (2009) 1394–1398.
  41. L.J.C. Chuan M C, Release behavior of chromium from tannery sludge, Water Res., 30 (1996) 932–938.
  42. L.C. Chan, X.Y. Gu, J. Wong, Comparison of bioleaching of heavy metals from sewage sludge using iron- and sulfur-oxidizing bacteria, Adv. Environ. Res., 7 (2003) 603–607.
  43. H.W. Ryu, H.S. Moon, E.Y. Lee, K.S. Cho, H. Choi, Leaching characteristics of heavy metals from sewage sludge by Acidithiobacillus thiooxidans MET, J. Environ. Qual., 32 (2003) 751–759.
  44. J. Wong, L. Xiang, L.C. Chan, PH requirement for the bioleaching of heavy metals from anaerobically digested wastewater sludge, Water Air Soil Poll., 138 (2002) 25–35.
  45. H. Xiong, Y. Liao, L. Zhou, Influence of chloride and sulfate on formation of akaganeite and schwertmannite through ferrous biooxidation by Acidithiobacillus ferrooxidans cells, Environ. Sci. Technol., 42 (2008) 8681–8686.
  46. L. Ma, X. Wang, J. Tao, X. Feng, K. Zou, Y. Xiao, Y. Liang, H. Yin, X. Liu, Bioleaching of the mixed oxide-sulfide copper ore by artificial indigenous and exogenous microbial community, Hydrometallurgy, 169 (2017) 41–46.
  47. B. Ebbers, L.M. Ottosen, P.E. Jensen, Electro dialytic treatment of municipal wastewater and sludge for the removal of heavy metals and recovery of phosphorus, Electrochim. Acta, 181 (2015) 90–99.
  48. Y. Wang, Z. Pan, J. Lang, J. Xu, Y. Zheng, Bioleaching of chromium from tannery sludge by indigenous Acidithiobacillus thiooxidans, J. Hazard. Mater., 147 (2007) 319–324.
  49. Q. Zhou, J. Gao, Y. Li, S. Zhu, L. He, W. Nie, R. Zhang, Bioleaching in batch tests for improving sludge dewaterability and metal removal using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans after cold acclimation, Water Sci. Technol., 76 (2017) 1347–1359.