Improving granular sludge stability via stimulation of extracellular polymeric substance production by adding layered double hydroxides

  • X. Xu
  • J. LiuEmail author
  • H. Sun
Original Paper


One of the main challenges for aerobic granular sludge in applications is its stability. In this study, the interaction between layered double hydroxide and extracellular polymeric substance was investigated and the mechanism for enhancing stability of aerobic granular sludge was also analyzed. Three sequencing batch reactors with nothing added (reactor 1), with layered double hydroxide added (reactor 2) and with metal ion solution added (reactor 3) were set up to investigate sludge developing characteristics and reactor performances, respectively. It was found that the mixed liquid suspended solids, sludge volume index and chemical oxygen demand removal efficiency of reactor 2 were better than those of reactors 1 and 3. At the same time, the concentrations of protein and polysaccharides extracted from the sludge in reactor 2 were also higher than those in reactors 1 and 3. This is possibly because with layered double hydroxide added, continuously and controllably released metal ions stimulate more extracellular polymeric substance production than the others and increase the hydrophobicity of the sludge. Fourier transform infrared spectroscopy characterization showed that the functional groups could combine with metal ions. A stable structure such as metal ions-extracellular polymeric substance–metal ion network may be formed and enhanced the granular sludge stability. This investigation provides a possibility for further application of layered double hydroxide on acceleration of sludge granulation and improvement in granule stability.


Aerobic granular sludge Controlled release Polysaccharides Protein 



Layered double hydroxide


Extracellular polymeric substance


Aerobic granular sludge


Sequencing batch reactors


Mixed liquid suspended solids


Sludge volume index


Chemical oxygen demand






Organic loading rate


Fourier transform infrared spectroscopy



This work was financially supported by the National Natural Science Foundation of China (51578329, 51778352) and the Program for Innovative Research Team in University (IRT13078).


  1. Adav SS, Lee DJ (2008) Extraction of extracellular polymeric substances from aerobic granule with compact interior structure. J Hazard Mater 154:1120–1126CrossRefGoogle Scholar
  2. Badireddy AR et al (2010) Role of extracellular polymeric substances in bioflocculation of activated sludge microorganisms under glucose-controlled conditions. Water Res 44:4505–4516CrossRefGoogle Scholar
  3. Barth A (2000) The infrared absorption of amino acid side chains. Prog Biophys Mol Biol 74:141–173CrossRefGoogle Scholar
  4. Barth A, Zscherp C (2002) What vibrations tell about proteins. Q Rev Biophys 35:369–430CrossRefGoogle Scholar
  5. Cao XL et al (2014) Comparison of Mg2+ and Ca2+ enhancing anaerobic granulation in an expanded granular sludge-bed reactor. Sci China Chem 57:1596–1601CrossRefGoogle Scholar
  6. Clescerl LS (1998) Standard methods for the examination of water and wastewater 20th Ed. Am J Public Health Nations Health 4:113-XGoogle Scholar
  7. Comte S, Guibaud G, Baudu M (2006) Relations between extraction protocols for activated sludge extracellular polymeric substances (EPS) and EPS complexation properties: part I. Comparison of the efficiency of eight EPS extraction methods. Enzyme Microbial Technol 38:237–245CrossRefGoogle Scholar
  8. Deng S, Wang L, Su H (2016) Role and influence of extracellular polymeric substances on the preparation of aerobic granular sludge. J Environ Manag 173:49–54CrossRefGoogle Scholar
  9. Dignac M-F et al (1998) Chemical description of extracellular polymers: implication on activated sludge floc structure. Water Sci Technol 38:45–53CrossRefGoogle Scholar
  10. Dubois M et al (1955) Colorimetric method for determination of sugars and related substances. Anal Chem 28:350–356CrossRefGoogle Scholar
  11. Fang HHP, Xu LC, Chan KY (2002) Effects of toxic metals and chemicals on biofilm and biocorrosion. Water Res 36:4709–4716CrossRefGoogle Scholar
  12. Frølund B, Griebe T, Nielsen PH (1995) Enzymatic activity in the activated-sludge floc matrix. Appl Microbiol Biotechnol 43:755–761CrossRefGoogle Scholar
  13. Hao W et al (2016) The effect of metal ions on the microbial attachment ability of flocculent activate sludge. Environ Technol 37:722–731CrossRefGoogle Scholar
  14. Kang H et al (2015) Intracrystalline structure and release pattern of ferulic acid intercalated into layered double hydroxide through various synthesis routes. Appl Clay Sci 112–113:32–39CrossRefGoogle Scholar
  15. Kavita K et al (2014) Characterisation and anti-biofilm activity of extracellular polymeric substances from Oceanobacillus iheyensis. Carbohydr Polym 101:29–35CrossRefGoogle Scholar
  16. Konczak B, Karcz J, Miksch K (2014) Influence of calcium, magnesium, and iron ions on aerobic granulation. Appl Biochem Biotechnol 174:2910–2918CrossRefGoogle Scholar
  17. Lee DJ et al (2010) Advances in aerobic granule formation and granule stability in the course of storage and reactor operation. Biotechnol Adv 28:919–934CrossRefGoogle Scholar
  18. Li XF et al (2008) Correlation between extracellular polymeric substances and aerobic biogranulation in membrane bioreactor. Sep Purif Technol 59:26–33CrossRefGoogle Scholar
  19. Li XM et al (2009) Enhanced aerobic sludge granulation in sequencing batch reactor by Mg2+ augmentation. Bioresour Technol 100:64–67CrossRefGoogle Scholar
  20. Lin YM et al (2015) Sustainable polysaccharide-based biomaterial recovered from waste aerobic granular sludge as a surface coating material. Sustain Mater Technol 4:24–29Google Scholar
  21. Liu J (2014) Enhanced aerobic sludge granulation with layered double hydroxide. Biointerface Res Appl Chem 4:736–740Google Scholar
  22. Liu Y, Liu QS (2006) Causes and control of filamentous growth in aerobic granular sludge sequencing batch reactors. Biotechnol Adv 24:115–127CrossRefGoogle Scholar
  23. Liu Y et al (2004) A thermodynamic interpretation of cell hydrophobicity in aerobic granulation. Appl Microbiol Biotechnol 64:410–415CrossRefGoogle Scholar
  24. Liu J et al (2013) Adsorption of bacteria onto layered double hydroxide particles to form biogranule-like aggregates. Appl Clay Sci 75–76:39–45CrossRefGoogle Scholar
  25. Liu J et al (2014a) Enhanced decolourisation of methylene blue by LDH-bacteria aggregates with bioregeneration. Chem Eng J 242:187–194CrossRefGoogle Scholar
  26. Liu Y et al (2014b) Regulation of aerobic granular sludge reformulation after granular sludge broken: effect of poly aluminum chloride (PAC). Bioresour Technol 158:201–208CrossRefGoogle Scholar
  27. Moghaddam SS, Moghaddam MRA (2016) Aerobic granular sludge for dye biodegradation in a sequencing batch reactor with anaerobic/aerobic cycles. CLEAN Soil Air Water 44:438–443CrossRefGoogle Scholar
  28. Ni SQ et al (2013) Effect of magnetic nanoparticles on the performance of activated sludge treatment system. Bioresour Technol 143:555–561CrossRefGoogle Scholar
  29. Ochoa-Herrera V et al (2011) Toxicity of copper(II) ions to microorganisms in biological wastewater treatment systems. Sci Total Environ 412–413:380–385CrossRefGoogle Scholar
  30. Ren TT et al (2008) Calcium spatial distribution in aerobic granules and its effects on granule structure, strength and bioactivity. Water Res 42:3343–3352CrossRefGoogle Scholar
  31. Seviour T et al (2009) Gel-forming exopolysaccharides explain basic differences between structures of aerobic sludge granules and floccular sludges. Water Res 43:4469–4478CrossRefGoogle Scholar
  32. Show KY, Lee DJ, Tay JH (2012) Aerobic granulation: advances and challenges. Appl Biochem Biotechnol 167:1622–1640CrossRefGoogle Scholar
  33. Su KZ, Yu HQ (2005) Formation and characterization of aerobic granules in a sequencing batch reactor treating soybean-processing wastewater. Environ Sci Technol 39:2818–2827CrossRefGoogle Scholar
  34. Sun H et al (2017) Role of layered double hydroxide in improving the stability of aerobic granular sludge. CLEAN Soil Air Water 45:1–7CrossRefGoogle Scholar
  35. Tang C et al (2013) Research advances in aerobic granule stability enhancement. Chem Ind Eng Prog 5:96–101Google Scholar
  36. Wei D et al (2016) Extracellular polymeric substances for Zn(II) binding during its sorption process onto aerobic granular sludge. J Hazard Mater 301:407–415CrossRefGoogle Scholar
  37. Yan L et al (2015) Role and significance of extracellular polymeric substances from granular sludge for simultaneous removal of organic matter and ammonia nitrogen. Bioresour Technol 179:460–466CrossRefGoogle Scholar
  38. Yu HQ, Tay JH, Fang HHP (2001) The roles of calcium in sludge granulation during UASB reactor start-up. Water Res 35:1052–1060CrossRefGoogle Scholar
  39. Zhang L et al (2007) Role of extracellular protein in the formation and stability of aerobic granules. Enzyme Microbial Technol 41:551–557CrossRefGoogle Scholar
  40. Zhang Q, Hu J, Lee DJ (2016) Aerobic granular processes: current research trends. Bioresour Technol 210:74–80CrossRefGoogle Scholar

Copyright information

© Islamic Azad University (IAU) 2018

Authors and Affiliations

  1. 1.School of Environmental and Chemical EngineeringShanghai UniversityShanghaiPeople’s Republic of China

Personalised recommendations