Improvement of Anaerobic Digestion of Sewage Sludge, Using Combined Hydrogen Peroxide and Thermal Pre-Treatment

Document Type: Original Research Paper


School of Environment, Colledge of Engineering, University of Tehran, Tehran, Iran


The present study investigates the influence of individual and combined hydrogen peroxide and thermal pre-treatment of waste activated sludge on anaerobic digestion. For so doing, it employs anaerobic batch reactors in the mesophilic conditions. For comparison, soluble fractions of organic matter, biogas production, biochemical methane potential, removal of chemical oxygen demand (COD), and volatile solids (VS) have been measured during the anaerobic digestion process in systems with and without pre-treatment. Hydrogen peroxide pre-treatment has been tested in two concentrations of 30 g H2O2/kg VS and 60 g H2O2/kg VS and thermal pre-treatment has been performed at two temperatures of 75℃ and 90℃. According to the results, the solubalisation of organic matter considerably improves, when combined hydrogen peroxide and thermal pre-treatment is employed. As a result, in comparison to the control reactor, higher amounts of biogas (71%) and methane (81%) have been produced in the bioreactor, pre-treated with combined hydrogen peroxide (30 g H2O2/kg VS) and heat (90 ℃). In addition, the removal efficiency of COD and VS from the digested sludge has been enhanced in the pre-treated reactors (up to 39% and 92%, respectively) in comparison to the control reactor. The improved methane yield, COD, and VS are of paramount importance, not only because higher amounts of renewable energy are obtained from the anaerobic digestion process, but because sludge transport costs are reduced and the digested sludge obtains a higher potential application to agricultural lands.


APHA. (2012). Standard Methods. For the Examination of Water and Wastewater.

Appels, L., Baeyens, J., Degrève, J. and Dewil, R. (2008). Principles and potential of the anaerobic digestion of waste-activated sludge. Prog. Energy Combust. Sci., 34(6); 755–781.

Appels, L., Degrève, J., Van der Bruggen, B., Van Impe, J. and Dewil, R. (2010). Influence of low temperature thermal pre-treatment on sludge solubilisation, heavy metal release and anaerobic digestion. Bioresour. Technol., 101(15); 5743–5748.

Boulanger, A., Pinet, E., Bouix, M., Bouchez, T. and Mansour, A.A. (2012). Effect of inoculum to substrate ratio (I/S) on municipal solid waste anaerobic degradation kinetics and potential. Waste Manag., 32(12); 2258–2265.

Campo, G., Cerutti, A., Zanetti, M., Scibilia, G., Lorenzi, E. and Ruffino, B. (2017). Enhancement of waste activated sludge (WAS) anaerobic digestion by means of pre-and intermediate treatments. Technical and economic analysis at a full-scale WWTP. J. Environ. Manage.

Carballa, M., Duran, C. and Hospido, A. (2011). Should we pretreat solid waste prior to anaerobic digestion? An assessment of its environmental cost. Environ. Sci. Technol., 45(24); 10306–10314.

Carrère, H., Dumas, C., Battimelli, A., Batstone, D.J., Delgenès, J.P., Steyer, J.P. and Ferrer, I. (2010). Pretreatment methods to improve sludge anaerobic degradability: A review. J. Hazard. Mater.

Choi, J.-M., Han, S.-K. and Lee, C.-Y. (2018). Enhancement of methane production in anaerobic digestion of sewage sludge by thermal hydrolysis pretreatment. Bioresour. Technol., 259; 207–213.

Dhar, B.R., Nakhla, G. and Ray, M.B. (2012). Techno-economic evaluation of ultrasound and thermal pretreatments for enhanced anaerobic digestion of municipal waste activated sludge. Waste Manag., 32(3); 542–549.

Dubois, M., Gilles, K.A., Hamilton, J.K., Rebers, P.A. and Smith, F. (1956). Colorimetric Method for Determination of sugars and related substances. Anal. Chem., 28(3); 350–356.

Ennouri, H., Miladi, B., Diaz, S.Z., Güelfo, L.A.F., Solera, R., Hamdi, M. and Bouallagui, H. (2016). Effect of thermal pretreatment on the biogas production and microbial communities balance during anaerobic digestion of urban and industrial waste activated sludge. Bioresour. Technol., 214; 184–191.

Farhat, A., Asses, N., Ennouri, H., Hamdi, M. and Bouallagui, H. (2018). Combined effects of thermal pretreatment and increasing organic loading by co-substrate addition for enhancing municipal sewage sludge anaerobic digestion and energyproduction. Process Saf. Environ. Prot.

Foladori, P., Bruni, L., Tamburini, S. and Ziglio, G. (2010). Direct quantification of bacterial biomass in influent, effluent and activated sludge of wastewater treatment plants by using flow cytometry. Water Res., 44(13); 3807–3818.

Guan, R., Li, X., Wachemo, A.C., Yuan, H., Liu, Y., Zou, D., Zuo, X. and Gu, J. (2018). Enhancing anaerobic digestion performance and degradation of lignocellulosic components of rice straw by combined biological and chemical pretreatment. Sci. Total Environ., 637; 9–17.

Guan, R., Yuan, X., Wu, Z., Jiang, L., Li, Y. and Zeng, G. (2018). Principle and application of hydrogen peroxide based advanced oxidation processes in activated sludge treatment: A review. Chem. Eng. J.

Jiang, G. and Yuan, Z. (2013). Synergistic inactivation of anaerobic wastewater biofilm by free nitrous acid and hydrogen peroxide. J. Hazard. Mater., 250–251; 91–98.

Kim, D., Lee, K. and Park, K.Y. (2015). Enhancement of biogas production from anaerobic digestion of waste activated sludge by hydrothermal pre-treatment. Int. Biodeterior. Biodegradation., 101; 42–46.

King, P.A., Anderson, V.E., Edwards, J.O., Gustafson, G., Plumb, R.C. and Suggs, J.W. (1992). A stable solid that generates hydroxyl radical upon dissolution in aqueous solutions: reaction with proteins and nucleic acid. J. Am. Chem. Soc., 114(13); 5430–5432.

Li, C., Wang, X., Zhang, G., Li, J., Li, Z., Yu, G. and Wang, Y. (2018). A process combining hydrothermal pretreatment, anaerobic digestion and pyrolysis for sewage sludge dewatering and co-production of biogas and biochar: Pilot-scale verification. Bioresour. Technol., 254; 187–193.

Li, X., Zhao, J., Wang, D., Yang, Q., Xu, Q., Deng, Y., Yang, W. and Zeng, G. (2016). An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid. Chemosphere., 144; 160–167.

Liu, J., Yang, M., Zhang, J., Zheng, J., Xu, H., Wang, Y. and Wei, Y. (2018). A comprehensive insight into the effects of microwave-H2O2 pretreatment on concentrated sewage sludge anaerobic digestion based on semi-continuous operation. Bioresour. Technol., 256; 118–127.

Lobachev, V.L. and Rudakov, E.S. (2006). The chemistry of peroxynitrite. Reaction mechanisms and kinetics. Russ. Chem. Rev., 75(5); 375–396.

Lowry, O.H., Rosebrough, N.J., Farr, A.L. and Randall, R.J. (1951). Protein measurement with the Folin phenol reagent. J. Biol. Chem., 193(1); 265–275.

Ma, B., Peng, Y., Wei, Y., Li, B., Bao, P. and Wang, Y. (2015). Free nitrous acid pretreatment of wasted activated sludge to exploit internal carbon source for enhanced denitrification. Bioresour. Technol., 179, 20–25.

Nazari, L., Yuan, Z., Santoro, D., Sarathy, S., Ho, D., Batstone, D., Xu, C.C. and Ray, M.B. (2017). Low-temperature thermal pre-treatment of municipal wastewater sludge: Process optimization and effects on solubilization and anaerobic degradation. Water Res., 113; 111–123.

Neumann, P., González, Z. and Vidal, G. (2017). Sequential ultrasound and low-temperature thermal pretreatment: process optimization and influence on sewage sludge solubilization, enzyme activity and anaerobic digestion. Bioresour. Technol., 234; 178–187.

Neyens, E., Baeyens, J., Dewil, R. and De Heyder, B. (2004). Advanced sludge treatment affects extracellular polymeric substances to improve activated sludge dewatering. J. Hazard. Mater.

Nonoyama, N., Oshima, H., Shoda, C. and Suzuki, H. (2001). The reaction of peroxynitrite with organic molecules bearing a biologically important functionality. The multiplicity of reaction modes as exemplified by hydroxylation, nitration, nitrosation, dealkylation, oxygenation, and oxidative dimerization and clea. Bull. Chem. Soc. Jpn., 74(12); 2385–2395.

Peterson, G.L. (1977). A simplification of the protein assay method of Lowry et al. which is more generally applicable. Anal. Biochem., 83(2); 346–356.

Pilli, S., More, T.T., Yan, S., Tyagi, R.D. and Surampalli, R.Y. (2016). Fenton pre-treatment of secondary sludge to enhance anaerobic digestion: Energy balance and greenhouse gas emissions. Chem. Eng. J., 283; 285–292.

Pilli, S., Yan, S., Tyagi, R.D. and Surampalli, R.Y. (2015)a. Thermal pretreatment of sewage sludge to enhance anaerobic digestion: a review. Crit. Rev. Environ. Sci. Technol., 45(6); 669–702.

Pilli, S., Yan, S., Tyagi, R.D. and Surampalli, R.Y. (2015)b. Overview of Fenton pre-treatment of sludge aiming to enhance anaerobic digestion. Rev. Environ. Sci. Biotechnol., 14(3); 453–472.

Rozendal, R.A., Leone, E., Keller, J. and Rabaey, K. (2009). Efficient hydrogen peroxide generation from organic matter in a bioelectrochemical system. Electrochem. commun.

Sanscartier, D., MacLean, H.L. and Saville, B. (2012). Electricity production from anaerobic digestion of household organic waste in Ontario: Techno-economic and GHG emission analyses. Environ. Sci. Technol.

Sólyom, K., Mato, R.B., Pérez-Elvira, S.I. and Cocero, M.J. (2011). The influence of the energy absorbed from microwave pretreatment on biogas production from secondary wastewater sludge. Bioresour. Technol., 102(23); 10849–10854.

Svensson, K., Kjørlaug, O., Higgins, M.J., Linjordet, R. and Horn, S.J. (2018). Post-anaerobic digestion thermal hydrolysis of sewage sludge and food waste: Effect on methane yields, dewaterability and solids reduction. Water Res., 132; 158–166.

Tiehm, A., Nickel, K., Zellhorn, M., Neis, U. and Tiehm, A. (2001). Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization. Water Res., 35(8), 2003–2009.

Walker, M., Zhang, Y., Heaven, S. and Banks, C. (2009). Potential errors in the quantitative evaluation of biogas production in anaerobic digestion processes. Bioresour. Technol., 100(4); 6339–6346.

Wang, Q., Jiang, G., Ye, L. and Yuan, Z. (2014). Enhancing methane production from waste activated sludge using combined free nitrous acid and heat pre-treatment. Water Res., 63; 71–80.

Wang, Q., Sun, J., Song, K., Zhou, X., Wei, W., Wang, D., Xie, G.-J., Gong, Y. and Zhou, B. (2018). Combined zero valent iron and hydrogen peroxide conditioning significantly enhances the dewaterability of anaerobic digestate. J. Environ. Sci., 67; 378–386.

Yang, L., Huang, Y., Zhao, M., Huang, Z., Miao, H., Xu, Z. and Ruan, W. (2015). Enhancing biogas generation performance from food wastes by high-solids thermophilic anaerobic digestion: Effect of pH adjustment. Int. Biodeterior. Biodegrad., 105; 153–159.

Zahedi, S., Icaran, P., Yuan, Z. and Pijuan, M. (2016). Assessment of free nitrous acid pre-treatment on a mixture of primary sludge and waste activated sludge: Effect of exposure time and concentration. Bioresour. Technol., 216; 870–875.

Zahedi, S., Icaran, P., Yuan, Z. and Pijuan, M. (2017). Enhancing sludge biodegradability through free nitrous acid pre-treatment at low exposure time. Chem. Eng. J., 321; 139–145.

Zhang, D., Chen, Y., Zhao, Y. and Ye, Z. (2011). A new process for efficiently producing methane from waste activated sludge: Alkaline pretreatment of sludge followed by treatment of fermentation liquid in an EGSB reactor. Environ. Sci. Technol., 45(2); 803–808.

Zhang, S., Guo, H., Du, L., Liang, J., Lu, X., Li, N. and Zhang, K. (2015). Influence of NaOH and thermal pretreatment on dewatered activated sludge solubilisation and subsequent anaerobic digestion: focused on high-solid state. Bioresour. Technol., 185; 171–177.

Zhang, T., Wang, Q., Ye, L., Batstone, D. and Yuan, Z. (2015). Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown. Sci. Rep., 5.