1. P. Pietraszek, J. Podedworna, Laboratory Exercises in Sewage Sludge Technology, Publishing House of the Warsaw University of Technology, Warsaw, 1990 (in Polish).
  2. Council Directive 91/271/EEC of 21 May 1991 Concerning Urban Wastewater Treatment. Available at (Accessed on 30 May 1991).
  3. Sewage Sludge Produced and Disposed in Europe in 2020, By Country. Available at (Accessed on 29 June 2023).
  4. E. Fiałkowska, J. Fryda, A. Pajdak-Stós, K. Wiąckowski, Activated Sludge, Biology and Microscopic Analysis, Seidel - Przywecki Publishing House, Warsaw, 2010, (in Polish).
  5. Q. Wu, D. Zou, X. Zheng, F. Liu, L. Li, Z. Xiao, Effects of antibiotics on anaerobic digestion of sewage sludge: performance of anaerobic digestion and structure of the microbial community, Sci. Total Environ., 845 (2022) 157384, doi: 10.1016/j.scitotenv.2022.157384.
  6. M. Czatzkowska, M. Harnisz, E. Korzeniewska, I. Koniuszewska, Inhibitors of the methane fermentation process with particular emphasis on the microbiological aspect: a review, Energy Sci. Eng., 8 (2020) 1880–1897.
  7. G.-C. Mitraka, K.N. Kontogiannopoulos, M. Batsioula, G.F. Banias, A.I. Zouboulis, P.G. Kougias, A comprehensive review on pretreatment methods for enhanced biogas production from sewage sludge, Energies, 15 (2022) 6536, doi: 10.3390/en15186536.
  8. T.A.T. de Sousa, F.P. do Monte, J.V. do Nascimento Silva, W.S. Lopes, V.D. Leite, J.B. van Lier, J.T. de Sousa, Alkaline and acid solubilisation of waste activated sludge, Water Sci. Technol., 83 (2021) 2980–2996.
  9. J.-S. Guo, F. Fang, P. Yan, Y.-P. Chen, Sludge reduction based on microbial metabolism for sustainable wastewater treatment, Bioresour. Technol., 297 (2020) 122506, doi: 10.1016/j.biortech.2019.122506.
  10. A. Gonzalez, A.T.W.M. Hendriks, J.B. van Lier, M. de Kreuk, Pre-treatments to enhance the biodegradability of waste activated sludge: elucidating the rate limiting step, Biotechnol. Adv., 36 (2018) 1434–1469.
  11. A. Elliott, T. Mahmood, Pretreatment technologies for advancing anaerobic digestion of pulp and paper biotreatment residues, Water Res., 41 (2007) 4273–4286.
  12. G. Erden, A. Filibeli, Effects of Fenton pre-treatment on waste activated sludge properties, Clean (Weinh), 39 (2011) 626–632.
  13. S. Yu, G. Zhang, J. Li, Z. Zhao, X. Kang, Effect of endogenous hydrolytic enzymes pretreatment on the anaerobic digestion of sludge, Bioresour. Technol., 146 (2013) 758–761.
  14. M. Raynaud, J. Vaxelaire, J. Olivier, E. Dieude-Fauvel, J.C. Baudez, Compression dewatering of municipal activated sludge: effects of salt and pH, Water Res., 46 (2012) 4448–4456.
  15. S. Zahedi, F. Ferrari, G. Blandin, J.L. Balcazar, M. Pijuan, Enhancing biogas production from the anaerobic treatment of municipal wastewater by forward osmosis pretreatment, J. Cleaner Prod., 315 (2021) 128140, doi: 10.1016/j. jclepro.2021.128140.
  16. M. Recktenwald, J. Wawrzynczyk, E. Szwajcer, D.O. Norrlöw, Enhanced efficiency of industrial-scale anaerobic digestion by the addition of glycosidic enzymes, J. Environ. Sci. Health. Part A Toxic/Hazard. Subst. Environ. Eng., 43 (2008) 1536–1540.
  17. J. Wawrzynczyk, M. Recktenwald, D.O. Norrlöw E. Szwajcer, Solubilisation of sludge by combined chemical and enzymatic treatment, Afr. J. Biotechnol., 6 (2007) 1994–1999.
  18. R.S. Almukhtar, A.A. Alwasiti, M.T. Naser, Enhancement of biogas production and organic reduction of sludge by different pretreatment processes, Iraqi J. Chem. Pet. Eng., 13 (2012) 19–31.
  19. S. Myszograj, A. Jędrczak, M. Suchowska-Kisielewicz, Z. Sadecka, Thermal and Chemical Disintegration of Excessive Sewage Sludge, The 1st International Global Virtual Conference, 2013. Available at:
  20. L. Appels, A. van Assche, K. Willems, J. Degreve, J. van Impe, R. Dewil, Peracetic acid oxidation as an alternative pretreatment for the anaerobic digestion of waste activated sludge, Bioresour. Technol., 102 (2011) 4124–4130.
  21. W. Wonglertarak, B. Wichitsathian, Alkaline pretreatment of waste activated sludge in anaerobic digestion, J. Clean Energy Technol., 2 (2014) 118–121.
  22. M. Weemaes, H. Grootaerd, F. Simons, W. Verstraete, Anaerobic digestion of ozonied biosolids, Water Res., 34 (2000) 2330–2336.
  23. M. Shang, H. Hou, Studies on Effect of Peracetic Acid Pretreatment on Anaerobic Fermentation Biogas Production From Sludge, Power and Energy Engineering Conference, Asia Pacific, 2009.
  24. A.M. Karczmarek, J. Gaca, Effect of two-stage thermal disintegration on particle size distribution in sewage sludge, Pol. J. Chem. Technol., 3 (2015) 69–73.
  25. I. Zawieja, P. Wolski, Effect of hybrid method of excess sludge disintegration on the increase of their biodegradalibity, Environ. Prot. Eng., 39 (2013) 153–165.
  26. C. Bougrier, J.P. Delgenés, H. Carrére, Effects of thermal treatments on five different waste activated sludge samples solubilisation, physical properties and anaerobic digestion, Chem. Eng. J., 139 (2008) 236–244.
  27. E.S.M. Borges, C.A.L. Chernicharo, Effect of thermal treatment of anaerobic sludge on the bioavailability and biodegradability characteristics of the organic fraction, Braz. J. Chem. Eng., 26 (2009) 469–480.
  28. X. Li, S. Guo, Y. Peng, Y. He, S. Wang, L. Li, M. Zhao, Anaerobic digestion using ultrasound as pretreatment approach: changes in waste activated sludge, anaerobic digestion performances and digestive microbial populations, Biochem. Eng. J., 139 (2018) 139–145.
  29. A. Tiehm, K. Nickel, M. Zellhorn, U. Neis, Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization, Water Res., 35 (2001) 2003–2009.
  30. M.D.L.D. Castro, F.R.P. Capote, Analytical Application of Ultrasound, Elsevier, 2007.
  31. Y.T. Shah, A.B. Pandit, V.S. Moholkar Cavitation Reaction Engineering, Kluwer Academic/Plenum Publishers, New York, 1999.
  32. R.M. Wu, G.W. Tsou, D.J. Lee, Estimate of sludge floc permeability, Chem. Eng. J., 80 (2000) 37–42.
  33. I. Zawieja, R. Włodarczyk, M. Kowalczyk, Biogas generation from sonicated excess sludge, Water, 11 (2019) 2127, doi: 10.3390/w11102127.
  34. G. Erden, A. Filibeli, Ultrasonic pre-treatment of biological sludge: consequences for disintegration, anaerobic biodegradability, and filterability, J. Chem. Technol. Biotechnol., 85 (2010) 145–150.
  35. Standard PN-EN 12879 Water and Sewage, Special Tests of Sludge, Determination of the Content of Water, Dry Matter, Organic Substances and Minerals in Sewage Sludge, Standardization Publishing House, Warsaw, Poland, 1991.
  36. International Measurements Standards ISO 7027, Water Quality, International Organization for Standards, Geneva, Switzerland, 2016.
  37. S. Myszograj, Z. Sadecka, COD fractions in the processes of mechanical and biological wastewater treatment on the example of the sewage treatment plant in Sulechów, Annu. Set Environ. Prot., 6 (2004) 233–244 (in Polish).
  38. ATV - DVWK - A 131 P, Guideline, Dimensioning of Single- Stage Sewage Treatment Plants With Activated Sludge, Seidel-Przywecki Publishing House, Poland, Warsaw, 2002.
  39. Standard PN-75/C-04616/04 Water and Sewage, Special Studies of Sludge, Determination of Volatile Fatty Acids in Sewage Sludge and Over-Sludge Waters by Steam Distillation, Standardization Publishing House, Warsaw, Poland, 1991 (in Polish).
  40. Ł. Fukas-Płonka, E. Zielewicz-Madej, Stabilization of excess sludge in the methane fermentation process, Environ. Eng. Prot., 3 (2000) 37–48.
  41. Standards PN-75/C-04616/07, Water and Sewage, Special Tests of Sludge, Determination of the Fermentation Capacity of Sewage Sludge and the Degree of Its Fermentation Under Static Conditions and in a Continuous Process, Standardization Publishing House, Warsaw, Poland, 2019.
  42. K. Michalska, K. Miazek, L. Krzystek, S. Ledakowicz, Influence of pretreatment with Fenton’s reagent on biogas production and methane yield from lignocellulosic biomass, Bioresour. Technol., 119 (2012) 72–78.
  43. L. Ming-Chun, L. Chien Jung, L. Chih-Hsiang, T. Wang- Ping, Dewatering of activated sludge by Fenton’s reagent, Adv. Environ. Res., 7 (2003) 667–670.
  44. M. Dębowski, M. Krzemieniewski, M. Zieliński, Constant magnetic field influence on stabilization of excess sludge with Fenton’s reagent, Pol. J. Environ. Stud., 16 (2007) 43–50.
  45. M.I. Badawy, E.M. Alim, Fenton’s peroxidation and coagulation processes for the treatment of combined industrial and domestic wastewater, J. Hazard. Mater., 136 (2006) 961–966.
  46. M. Ksibi, Chemical oxidation with hydrogen peroxide for domestic wastewater treatment, Chem. Eng. J., 119 (2006) 161–165.
  47. E. Neyens, J. Baeyens, A review of classic Fenton’s peroxidation as an advanced oxidation technique, J. Hazard. Mater., 98 (2003) 33–50.
  48. E. Feki, A. Battimelli, S. Sayadi, A. Dhouib, S. Khoufi, High-rate anaerobic digestion of waste activated sludge by integration of electro-Fenton process, Molecules, 25 (2020) 626, doi: 10.3390/ molecules25030626.
  49. J. Kazimierowicz, M. Dębowski, M. Zieliński, Effect of pharmaceutical sludge pre-treatment with Fenton/Fentonlike reagents on toxicity and anaerobic digestion efficiency, Int. J. Environ. Res. Public Health, 20 (2022) 271, doi: 10.3390/ ijerph20010271.
  50. P. Woon-Ji, A. Johng-Hwa, Effects of microwave pretreatment on mesophilic anaerobic digestion for mixture of primary and secondary sludges compared with thermal pretreatment, Environ. Eng. Res., 16 (2011) 103–109.
  51. B. Shrestha, R. Hernandez, D.L.B. Fortela, W. Sharp, A. Chistoserdov, D. Gang, E. Revellame, W. Holmes, M.E. Zappi, A review of pretreatment methods to enhance solids reduction during anaerobic digestion of municipal wastewater sludges and the resulting digester performance: implications to future urban biorefineries, Appl. Sci., 10 (2020) 9141, doi: 10.3390/app10249141.
  52. J. Akunna, Anaerobic Waste-Wastewater Treatment and Biogas Plants: A Practical Handbook, CRC Press, Boca Raton, FL, USA, 2018.
  53. N. Wood, H. Tran, E. Master, Pretreatment of pulp mill secondary sludge for high-rate anaerobic conversion to biogas, Bioresour. Technol., 100 (2009) 5729–5735.
  54. U. Brémond, R. de Buyer, J.-P. Steyer, N. Bernet, H. Carrere, Biological pretreatments of biomass for improving biogas production: an overview from lab scale to full-scale, Renewable Sustainable Energy Rev., 90 (2018) 583–604.