Journal of Environmental Health and Sustainable Development

en Comparative Efficiency of Mesophilic Anaerobic Digestion and Aerated Static Pile Composting in the Stabilization of Municipal Wastewater Sludge Environmental Health, Sciences, and Engineering Original articles <div style="text-align: justify;">Introduction: Stabilization of municipal wastewater sludge is a critical requirement for mitigating environmental and public health risks. This study provides a comparative evaluation of mesophilic anaerobic digestion (AD) and aerated static pile (ASP) composting for sludge stabilization at Iran’s largest municipal wastewater treatment plant, with a focus on process efficiency, hygienic quality, and end-product usability. Materials and Methods: Laboratory-scale experiments were conducted using batch mesophilic anaerobic digestion (35 °C, 24 days) and aerated static pile composting. The composting process employed sludge conditioned with bulking and amendment agents under controlled aeration, including a 6-day thermophilic phase within a 30-day operational period. Process performance was assessed based on volatile solids reduction, pathogen inactivation, and biogas production. Results: ASP composting demonstrated superior stabilization and hygienization performance, achieving more than 50% volatile solids reduction and over 3-log fecal coliform reduction, resulting in compost meeting USEPA Class A standards. In contrast, anaerobic digestion achieved approximately 40% volatile solids reduction and produced 5405 mL of biogas, yielding biosolids classified as USEPA Class B. Conclusion: While mesophilic anaerobic digestion offers the advantage of renewable energy recovery, aerated static pile composting provides a more hygienically robust pathway for producing stabilized, high-quality compost suitable for agricultural applications. The findings highlight that the selection of sludge treatment technology should be context-driven, balancing priorities between energy generation and the production of sanitized, agriculturally valuable biosolids.</div> Wastewater, Sewage Sludge, Anaerobic Digestion, Composting, Aeration, Biogas. 2843 2858 http://jehsd.ssu.ac.ir/browse.php?a_code=A-10-1151-1&slc_lang=en&sid=1 Mohammad Hasan Kowsari Mohammadhasan.kowsari@yahoo.com 0000-0002-9468-767X No Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran Mojtaba Yeganeh mybb123@yahoo.com 0000-0002-6790-670X No Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran Mohsen Ansari mohsen.ansari90@yahoo.com 0000-0003-0428-9705 No Department of Environmental Health Engineering, School of Public Health, Qazvin University of Medical Sciences, Qazvin, Iran Behnaz Abdolahi Nejad behnazabdollahinejad94@gmail.com 0000-0003-0104-7620 No Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran Masoumeh Hasham Firooz masume.firooz@yahoo.com 0000-0002-5410-3924 No Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mahdi Farzadkia mahdifarzadkia@gmail.com 0000-0001-7795-9461 Yes Research Center for Environmental Health Technology, Iran University of Medical Sciences, Tehran, Iran