Effect of thermal pretreatment on digestability of thickened waste activated sludge and primary sludge in two-stage anaerobic digestion

Abstract

First and foremost, I would like to express my gratitude to my supervisor Dr. Parker for his great supervision, professionalism and patience during this research. I am always thankful to him for teaching me how to critically think about everything. I am sincerely grateful that I had the opportunity to work with such a smart, thoughtful, and encouraging supervisor. I cannot thank him enough for all he has done for me. I am thankful to Dr. Elsayed for always being helpful and kind to me. His valuable advice and nice manner are sincerely acknowledged. I owe him debt of gratitude for his support to work throughout the project. I want to give my sincere thanks to Mark Sobon and Mark Merlau for their technical assistance and Terry Ridgway for their valuable help in Lab. I am grateful to Bipro Dhar for teaching me several experimental techniques and for patiently answering my many questions. Special thanks go to Robert K. Thomas, Aline Rosa, Cameron Adams and Gary Voorthuyzen for helping me with the operation and maintenance of my bench-scale reactors. Lastly, I would like to acknowledge the endless support of my mother for taking full responsibility of my three kids. I would like to thank my husband, Mohammad Nazrul Islam who supported my decision to complete graduate studies and encouraged me every step along the way. v

Effect of Hydrothermal Pre-treatment on Production of Volatile Fatty Acids from Thickened Waste Activated Sludge using Semi-continuous Fermentation

“…The results represents average values of the various samples. The TCOD is in accordance with the literature (Davidsson et al 2008) and (Sarwar 2015).…”

“…The SCOD concentration, however, observed in HTP was increased which would ensure breakdown of complex materials into simpler organics. Also, beyond a value of 3000mg/l, ammonia tends to inhibit anaerobic digestion systems (Sarwar 2015). The increase in pH justifies the presence of ammonia level, indicating finish of fermentation process.…”

“…Lastly, HTP also increases metabolic activity of the sludge. Sarwar (2015) reported that sCOD solubilisation increased by 28-45% after the pretreatment. Nevertheless, the efficiency highly depend on the type of sludge, properties of sludge, chemical composition of sludge and microbes, mode of carrying out the pretreatment.…”

“…VFA's are acids produced in hydrolysis and acidogenesis/acidic fermentation. (Sarwar 2015)However, it is well evident that hydrolysis is a rate limiting step, and thus to increase hydrolysis and production of VFA, the municipal wastewater sludge is pre-treated. Many studies have been done comparing different pre-treatment methods.…”

Modeling, Instrumentation, Automation, and Optimization of Water Resource Recovery Facilities

“…Four product groups have been identified by Zuidervliet et al (2015) as promising candidates for the recovery of high value commodities in WRRFs: VFA, methanol and other alcohols, polyhydroxyalkulloutes (PHA), and microbial electrolysis cell (MEC) products such as hydrogen peroxide and sodium hydroxide. Lopez et al (2015) summarized fifteen Nocardia control strategies based on research from nine facilities and operating staff at all levels including preventative, physical, and chemical measures and recommend those best-suited for a nutrient removal plant upgrade while avoiding excessive cost Sarwar et al (2015). found that 30 minutes pretreatment of TWAS at 150°C and 3 bar prior to laboratory-scale PS plus TWAS digestion in a two stage (acid-methane phase) mesophilic anaerobic digestion system operated at 2 days acid and 13 days gas phase SRT increased methane generation by 25% Sukaová et al (2015).…”