Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Burger, Gillian; Parker, Wayne

doi:10.2175/193864713813536985

Cited by 4 publications

(3 citation statements)

References 34 publications

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“…Thus, the decrease in the VSS/TSS ratio found was only 7% across all three Systems and was statistically insignificant. Bougrier et al (2008) and Burger (2012) reported 9% and 10% decreases in the VSS/TSS ratio of a sludge that was pretreated at 150 0 C. Therefore, the ratio found from this study was comparable to the findings of literature mentioned above. Thus, it was concluded that no mineralization occurred during pretreatment and only solubilisation took place to convert a PCOD to sCOD.…”

Section: Suspended Solidssupporting

confidence: 90%

“…Thermal hydrolysis processes can be categorized in two groups; pretreatment below 100 0 C is considered a low temperature (LT) pretreatment and pretreatment above 100 0 C under pressure is known as high pressure thermal hydrolysis (HPTH) (Burger, 2012). LT pre-treatment's have been found to increase sludge solubilisation with less energy than HPTH, but do not improve sludge digestion (Nielsen et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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

Sarwar

2015

proc water environ fed

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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

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Section: Suspended Solidssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

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

Sarwar

2015

proc water environ fed

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“…To normalize the results to feed concentrations the extent of COD solubilisation was calculated using Eq. 2 [16].…”

Section: Resultsmentioning

confidence: 99%

Codigestion of high pressure thermal hydrolysis‐treated thickened waste activated sludge with primary sludge in two‐stage anaerobic digestion

Sarwar

Elbeshbishy

Parker

2017

Env Prog and Sustain Energy

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Pretreatment of thickened waste activated sludge (TWAS) with high pressure thermal hydrolysis (HPTH) prior to codigestion with primary sludge (PS) in two-stage anaerobic digestion was evaluated at two systems hydraulic residence times (HRTs). Pretreatment increased the soluble COD (SCOD) entering the acidogenic digester and at a 2 day HRT the increase in SCOD through the digester was also enhanced. With a 1 day HRT in the acidogenic digester the increment in SCOD concentrations was smaller in the pretreated reactor than in the control reactor suggesting there is a minimum residence time required to maintain hydrolysis of pretreated TWAS. At the 2 day HRT fermentation to volatile fatty acids (VFA) was similar in both reactors despite the considerably higher SCOD concentrations in the pretreated sludge. In contrast, at the 1 day HRT the pretreated digester VFA concentrations were 36% higher than that of the control digester. The control and pretreated methanogenic digesters operating at an HRT of 13 days had average total COD (TCOD) removal efficiencies of 45 and 52%, respectively which was consistent with an increase in methane yield from 0.19 L CH 4 /g COD for the control system to 0.23 L CH 4 /g COD for the pretreated system. With an HRT of 9 days, the corresponding TCOD removal efficiencies were reduced to 43% in and 48% respectively and the methane yields were 0.14 and 0.16 L CH 4 /g COD, respectively. COD removal to methane was found to be not significantly different between the control and pretreated systems at the reduced HRT.

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Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

Parker

Kianmehr

2018

Water Science and Technology

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A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.

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Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Cited by 4 publications

References 34 publications

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

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

Codigestion of high pressure thermal hydrolysis‐treated thickened waste activated sludge with primary sludge in two‐stage anaerobic digestion

Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

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