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

2017 ◽  
Vol 37 (1) ◽  
pp. 425-433 ◽  
Author(s):  
Rubaiya Sarwar ◽  
Elsayed Elbeshbishy ◽  
Wayne J. Parker
Keyword(s):  
High Pressure ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Two Stage ◽  
Primary Sludge

Two-stage thermophilic-mesophilic anaerobic digestion of waste activated sludge from a biological nutrient removal plant

2006 ◽  
Vol 53 (8) ◽  
pp. 149-157 ◽  
Author(s):  
S. Watts ◽  
G. Hamilton ◽  
J. Keller
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Treatment Plant ◽  
Single Stage ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Two Stage ◽  
Primary Sludge ◽  
Second Stage

A two-stage thermophilic-mesophilic anaerobic digestion pilot-plant was operated solely on waste activated sludge (WAS) from a biological nutrient removal (BNR) plant. The first-stage thermophilic reactor (HRT 2 days) was operated at 47, 54 and 60 °C. The second-stage mesophilic digester (HRT 15 days) was held at a constant temperature of 36–37 °C. For comparison with a single-stage mesophilic process, the mesophilic digester was also operated separately with an HRT of 17 days and temperature of 36–37 °C. The results showed a truly thermophilic stage (60 °C) was essential to achieve good WAS degradation. The lower thermophilic temperatures examined did not offer advantages over single-stage mesophilic treatment in terms of COD and VS removal. At a thermophilic temperature of 60 °C, the plant achieved 35% VS reduction, representing a 46% increase compared to the single-stage mesophilic digester. This is a significant level of degradation which could make such a process viable in situations where there is no primary sludge generated. The fate of the biologically stored phosphorus in this BNR sludge was also investigated. Over 80% of the incoming phosphorus remained bound up with the solids and was not released into solution during the WAS digestion. Therefore only a small fraction of phosphorus would be recycled to the main treatment plant with the dewatering stream.

Influence on anaerobic digestion by intermediate thermal hydrolysis of waste activated sludge and co-digested wheat straw

2018 ◽  
Vol 72 ◽  
pp. 186-192 ◽  
Author(s):  
Michael Bjerg-Nielsen ◽  
Alastair James Ward ◽  
Henrik Bjarne Møller ◽  
Lars Ditlev Mørck Ottosen
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Wheat Straw ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Hydrolysis Of

scholarly journals Ammonia–methane two-stage anaerobic digestion of dehydrated waste-activated sludge

2008 ◽  
Vol 79 (6) ◽  
Author(s):  
Yutaka Nakashimada ◽  
Yasutaka Ohshima ◽  
Hisao Minami ◽  
Hironori Yabu ◽  
Yuzaburo Namba ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Two Stage

Characterization of sludges for predicting anaerobic digester performance

2008 ◽  
Vol 57 (5) ◽  
pp. 721-726 ◽  
Author(s):  
R. Jones ◽  
W. Parker ◽  
Z. Khan ◽  
S. Murthy ◽  
M. Rupke
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Anaerobic Conditions ◽  
Modified Model ◽  
Primary Sludge ◽  
First Order ◽  
Decay Products ◽  
Aerobic And Anaerobic

Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges. For primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described with a first order decay function with a coefficient of 0.0075 d−1. For continuous flow digesters operating at SRTs of 30–60 days, the predicted VSS destruction with the modified model was approximately 10% higher than that predicted on the basis of inert endogenous decay products.

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