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

Oxidative and thermo-oxidative co-treatment with anaerobic digestion of excess municipal sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 237-244 ◽  
Author(s):  
J.A. Cacho Rivero ◽  
N. Madhavan ◽  
M.T. Suidan ◽  
P. Ginestet ◽  
J.-M. Audic
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Fecal Coliform ◽  
Single Stage ◽  
Waste Activated Sludge ◽  
Municipal Sludge ◽  
Two Stage ◽  
Two Stages ◽  
Solids Removal

The effect of oxidative and thermo-oxidative co-treatment of excess municipal sludge was investigated. A mixture of primary and waste activated sludge was anaerobically treated using two different configurations: i) two stages and ii) a single stage with recycling. Oxidative or thermo-oxidative co-treatment placed in between the reactor or in the recycle line was studied. A two-stage configuration with no co-treatment served as a control and resulted in 50.1% overall solids removal. Compared to the control, an increase in solids removal of 10.8 and 2.7% was observed when oxidative co-treatment was placed between reactors and in the recycle line respectively. When thermo-oxidative co-treatment was placed between the two stages or in the recycle line an increase in solids removal of 25.1 and 26.9% respectively was observed. The performances of the different configurations were also evaluated with parameters such as COD, TKN, ammonia, and fecal coliform concentration.

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.

Upgrading of the anaerobic digestion of waste activated sludge by combining temperature-phased anaerobic digestion and intermediate ozonation

2009 ◽  
Vol 59 (1) ◽  
pp. 185-193 ◽  
Author(s):  
T. Kobayashi ◽  
Y. Y. Li ◽  
H. Harada ◽  
H. Yasui ◽  
T. Noike
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Waste Activated Sludge ◽  
Two Stage ◽  
Flocculation Efficiency ◽  
In Series ◽  
Stage System ◽  
Mesophilic Digestion ◽  
Pre Treatment

Upgrading of the anaerobic digestion of waste activated sludge (WAS) by the combination of temperature-phased two-stage digestion and intermediate ozonation was investigated by a continuous experiment with two processes, TM and TOM. The TM process is a temperature-phased two-stage system, which consists of a thermophilic digester and a mesophilic digester in series. The TOM process is a temperature-phased two-stage process with the intermediate ozonation. Two processes were operated at hydraulic retention times of 30 days for over 123 days. Waste activated sludge taken from wastewater treatment plant was fed as a substrate. Microbial community structure in each digester was analysed with molecular tools. Despite of less amount of ozone dose in TOM than ozone pre-treatment process, better effect of ozonation on performance improvement was obtained in TOM. TOM had the highest methane yield and CODCr reduction among comparative processes. Furthermore, flocculation efficiency of TOM followed that of mesophilic digestion. Quality of dewatered supernatant is comparable to mesophilic digestion.

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