Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment

2016 ◽  
Vol 43 (5) ◽  
pp. 713-717 ◽  
Author(s):  
Tingting Zhang ◽  
Qilin Wang ◽  
Liu Ye ◽  
Zhiguo Yuan
Keyword(s):  
Anaerobic Digestion ◽  
Nitrous Acid ◽  
Acid Treatment ◽  
Full Scale ◽  
Digested Sludge ◽  
Free Nitrous Acid ◽  
Anaerobically Digested Sludge

Enhanced dewaterability of anaerobically digested sludge by in-situ free nitrous acid treatment

2020 ◽  
Vol 169 ◽  
pp. 115264 ◽  
Author(s):  
Yifu Li ◽  
Dongbo Wang ◽  
Guojing Yang ◽  
Xingzhong Yuan ◽  
Qiuxiang Xu ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Acid Treatment ◽  
Digested Sludge ◽  
Free Nitrous Acid ◽  
Anaerobically Digested Sludge

Enhancing post aerobic digestion of full-scale anaerobically digested sludge using free nitrous acid pretreatment

Chemosphere ◽  
2016 ◽  
Vol 150 ◽  
pp. 152-158 ◽  
Author(s):  
Qilin Wang ◽  
Xu Zhou ◽  
Lai Peng ◽  
Dongbo Wang ◽  
Guo-Jun Xie ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Full Scale ◽  
Acid Pretreatment ◽  
Digested Sludge ◽  
Aerobic Digestion ◽  
Free Nitrous Acid ◽  
Anaerobically Digested Sludge

High-performance closed loop anaerobic digestion using pre/post sludge ozonation

2003 ◽  
Vol 47 (12) ◽  
pp. 261-267 ◽  
Author(s):  
R. Goel ◽  
H. Yasui ◽  
C. Shibayama
Keyword(s):  
Anaerobic Digestion ◽  
High Performance ◽  
Closed Loop ◽  
Total Volatile ◽  
Digested Sludge ◽  
Ozone Dose ◽  
Volatile Solids ◽  
Reduction Efficiency ◽  
Anaerobically Digested Sludge ◽  
Removal Efficiencies

To maximize the sludge degradation efficiencies during anaerobic digestion, pre-ozonation of raw activated sludge and/or post-ozonation of anaerobically digested sludge were used in combination with a reactor operated without solid withdrawal (closed loop operation scheme). Out of the two studied configurations, the configuration with the post-ozonation of digested sludge was found to be superior with respect to degradation efficiencies, lower accumulation of total volatile solids (TVS) and lower required ozone dose. The TVS concentration in the reactor with post ozonation was found to be around 26 ± 2 g/l at an average TVS loading of 0.6 kgTVS/m3.d. The maximum TVS removal efficiencies were observed to be around 85% with average specific gas recoveries of 0.36 l CH4/gTVS fed. The ozone dose of 3% on the recycle sludge was found to be sufficient as it was observed that the higher ozone doses of 6% neither improved the TVS reduction efficiency nor reduced the TVS concentration in the reactor. The ozone requirements were estimated at around 0.054 gO3/gTVS removed or 0.045 gO3/gTVS fed. The soluble COD concentrations from the reactor ranged from 500-875 mg/l with negligibly small amount of VFA. The average COD in the centrate of the digested sludge was around 3000 mg/l suggesting the presence of colloidal COD in the reactors.

Full-scale application of anaerobic digestion process with partial ozonation of digested sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 245-252 ◽  
Author(s):  
H. Yasui ◽  
K. Komatsu ◽  
R. Goel ◽  
Y. Y. Li ◽  
T. Noike
Keyword(s):  
Anaerobic Digestion ◽  
Full Scale ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
New Process ◽  
Sludge Cake ◽  
Dewatered Sludge ◽  
Solid Liquid ◽  
Solid Liquid Separation

For improving sludge digestion and biogas recovery, a new anaerobic digestion process combined with ozonation was tested at a full-scale unit for 2 years and its performance was compared with a simultaneously operated conventional anaerobic digestion process. The new process requires two essential modifications, which includes ozonation for enhancing the biological degradability of sludge organics and concentrating of solids in the digester through a solid/liquid separation for extension of SRT. These modifications resulted in high VSS degradation efficiency of ca. 88%, as much as 1.3 times of methane production and more than 70% reduction in dewatered sludge cake production. Owing to accumulation of inorganic solids in the digested sludge, water content of the dewatered sludge cake also reduced from 80% to 68%. An energy analysis suggested that no supplemental fuel was necessary for the subsequent incineration of the cake from the new process scheme. The process is suitable to apply to a low-loaded anaerobic digestion tank, where power production is used.

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