Anaerobic digestion of food waste in a hybrid anaerobic solid–liquid system with leachate recirculation in an acidogenic reactor

2008 ◽  
Vol 41 (2) ◽  
pp. 198-201 ◽  
Author(s):  
Olena Stabnikova ◽  
Xue-Yan Liu ◽  
Jing-Yuan Wang
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Liquid System ◽  
Leachate Recirculation ◽  
Acidogenic Reactor ◽  
Solid Liquid

Enhancement of food waste digestion in the hybrid anaerobic solid-liquid system

2008 ◽  
Vol 57 (9) ◽  
pp. 1369-1373 ◽  
Author(s):  
X. Y. Liu ◽  
H. B. Ding ◽  
S. Sreeramachandran ◽  
O. Stabnikova ◽  
J. Y. Wang
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Waste Treatment ◽  
Liquid System ◽  
Net Energy ◽  
Two Phase ◽  
Treatment Processes ◽  
Pre Treatment ◽  
Solid Liquid ◽  
Net Energy Gain

The hybrid anaerobic solid-liquid (HASL) system is a modified two-phase anaerobic digester for food waste treatment. To enhance the performance of anaerobic digestion in the HASL system, thermal pre-treatment (heating at 150°C for 1 h) and freezing/thawing (freezing for 24 h at−20°C and then thawing for 12 h at 25°C) were proposed for food waste pre-treatment before the anaerobic digestion. Both processes were able to alter the characteristics and structure of food waste favoring substance solubilization, and hence production of methane. However, there was no net energy gain when the energy required by the pre-treatment processes was taken into account.

Digestion of frozen/thawed food waste in the hybrid anaerobic solid–liquid system

2008 ◽  
Vol 28 (9) ◽  
pp. 1654-1659 ◽  
Author(s):  
O. Stabnikova ◽  
X.Y. Liu ◽  
J.Y. Wang
Keyword(s):  
Food Waste ◽  
Liquid System ◽  
Solid Liquid

Two-Phase Mesophilic Anaerobic Co-Digestion of Food Waste and Sewage Sludge: Effect of Hydraulic Retention Time

2014 ◽  
Vol 852 ◽  
pp. 789-796 ◽  
Author(s):  
Guo Hua Wang ◽  
Lei Wang ◽  
Xue Jun Tan ◽  
Yi Xian Wang ◽  
Feng Wang
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Food Waste ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Removal Rate ◽  
Two Phase ◽  
Acidogenic Reactor ◽  
In Series ◽  
The Impact

The impact of hydraulic retention time (HRT) on two-phase mesophilic (35°C) anaerobic co-digestion of food waste and sewage sludge was studied under mixing ratio of 1:1 on the TS basis. Laboratory-scale, two-phase anaerobic digestion systems were employed with each system consisting of an acidogenic reactor and a methanogenic reactor linked in series. For the acidogenic phase, an increase of volatile fatty acid (VFA) concentration was observed as HRT increased from 1d to 5d and the HRT of 5d was recommended for significantly higher VFA production and less propionate percentage, which could provide stable and favourable substrates for the methane reactor. Under acidogenic HRT of 5d, 20d was proved to be the optimum HRT for methanogenic phase with the methane content, methane production rate, methane yield and two-phase VS removal rate reached 71%, 0.7L/(L·d), 0.69L/gVSremoved and 64.7%, respectively. Results verified that the constraints of conventional anaerobic digestion for food waste or sewage sludge separately could be overcome by synergistic effect of co-digestion strategy and two-phase treatment.

Effect of leachate recirculation on mesophilic anaerobic digestion of food waste

2012 ◽  
Vol 32 (3) ◽  
pp. 400-403 ◽  
Author(s):  
Haleh Shahriari ◽  
Mostafa Warith ◽  
Mohamed Hamoda ◽  
Kevin J. Kennedy
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Leachate Recirculation

A comparative study of anaerobic digestion of food waste in a single pass, a leachate recycle and coupled solid/liquid reactors

2003 ◽  
Vol 47 (1) ◽  
pp. 319-324 ◽  
Author(s):  
H.L. Xu ◽  
J.Y. Wang ◽  
H. Zhang ◽  
J.H. Tay
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Methane Content ◽  
Anaerobic Sludge ◽  
Methane Fermentation ◽  
Two Phase ◽  
Single Pass ◽  
Digestion Process ◽  
Solid Liquid ◽  
Methanogenic Phase

A single pass reactor (R1), a leachate recycle reactor (R2) and a coupled solid/liquid bioreactor (R3-Rm) for anaerobic digestion of food waste were comparatively investigated in terms of digestion process and treatment efficiency. The coupled solid/liquid bioreactor is an enhanced two-phase system and distinctive from a traditional two-phase process with an upflow anaerobic sludge blanket (UASB) reactor as the methanogenic phase and a circulation of treated leachate between the acidification and methanogenic phases. In comparison with R1 and R2, R3-Rm enhanced the digestion process and increased the methane content of biogas. 100% of the R3-Rm methane yield was from the methanogenic phase with average methane content of 71%. The significant enhancement was also confirmed by the removal of 79% of total organic carbon (TOC), 60% of volatile solids (VS) and 80% of total COD in 12 days running of R3-Rm. However, no active methane fermentation was detected in R1 and R2 during 60 days operation. The results in this laboratory-scale study show that the rapid accumulation of volatile fatty acids (VFAs) due to the rapid acidification of food waste inhibits the development of effective methane fermentation in single pass and leachate recycle reactors. The coupled solid/liquid bioreactor is more efficient in converting food waste into methane and carbon dioxide.

Semi-continuous anaerobic digestion of food waste using a hybrid anaerobic solid-liquid bioreactor

2003 ◽  
Vol 48 (4) ◽  
pp. 169-174 ◽  
Author(s):  
J.-Y. Wang ◽  
H.-L. Xu ◽  
H. Zhang ◽  
J.-H. Tay
Keyword(s):  
Anaerobic Digestion ◽  
Solid Waste ◽  
Food Waste ◽  
Biogas Production ◽  
Continuous Operation ◽  
Methane Content ◽  
High Rate ◽  
Uasb Reactor ◽  
Two Phase ◽  
Solid Liquid

A hybrid anaerobic solid-liquid (HASL) bioreactor was developed to enhance food waste conversion. The HASL bioreactor is a modified two-phase anaerobic digestion system with a solid waste reactor and a high-rate anaerobic wastewater reactor, which was a UASB reactor. In this study, the methanogenesis in the UASB reactor was investigated under a semi-continuous operation of the food waste digestion system. The HASL process, including 7 days of start-up and 23 days of semi-continuous operation followed by 6 days of batch operation, was commenced by loading 2.8 kg of shredded food waste. During the semi-continuous operation, 0.2 kg of the same waste was loaded daily. The leachate from acidification phase, i.e., solid waste reactor, remained acidic (pH 4.9-5.5) and high in total VFA (TVFA), 9,500-11,500 mg/L, and COD (8,000-11,800 mg/L) levels. In the methanogenesis phase, i.e., UASB reactor, effective TVFA and COD removals (88 ± 5% and 85 ± 7%, respectively) were obtained, while the methane content was 71%. At the end of operation, about 78% of VS added in the HASL bioreactor was removed, while TOC and total COD reductions were 78% and 79%, respectively. The results showed that the use of UASB reactor in the semi-continuous HASL system can enhance the methanogenesis process and increase the methane content in biogas production.

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