Anaerobic digestion of corn ethanol thin stillage in batch and by high-rate down-flow fixed film reactors

2012 ◽  
Vol 66 (9) ◽  
pp. 1834-1841 ◽  
Author(s):  
A. Wilkinson ◽  
K. J. Kennedy
Keyword(s):  
Anaerobic Digestion ◽  
High Rate ◽  
Organic Loading Rate ◽  
Clean Water ◽  
Corn Ethanol ◽  
Thin Stillage ◽  
Treated Effluent ◽  
Fixed Film ◽  
Vs Removal ◽  
Removal Efficiencies

Thin stillage (CTS) from a dry-grind corn ethanol plant was evaluated as a carbon source for anaerobic digestion (AD) by batch and high rate semi-continuous down-flow stationary fixed film (DSFF) reactors. Biochemical methane potential (BMP) assays were carried out with CTS concentrations ranging from approximately 2,460–27,172 mg total chemical oxygen demand (TCOD) per litre, achieved by diluting CTS with clean water or a combination of clean water and treated effluent. High TCOD, SCOD and volatile solids (VS) removal efficiencies of 85 ± 2, 94 ± 0 and 82 ± 1% were achieved for CTS diluted with only clean water at an organic concentration of 21,177 mg TCOD per litre, with a methane yield of 0.30 L methane per gram TCODremoved at standard temperature and pressure (STP, 0 °C and 1 atmosphere). Batch studies investigating the use of treated effluent for dilution showed promising results. Continuous studies employed two mesophilic DSFF anaerobic digesters treating thin stillage, operated at hydraulic retention times (HRT) of 20, 14.3, 8.7, 6.3, 5 and 4.2 d. Successful digestion was achieved up to an organic loading rate (OLR) of approximately 7.4 g TCOD L−1d−1 at a 5 d HRT with a yield of 2.05 LCH4 L−1d−1 (at STP) and TCOD and VS removal efficiencies of 89 ± 3 and 85 ± 3%, respectively.

Suitability of anaerobic digestion effluent as process water for corn fuel ethanol fermentation

2014 ◽  
Vol 69 (9) ◽  
pp. 1894-1899 ◽  
Author(s):  
Ke Wang ◽  
Jian-Hua Zhang ◽  
Pei Liu ◽  
Zhong-Gui Mao
Keyword(s):  
Anaerobic Digestion ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Fuel Ethanol ◽  
Ammonium Nitrogen ◽  
Process Water ◽  
Ammonium Concentration ◽  
Net Energy ◽  
Corn Ethanol ◽  
Thin Stillage

A corn fuel ethanol plant integrated with anaerobic digestion treatment of thin stillage increases the net energy balance. Furthermore, the anaerobic digestion effluent (ADE) can be reused as a potential substitute for process water in the ethanol fermentation. In this study, the suitability of ADE as process water for corn ethanol fermentation was investigated by analyzing the potential inhibitory components in the ADE. It was found that ammonium influenced the growth and metabolism of Saccharomyces cerevisiae. Maximum ethanol production was obtained when the concentration of ammonium nitrogen was 200 mg/L, and ammonium could replace urea as the nitrogen source for S. cerevisiae under this concentration. In the ethanol fermentation with a higher concentration of ammonium, more glycerol was produced, thereby resulting in the decrease of ethanol production. In addition, components except ammonium in the ADE caused no inhibition to ethanol production. These results suggest that ADE could be reused as process water for corn ethanol fermentation without negative effect when ammonium concentration is well controlled.

Effects on anaerobic digestion of sewage sludge pretreatment

1997 ◽  
Vol 35 (10) ◽  
pp. 207-211 ◽  
Author(s):  
H. B. Choi ◽  
K. Y. Hwang ◽  
E. B. Shin
Keyword(s):  
Anaerobic Digestion ◽  
Protein Concentration ◽  
Operating Conditions ◽  
Waste Activated Sludge ◽  
Batch Experiments ◽  
Mechanical Pretreatment ◽  
Sludge Pretreatment ◽  
Volatile Solids ◽  
Vs Removal ◽  
Removal Efficiencies

This research investigates the effect of sludge pretreatment on the anaerobic digestion of waste-activated sludge (WAS). In the key of this sludge pretreatment process, bacteria in the WAS were ruptured by mechanical jet and smashed under pressurized conditions. The protein concentrations in the sludge varied significantly after pretreatment. Protein concentration increased according to jet times and pressure. In batch experiments, volatile solids (VS) removal efficiencies were 13∼50% when the WAS pretreated once under 30 bar was fed into an anaerobic digester with 2∼26 day retention time. In the same operating conditions, when intact WAS was fed into the digester, VS removal efficiencies were 2∼35%. Therefore, it is recognized that higher digestion efficiencies of the WAS were obtained through a mechanical pretreatment of sludge.

Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors

2005 ◽  
Vol 51 (6-7) ◽  
pp. 421-430 ◽  
Author(s):  
E. Melin ◽  
T. Leiknes ◽  
H. Helness ◽  
V. Rasmussen ◽  
H. Ødegaard
Keyword(s):  
Membrane Fouling ◽  
Loading Rate ◽  
Biofilm Reactor ◽  
Cod Removal ◽  
High Rate ◽  
Organic Loading Rate ◽  
Membrane Pore ◽  
Moving Bed ◽  
Loading Rates ◽  
Removal Efficiencies

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.1 to 26.6 g COD m−2 d−1. The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3–5.6 l m−2 h−1). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3–4 h HRT and 83% at 0.75–1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79–81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 μm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.

Anaerobic digestion of thin stillage of corn ethanol plant in a novel anaerobic baffled reactor

2018 ◽  
Vol 78 ◽  
pp. 541-552 ◽  
Author(s):  
Farid Sayedin ◽  
Azadeh Kermanshahi-pour ◽  
Sophia (Quan) He
Keyword(s):  
Anaerobic Digestion ◽  
Corn Ethanol ◽  
Thin Stillage ◽  
Anaerobic Baffled Reactor ◽  
Ethanol Plant

scholarly journals Ammonia threshold for inhibition of anaerobic digestion of thin stillage and the importance of organic loading rate

2015 ◽  
Vol 9 (2) ◽  
pp. 180-194 ◽  
Author(s):  
Jan Moestedt ◽  
Bettina Müller ◽  
Maria Westerholm ◽  
Anna Schnürer
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Thin Stillage

Development of a methanogenic process to degrade exhaustively the organic fraction of municipal “grey waste” under thermophilic and hyperthermophilic conditions

2000 ◽  
Vol 41 (3) ◽  
pp. 83-91 ◽  
Author(s):  
P.A. Scherer ◽  
G.-R. Vollmer ◽  
T. Fakhouri ◽  
S. Martensen
Keyword(s):  
Loading Rate ◽  
Cellulose Degradation ◽  
Gas Production ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Organic Fraction ◽  
Biogas Yield ◽  
Conversion Rates ◽  
Vs Removal ◽  
Removal Efficiencies

Different laboratory-scale, continuously driven reactor concepts (up to 3 reactors in series, max. 70°C) for anaerobic digestion of the organic fraction of municipal grey waste were investigated. Over a period of 2½ years several setups of reactors being daily fed and held in steady state balance were investigated. The preferred variant was a 2-stage setup with a HRT of 4.3d for the 1st and 14.2d for the 2nd reactor. Removal efficiencies of VS obtained by comparing the organic loading rate (OLR, g VS/l/d) of the effluent with the OLR of the feed could reach 80%. Removal efficiencies determined indirectly by the combined biogas yield of the 1st and 2nd reactor stage revealed even up to 91.5% of the theoretical possible yield of 807 l/kgVS. The produced gas had a methane content of 60–65%. A completely distinct hydrolysis stage with a gas production of only 1.6–5.5% of the theoretical yield could be reached by hyperthermophilic conditions (60–70°C) or by a HRT of 1.25d. It also demonstrated that a stable methanogenesis was not possible at temperatures of 60–70°C. Kinetic analyses of the 2nd reactor stage revealed that the degradation of VS fell from 80 to 40% with raising organic loading rate (OLR) from 3 to 11 g VS/l/d. In contrast to this the VS-removal of the first hydrolysis reactor stage increased linearily from 5 to 20% at raising OLR's from 12 to 26 g VS/l/d. The same kinetics with linear increase exhibited the specific cellulose degradation with conversion rates of 0.1–3x109 g cellulose/single bacterium (10–12 g)/d. This was an indication for the cellulose degradation as a rate limiting step. Both reactor stages combined allowed an optimal VS removal efficiency at OLR of 10 g VS/l/d. Analysis of bacterial populations of 28 reactors were referred either to eubacteria utilizing different sugars or cellulose or acetate or H2–CO2 or archaea (plus antibiotics) with acetate or H2–CO2 as substrate. H2–CO2 utilizers with numbers of 108–1010/g TS dominated obviously the acetotrophic methanogens by the factor 10–10,000. This explained the observed short HRTs being possible.

Simultaneous treatment of sewage sludge and food waste by the unified high-rate anaerobic digestion system

2006 ◽  
Vol 53 (6) ◽  
pp. 29-35 ◽  
Author(s):  
H.-W. Kim ◽  
S.-K. Han ◽  
H.-S. Shin
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Production Rate ◽  
Food Waste ◽  
High Rate ◽  
Organic Loading Rate ◽  
Simultaneous Treatment ◽  
Methanogenic Activity ◽  
Ch4 Production ◽  
Methane Production Rate

This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, the UHAD system showed higher CH4 recovery (>70%), CH4 yield (0.3 L CH4/g VSadded) and CH4 production rate (0.6 L CH4/L/d) than the control system. In the specific methanogenic activity (SMA) tests on thermophilic biomass of the UHAD system, the average SMA of acetate (102 mL CH4/gVSS/d) was much higher than those of butyrate (85 mL CH4/g SS/d) and propionate (42 mL CH4/gVSS/d). It was demonstrated that the UHAD system for co-digestion resulted in higher methane yield and methane production rate due to sequencing batch operation, thermophilic digestion, and co-digestion. The enhanced performance could be attributed to longer retention time of active biomass, faster hydrolysis, higher CH4 conversion rate, and balanced nutrient conditions of co-substrate in the UHAD system. Consequently, this optimized unification could be a viable option for the simultaneous treatment of two types of OFMSW with high stability.

High-rate anaerobic digestion of palm oil mill effluent in an upflow anaerobic sludge-fixed film bioreactor

2006 ◽  
Vol 41 (2) ◽  
pp. 370-379 ◽  
Author(s):  
G.D. Najafpour ◽  
A.A.L. Zinatizadeh ◽  
A.R. Mohamed ◽  
M. Hasnain Isa ◽  
H. Nasrollahzadeh
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
High Rate ◽  
Palm Oil Mill Effluent ◽  
Anaerobic Sludge ◽  
Fixed Film ◽  
Palm Oil Mill ◽  
Fixed Film Bioreactor

scholarly journals High-Rate Anaerobic Digestion of Waste Activated Sludge by Integration of Electro-Fenton Process

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 626 ◽  
Author(s):  
Emna Feki ◽  
Audrey Battimelli ◽  
Sami Sayadi ◽  
Abdelhafidh Dhouib ◽  
Sonia Khoufi
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Continuous Fermentation ◽  
Removal Rate ◽  
High Rate ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Capillary Suction ◽  
Biogas Yield

Anaerobic digestion (AD), being the most effective treatment method of waste activated sludge (WAS), allows for safe disposal. The present study deals with the electro-Fenton (EF) pretreatment for enhancing the WAS biogas potential with low-cost iron electrodes. The effect of pretreatment on the physicochemical characteristics of sludge was assessed. Following EF pretreatment, the pH, conductivity, soluble chemical oxygen demand (SCOD), and volatile fatty acids (VFA) increased to 7.5, 13.72 mS/cm, 4.1 g/L, and 925 mg/L, respectively. Capillary suction time (CST) analysis highlighted the dewaterability effect of EF on WAS, as demonstrated by the decrease in CST from 429 to 180 s following 30 min of pretreatment. Batch digestion assays presented an increase in the biogas yield to 0.135 L/g volatile solids (VS) after 60 min of EF pretreatment in comparison to raw sludge (0.08 L/g VS). Production of biogas was also found to improve during semi-continuous fermentation of EF-pretreated sludge conducted in a lab-scale reactor. In comparison to raw sludge, EF-pretreated sludge produced the highest biogas yield (0.81 L biogas/g VS) with a high COD removal rate, reaching 96.6% at an organic loading rate (OLR) of 2.5 g VS/L. d. Results revealed that the EF process could be an effective WAS disintegration method with maximum recovery of bioenergy during AD.

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