Effects of Gas Supplying Patterns on Aerobic Anaerobic Biogas Production of Rice Straw

2019 ◽  
Vol 14 (7) ◽  
pp. 642-648
Author(s):  
Jingyu Li ◽  
Qinghua Ding ◽  
Wenzhe Li ◽  
Weijia Gong
Keyword(s):  
Rice Straw ◽  
Degradation Rate ◽  
Biogas Production ◽  
Renewable Resource ◽  
Gas Production ◽  
Utilization Rate ◽  
Control Group ◽  
Energy And Environment ◽  
Total Enzyme Activity ◽  
Air Supply

Background: Rice straw as a plant photosynthesis product, is a valuable renewable resource and it contains protein, fat, cellulose, hemicellulose, lignin and ash. It has received wide attention for biogas can solve both the energy and environment problems. Objective: To improve the degradation rate of rice straw in aerobic and anaerobic bi-phase fermentation process. Methods: Different aerobic methods were adopted to improve the degradation rate of aerobic acid producing cellulose. Results: The results showed that in different ways of gas supply test experiments the total enzyme activity of aeration mode was higher than that of the stirring air supply mode, which indicated that the aeration mode was more favorable to the growth of mixed strains of Trichoderma and Aspergillus. The gas production of TS was 438.69 mL•g-1, which was higher than both the stirring group and control group. Conclusion: The degradation utilization rate of rice straw solid organic matter can be significantly improved using method of aeration mode, and the conversion of straw biomass into biogas was promoted.

scholarly journals Comparison Effects of Ruminal Crabtree-Negative Yeasts and Crabtree-Positive Yeasts for Improving Ensiled Rice Straw Quality and Ruminal Digestion Using In Vitro Gas Production

2020 ◽  
Vol 6 (3) ◽  
pp. 109 ◽  
Author(s):  
Chanon Suntara ◽  
Anusorn Cherdthong ◽  
Suthipong Uriyapongson ◽  
Metha Wanapat ◽  
Pin Chanjula
Keyword(s):  
Rice Straw ◽  
Dry Matter ◽  
Gas Production ◽  
Neutral Detergent Fiber ◽  
Control Group ◽  
In Vitro Digestibility ◽  
Pichia Kudriavzevii ◽  
Yeast Strains ◽  
In Vitro Gas Production

The objective of this study was to compare the effects of Crabtree-negative ruminal yeast and Crabtree-positive yeast in ensiled rice straw (RS) on the ensilage quality, nutritive value, and microorganism composition, including the evaluation of the ensiled RS using the in vitro gas production technique. The experiment was conducted in a 4 × 3 factorial arrangement in a randomized complete design. Factor A was yeast species with no inoculant, Crabtree-negative yeasts (Pichia kudriavzevii KKU20 and Candida tropicalis KKU20), and Crabtree-positive yeast (Saccharomyces cerevisae), whereas factor B was ensilage times (7, 14, and 21 days). The rate of growth was revealed to be lower in Crabtree-positive yeasts than the other Crabtree-negative yeast strains (p < 0.01). RS ensiled with S. cerevisiae showed decreased dry matter (DM) content by 9.0% when compared to the sample without a yeast inoculant. In addition, organic matter (OM) content was greater (p < 0.01) for P. kudriavzevii KKU20 than C. tropicalis KKU20 and without an inoculant. Neutral detergent fiber (NDF) content was significantly decreased (p < 0.01) by yeast inoculants by about 2.75% when compared to the control group. Lactic acid bacteria (LAB) and aerobic bacteria were low (p < 0.05) when yeasts were added. However, no interaction was found between yeast and ensilage times on the quality of ensiled RS (p > 0.05). The P. kudriavzevii KKU20 addition was associated with the highest value (p < 0.01) of gas produced—an insoluble fraction (b), potential extent of gas production (a + b), and cumulative gas production at 96 h—when compared with S. cerevisiae or the control group. The highest in vitro dry matter digestibility and in vitro neutral detergent fiber digestibility was observed in RS ensiled with P. kudriavzevii KKU20 for 14 days (p < 0.01, p < 0.05). The maximum total volatile fatty acids (VFAs) at 4 and 8 h of incubation and the mean value were observed in RS ensiled with P. kudriavzevii KKU20 (p < 0.01). RS ensiled with all yeast strains showed an increased propionate concentration at 8 h (p < 0.01). In conclusion, ensiling RS with isolated Crabtree-negative ruminal yeasts could benefit feed digestion and in vitro gas production more than Crabtree-positive yeast does. P. kudriavzevii KKU20, an isolated Crabtree-negative ruminal yeast used to treat RS, had the highest potential for increasing cumulative gas production and enhancing in vitro digestibility.

scholarly journals Effect of yeast addition on the biogas production performance of a food waste anaerobic digestion system

2020 ◽  
Vol 7 (8) ◽  
pp. 200443
Author(s):  
Ming Gao ◽  
Shuang Zhang ◽  
Xinxin Ma ◽  
Weijie Guan ◽  
Na Song ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Biogas Production ◽  
Gas Production ◽  
Production Performance ◽  
Organic Load ◽  
Control Group ◽  
Volatile Solids ◽  
Volatile Organic ◽  
The Stability

Food waste contains numerous easily degradable components, and anaerobic digestion is prone to acidification and instability. This work aimed to investigate the effect of adding yeast on biogas production performance, when substrate is added after biogas production is reduced. The results showed that the daily biogas production increased 520 and 550 ml by adding 2.0% (volatile solids; VS) of activated yeast on the 12th and 37th day of anaerobic digestion, respectively, and the gas production was relatively stable. In the control group without yeast, the increase of gas production was significantly reduced. After the second addition of substrate and yeast, biogas production only increased 60 ml compared with that before the addition. After fermentation, the biogas production of yeast group also increased by 33.2% compared with the control group. Results of the analysis of indicators, such as volatile organic acids, alkalinity and propionic acid, showed that the stability of the anaerobic digestion system of the yeast group was higher. Thus, the yeast group is highly likely to recover normal gas production when the biogas production is reduced, and substrate is added. The results provide a reference for experiments on the industrialization of continuous anaerobic digestion to take tolerable measures when the organic load of the feed fluctuates dramatically.

scholarly journals Application of Modified Gompertz Model to Study on Biogas production from middle temperature co-digestion of pig manure and dead pigs

2019 ◽  
Vol 118 ◽  
pp. 03022
Author(s):  
Hongguang Zhu ◽  
Jing Yang ◽  
Cheng Xiaowei
Keyword(s):  
Anaerobic Digestion ◽  
Degradation Rate ◽  
Biogas Production ◽  
Raw Materials ◽  
Gompertz Model ◽  
Gas Production ◽  
Raw Material ◽  
Pig Manure ◽  
Middle Temperature ◽  
Modified Gompertz Model

The dead pig is an organic waste rich in oil and protein, and is an ideal anaerobic digestion raw material. This study based on single factor ANOVA and Modified Gompertz model. It investigated the effects of the ratio of dead pigs on biogas production by middle temperature co-digestion of pig manure and dead pigs. And the biogas production potential was determined. The results showed that there was no significant correlation between the ratio of dead pigs and the biogas production. The ratio would significantly affect the average methane content and degradation rate. When the addition ratio was in the range of 3 to 15%, the biogas production was between 191.39 and 202.44 (L/kg VS). The average contents of methane were 50.67%, 50.35%, 41.83%, 45.53% and 44.57%, respectively. The time required to reach 80% of the biogas production was 28, 34, 36, 65 and 63 days, respectively. The degradation rate of the raw materials was generally decreased with the increase of the addition ratio. The results of Modified Gompertz model fitting showed that the mixed raw materials had a fully anaerobic digestion with high utilization rate and short hysteresis in the range of 0 ~ 9%. Therefore, a hydraulic retention time (HRT) of 30 days and the addition ratio was in the range of 0 to 6% could be recommended for a continuous digester. It could get a better gas production and higher raw material utilization.

Effects of Ferric Salts on Sludge Anaerobic Digestion and Desulphurization

2018 ◽  
Vol 913 ◽  
pp. 887-892
Author(s):  
Run Zhuan ◽  
Guang Yang ◽  
Guang Ming Zhang ◽  
Wei Wang
Keyword(s):  
Anaerobic Digestion ◽  
Ferric Chloride ◽  
Biogas Production ◽  
Removal Rate ◽  
Sulfur Removal ◽  
Gas Production ◽  
Control Group ◽  
Potassium Ferrate ◽  
Nitrogen And Phosphorus ◽  
Remarkable Effect

The treatment and disposal of excess sludge is a great challenge. Anaerobic digestion can achieve sludge reduction and harmless. However, its application is largely limited due to the low biogas production, low organic matters removal rate, odor gas production, corrosive gas destroying equipment. Sulfur is a key element resulting in these problems. In this research, potassium ferrate and ferric chloride were added to enhance anaerobic digestion. The research investigated the effects on biogas production, H2S content, microbial diversity with the addition of potassium ferrate and ferric chloride. We found that with 2.5 mg/g TS potassium ferrate, the enhancement was the highest, the total biogas production improved 18% compared with control group and organic removal rate reached 30.66%. Considering the effect of sulfur removal, 5 mg/g TS potassium ferrate resulted in the best effect, the content of H2S gas decreased 139.4%. With 2.5 mg/g TS ferric chloride, total biogas production improved 8% comparing with the control group, the content of H2S gas decreased 46%, no remarkable effect was found on the content of nitrogen and phosphorus in slurry.

Effect of H3PO4 Pretreatment on Biogas Production of Rice Straw during Anaerobic Digestion

2014 ◽  
Vol 953-954 ◽  
pp. 216-219
Author(s):  
Ben Lin Dai ◽  
An Feng Zhu ◽  
Fei Hu Mu ◽  
Ning Xu ◽  
Zhen Wu
Keyword(s):  
Anaerobic Digestion ◽  
Rice Straw ◽  
Biogas Production ◽  
Low Cost ◽  
Gas Production ◽  
Methane Content ◽  
Pretreatment Conditions ◽  
Peak Value

To improve the gas production ability, relatively low cost H3PO4was chosen as the pretreating agent in this study. Rice straws were pretreated by four different weight percentages (2%, 4%, 6% and 8%) of H3PO4retting for seven days in an biochemical incubator at (25±1) °C, and the effects with different conditions of H3PO4pretreatment on anaerobic digestion of rice straws for variation of components and anaerobic digestion performance (under temperature of (35±1) °C) were studied. The results showed that the peak value of biogas production was attained on the 1stday for using 6% H3PO4pretreatment on rice straw, which is 2284 mL. The test daily methane content of different pretreatment conditions mainly ranges from 3.8% to 43.1%, with the highest recorded at the 12thday of the 2% H3PO4- treated rice straw. The cumulative biogas production of 6% H3PO4pretreatment was the highest, about 16 474 mL.

Biodegradation mechanism of biogas production by modified rice straw fermentation

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8862-8882
Author(s):  
Enhai Liu ◽  
Baozhong Zhu ◽  
Shengyong Liu ◽  
Hailong Yu ◽  
Zhiping Zhang ◽  
...  
Keyword(s):  
Rice Straw ◽  
Biogas Production ◽  
Raw Materials ◽  
Degradation Mechanism ◽  
Raw Material ◽  
White Rot ◽  
Control Group ◽  
Biogas Yield ◽  
Optimal Ratio ◽  
Pre Treatment

Based on the literature on the degradation mechanism and the change of micro-functional groups in the fermentation process of modified rice straw, this study aimed to solve the problems of low biogas production rate and poor stability of the biogas production system. In this work, mathematical equations were developed and combined with duck dung and rice straw mixed raw material to perform a fermentation test. The molecular micro-functional group changes of cellulose, hemicellulose, and lignin were studied to obtain the optimal ratio of mixed raw materials for fermentation and to explore the optimization mechanism of its fermentation biogas production. Experimental results showed that the optimal ratio of mixed raw materials was 2.8:1, and the inclusion of a suitable amount of Mn2+(concentration of 2 mol × L-1) was able to strengthen MnP activity and improve the ability of white-rot fungi to rupture β-O-4 bonds. A modification pre-treatment via activated carbon-based solid acid was performed, and the experimental group generated 15.8% more cumulative biogas than the control group. The biogas yield reached its peak when 300 g of inoculum was added to the pre-treatment at a concentration of 30%.

Inhibition kinetics for propionate degradation using propionate-enriched mixed cultures

1998 ◽  
Vol 38 (8-9) ◽  
pp. 443-451 ◽  
Author(s):  
S. H. Hyun ◽  
J. C. Young ◽  
I. S. Kim
Keyword(s):  
Phase I ◽  
Competitive Inhibition ◽  
Gas Production ◽  
Phase Iii ◽  
Utilization Rate ◽  
Inhibition Kinetics ◽  
Wide Range ◽  
Propionate Degradation ◽  
Acetate Utilization ◽  
Velocity Coefficient

To study propionate inhibition kinetics, seed cultures for the experiment were obtained from a propionate-enriched steady-state anaerobic Master Culture Reactor (MCR) operated under a semi-continuous mode for over six months. The MCR received a loading of 1.0 g propionate COD/l-day and was maintained at a temperature of 35±1°C. Tests using serum bottle reactors consisted of four phases. Phase I tests were conducted for measurement of anaerobic gas production as a screening step for a wide range of propionate concentrations. Phase II was a repeat of phase I but with more frequent sampling and detailed analysis of components in the liquid sample using gas chromatography. In phase III, different concentrations of acetate were added along with 1.0 g propionate COD/l to observe acetate inhibition of propionate degradation. Finally in phase IV, different concentrations of propionate were added along with 100 and 200 mg acetate/l to confirm the effect of mutual inhibition. Biokinetic and inhibition coefficients were obtained using models of Monod, Haldane, and Han and Levenspiel through the use of non-linear curve fitting technique. Results showed that the values of kp, maximum propionate utilization rate, and Ksp, half-velocity coefficient for propionate conversion, were 0.257 mg HPr/mg VSS-hr and 200 mg HPr/l, respectively. The values of kA, maximum acetate utilization rate, and KsA, half-velocity coefficient for acetate conversion, were 0.216 mg HAc/mg VSS-hr and 58 mg HAc/l, respectively. The results of phase III and IV tests indicated there was non-competitive inhibition when the acetate concentration in the reactor exceeded 200 mg/l.

scholarly journals Effect of Mixing Regimes on Cow Manure Digestion in Impeller Mixed, Unmixed and Chinese Dome Digesters

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2540
Author(s):  
Abiodun O. Jegede ◽  
Grietje Zeeman ◽  
Harry Bruning
Keyword(s):  
Urban Areas ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Gas Production ◽  
Cow Manure ◽  
Volatile Solid ◽  
Treatment Efficiency ◽  
Ambient Temperatures ◽  
Ch4 Production ◽  
Mixing Regime

This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 °C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.

Effects of Different Treatments on Properties of Biogas Fermentation with Ginger Skin

2014 ◽  
Vol 953-954 ◽  
pp. 284-289
Author(s):  
Jing Hui Liu ◽  
Wi Di Zhang ◽  
Fang Yin ◽  
Jing Liu ◽  
Xing Ling Zhao ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Gas Production ◽  
Methane Content ◽  
Raw Material ◽  
Pig Manure ◽  
Natural Decay ◽  
Gas Potential ◽  
Direct Fermentation

In order to obtain gas potential and characteristics of ginger skin in biogas fermentation as raw material, and explore effect of different treatments on properties of biogas fermentation with ginger skin. At the temperature of 30°C, biogas fermentations with ginger skin were treated in two ways (natural decay and mixed with pig manure). Experiments were respectively set five different treatments (direct fermentation, natural decay, adding pig manure after natural decay (TS content of pig manure / TS content of ginger skin were respectively 1:1, 2:1 and 3:1)). The results showed gas potential of ginger skin and total gas production were respectively 118.08ml/gTS and 320ml, after the 11th day, the fermentation was in a serious acidification, as a result of stopping gas production. The fermentations with ginger skin which went through natural decay and adding pig manure after natural decay can both eliminate acidification which caused by use of ginger skin directly, and conduce to the fermentation with ginger skin. The fermentation with ginger skin which went through natural decay had higher degradation rate of TS, total gas production, TS gas potential and methane content than fermentation with ginger skin directly.

Full scale co-digestion of organic waste

2000 ◽  
Vol 41 (3) ◽  
pp. 195-202 ◽  
Author(s):  
H. Kübler ◽  
K. Hoppenheidt ◽  
P. Hirsch ◽  
A. Kottmair ◽  
R. Nimmrichter ◽  
...  
Keyword(s):  
Negative Impact ◽  
Biogas Production ◽  
Electrical Power ◽  
Nutrient Content ◽  
Primary Energy ◽  
Gas Production ◽  
Waste Streams ◽  
Volatile Solids ◽  
Operation Results ◽  
The Impact

Operational results of a co-digestion facility were assessed over a period of 18 months. The organic fraction of municipal solid waste (OFMSW) contains a considerable amount of contaminants and grit (up to 6% w/w). A BTA-Pulper efficiently treated the different waste streams and converted a high amount of volatile solids (VS) into the digester feedstock. The seasonal fluctuations of the waste composition significantly influenced the biogas production. The impact of this seasonally variant degradability of VS had to be considered by evaluating the operation results. The waste streams investigated did not show any negative impact on digester performance. The hydraulic retention time (HRT) in the digester considerably affected the VS-reduction. Despite a considerable decrease of VS-degradation a reduction of HRT from 14 to 8 days slightly improves the gas production rate (GPR). An activated sludge system efficiently reduced the pollution of the effluent.The nutrient content of the anaerobic compostwas favourable and the content of pollutants was low. The facility produced surplus electrical power up to 290 MJ/t. An overall energy balance shows that the facility substitutes primary energy.

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