scholarly journals Anaerobic co-digestion of agricultural biomass with industrial wastewater for biogas production

2021 ◽  
Author(s):  
◽  
Edward Kwaku Armah
Keyword(s):  
South Africa ◽  
Industrial Wastewater ◽  
Loading Rate ◽  
Biogas Production ◽  
Organic Loading Rate ◽  
Gravimetric Analysis ◽  
Organic Loading ◽  
Agricultural Biomass ◽  
Biogas Yield ◽  
First Order

With the increasing demand for clean and affordable energy which is environmentally friendly, the use of renewable energy sources is a way for future energy generation. South Africa, like most countries in the world are over-dependent on the use of fossil fuels, prompting most current researchers to seek an affordable and reliable source of energy which is also,a focal point of the United Nations Sustainable Development Goal 7. In past decades, the process of anaerobic digestion (AD) also referred to as monodigestion, has proven to be efficient with positive environmental benefits for biogas production for the purpose of generating electricity, combined heat and power. However, due to regional shortages, process instability and lower biogas yield, the concept of anaerobic co-digestion (AcoD) emerged to account for these drawbacks. Given the considerable impact that industrial wastewater (WW) could provide nutrients in anaerobic biodigesters, the results of this study could apprise decisionmakers and the government to further implement biogas installations as an alternative energy source. The study aims at optimising the biogas production through AcoD of the agricultural biomasses: sugarcane bagasse (SCB) and corn silage (CS) with industrial WW sourced from Durban, KwaZulu-Natal, South Africa. The study commenced with the characterisation of the biomasses under this study with proximate and ultimate analysis using the Fourier transform infrared spectroscopy (FTIR), the thermo gravimetric analysis (TGA), the scanning electron microscopy (SEM) and the differential scanning calorimetry (DSC). The untreated biomass was subjected to biochemical methane potential (BMP) tests to optimise and predict the biogas potential for the selected biomass. A preliminary run was carried out with the agricultural biomass to determine which of the WW streams would yield the most biogas. Among the four WW streams sourced at this stage, two WW streams; sugar WW (SWW) and dairy WW (DWW) produced the highest volume of biogas in the increasing order; SWW ˃ DWW ˃ brewery WW > municipal WW. Therefore, both SWW and DWW were selected for further process optimisation with each biomass. Using the response surface methodology (RSM), the factors considered were temperature (25-55 °C) and organic loading rate (0.5-1.5 gVS/100mL); and the response was the biogas yield (m3 /kgVS). Maximum biogas yield and methane (CH4) content were found to be 5.0 m3 /kgVS and 79%, respectively, for the AcoD of CS with SWW. This established the association that existed among the set temperatures of the digestion process and the corresponding organic loading rate (OLR) of the AcoD process operating in batch mode. Both CS and SCB have been classified as lignocellulosic and thus, ionic liquid (IL) pretreatment was adapted in this study to ascertain their potential on the biogas yield. Results showed that the maximum biogas yield and CH4 content were found to be 3.9 m3 /kgVS and 87%, respectively, after IL pretreatment using 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) for CS with DWW at 55°C and 1.0 gVS/100mL. The IL pretreatment yielded lower biogas but of higher purity of CH4 than the untreated biomass. Data obtained from the BMP tests for the untreated and pretreated biomasses were tested with the existing kinetic models; first order, dual pooled first order, Chen and Hashimoto and the modified Gompertz. The results showed that for both untreated and pretreated biomass, the modified Gompertz had the best fit amongst the four models tested with coefficient of correlation, R 2 values of 0.997 and 0.979, respectively. Comparatively, the modified Gompertz model could be the preferred model for the study of industrial WW when used as co-substrate during AcoD for biogas production. The study showed that higher biogas production and CH4 contents were observed when CS was employed as a reliable feedstock with maximum volume of the untreated and pretreated feedstock reported at 31 L and 20 L respectively.

Anaerobic digestion of Jatropha curcas L. press cake and effects of an iron-additive

2011 ◽  
Vol 29 (11) ◽  
pp. 1171-1176 ◽  
Author(s):  
Thomas Schmidt
Keyword(s):  
Anaerobic Digestion ◽  
Jatropha Curcas ◽  
Loading Rate ◽  
Press Cake ◽  
Biogas Production ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Biogas Yield ◽  
Jatropha Curcas L ◽  
The Stability

Oil production from Jatropha curcas L. seeds generates large amounts of Jatropha press cake (JPC) which can be utilized as a substrate for biogas production. The objective of this work was to investigate anaerobic mono-digestion of JPC and the effects of an iron additive (IA) on gas quality and process stability during the increase of the organic loading rate (OLR). With the increase of the OLR from 1.3 to 3.2 gVS L−1 day−1, the biogas yield in the reference reactor (RR) without IA decreased from 512 to 194 LN kgVS−1 and the CH4 concentration decreased from 69.3 to 44.4%. In the iron additive reactor (IAR), the biogas yield decreased from 530 to 462 LN kgVS−1 and the CH4 concentration decreased from 69.4 to 61.1%. The H2S concentration in the biogas was reduced by addition of the IA to values below 258 ppm in the IAR while H2S concentration in the RR increased and exceeded the detection limit of 5000 ppm. The acid capacity (AC) in the RR increased to more than 20 g L−1, indicating an accumulation of organic acids caused by process instability. AC values in the IAR remained stable at values below 5 g L−1. The results demonstrate that JPC can be used as sole substrate for anaerobic digestion up to an OLR of 2.4 gVS l−1 day−1. The addition of IA has effectively decreased the H2S content in the biogas and has improved the stability of the anaerobic process and the biogas quality.

Effect of Organic Loading Rate (OLR) of Slurry on Biogas Production Quality

2015 ◽  
Vol 1115 ◽  
pp. 325-330
Author(s):  
Maizirwan Mel ◽  
Nadiah Mohd Suhuli ◽  
Avicenna ◽  
Sany Izan Ihsan ◽  
Ahmad Faris Ismail ◽  
...  
Keyword(s):  
Loading Rate ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Continuous System ◽  
Total Solid ◽  
Organic Loading Rate ◽  
Cow Dung ◽  
Feeding Rates ◽  
Organic Loading ◽  
Biogas Yield

In this study, three different concentration of organic loading rate (OLR) were investigated to examine the effect of the change in the organic loading rate on the efficiency of the biogas production. Daily amount of biogas of different type of organic loading rate (OLR), rates of production of biogas, removal efficiencies of chemical oxygen demand (COD), total solid (TS) matter, volatile solids (VS) matter from the slurry were investigated in 30 days retention tyme using 50 L digester. The digester was operated at different organic feeding rates of 25000 mg/L COD, 50000 mg/L COD, and 75000 mg/L COD. The material used in this system is the fruits waste, vegetables waste and cow dung. The system operated in continuous system. The reactor showed stable performance with the highest quality of methane (concentration about70.3% of CH4) and rate of biogas production is 38.1 L/day with COD reduction of 52.1% during organic loading rate 50000 mg/L COD. As the organic loading rate was increased, the COD degradation and biogas yield decreased. Based on this result, the OLR of 50000 mg/L COD is suggested as design criteria for pilot biogas production.

scholarly journals Effect of Hydraulic Retention Time on Biogas Production from Cow Dung in A Semi Continuous Anaerobic Digester

2018 ◽  
Vol 7 (2) ◽  
pp. 93-100 ◽  
Author(s):  
Agus Haryanto ◽  
Sugeng Triyono ◽  
Nugroho Hargo Wicaksono
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Biogas Production ◽  
Stable Condition ◽  
Anaerobic Digester ◽  
Organic Loading Rate ◽  
Cow Dung ◽  
Biogas Yield ◽  
Average Analysis

The efficiency of biogas production in semi-continuous anaerobic digester is influenced by several factors, among other is loading rate. This research aimed at determining the effect of hydraulic retention time (HRT) on the biogas yield. Experiment was conducted using lab scale self-designed anaerobic digester of 36-L capacity with substrate of a mixture of fresh cow dung and water at a ratio of 1:1. Experiment was run with substrate initial amount of 25 L and five treatment variations of HRT, namely 1.31 gVS/L/d (P1), 2.47 gVS/L/d (P2), 3.82 gVS/L/d (P3), 5.35 gVS/L/d (P4) and 6.67 gVS/L/d (P5). Digester performance including pH, temperature, and biogas yield was measured every day. After stable condition was achieved, biogas composition was analyzed using a gas chromatograph. A 10-day moving average analysis of biogas production was performed to compare biogas yield of each treatment. Results showed that digesters run quite well with average pH of 6.8-7.0 and average daily temperature 28.7-29.1. The best biogas productivity (77.32 L/kg VSremoval) was found in P1 treatment (organic loading rate of 1.31 g/L/d) with biogas yield of 7.23 L/d. With methane content of 57.23% treatment P1 also produce the highest methane yield. Biogas production showed a stable rate after the day of 44. Modified Gompertz kinetic equation is suitable to model daily biogas yield as a function of digestion time.Article History: Received March 24th 2018; Received in revised form June 2nd 2018; Accepted June 16th 2018; Available onlineHow to Cite This Article: Haryanto, A., Triyono, S., and Wicaksono, N.H. (2018) Effect of Loading Rate on Biogas Production from Cow Dung in A Semi Continuous Anaerobic Digester. Int. Journal of Renewable Energy Development, 7(2), 93-100.https://doi.org/10.14710/ijred.7.2.93-100

scholarly journals The feasibility of trace element supplementation for stable operation of wheat stillage-fed biogas tank reactors

2011 ◽  
Vol 64 (2) ◽  
pp. 320-325 ◽  
Author(s):  
J. Gustavsson ◽  
B. H. Svensson ◽  
A. Karlsson
Keyword(s):  
Trace Element ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Biogas Production ◽  
Organic Loading Rate ◽  
Stable Operation ◽  
Organic Loading ◽  
Process Stability ◽  
Volatile Solids ◽  
High Sulfate

The aim of this study was to investigate the effect of trace element supplementation on operation of wheat stillage-fed biogas tank reactors. The stillage used was a residue from bio-ethanol production, containing high levels of sulfate. In biogas production, high sulfate content has been associated with poor process stability in terms of low methane production and accumulation of process intermediates. However, the results of the present study show that this problem can be overcome by trace element supplementations. Four lab-scale wheat stillage-fed biogas tank reactors were operated for 345 days at a hydraulic retention time of 20 days (37 °C). It was concluded that daily supplementation with Co (0.5 mg L−1), Ni (0.2 mg L−1) and Fe (0.5 g L−1) were required for maintaining process stability at the organic loading rate of 4.0 g volatile solids L−1 day−1.

scholarly journals Adjusting Organic Load as a Strategy to Direct Single-Stage Food Waste Fermentation from Anaerobic Digestion to Chain Elongation

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1487
Author(s):  
Vicky De Groof ◽  
Marta Coma ◽  
Tom C. Arnot ◽  
David J. Leak ◽  
Ana B. Lanham
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Loading Rate ◽  
Biogas Production ◽  
Single Stage ◽  
Stirred Tank ◽  
Chain Elongation ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Operating Strategy

Production of medium chain carboxylic acids (MCCA) as renewable feedstock bio-chemicals, from food waste (FW), requires complicated reactor configurations and supplementation of chemicals to achieve product selectivity. This study evaluated the manipulation of organic loading rate in an un-supplemented, single stage stirred tank reactor to steer an anaerobic digestion (AD) microbiome towards acidogenic fermentation (AF), and thence to chain elongation. Increasing substrate availability by switching to a FW feedstock with a higher COD stimulated chain elongation. The MCCA species n-caproic (10.1 ± 1.7 g L−1) and n-caprylic (2.9 ± 0.8 g L−1) acid were produced at concentrations comparable to more complex reactor set-ups. As a result, of the adjusted operating strategy, a more specialised microbiome developed containing several MCCA-producing bacteria, lactic acid-producing Olsenella spp. and hydrogenotrophic methanogens. By contrast, in an AD reactor that was operated in parallel to produce biogas, the retention times had to be doubled when fed with the high-COD FW to maintain biogas production. The AD microbiome comprised a diverse mixture of hydrolytic and acidogenic bacteria, and acetoclastic methanogens. The results suggest that manipulation of organic loading rate and food-to-microorganism ratio may be used as an operating strategy to direct an AD microbiome towards AF, and to stimulate chain elongation in FW fermentation, using a simple, un-supplemented stirred tank set-up. This outcome provides the opportunity to repurpose existing AD assets operating on food waste for biogas production, to produce potentially higher value MCCA products, via simple manipulation of the feeding strategy.

Effect of Organic Loading Rate (OLR) on Biogas Yield Using a Single and Three-Stages Continuous Anaerobic Digestion Reactors

2018 ◽  
Vol 39 ◽  
pp. 147-155 ◽  
Author(s):  
Ejiroghene Kelly Orhorhoro ◽  
Patrick Okechukwu Ebunilo ◽  
Godwin Ejuvwedia Sadjere
Keyword(s):  
Waste Water ◽  
Loading Rate ◽  
Single Stage ◽  
Organic Loading Rate ◽  
Cow Dung ◽  
Organic Loading ◽  
Continuous Increase ◽  
Biogas Yield ◽  
Load Rate ◽  
Three Stages

The rate at which feedstock is added to the anaerobic digester (AD) reactor has to be adjusted for the growth rate of methanogens bacteria. Increase in biogas yield is as a result of improved mathanogens forming bacteria. Under loading and over loading of feedstock in the AD reactor has effect on methanogens forming bacteria. If more feedstock is added than the bacteria are able to degrade, the process will become acidic. Feedstock has to been fed to the reactor at a uniform rate and volume. If feeding pattern has to change, this must be done gradually so that bacteria can adapt to the new conditions. For optimum biogas yield, required amount of feedstock must be added to the AD reactor. The aim of this research work is to determine the effect of organic loading rate (OLR) on biogas yield from food waste, water hyacinth, cow dung, waste water from abattoir, poultry dropping and pig dung. The experimental set up comprises of single stage and three-stage continuous AD reactors. The same quantity and composition of feedstock were used and this was subjected to a variation of OLR 0.5 kg/m3(1.5 kg/m3, 2 kg/m3, 2.5 kg/m3, and 3 kg/m3). The experiment was conducted within a mesophilic temperature range of 36°C-37°C, percentage total solid (%TS) of 9.98% and percentage volatile solid (%VS) of 78%. pH meter was used to monitored the daily pH reading of the slurry. It was observed that the quantity of biogas yield from the feedstock increases with increasing organic load rate to the optimum value of 1.5 kg/m3and started decreasing above the optimum value for a single stage AD reactor but this was not the case for the three-stages continuous AD reactors that experienced continuous increase in biogas yield with a successive increase in OLR from 1-5 kg/m3-3.0 kg/m3.

scholarly journals Performance of AnMBR in Treatment of Post-consumer Food Waste: Effect of Hydraulic Retention Time and Organic Loading Rate on Biogas Production and Membrane Fouling

2021 ◽  
Vol 8 ◽  
Author(s):  
Javkhlan Ariunbaatar ◽  
Robert Bair ◽  
Onur Ozcan ◽  
Harish Ravishankar ◽  
Giovanni Esposito ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Food Waste ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Biogas Production ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Side Stream ◽  
Removal Efficiencies

Anaerobic digestion of food waste (FW) is typically limited to large reactors due to high hydraulic retention times (HRTs). Technologies such as anaerobic membrane reactors (AnMBRs) can perform anaerobic digestion at lower HRTs while maintaining high chemical oxygen demand (COD) removal efficiencies. This study evaluated the effect of HRT and organic loading rate (OLR) on the stability and performance of a side-stream AnMBR in treating diluted fresh food waste (FW). The reactor was fed with synthetic FW at an influent concentration of 8.24 (± 0.12) g COD/L. The OLR was increased by reducing the HRT from 20 to 1 d. The AnMBR obtained an overall removal efficiency of >97 and >98% of the influent COD and total suspended solids (TSS), respectively, throughout the course of operation. The biological process was able to convert 76% of the influent COD into biogas with 70% methane content, while the cake layer formed on the membrane gave an additional COD removal of 7%. Total ammoniacal nitrogen (TAN) and total nitrogen (TN) concentrations were found to be higher in the bioreactor than in the influent, and average overall removal efficiencies of 17.3 (± 5) and 61.5 (± 3)% of TAN and TN, respectively, were observed with respect to the bioreactor concentrations after 2 weeks. Total phosphorus (TP) had an average removal efficiency of 40.39 (± 5)% with respect to the influent. Membrane fouling was observed when the HRT was decreased from 7 to 5 d and was alleviated through backwashing. This study suggests that the side-stream AnMBR can be used to successfully reduce the typical HRT of wet anaerobic food waste (solids content 7%) digesters from 20 days to 1 day, while maintaining a high COD removal efficiency and biogas production.

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