Evaluation of Anaerobic Co-Digestion to Enhance the Efficiency of Livestock Manure Anaerobic Digestion

In this paper, the anaerobic co-digestion of three different organic wastes, including livestock manure, slaughterhouse waste, and agricultural by-products (ABs), was carried out to enhance the efficiency of mono-digestion of livestock manure. The characteristics of co-digestion were evaluated at different mixing ratios. The experiment was performed using the Batch test and was divided into two parts. The first experimental section (EXP. 1) was designed to evaluate the seasonal characteristics of ABs, which are the different ratios of fruits and vegetables, where the mixing ratio of spring (fruits:vegetables = 3:7) showed the highest biogas yield (0.24 m3/kg volatile solids). The second experiment (EXP. 2) was conducted by using ABs in the ratio that gave the highest biogas yield in EXP. 1 in combinations of three wastes livestock manure, slaughterhouse waste, and ABs. The highest CH4 yield was 0.84 m3/kg volatile solids (VS), which was obtained with a mixing ratio that had even amounts of the three feedstocks. In addition, the results of the second biochemical methane potential test, which assessed the digestive efficiency according to the mixing ratio of the three types of organic waste, showed that the CH4 production rate of the merged digestion was approximately 1.03–1.29 times higher than that of the mono-digestion of livestock manure. The results of our experiment were verified using the modified Gompertz model, the results of which were relatively similar to the experimental results.

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Biomethane Potential of Sludges from a Brackish Water Fish Hatchery

Applied Sciences ◽

10.3390/app11020552 ◽

2021 ◽

Vol 11 (2) ◽

pp. 552

Author(s):

Francesco da Borso ◽

Alessandro Chiumenti ◽

Giulio Fait ◽

Matia Mainardis ◽

Daniele Goi

Keyword(s):

Brackish Water ◽

Gompertz Model ◽

Experimental Tests ◽

Lag Phase ◽

Phase Duration ◽

Fish Hatchery ◽

Volatile Solids ◽

Water Recirculation ◽

Methane Potential ◽

Intensive Aquaculture

The development of intensive aquaculture is facing the challenge of the sustainable management of effluents. The reproductive sectors (i.e., hatcheries) mainly use water recirculation systems (RAS), which discharge a portion of wastewater. Anaerobic digestion (AD) could reduce the environmental impact of this waste stream while producing biogas. The study is focused on the biochemical methane potential (BMP) of brackish fish hatchery sludges. Wastewater was concentrated by microfiltration and sedimentation and thickened sludges were treated in a BMP system with different inoculum/substrate (I/S) volatile solids ratios (from 50:1 to no inoculum). The highest I/S ratio showed the highest BMP (564.2 NmL CH4/g VS), while different I/S ratios showed a decreasing trend (319.4 and 127.7 NmL CH4/g VS, for I/S = 30 and I/S = 3). In absence of inoculum BMP resulted of 62.2 NmL CH4/g VS. The kinetic analysis (modified Gompertz model) showed a good correlation with the experimental data, but with a long lag-phase duration (from 14.0 to 5.5 days) in particular with the highest I/S. AD applied to brackish water sludges can be a promising treatment with interesting methane productions. For a continuous, full-scale application further investigation on biomass adaptation to salinity and on retention times is needed. Further experimental tests are ongoing.

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Effect of Combined Inoculation on Biogas Production from Hardly Degradable Material

Energies ◽

10.3390/en12020217 ◽

2019 ◽

Vol 12 (2) ◽

pp. 217 ◽

Cited By ~ 8

Author(s):

Spyridon Achinas ◽

Gerrit Euverink

Keyword(s):

Wastewater Treatment Plants ◽

Biogas Production ◽

Mixing Ratio ◽

Organic Fraction ◽

Anaerobic Digesters ◽

Biogas Yield ◽

Mixing Ratios ◽

Batch Tests ◽

Optimal Mixing ◽

Mesophilic Conditions

The goal of this research was to appraise the effect of combined inoculation on the performance of anaerobic digesters treating hardly degradable material, and particularly the pressed fine sieved fraction (PFSF) derived from wastewater treatment plants (WWTPs). Batch tests were conducted in mesophilic conditions in order to examine the optimal mixing ratio of inoculums. Mixing ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 of three different inoculums were applied in the batch tests. The findings indicated that the inoculation of digested activated sludge with digested organic fraction of municipal solid waste (MSW) in the ratio 25:75 resulted in a higher PFSF degradation and a higher biogas yield. The results from the kinetic analysis fit well with the results from the batch experiment.

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Assessment of the biochemical methane potential of mono- and co-digested dairy farm wastes

Waste Management & Research ◽

10.1177/0734242x19871999 ◽

2019 ◽

Vol 38 (1) ◽

pp. 88-99 ◽

Cited By ~ 5

Author(s):

Mohamad Adghim ◽

Mohamed Abdallah ◽

Suhair Saad ◽

Abdallah Shanableh ◽

Majid Sartaj

Keyword(s):

Methane Production ◽

Dairy Farm ◽

Gompertz Model ◽

Maximum Error ◽

Methane Yield ◽

Cow Manure ◽

Biochemical Methane Potential ◽

Volatile Solids ◽

Waste Milk ◽

Methane Potential

This study aimed to evaluate the methane potential of mono- and co-digested dairy farm wastes. The tested substrates included manure from lactating, dry, and young cows, as well as waste milk and feed waste. The highest methane yield was achieved from the lactating cow manure, which produced an average of 412 L of CH4 kg−1 volatile solids, followed by young and dry cow manures (332 and 273 L of CH4 kg−1 volatile solids, respectively). Feed and milk yielded an average of 325 and 212 L of CH4 kg−1 volatile solids, respectively. Co-digesting the manures from lactating and young cows with feed improved methane production by 7%. However, co-digesting the dry cow manure with feed achieved only 85% of the calculated methane yield. Co-digesting manure and milk at a ratio of 70:30 enhanced the methane potential from lactating, dry, and young cow manures by 19, 30, and 37%, respectively. Moreover, co-digesting lactating, dry, and young cow manures with milk at a ratio of 30:70 enhanced the methane yield by 60, 30, and 88%, respectively. The cumulative methane production of all samples was accurately described using the Gompertz model with a maximum error of 10%. Carbohydrates contributed the most to methane potential, while proteins and lipids were limiting.

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Effects of Lipase Addition, Hydrothermal Processing, Their Combination, and Co-Digestion with Crude Glycerol on Food Waste Anaerobic Digestion

Fermentation ◽

10.3390/fermentation7040284 ◽

2021 ◽

Vol 7 (4) ◽

pp. 284

Author(s):

Xiaojue Li ◽

Naoto Shimizu

Keyword(s):

Anaerobic Digestion ◽

Food Waste ◽

Methane Production ◽

Crude Glycerol ◽

Anaerobic Fermentation ◽

Gompertz Model ◽

Volatile Solids ◽

Methane Potential ◽

Better Than ◽

Modified Gompertz Model

To enhance anaerobic fermentation during food waste (FW) digestion, pretreatments can be applied or the FW can be co-digested with other waste. In this study, lipase addition (LA), hydrothermal pretreatment (HTP), and a combination of both methods (HL) were applied to hydrolyze organic matter in FW. Furthermore, the effects of crude glycerol (CG), which provided 5%, 10%, and 15% of the volatile solids (VS) as co-substrate (denoted as CG5, CG10, and CG15, respectively), on the anaerobic digestion of FW were assessed. With an increasing proportion of CG in the co-digestion experiment, CG10 showed higher methane production, while CG15 negatively affected the anaerobic digestion (AD) performance owing to propionic acid accumulation acidifying the reactors and inhibiting methanogen growth. As the pretreatments partially decomposed hard-to-degrade substances in advance, pretreated FW showed a stronger methane production ability compared with raw FW, especially using the HL method, which was significantly better than co-digestion. HL pretreatment was shown to be a promising option for enhancing the methane potential value (1.773 NL CH4/g VS) according to the modified Gompertz model.

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Effect of co-digestion of food waste and cow dung on biogas yield

E3S Web of Conferences ◽

10.1051/e3sconf/202018101005 ◽

2020 ◽

Vol 181 ◽

pp. 01005

Author(s):

Makhura Emmanuel Pax ◽

Edison Muzenda ◽

Tumeletso Lekgoba

Keyword(s):

Anaerobic Digestion ◽

Moisture Content ◽

Food Waste ◽

Biogas Production ◽

Cow Dung ◽

Mixing Ratio ◽

Total Solids ◽

Biogas Yield ◽

Volatile Solids ◽

Thermophilic Conditions

This paper aims at finding the effect of co-digestion of cow dung and food waste on total biogas yield. Biogas production was improved through co-digestion of cow dung and food waste (FW) containing a small fraction of inoculum under mesophilic temperature (37ºC) over a retention time of 24 days. Co-digestion ratios of 1:1, 2:1 and 3:1 for cowdung/foodwaste were used for the study on anaerobic digestion on the co digested matter. Tests were carried out starting with the preparation of substrates, substrate characterization to determine the moisture content (MC), total solids (TS), volatile solids (VS) and ultimately batch anaerobic digestion experiments under thermophilic conditions (370C). The moisture content, volatile solids and total solids for food waste were 78, 22 and 90.7% respectively while the characteristics for cow dung were 67.2, 32.8 and 96.0 % respectively. From the study, a mixing ratio of cow dung: food waste of 1:2 was found to be the optimum substrate mixture for biogas production at 25595.7 Nml. The accumulated gas volumes of 18756.6, 14042.5, 13940.8 and 13839.1 Nml were recorded for cow dung: food waste ratios of 2:1, 1:1, 1:3 and 3:1 respectively. For a co-digestion containing more of the food waste than cow dung, a higher volume of biogas is produce.

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Assessment of Tropospheric Concentrations of NO2 from the TROPOMI/Sentinel-5 Precursor for the Estimation of Long-Term Exposure to Surface NO2 over South Korea

Remote Sensing ◽

10.3390/rs13101877 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1877

Author(s):

Ukkyo Jeong ◽

Hyunkee Hong

Keyword(s):

South Korea ◽

Spatial Resolution ◽

Atmospheric Composition ◽

Mixing Ratio ◽

Mean Values ◽

Mixing Ratios ◽

Tropospheric No2 ◽

Korean Ministry ◽

Surface Mixing ◽

Rural Sites

Since April 2018, the TROPOspheric Monitoring Instrument (TROPOMI) has provided data on tropospheric NO2 column concentrations (CTROPOMI) with unprecedented spatial resolution. This study aims to assess the capability of TROPOMI to acquire high spatial resolution data regarding surface NO2 mixing ratios. In general, the instrument effectively detected major and moderate sources of NO2 over South Korea with a clear weekday–weekend distinction. We compared the CTROPOMI with surface NO2 mixing ratio measurements from an extensive ground-based network over South Korea operated by the Korean Ministry of Environment (SKME; more than 570 sites), for 2019. Spatiotemporally collocated CTROPOMI and SKME showed a moderate correlation (correlation coefficient, r = 0.67), whereas their annual mean values at each site showed a higher correlation (r = 0.84). The CTROPOMI and SKME were well correlated around the Seoul metropolitan area, where significant amounts of NO2 prevailed throughout the year, whereas they showed lower correlation at rural sites. We converted the tropospheric NO2 from TROPOMI to the surface mixing ratio (STROPOMI) using the EAC4 (ECMWF Atmospheric Composition Reanalysis 4) profile shape, for quantitative comparison with the SKME. The estimated STROPOMI generally underestimated the in-situ value obtained, SKME (slope = 0.64), as reported in previous studies.

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Batch Anaerobic Co-Digestion and Biochemical Methane Potential Analysis of Goat Manure and Food Waste

Energies ◽

10.3390/en14071952 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1952

Author(s):

Ayobami Orangun ◽

Harjinder Kaur ◽

Raghava R. Kommalapati

Keyword(s):

Food Waste ◽

Gompertz Model ◽

Water Displacement ◽

Biochemical Methane Potential ◽

Greenhouse Gasses ◽

Nonlinear Regression Models ◽

The Us ◽

Methane Potential ◽

Goat Manure ◽

Modified Gompertz Model

The improper management of goat manure from concentrated goat feeding operations and food waste leads to the emission of greenhouse gasses and water pollution in the US. The wastes were collected from the International Goat Research Center and a dining facility at Prairie View A&M University. The biochemical methane potential of these two substrates in mono and co-digestion at varied proportions was determined in triplicates and processes were evaluated using two nonlinear regression models. The experiments were conducted at 36 ± 1 °C with an inoculum to substrate ratio of 2.0. The biomethane was measured by water displacement method (pH 10:30), absorbing carbon dioxide. The cumulative yields in goat manure and food waste mono-digestions were 169.7 and 206.0 mL/gVS, respectively. Among co-digestion, 60% goat manure achieved the highest biomethane yields of 380.5 mL/gVS. The biodegradabilities of 33.5 and 65.7% were observed in goat manure and food waste mono-digestions, while 97.4% were observed in the co-digestion having 60% goat manure. The modified Gompertz model is an excellent fit in simulating the anaerobic digestion of food waste and goat manure substrates. These findings provide useful insights into the co-digestion of these substrates.

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Biochemical Methane Potential of Cork Boiling Wastewater at Different Inoculum to Substrate Ratios

Applied Sciences ◽

10.3390/app11073064 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3064

Author(s):

Roberta Mota-Panizio ◽

Manuel Jesús Hermoso-Orzáez ◽

Luis Carmo-Calado ◽

Gonçalo Lourinho ◽

Paulo Sérgio Duque de Brito

Keyword(s):

Anaerobic Digestion ◽

Biogas Production ◽

Treatment Plant ◽

Organic Substrates ◽

Biochemical Methane Potential ◽

Volatile Solids ◽

Working Volume ◽

Methane Potential ◽

Bmp Test ◽

Cork Industry

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and inoculum (digested sludge from a wastewater treatment plant (WWTP)), with a ratio of inoculum/substrate (Ino/CBW) of 1:1 and 2:1 on the basis of volatile solids (VSs); the codigestion with food waste (FW) had a ratio of 2/0.7:0.3 (Ino/CBW:FW) and the codigestion with cow manure (CM) had a ratio of 2/0.5:0.5 (Ino/CBW:CM). Biogas and methane production was proportional to the inoculum substrate ratio (ISR) used. BMP tests have proved to be valuable for inferring the adequacy of anaerobic digestion to treat wastewater from the cork industry. The results indicate that the biomethane potential of CBWs for Ino/CBW ratios 1:1 and 2:1 is very low compared to other organic substrates. For the codigestion tests, the test with the Ino/CBW:CM ratio of 2/0.7:0.3 showed better biomethane yields, being in the expected values. This demonstrated that it is possible to perform the anaerobic digestion (AD) of CBW using a cosubstrate to increase biogas production and biomethane and to improve the quality of the final digestate.

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Optimizing anaerobic co-digestion of goat manure and cotton gin trash using biochemical methane potential (BMP) test and mathematical modeling

SN Applied Sciences ◽

10.1007/s42452-021-04706-1 ◽

2021 ◽

Vol 3 (8) ◽

Author(s):

Harjinder Kaur ◽

Raghava R. Kommalapati

Keyword(s):

Liquid Fraction ◽

Gompertz Model ◽

Biochemical Methane Potential ◽

Methane Potential ◽

Mathematical Equations ◽

Goat Manure ◽

Bmp Test ◽

Batch Bioreactors ◽

Modified Gompertz Model ◽

Cotton Gin

AbstractAnaerobic co-digestion is widely adopted to enhance process efficacy by balancing the C/N ratio of the feedstock while converting organic wastes to biomethane. Goat manure (GM) and cotton gin trash (CGT) were anaerobically co-digested in triplicate batch bioreactors. The process was optimized and evaluated utilizing mathematical equations. The liquid fraction of the digestate was analyzed for nitrate and phosphate. The co-digestions with 10 and 20% CGT having the C/N ratios of 17.7 and 19.8 yielded the highest and statistically similar 261.4 ± 4.8 and 262.6 ± 4.2 mL/gvs biomethane, respectively. The biodegradability (BD) of GM and CGT was 94.5 ± 2.7 and 37.6 ± 0.8%, respectively. The BD decreased proportionally with an increase in CGT percentage. The co-digestion having 10% CGT yielded 80–90% of biomethane in 26–39 d. The modified Gompertz model-predicted and experimental biomethane values were similar. The highest synergistic effect index of 15.6 ± 4.7% was observed in GM/CGT; 30:70 co-digestion. The concentration of nitrate and phosphate was lower in the liquid fraction of digestate than the feedstocks, indicating that these nutrients stay in the solid fraction. The results provide important insights in agro-waste management, further studies determining the effects of effluent application on plants need to be conducted.

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One-Year Characterization and Reactivity of Isoprene and Its Impact on Surface Ozone Formation at A Suburban Site in Guangzhou, China

Atmosphere ◽

10.3390/atmos10040201 ◽

2019 ◽

Vol 10 (4) ◽

pp. 201 ◽

Cited By ~ 2

Author(s):

Yu Zou ◽

Xue Jiao Deng ◽

Tao Deng ◽

Chang Qin Yin ◽

Fei Li

Keyword(s):

Surface Ozone ◽

Atmospheric Composition ◽

Anthropogenic Factors ◽

Mixing Ratio ◽

Night Time ◽

Subtropical Zone ◽

Guangzhou City ◽

Mixing Ratios ◽

One Year ◽

Suburban Site

Isoprene has a potentially large effect on ozone (O3) formation in the subtropical, highly polluted city of Guangzhou. Online measurements of isoprene in Guangzhou city are scarce; thus, isoprene levels were monitored for one year at the Guangzhou Panyu Atmospheric Composition Station (GPACS), a suburban site in Guangzhou, using an online gas chromatography-flame ionization detector (GC–FID) system to investigate the characterization and reactivity of isoprene and its effect on the O3 peak profile in different seasons. The results showed that the daily average mixing ratios of isoprene at GPACS were 0.40, 2.20, 1.40, and 0.13 mixing ratio by volume (ppbv) in spring, summer, autumn, and winter, respectively. These values were considerably higher than the mixing ratios of isoprene in the numerous other subtropical and temperate cities around the world. Furthermore, isoprene ranked first with regard to O3 formation potential (OFP) and propylene-equivalent mixing ratio among 56 measured non–methane hydrocarbons (NMHCs). The ratios of isoprene to cis-2-butene, an exhaust tracer, were determined to estimate the fractions of biogenic and anthropogenic emissions. The results revealed a much greater contribution from biogenic than anthropogenic factors during the daytime in all four seasons. In addition, night-time isoprene emissions were mostly associated with vehicles in winter, and the residual isoprene that remained after photochemical loss during the daytime also persisted into the night. The high levels of isoprene in summer and autumn may cause the strong and broad peaks of the O3 profile because of its association with the most favorable meteorological conditions (e.g., high temperature and intense solar radiation) and the highest OH mixing ratio, which could affect human health by exposing people to a high O3 mixing ratio for prolonged periods. The lower mixing ratios of isoprene resulted in a weak and sharp peak in the O3 profile in both spring and winter. The high level of isoprene in the subtropical zone could accentuate its large impact on atmospheric oxidant capacity and air quality in Guangzhou city.

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