Performance of Anaerobic Co-digestion of Pig Slurry with Pineapple (Ananas comosus) Bio-waste Residues (original) (raw)
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Heliyon, 2023
The demand for energy has been growing over the years to match development and population growth. The current sustainable development model advocates for the use of renewable (green) energy sources with an aim of lowering carbon emissions thereby mitigating the effects of climate change. A circular economy aspires to keep materials in use for as long as possible thus the reuse of agricultural waste especially in energy generation is a step in this direction. This study reports on the optimization of anaerobic digestion parameters for biogas production when wastes from pineapple are co-digested with those from livestock. The volume of biogas yield was optimized with regards to temperature, pH value, and mixing ratio of the substrates using Box Behnken Design (BBD), a class of Response Surface Methodology (RSM). This was achieved through a software package, Design Expert 13.The experiments were performed using Rehau home gas systems of 6 m 3 in Jomo Kenyatta University of Agriculture and Technology. Pineapple wastes were co-digested with livestock waste in the ratio of 1:1, 1:2 and 1:3. The numerical optimization results revealed that the maximum biogas yield was 1.98 m 3 when the pH was set at 6.0, temperature at 30 • C and pineapple mixing ratio at 62.5%. The results from this study can form a basis for policy makers in formulating strategies to guide adoption of biogas generated from agricultural waste as a key green energy for the economy.
Energies
Anaerobic digestion technology can play a significant role in the transition to a low-carbon and circular economy by producing bioenergy (biomethane) and organic fertilizer (digestate). This study proposes a valorization approach for three waste streams widely produced in the Mediterranean area: fish waste (FW), pig slurry (PS), and orange pomace (OP). The FW lipid content can enhance biomethane yield as long as inhibition by long-chain fatty acids is prevented. In this study, the effect of introducing 25% and 50% FW to the anaerobic co-digestion of a reference mixture consisting of 80% PS and 20% OP pulp (OPP) was studied. Co-digestion using 50% FW presented the maximum biomethane yield (669.68 ± 8.32 mL CH4/g VSadded), which corresponds to a 37% increase compared to the reference. No inhibition was detected during the anaerobic digestion assay. The kinetic study showed that the introduction of FW led to a reduction in the degradation rate constant by up to 30%. The lag phase incre...
The Performance of Anaerobic Co-digester of Swine Slurry and Food Waste
Korean Journal of Soil Science and Fertilizer, 2011
In order to assess the performance of co-digester using pig slurry and food waste at the farm scale biogas production facility, the anaerobic facility that adopts the one-stage CSTR of 5 m 3 day-1 input scale was designed and installed under the conditions of the OLR of 2.33 kg m-3 day-1 and HRT of 30 days in an pig farmhouse. Several operation parameters were monitored for assessment of the process performance. The anaerobic facility was operated in three stages to compare the performance of the anaerobic co-digester. In the Stage I, that was fed with a mix of pig slurry to food waste ratio of 7:3 in the input volume, where input TS content was 4.7 (± 0.8) %, and OLR was 0.837-1.668 kg-VS m-3 day-1. An average biogas yield observed was 252 Nm 3 day-1 with methane content 67.9%. This facility was capable of producing an electricity of 626 kWh day-1 and a heat recovery of 689 Mcal day-1. In Stage II, that was fed with a mixture of pig slurry and food waste at the ratio of 6:4 in the input volume, where input TS content was 6.9 (± 1.9) %, and OLR was 1.220-3.524 kg-VS m-3 day-1. The TS content of digestate was increased to 3.0 (± 0.3) %. In Stage III, that was fed with only pig slurry, input TS content was 3.6 (± 2.0) %, and OLR was 0.182-2.187 kg-VS m-3 day-1. In stage III, TS and volatile solid contents in the input pig slurry were highly variable, and input VFAs and alkalinity values that affect the performance of anaerobic digester were also more variable and sensitive to the variation of input organic loading during the digester operation. The biogas produced in the stage III, ranged from 11.3 to 170.0 m 3 day-1 , which was lower than 222.5-330.2 m 3 day-1 produced in the stage II.
Energy production from anaerobic co-digestion processing of cow slurry, olive pomace and apple pulp
Renewable Energy, 2015
This paper deals with anaerobic co-digestion of cow slurry, apple pulp and olive pomace mixture and results obtained shown that the production of methane by codigestion of cow slurry, olive pomace and apple pulp is not only possible but also economically and energetically attractive. Tests were performed with a pilot scale anaerobic digester, 128 l in volume, operating under batch and fed-batch condition. The biogas production, methane yield and quality, plus other operating parameters were evaluated under four feeding regimes, to simulate a real situation. Stable biogas production was obtained of about 400 l/kg Volatile Solids at a Hydraulic Retention Time of 40 days in a mixture containing 85% cow slurry, 10% olive pomace and 5% apple pulp (% by volume). The percentage of methane inside the biogas was around 52% and the maximum COD removal was 63%.
International Journal of Renewable Energy Technology, 2018
This work evaluated the effects of feed/inoculums ratio, temperature and agitation speed on biomethanisation of the mixture of cattle dung, pig dung, and poultry droppings for enhanced biogas/biomethane production. The biomethanisation experiments were carried out in anaerobic digesters at different process variables of feed/inoculums ratio (1:1, 1:2, 1:3, 2:1 and 3:1), temperature (25-60ºC), and agitation speed (30-70 rpm). The digesters were incubated for 70 days. The results showed positive influence of feed/inoculum ratio, temperature and agitation speed on cumulative biogas yield, biomethane content and start-up time of biomethanisation. Modified Gompertz and Exponential Rise to Maximum kinetic models showed better correlation of the cumulative biogas production. The estimated values of the thermodynamic properties (Gibbs free energy, enthalpy, entropy change and activation energy) suggested that the biomethanisation process was thermodynamically feasible, spontaneous and endothermic in nature suggesting hydrogenotrophic methanogenesis pathway.
Co-digestion of pig slurry and organic wastes from food industry
1999
Anaerobic digestion of pig slurry can be a good option to get a higher value for these wastes. Although thermophilic anaerobic digestion is more efficient than mesophilic anaerobic digestion, it presents some limitations, like less stability and an increased effect of some inhibitors. The main inhibitor for pig slurries is free ammonia. In order to improve the methane production, some mixtures of slurry and organic wastes from food industry were tested, like wastes from fruit and olive oil refinery industries (pear waste and oil bleaching earth). A batch experiment was carried out, in order to determine the maximum potential of methane production and biodegradability of these wastes. The experiment was developed in mesophilic and thermophilic ranges (35º and 55º). The mesophilic results were better than the thermophilic ones, showing a large inhibition by ammonia in the thermophilic range. In both temperature ranges, the methane production was improved by addition of a co-substrate. The higher methane production was obtained from the codigestion of slurry and oil bleaching earth (95% and 5% respectively). The methane yield was 344 mL CH4/g VS initial , which is 2.4 times the methane yield for slurry (144.0 mL CH4/g VS initial).
Biomass Conversion and Biorefinery, 2021
Tunisia is one of the developing countries which faces crucial challenges, the most prominent of which are the production of organic waste, the need for an appropriate waste treatment, and the demand for water and energy conservation. To this end, the present research was designed to develop a technical concept on closed cycle "biowaste to bioenergy" treating food waste (FW) through combined biological processes. In this approach, semi-continuous anaerobic co-digestion (ACoD) of FW, wheat straw (WS), and cattle manure (CM) was tested to investigate the relationship between the effect of the feedstock mixtures and C:N ratio on biogas and digestate generation at different organic loading rates (OLRs) ranging from 2 to 3.6 kg VS/m 3 .d. Results showed that the mono-digested FW was optimal and reached 565.5 LN/kg VS in at an OLR of 2.4 kg VS/ m 3 .d, and then a drop of biogas production was recorded. However, for co-digested substrates, the optimum mixture ratio was FW:CM 75:25, where 62%, 39.89%, 91.26%, 130.9%, and 119.97% of the biogas yield improved for OLRs ranging from 2 to 3.6 kg VS/m 3 .d, respectively. Admittedly, the target of this work was to enhance the ACoD process, but it also examined the exploitation of different AD effluents. Therefore, special attention was paid to the generated digestates to decide how it can be efficiently upcycled later. Thus, the closed cycle "biowaste to bioenergy" treatment met two of the major Tunisian concerns: efficient organic waste management and sustainable bioenergy production.
Bioreactor performance in anaerobic digestion of fruit and vegetable wastes
Process Biochemistry, 2005
This work reviews the potential of anaerobic digestion for material recovery and energy production from fruit and vegetable wastes (FVW). These wastes contain 8-18% total solids (TS), with a total volatile solids (VS) content of 86-92%. The organic fraction includes about 75% easy biodegradable matter (sugars and hemicellulose), 9% cellulose and 5% lignin. Anaerobic digestion of FVW was studied under different operating conditions using different types of bioreactors. It permits the conversion of 70-95% of organic matter to methane, with a volumetric organic loading rate (OLR) o f 1-6.8 g versatile solids (VS)/l day. A major limitation of anaerobic digestion of FVW is a rapid acidification of these wastes decreasing the pH in the reactor, and a larger volatile fatty acids production (VFA), which stress and inhibit the activity of methanogenic bacteria. Continuous two-phase systems appear as more highly efficient technologies for anaerobic digestion of FVW. Their greatest advantage lies in the buffering of the organic loading rate taking place in the first stage, allowing a more constant feeding rate of the methanogenic second stage. Using a two-stage system involving a thermophilic liquefaction reactor and a mesophilic anaerobic filter, over 95% volatile solids were converted to methane at a volumetric loading rate of 5.65 g VS/l d. The average methane production yield was about 420 l/kg added VS.
Frontiers in Sustainable Food Systems
In the past years, there has been steady growth in work relating to improve resource efficiency through waste minimization and bioenergy recovery to mitigate climate change. Agro-food industries produce large amounts of bio-waste, challenging innovative energetic valorization strategies in the framework of circular economy principles. Anaerobic digestion (AD) technology is an interesting route to stabilize organic matter and produce biogas as a renewable energy source. This study involves continuous co-digestion of pig slurry (PS), cereal and exhausted coffee wastes (CECW) performed in a continuously stirred tank reactor, with a hydraulic retention time (HRT) of 16 days under at mesophilic conditions (36.9 ± 0.3°C). The experimental trials, were designed to include different cereal and exhausted coffee liquor (CECL) shares in the feeding mixture, corresponding to different PS to CECL ratios (PS:CECL), respectively: 100:0 (T0), 90:10 (T1), 80:20 (T2), and 70:30 (T3), in terms of perc...
Waste management (New York, N.Y.), 2016
The feasibility of co-digestion of blends of two different animal by-products (pig manure and pasteurized slaughterhouse waste) and recovered glycerine was studied in mesophilic conditions. Experiments were performed in a lab-scale CSTR along 490days, with a hydraulic retention time of 21-33days and with a step-wise increased organic loading rate, by adding and/or changing the wastes ratio, from 0.8 to 3.2kgCODm(-3)d(-1). The best methane production rate (0.64Nm(3)CH4m(-3)d(-1)) represented an increment of 2.9-fold the initial one (0.22Nm(3)CH4m(-3)d(-1) with pig manure solely). It was attained with a ternary mixture composed, in terms of inlet volatile solids, by 35% pig slurry, 47% pasteurized slaughterhouse waste and 18% glycerine. This blend was obtained through a stepwise C/N adjustment: this strategy led to a more balanced biodegradation due to unstressed bacterial populations through the performance, showed by the VFA-related indicators. Besides this, an improved methane yiel...