Co-digestion Of Cattle Manure Research Articles

Enhanced anaerobic co-digestion of cattle manure with food waste and pig manure: Statistical optimization of pretreatment condition and substrate mixture ratio

This study investigated the optimal pretreatment condition and mixture ratio of cattle manure (CM) for its efficient anaerobic co-digestion (AcoD) with food waste (FW) and pig manure (PM). The pretreatment performances of thermal (TM), microwave (MW), and ultrasound (US) technologies and the AcoD performance were statistically and experimentally evaluated at various mixture ratios of CM, FW, and PM. The results revealed that the most effective pretreatment condition with the TM, MW, and US pretreatments was 129.3 °C for 49.6 min, 824.2 W for 7.3 min, and 418.0 W for 36.3 min, respectively. The best AcoD performance of optimally pretreated CM (PCM) was achieved when 30.5 % PCM was mixed with 42.5 % FW and 27.0 % PM. A long-term evaluation showed that the start-up rate for the anaerobic mono-digestion of PCM was 2.3 times faster than that of CM and the amount of methane produced was 4.7 times higher; process stability was thus preferentially maintained under a higher organic loading rate (OLR) (2.0 kg-VS/m3∙d). The start-up rate for the AcoD of PCM with FW and PM was 1.2 times higher than that of the AcoD of CM with FW and PM. Although the performance gap between the AcoD reactors after steady state was not significantly different, the PCM AcoD reactor provided a more stable operation under a higher OLR (5.0 kg-VS/m3∙d). This study demonstrates that the pretreatment and co-digestion of CM could significantly enhance the production of biogas and improve process stability.

Unveiling the synergy of Chlorella sp. and cattle manure co-digestion under high feeding load

The synergy in anaerobic co-digestion (AcoD) of cattle manure (CM) and Chlorella sp. (Ch) Under high feeding loads (50 g VS/L) was investigated with different mixing gradients in terms of organic constitute, process parameters, and microbial community structure. AcoD enhanced the methane yield of CM by 9.3%–22.8% and Ch by 3.9%–16.7%, compared with their mono-digestion. The suitable protein/carbohydrates ratio was the important reason for having such a synergetic effect between carbohydrates-rich and protein-rich feedstock. AcoD of CM and Ch at the ratio of 8:2 showed a high methane yield enhanced, the fastest methane production rate, and a high relative abundance of Methanosaeta, which may be an available matching strategy for further application. The relative abundance of acetoclastic methanogen decreased with the increase of total ammonia nitrogen (TAN), and the fast methane production rate is associated with the syntrophism and high relative abundance of Syner-01 and Methanosaeta.

Biogas Production from Co-digestion of Cattle Manure, Oryza sativa and Phaseolus vulgaris in Plug Flow Digester

The possibility for producing biogas from the simultaneous co-digestion of phaseolus vulgaris, oryza sativa, and cattle dung in a plug flow digester was examined. Oryza sativa and phaseolus vulgaris are very common food waste found in Nigeria. The market-purchased food waste was ground in a kitchen processor to a thickness of less than 2 mm. Three digesters with effective capacities of 0.0083 m3 were created. The digesters were fed with food waste and cattle dung which served as the inoculum at different feeding rates of 0.05 kg every three days, 0.1 kg every three days, and 0.3 kg every three days. During the trial period, chemical oxygen demand (COD), total solids (TS), and volatile solids (VS) were measured to ascertain the system's effectiveness. The parameter utilized to gauge the process stability was pH. When feeding at a rate of 0.1 kg every three days, digester 2 produced the most gas. The least amount of biogas was generated by digester 3 at a feed rate of 0.3 kg every three days. After 19 days, the effluent for digesters 1, 2, and 3 had COD values of 810.49 mg/l, 940.17 mg/l, and 987.68 mg/l, respectively. After 20 days, the effluent from digesters 1, 2, and 3 had amounts of TS and VS that were, respectively, 1.82%, 6.24%, 10.76%, and 10.70%, 6.24%, 42.81%. The measured pH range was 7.98 to 8.86, and there was no discernible difference across the three digesters (p>0.05). The ideal feed rate for the digestion of waste and biogas production was determined to be 0.1 kg every three days.

Energy Production from Cattle Manure within a Life Cycle Assessment Framework: Statistical Optimization of Co-Digestion, Pretreatment, and Thermal Conditions

Waste to energy processes from anaerobic digestion (WtE-AD) from cattle manure (CM) have low CH4 yields due to CM’s structural composition. The search for alternatives to increase the energy yields of these processes must consider the optimization of operating parameters within a framework of mitigating the environmental footprint. The goal of this paper is to provide a statistical optimization strategy based on experimental designs to improve CH4 yields and reduce the environmental profile of CM valorization through a WtE-AD process. Biochemical methane potential tests were conducted to determine the energetic and environmental effects that alkaline pretreatments, different AD temperatures, and co-digestion formulations with fruit and vegetable waste (FVW) have on the WtE-AD process from CM. The evaluation was conducted following a life cycle assessment approach through energy balances. The results indicate that the highest CH4 yield (384.3 mL CH4 g VS−1) and the lowest environmental impact (−0.06 kg CO2 eq kWh−1 of electricity production) were achieved with the co-digestion of CM with FVW 1:1, pretreatment with 10 g NaOH 100 g−1 of VS of CM, and a temperature of 45 °C. It was found that the CM pretreatment with NaOH substantially increases the energy profile of the WtE-AD process without compromising the environmental impact since greenhouse gas emissions in chemical production are negligible.

Methane production enhancement of a family-scale biogas digester using cattle manure and corn stover under cold climates

The enhancement in methane production under cold climates is one of the essential prerequisites to enable year-round performance improvement of any biogas plant. In Egypt, the winter is reasonably cold which offers a good opportunity to study the enhancement in the methane yield and corresponding performance improvement of a family-scale biogas digester using the co-digestion technique. This work reports the field performance of floating-dome type biogas digester using anaerobic co-digestion (AcoD) of cattle manure (CM) with a milled corn stover (CS). The performance of AcoD is compared with the performance of anaerobic mono-digestion (AmoD) of CM under winter conditions. Moreover, a numerical method for preparing the digested slurry is defined for the ease of the farmers. Results revealed that using AcoD was led to a significant increase in the average daily, cumulative, and specific methane yield by 40.30, 42.43, and 39.65%, respectively over AmoD. Additionally, AcoD gave an explicit increment in the average methane volume, average daily, and total gained biogas energy by 11.42, 40.16, and 42.43%, respectively over AmoD. Hence, the major findings of the present work proved that the co-digestion of CM and CS improves the performance of biogas digester under open-field conditions in the winter season.

Green Dairy Plant: Process Simulation and Economic Analysis of Biogas Use in Milk Drying

A project of a new milk drying unit processing 4800 kg/h of fresh milk into milk powder with expected steam consumption of 1000 kg/h (equivalent to ca. 2.6 GJ/h) was assessed. In this paper, investment profitability of this project was analyzed combining mathematical modeling, market analysis, and parametric sensitivity study. Aspen Plus was used as the simulation environment to determine values of key process variables—major streams, mass flows, and energy consumption. Co-digestion of cattle manure in an adjacent biogas plant was considered to provide biogas to partially or completely substitute natural gas as an energy source. As biogas composition from potential co-digestion was unknown, variable methane content from 45 to 60 mol.% was considered. In the next step, thorough economic analysis was conducted. Diverse effects of biogas addition depending on market prices, biogas treatment costs, and biogas methane content were simulated and evaluated. In a market situation closest to reality, biogas mixing to boiler fuel decreased simple payback period from 11.2 years to 5.1 years. However, if biogas treatment costs were high (final biogas price equal to or above 0.175 EUR/m3), the simple payback period was increased two- to sixfold, making the analyzed project practically unfeasible.

Optimization of Cattle Manure and Food Waste Co-Digestion for Biohydrogen Production in a Mesophilic Semi-Continuous Process

Biohydrogen production from organic solid waste has shown particular advantages over other methods owing to the combination of waste reduction and bioenergy production. In this study, biohydrogen production from the co-digestion of cattle manure and food waste was optimized in a mesophilic semi-continuous process. To maximize hydrogen production, the effects of the mixing ratio (the proportion of food waste in the substrate), substrate concentration, and hydraulic retention time (HRT) on the co-digestion were systematically analyzed using a Box–Behnken design. The results showed that strong interactive effects existed between the three factors, and they had a direct effect on the responses. Hydrogen was primarily produced via the butyrate pathway, which was accompanied by the competing heterolactic fermentation pathway. Propionate and valerate produced from lipids and proteins, respectively, were obtained along with butyrate. The optimal process parameters included a mixing ratio of 47% to 51%, a substrate concentration of 76 to 86 g L−1, and an HRT of 2 d. Under these optimal conditions, the hydrogen production rate and hydrogen yield were higher than 1.00 L L−1 d−1 and 30.00 mL g−1 VS, respectively, and the predicted results were consistent with the experimental data. The results indicate that the co-digestion of cattle manure and food waste is a practical and economically promising approach for biohydrogen production.

Enhancement of biogas production from rape straw using different co-pretreatment techniques and anaerobic co-digestion with cattle manure

The present study investigated the possibility of valorizing rape straw through anaerobic digestion and the possibility of improving biomethane yield by pretreatment with H2SO4, combined H2SO4 with steam explosion (SE) and SE combined with superfine grinding (SFG). To evaluate the pretreatment method efficiency, several analytical techniques were applied. Additionally, the performance of co-digesting of cattle manure (CM) with pretreated rape straw (PRS) at different ratios was evaluated. The results showed that combined pretreatment could dissolve the lignocellulosic fiber structure, which positively stimulated methane yield. The highest cumulative CH4 yield (CMY) of 305.7 mLg−1VS was achieved by combined SE at 180 °C for 5 min with SFG, which was 77.84% higher than the untreated. The CMY was further improved by 11.4–59% higher than the control (CM) using co-digestion. This study confirmed that, under optimal parameters of AD, pretreatment with SEG180 could significantly boost the CMY from co-digestion of CM and PRS.

Co-digestion of Cattle Manure and Tea Waste for Biogas Production

The increase of world population brings energy and food requirements. Increasing energy demand drives humanity towards new energy sources and work towards energy efficiency developments. Concordantly, due to population growth, the amount of waste is also increasing and causing environmental -issues. Biogas production by co-digestion of wastes -could be a common solution to both issues. Animal manures are typically used as a main substrate in co-digestion applications. Tea waste is used as a co-substrate in this -work due to having large production and consumption volume in Turkey. The aim of this study is to emerge new methods for disposal and reuse of household tea waste. For this purpose, co-digestion method was carried out to determine the biogas potential of household tea waste. Laboratory scale batch type co-digestion is carried out for 80 days under mesophilic (37±2 o C) conditions. All reactors fed with different mixing ratio of wastes and operated with different stirring speeds. The results showed that co-digestion of the wastes have positive impact on biogas and methane yield. Optimum biogas yield is 296.89 mL/gVS and 77.10% methane content are obtained from A2 which consist of 75% cattle manure and 25% tea waste with 100 rpm stirring speed. According to the results, co-digestion of cattle manure and household tea waste both have a positive effect on biogas production and methane content of biogas.

Optimization of biogas productivity in lab-scale by response surface methodology

Abstract Optimization of canola residues in co-digestion with cattle manure for enhanced biogas yield was carried out using response surface methodology (RSM) and Box – Behnken design of the experiment. The effects of inoculum, total solids (TS), temperature (psychrophilic, mesophilic and thermophilic conditions) and stirring time (duration) in three levels were investigated. After applying of thermo mechanical pretreatment, 29 tests were performed. The experimental results showed that the temperature variable had the greatest effect in the model. The optimum degree of variables achieved in anaerobic digestion was 52.49 °C of temperature, 3.12 min day−1 of stirring time, 7.02% TS of substrate working volume and 22.17% inoculum (22.17% TS) with a methane yield of 403.63 L kg−1 in thermophilic conditions. The optimum degree of variables was: stirring time 3.57 min day−1, 7.41% TS of substrate working volume, 26.26% inoculum (26.26% TS) and temperature at 40.36 °C with a methane yield of 376.76 L kg−1VS in mesophilic conditions. The high value of R2 (0.9983) showed that the model can efficiently be applied to prediction of methane production from the co-digestion of cattle manure and canola residues. Both mesophilic and thermophilic conditions were suitable in terms of energy production, however, the mesophilic conditions showed more positive energy balance and higher Net Energy Gain (NEG) than the thermophilic conditions.

Co-digestion of cattle manure and grass harvested with different technologies. Effect on methane yield, digestate composition and energy balance

The effect of co-digestion of grass with cattle manure (CM) on digestate composition, methane (CH4) yield and energetic and economic balances was investigated by using three different harvesting technologies in two continuous experiments. Both experiments performed at thermophilic temperature and a 25-day hydraulic retention time. Results showed that the addition of 5% grass in fresh matter increased the volumetric CH4 production by around 20% and the organic matter content of the digestate, decreased the protein content and did not affect the N:P:K ratio. Residual CH4 production from the digestate increased and a 6% decrease in the CH4 concentration in the biogas was observed when grass was added to reactors. The best CH4 yield was achieved when excoriated grass was added, with increments of 20% and 35% compared to mono-digestion of CM in 15-L and 30-m3 reactors, respectively. Our results showed that the extra energy required for mixing and harvesting are the two operations with the highest energy inputs when grass is used for biogas, however in spite of the extra energy used, co-digestion of CM with grass is very favorable both, from an energetic and economic point of view, with excoriation being most favorable compared to other harvesting technologies.

High-solid Anaerobic Co-digestion of Sewage Sludge and Cattle Manure: The Effects of Volatile Solid Ratio and pH.

High-solid anaerobic digestion is an attractive solution to the problem of sewage sludge disposal. One method that can be used to enhance the production of volatile fatty acids (VFAs) and the generation of methane from anaerobic digestion involves combining an alkaline pretreatment step with the synergistic effects of sewage sludge and cattle manure co-digestion, which improves the activity of key enzymes and microorganisms in the anaerobic co-digestion system to promote the digestion of organic waste. In this study, we describe an efficient strategy that involves adjusting the volatile solid (VS) ratio (sewage sludge/cattle manure: 3/7) and initial pH (9.0) to improve VFA production and methane generation from the co-digestion of sludge and manure. The experimental results indicate that the maximum VFA production was 98.33 g/kg-TS (total solid) at the optimal conditions. Furthermore, methane generation in a long-term semi-continuously operated reactor (at a VS ratio of 3/7 and pH of 9.0) was greater than 120.0 L/kg-TS.

Computational fluid dynamics study on mixing mode and power consumption in anaerobic mono- and co-digestion

Computational fluid dynamics (CFD) was applied to investigate mixing mode and power consumption in anaerobic mono- and co-digestion. Cattle manure (CM) and corn stover (CS) were used as feedstock and stirred tank reactor (STR) was used as digester. Power numbers obtained by the CFD simulation were compared with those from the experimental correlation. Results showed that the standard k–ε model was more appropriate than other turbulence models. A new index, net power production instead of gas production, was proposed to optimize feedstock ratio for anaerobic co-digestion. Results showed that flow field and power consumption were significantly changed in co-digestion of CM and CS compared with those in mono-digestion of either CM or CS. For different mixing modes, the optimum feedstock ratio for co-digestion changed with net power production. The best option of CM/CS ratio for continuous mixing, intermittent mixing I, and intermittent mixing II were 1:1, 1:1 and 1:3, respectively.

Anaerobic codigestion of pretreated wheat straw with cattle manure and analysis of the microbial community

Wheat straw (WS) was pretreated with four concentrations of H2O2 (1%, 2%, 3%, and 4%) and was anaerobically codigested with dairy cattle manure (CM) at various ratios from 100:0 to 0:100. Wet-state H2O2 pretreatment effectively enhanced the biodegradability and methane yield of the WS. The optimal concentration of H2O2 for treating WS was 3%. The methane yield was higher with the codigestion of CM and H2O2-treated WS than with untreated WS and higher than with H2O2-treated WS alone or CM alone. A 40:60 ratio of H2O2-treated WS mixed with CM produced the highest yield of methane (320.8mLgvolatile solid (VS)−1). Results of high-throughput sequencing indicated that the methanogenic community shifted during the codigestion from the acetoclastic methanogens, Methanosarcina, to the hydrogenotrophic methanogens, Methanosphaera and Methanoculleus.

The kinetics of methane production from co-digestion of cattle manure.

In this article, the kinetics of methane production from co-digestion of liquid manure from cattle with the addition of winemaking waste, food waste and biowaste was investigated in order to describe and evaluate methanogenesis in terms of growth curve of methanogenic bacteria. Experiments were carried out in "Hohenheim"n biogas yield testing system at the temperature of 37 degrees C. The cumulative methane yield was 0.330 ± 0.038, 0.277 ± 0.041, 0.1480 ± 013 and 0.250 ± 0.025 m3 CH4 per kg oDM in normal condition, respectively in mono-digestion and co-digestion of liquid manure from cattle with winemaking, food and biowaste. The kinetic Gompertz parameters of methane production (P-potential yield of methane, R(m)-maximum methane production rate and λ-duration of lag phase) were analyzed. The highest potential methane yield (P) showed co-fermentation of liquid manure from cattle with biowaste 0.387 Nm3 (kg oDM)(-1), the highest methane production rate (R(m)) was 0.022 ± 0.003 Nm3 (kg oDM)(-1) day(-1) for mono-digestion of cattle slurry, the lowest 0.006 Nm3 (kg oDM)(-1) day(-1) was obtained during co-digestion with food waste. Duration of lag phase (λ) was within 10.17-14.60 days for all samples. Additional, the duration of digestion to produce 95% of the potential methane yield and efficient methane production was determined.

Regulating feeding and increasing methane yield from co-digestion of C5 molasses and cattle manure

The paper investigated the mesophilic (∼35°C) and thermophilic (∼50°C) co-digestion of cattle manure and C5 molasses for a variable organic loading rate (OLR). The small scale continuous reactor experiment revealed that thermophilic treatment yielded a maximum 313±16L/kg VS methane for the feeding ranged between 50% and 70% C5 (v/v). Mesophilic co-digestion, on the other hand, produced maximum 232±32L/kg VS methane when feeding was ranged between 31% and 47% C5 (v/v). The feeding strategy of this study was sophistically adjusted owing to the unstable volatile fatty acids (VFA) pattern, developed at different stages of the experiment. Attainable molasses feeding for both the co-digesters was maximum 70% (v/v) above which the total VFA caused serious instability to the reactor performance in terms of methane formation. This phenomenon is suspected to lead to inhibition and hence caused the experiment to halt at day 69.

Co-digestion of cattle manure with organic kitchen waste to increase biogas production using rumen fluid as inoculums

Anaerobic co-digestion strategies are needed to enhance biogas production when treating certain residues such as cattle/pig manure. Co-digestion of food waste with animal manure or other feedstocks with low carbon content can improve process stability and methane production. In this study, anaerobic digestion and co-digestion of cattle manure with organic kitchen waste using rumen fluid as inoculums have been experimentally tested to determine the biogas potential. Co-digestion substantially increased the biogas yields by 24 to 47% over the control (organic kitchen waste and dairy manure only). The highest methane yield of 14,653.5 ml/g-VS was obtained with 75% organic kitchen waste (OKW) and 25% cattle manure (CM) additions. In contrast, addition of 75% cattle manure caused inhibition of the anaerobic digestion process, and its cumulative methane yield was 23% lower than that with 25% cattle manure addition. Key words: Cattle manure, co-digestion, methane, organic kitchen waste, rumen fluid.

Thermophilic co-digestion of cattle manure and food waste supplemented with crude glycerin in induced bed reactor (IBR)

The aim of the present research work was to boost biogas production from cattle manure (CM) by adding food waste (FW) and crude glycerin (Gly) from the biodiesel industry as co-substrates. For this purpose, different quantities of FW and Gly were added to CM and co-digested in an induced bed reactor (IBR) at 55°C. Sonication pre-treatment was implemented in the CM+Gly mixture, applying 550kJ/kg TS to enhance the biodegradability of these co-substrates. The best results were obtained with mixtures of 87/10/3 (CM/FW/Gly) (w/w) operating at an organic loading rate of 7g COD/Lday, obtaining 92% COD removal, a specific methane yield of 640L CH4/kg VS and a methane production rate of 2.6L CH4/Lday. These results doubled those obtained in the co-digestion of CM and FW without the addition of Gly (330L CH4/kg VS and 1.2L CH4/Lday).

Substitution of Peat in Horticultural Seedlings: Suitability of Digestate-Derived Compost from Cattle Manure and Maize Silage Codigestion

The increasing demand for soilless media for horticultural crop production and the rising environmental concerns about the use of non-renewable resources such as peat as substrate has led to the search for alternative materials as constituents of growing media, such as waste organic by-products. Also, biogas production through the anaerobic digestion of organic wastes generates a potential fertilizer, the digested substrate (digestate). The aim of this work was to study the feasibility of using the composted solid fraction of a digestate obtained after the codigestion of cattle manure and maize–oat silage as a component in the formulation of growing media for the commercial seedling production of three species: tomato (Lycopersicon esculentum Mill.), muskmelon (Cucumis melo L.), and pepper (Capsicum annuum L.). Four substrates were compared: pure peat (control) and three mixtures containing 25%, 50%, and 75% by volume of compost with the corresponding amount of peat. Physical, physicochemical, and chemical analyses of the different growing media were carried out and the effects of the different mixtures of peat/compost on seed germination and on the nutritional status of the seedlings were also studied. In general, compost addition neither influenced negatively the physical and physicochemical properties nor produced any reduction in the germination rate in the species studied, but it did enhance the seedlings’ nutritional status.

Optimization of biogas production from cattle manure by pre-treatment with ultrasound and co-digestion with crude glycerin

Biogas production by co-digestion of cattle manure with crude glycerin obtained from biodiesel production was studied after pre-treatment of the cattle manure or mixtures of cattle manure with different amounts of added glycerin with ultrasound. Batch experiments with 1750mL of medium containing 1760g of screened cattle manure or mixtures of cattle manure (screened or ground) and 70–140mL or crude glycerin were incubated under mesophilic and thermophilic condition in stirred tank reactors. Under mesophilic conditions, the addition of 4% glycerin to screened manure increased biogas production by up to 400%. Application of sonication (20kHz, 0.1kW, and 4min) to a mixture of manure+4% glycerin increased production of biogas by up to 800% compared to untreated manure. The best results were obtained under thermophilic conditions using sonicated mixtures of ground cattle manure with 6% added glycerin (348L methane/kg COD removed were obtained).