Anaerobic Digestion Of Poultry Litter Research Articles

Anaerobic digestion of poultry litter: technical aspects to improve process performance and water saving

In order to mitigate the significant electricity consumption in poultry farming the anaerobic digestion (AD) has been adopted. This study aimed to obtain information about the dilution, solid/liquid separation, mass balance, and reuse of the biofertilizer (recycle) to dilute poultry litter and to promote water saving while generating an organic fertilizer richer in nutrients. Five dilutions (1:4, 1:6, 1:8, 1:10, and 1:12) were submitted to mass balance test followed or not by solid/liquid separation on a sieve. The fractions of the dilutions 1:6 to 1:10 (poultry litter:water, w:v) were subjected to a test to determine the biochemical methane potential, according to the VDI-4630 standards. The highest potential biogas production was obtained in the liquid fraction of the dilution 1:6, reaching 179.4 L CH4 kg−1 VSadded. This condition was subjected to a semi-continuous feeding to evaluate the biofertilizer to replace water to dilute poultry litter (recycle). The results showed that the replacement of 40% of the dilution water by the biofertilizer had no inhibitory effect on the anaerobic digestion process, reaching values of 236 and 226 L CH4 kg−1 VSadded without and with the recycle, respectively. The decrease in the use of water and an increase in nutrients contained in the effluent (biofertilizer) is reflected in a 66% larger area for corn production. A detailed study of economic feasibility is essential for decision-making on investment and its recovery (payback).Thus, the liquid fraction of the dilution 1:6 with the recycle allowed a 40% saving in the use of clean water for poultry litter dilution, providing a biofertilizer with higher amounts of nitrogen, one of the nutrients most demanded by most crops.

Employing micro-aeration in anaerobic digestion of poultry litter and wheat straw: Batch kinetics and continuous performance

In this study, different micro-aeration (MA) strategies for anaerobic digestion (AD) of poultry litter (PL) and wheat straw (WS) were examined. MA at different stages (pretreatment, middle, pretreatment plus middle, and daily) in batch AD of WS showed that daily MA had the highest increase (16.5 %) of the cumulative methane yield (CMY) compared to the control. Batch co-digestion (Co-AD) of WS and PL with daily MA obtained a furtherly improved (15.1 %) CMY of 225.44 N mL CH4/g vS added. The modified Gompertz model and Cone model were good in fitting the methane yield kinetics of MA engaged AD process (R2 greater than 0.99). Daily MA shortened the lag phase of Co-AD by 3.4 %. The sequencing batch reactor for the Co-AD of WS and PL showed an increased (21.5 %) daily methane yield when 0.5-h/d MA was employed. The results provided support for the application of micro-aeration in the AD of agricultural wastes.

Effects of litter from antimicrobial-fed broiler chickens on soil bacterial community structure and diversity

This study examined changes in soil bacterial community composition and diversity in response to fertilization with litter from chickens fed a diet without antibiotics and with bambermycin, penicillin, bacitracin, salinomycin, or mix of salinomycin and bacitracin. Litter (27.5 T/ha) was applied to 24 agricultural plots in the Fraser Valley of British Columbia. Nonfertilized plots were used as a negative control. Soil samples collected from the studied plots were used to quantify Escherichia coli by plate counts, and Clostridium perfringens by qPCR. The 16S rRNA gene sequencing was performed for microbiota analysis. Following litter application in December, the population size of E. coli was 5.4 log CFU/g; however, regardless of treatments, the results revealed 5.2 and 1.4 log CFU/g of E. coli in soil sampled in January and March, respectively. Fertilization with litter from antibiotic-treated birds increased (P<0.05) the relative abundance of Proteobacteria, Actinobacteria, and Firmicutes in soil, but decreased Acidobacteria and Verrucomicrobia groups. The alpha diversity parameters were higher (P<0.05) in nonfertilized soil compared to the fertilized ones, suggesting that litter application was a major factor in shaping the soil bacterial communities. These results may help develop efficient litter management strategies like composting, autoclaving, or anaerobic digestion of poultry litter before application to land for preservation of soil health and crop productivity.

Anaerobic Digestion of Poultry Litter: Technical Aspects to Improve Process Performance and Water Saving

Anaerobic Digestion of Poultry Litter: Technical Aspects to Improve Process Performance and Water Saving

Identification and characterization of microbial community of anaerobic digested poultry litter

Livestock farming have resulted in the release of excessive wastes which, contains abundant organic matter and microbial population. The need to develop an alternative and sustainable methods to minimize the waste generated and it effects on the environment led to the application of anaerobic digestion (AD) for the treatment of waste and generation of methane gas. The study focused on investigation of the microbiome involve in AD of poultry litter and was conducted using poultry litter as organic substrate under batch conditions at hydraulic retention time (HRT) of fifty-six (56) days in fifteen (15) liter fabricated digesters at 37OC. The pH, total solid (TS), moisture content (MC) total ammonia nitrogen, volatile solid (VS) was assessed before and after digestion while the microbial community diversity was analyzed using 16S rRNA amplicon-based next-generation sequencing (NGS). The results indicated a pH of 7.91±0.04 before digestion and 7.33±0.06 after digestion and a TS value of 56.40±0.6% before digestion and 6.30±0.34% after digestion. A collective biogas yield of 5.21±21.00 bars were recorded. The characterization of biogas analyzed with non-dispersive infrared (NDIR) gas analyzer (gas board 3100p) revealed a percentage methane content of 50.31±1.33. The microbial community indicate Bacteroidetes (46.37%), Firmicutes (48.37%), Proteobacteria (8.17%), as the most dominant phylum. This study suggests the importance of molecular analysis as a fundamental tool to gain insight and deeper understanding of anaerobic digester performances.

Effect of different inoculations on biogas and methane production through anaerobia biodigeston using residues from the avícola sector

The present study aimed to analyze the use of different digestates as inocula for the anaerobic digestion of poultry litter, evaluating the biogas and methane production. The inocula used were: bovine and porcine biofertilizer; with feeding loads of 0.67, 1.00 and 1.67 gVS L-1 day-1. Statistical analyses followed a split-plot design, where the main plot being inoculum and the feeding load as secondary. The experimental data were submitted to analysis of variance, at the level of 5% of significance. The following variable responses were considered: biogas production, specific biogas production as a function of volatile solids (VS) added to the biodigester, specific biogas production as a function of organic load, in terms of COD, and methane production. The highest rates of average biogas production, specific biogas production by VS added, specific production of biogas as a function of COD, and average methane production occurred with the use of bovine inoculum. Through the analysis of the total average percentage of methane production, productions of 63.0% and 54.5% for bovine and swine inoculum. Considering the results obtained, the use of bovine inoculum for the process of anaerobic digestion of poultry litter is recommended vinculado a produção de biogás e metano.

Inhibition of biomethane production under antibiotics in poultry litter

Anaerobiosis is a well-established biotechnology which treats animal manure for methanogenesis. The presence of various antibiotics in poultry waste may inhibit anaerobic digestion (AD). The current study aimed at investigating the effects of various antibiotics on the AD of poultry litter. The batch experiments were performed with an inoculum/substrate ratio of 1 in sealed glass vials incubated under anaerobic conditions at 37 °C for 21 days. The antibiotics, i.e., bacitracin (BAC), erythromycin (ERY), monensin (MON), and tetracycline (TET), were added at the concentration ranges of 0.02 to 0.1 mg mL−1. During the first week, the inhibitory effects of monensin were higher (36–60%) as compared with other antibiotics. For 8–15 days and 16–21 days, the inhibitory effects caused by erythromycin were 28–38%, followed by 21–35% of TET and 20–40% of BAC. MON showed lower inhibition during the final stages of experiment which might possibly be due to its biodegradation.

Effect of different inoculations on biogas and methane production through anaerobia biodigeston using residues from the avícola sector

The present study aimed to analyze the use of different digestates as inocula for the anaerobic digestion of poultry litter, evaluating the biogas and methane production. The inocula used were: bovine and porcine biofertilizer; with feeding loads of 0.67, 1.00 and 1.67 gVS L-1 day-1. Statistical analyses followed a split-plot design, where the main plot being inoculum and the feeding load as secondary. The experimental data were submitted to analysis of variance, at the level of 5% of significance. The following variable responses were considered: biogas production, specific biogas production as a function of volatile solids (VS) added to the biodigester, specific biogas production as a function of organic load, in terms of COD, and methane production. The highest rates of average biogas production, specific biogas production by VS added, specific production of biogas as a function of COD, and average methane production occurred with the use of bovine inoculum. Through the analysis of the total average percentage of methane production, productions of 63.0% and 54.5% for bovine and swine inoculum. Considering the results obtained, the use of bovine inoculum for the process of anaerobic digestion of poultry litter is recommended vinculado a produção de biogás e metano.

Anaerobic digestion of poultry litter – A consequential life cycle assessment

Concentrated land spreading of poultry litter has the potential to cause nutrient build-up in soils, eutrophication of water bodies, air pollution and the spread of pathogens. As a result, alternative routes for the disposal of poultry litter are being sought. A consequential life cycle assessment was conducted to examine several scenarios where biogas produced from poultry litter is used to generate heat and electricity or is upgraded to biomethane which can substitute natural gas.For all of the scenarios considered in this study, diverting poultry litter to anaerobic digestion leads to reduced environmental impacts for global warming, fine particulate matter formation and terrestrial acidification. However, the extent to which environmental impacts are reduced varies significantly across the scenarios. Displaced processes including electricity or natural gas, peat moss production and avoided land spreading of litter contribute the most to reducing environmental impacts.Consequential life cycle assessment is a suitable tool to inform decision-makers about the impact of introducing a new multifunctional technology like anaerobic digestion when considering the systems which are displaced. The results show the range of potential environmental outcomes, rather than predicting a single most-likely outcome. The results of this study indicate that anaerobic digestion is a suitable disposal route for poultry litter which may lead to reduced environmental impacts. This type of analysis is recommended when considering alternative feedstocks and valorisation pathways in the circular economy.

Effect of total solids content on anaerobic digestion of poultry litter with biochar

Methane production via anaerobic digestion of poultry litter provides a pathway for energy production from an abundant waste product. Recent studies have shown the use of biochar (pyrolysed biomass) can decrease methane production lag times and increase peak daily yields from ammonia-stressed low-solids anaerobic digesters. Due to the variety of feedstocks and digester configurations used, research to date has not yet determined the effect of biochar addition as a function of the digester total solids content. This study shows the addition of biochar reduces the lag time by a greater percentage in the digesters with a higher total solids content. There was a 17%, 27% and 41% reduction lag time due to biochar addition at total solids contents of 5%, 10% and 20%, respectively. The peak daily methane yield increased by 136% at 10% total solids. There was no significant increase in the peak yield at 5% total solids, while there was a 46% increase at 20% total solids. Real-time PCR analysis confirms the Methanosaetaceae family, which is a key methanogen due to its ability to facilitate direct interspecies electron transfer while attached to biochar, preferentially attaches to biochar. Furthermore, this research shows the attachment of the Methanosaetaceae family, does not decrease with increasing total solids content. A potential negative effect of biochar addition, a reduced volumetric efficiency, can be negated by using a shorter retention time. This new understanding will help to improve predictions of the impact of biochar addition for new digester designs operating in semi-solids and high-solids conditions.

Anaerobic co-digestion of poultry litter and wheat straw affected by solids composition, free ammonia and carbon/nitrogen ratio

In this study, the effects of three total solids levels (2%, 5% and 10% TS) of the mixtures of poultry litter and wheat straw at different percent volatile solids from wheat straw (0%, 25% and 50% VSWS), free ammonia nitrogen (FAN) and C/N ratio on co-digesting poultry litter with wheat straw were studied in batch experiments operated at 37 °C. The results showed that adjusting the substrate C/N ratio alone could not always result in high methane yields and biogas volumes. The maximum CH4 yield of 201 mL g–1 initial VS was observed in the 5% TS category with VSWS being 50%. The highest specific biogas volume produced (318 mL g–1 initial VS) was also obtained in the same solid category. A polynomial regression between FAN and the methanogenic activity was obtained with the correlation coefficient being 0.9472. A FAN inhibitory threshold concentration of 253.9 mg L–1 was found, and a total loss of methane production occurred when the FAN concentration reached 1000 mg L–1. An optimal TS content for anaerobic digestion of poultry litter with wheat straw was around 4.15% to achieve the best biogas yield. Similarly, for digesting poultry litter without addition of wheat straw, the TS content should be kept at around 6.8%.

Leaching and anaerobic digestion of poultry litter for biogas production and nutrient transformation

Anaerobic digestion of poultry litter is a potentially sustainable means of stabilizing this waste while generating biogas. However, technical challenges remain including seasonality of litter production, low C/N ratios, limited digestibility of bedding, and questions about transformation of nutrients during digestion. This study investigated biogas production and nutrient transformations during anaerobic digestion of poultry litter leachate and whole litter. Use of fresh litter collected from within the house was also compared to waste litter cake that was stored outdoors on the farm. The results showed that litter leachates had higher biomethane potential (0.24–0.30 L/gVS) than whole litter (0.15–0.16 L/gVS) and the insoluble bedding material left after leaching (0.08–0.13 L/gVS). Leachates prepared from waste litter cake had lower uric acid and higher acetic acid concentrations than fresh litter indicating that decomposition had occurred during storage. Consequently, waste litter cake had faster initial biogas production but lower final biogas yields compared to fresh litter. In all reactors, uric and acetic acids were completely consumed during digestion, phosphate levels decreased but ammonium levels increased. The results demonstrate that poultry litter leachate is amenable to digestion despite a low C/N ratio and that the remaining insoluble bedding material has been partially stripped of its nutrients. Moreover, litter can be stored prior to digestion but some losses in biomethane potential should be expected due to decomposition of organics during storage.

Mitigation of nitrogen in the poultry litter to enhance biomethane production

The objective of the study is to lower the nitrogen content in the substrate to mitigate the ammonia nitrogen generated in the anaerobic digestion of poultry litter using air stripping technique. The effect of nitrogen mitigation on the biomethane yield from poultry litter was studied in batch experiments with an organic load of 8 kg for a hydraulic retention time of 21 days in mesophilic ambiance. Air stripping results indicate that the free ammonia stripping is greatly influenced by the pH of the substrate and the aeration time. It is observed that the total Kjeldahl nitrogen content in the poultry litter substrate is reduced from 6.9% to 3.69% that is about a reduction of 53%. A significant improvement in the biomethane yield was noticed for poultry litter of which nitrogen content is lowered at a pH 11. The cumulative yield for air stripped substrate increased from 8.77 L/kg to 10.66 L/kg volatile solids. The biomethane production from air stripped poultry litter shows improvement of 18% compared to the control test. From this results, it is evident that the reduction in the nitrogen content of the substrate using air stripping at high pH value is a possible option for enhancing the biomethanisation of poultry litter.

ANAEROBIC DIGESTION STABILITY TEST BY SHEWHART CONTROL CHART

The complexity of the operation of the anaerobic digestion turns important to use a stability test to verify if the operating conditions are under control and the process is working as required. The current method to verify the process stability by the VFA/TA ratio consists of bands, but the stability bands vary according to the organic material. Indicators such as pH or constant biogas production are also used. Therefore, the aim of this study was to propose the use of Shewhart control chart for individual measures such as anaerobic digestion stability test and to demonstrate its use with the anaerobic digestion of poultry litter. This method showed to be advantageous because it standardizes a variation range for the process according to its average and verifies the stability by direct measures, such as the efficiency of organic material removal and biogas production.

English

Anaerobic digestion of poultry litter was studied with reutilization of its effluent in the process by pumping into reactor feeding, contributing to the moisture content and making part of the feeding organic load: 0.5 and 1.0 kg VS/m3/day, at evaluations 1 and 2, respectively. The hydraulic residence time lasted 10 days for both evaluations and the useful volume of reactor was 35 m3, with a semi-continuous reactor feeding, under field conditions. The stability of anaerobic digestion was verified through Shewhart control chart. Average efficiency of biogas production was 0.0119 m3/(kg VSadded) at evaluation 1 and 0.0429 m3/(kg VSadded) at evaluation 2. In the second evaluation, the study revealed that biogas produced more energy as methane than spent with electric energy in reactor feeding. According to Lower Process Capability Index (Cpl), measure developed for convenience engineering to quantify the performance of a process, the anaerobic digestion in the second evaluation was capable in its energy operations. Key words: Biogas, Lower Process Capability Index, operational energy viability index, Shewhart control chart, statistical process control.

Production of biogas from poultry litter mixed with the co-substrate cow dung

Poultry litter (a mixture of rice hulls, sawdust and chicken excreta of broilers) mixed with the co-substrate cow dung and poultry droppings was evaluated under anaerobic conditions for the production of biogas (methane). Four laboratory scale reactors, R1, R2, R3 and R4, were set up with different proportions of waste poultry litter, cow dung and poultry droppings and had a 6% total solid concentration. Digestion was carried out for 50 days at room temperature, 32±3°C. Volatile solid degradation and specific gas production in the four reactors was 46%, 51.99%, 51.96%, 43% and 0.263, 0.469, 0.419, 0.221l/g, respectively, based on the volatile solid (VS) feed. The methane yields were 71%, 72.5%, 72.6% and 70%, respectively. The COD reductions were 46.1%, 50.76%, 48.23% and 45.12%, respectively. A kinetic analysis showed that the anaerobic digestion of poultry litter with a co-substrate followed first order kinetics. Among the experimental reactors, R2 (25% cow dung, 75% poultry litter) gave the optimum results: a VS reduction of 51.99%, a specific gas yield of 0.469l/g and a methane yield of 72.5%.

Fed-batch cultivation of Arthrospira and Chlorella in ammonia-rich wastewater: Optimization of nutrient removal and biomass production

In the present work the cyanobacterium Arthrospira platensis and the microalga Chlorella vulgaris were fed-batch cultivated in ammonia-rich wastewater derived from the anaerobic digestion of poultry litter. Aim of the study was to maximize the biomass production along with the nutrient removal aiming to wastewater treatment. Ammonia and phosphorus removals were very high (>95%) for all cultures investigated. Both microorganisms were able to remove volatile fatty acids to an extent of >90%, indicating that they were capable of mixotrophic growth. Chemical oxygen demand and proteins were also removed in various degrees. In contrast, in all cultures carbohydrate concentration was increased. The biochemical composition of the microorganisms varied greatly and was influenced by the indicate that the nutrient availability. A. platensis accumulated carbohydrates (≈40%), while C. vulgaris accumulated lipids (≈50%), rendering them interesting for biofuel production.

Anaerobic Digestion of Poultry Litter: A Review

Poultry litter is an excellent example of how a source of organic nutrients became an expensive problem in concentrated poultry producing areas due to nutrient imbalance at the farm and regional scale resulting in water quality impairment in some watersheds. Recently, anaerobic digestion technology, which is a proven solution for waste reduction and energy production for dairy, swine, and other organic wastes, has been proposed for poultry litter utilization. Although anaerobic digestion is widely studied for many organic and agricultural wastes, it is less understood for poultry litter (combination of manure, spilled feed, feathers, and bedding material). This review presents a detailed analysis of anaerobic digestion of poultry litter in terms of technology and optimization techniques, goals of poultry litter disposal, and economics. The review suggests that anaerobic process does not fulfill the goal of poultry litter nutrient disposal problems. While selecting any alternative option for a given region, one must consider the goals of poultry litter disposal for that area.

Application of solid waste from anaerobic digestion of poultry litter in Agrocybe aegerita cultivation: mushroom production, lignocellulolytic enzymes activity and substrate utilization

The degradation and utilization of solid waste (SW) from anaerobic digestion of poultry litter by Agrocybe aegerita was evaluated through mushroom production, loss of organic matter (LOM), lignocellulolytic enzymes activity, lignocellulose degradation and mushroom nutrients content. Among the substrate combinations (SCs) tested, substrates composed of 10-20% SW, 70-80% wheat straw and 10% millet was found to produce the highest mushroom yield (770.5 and 642.9 g per 1.5 kg of substrate). LOM in all SCs tested varied between 8.8 and 48.2%. A. aegerita appears to degrade macromolecule components (0.6-21.8% lignin, 33.1-55.2% cellulose and 14-53.9% hemicellulose) during cultivation on the different SCs. Among the seven extracellular enzymes monitored, laccase, peroxidase and CMCase activities were higher before fruiting; while xylanase showed higher activities after fruiting. A source of carbohydrates (e.g., millet) in the substrate is needed in order to obtain yield and biological efficiency comparable to other commercially cultivated exotic mushrooms.

Liquid Effluent from Poultry Waste Bioremediation as a Nutrient Source for Hydroponic Cucumber Production

Fertilizer costs and increased awareness of point-source pollution are amplifying the pressures on farming, economics along with public demand for sustainable production methods and organically grown produce. Our research focuses on using effluent from thermophilic anaerobic digestion of poultry litter as an alternative fertilizer. Cucumbers (Cucumis sativus L.) were grown hydroponically using a bato bucket system to evaluate the effects of liquid effluent as a nutrient solution versus a commercial nutrient solution. Seeds of the beit alpha cultivar `Manar' were started in Horticubes and transplanted into buckets containing a perlite/coir media. The effluent fertilizer consisted of effluent diluted to the same ppm nitrogen found in the commercial fertilizer based on ammonium measured in the effluent. Hydroponic solutions were monitored twice a day to maintain a pH of 5.6-6.0. Fruit was harvested three times a week and graded on size and shape. Fruit of each grade were counted, weighed, and recorded. Average fruit weight and fruit number produced was statistically significant between the two fertilizer regimes with the commercial fruit, averaging 84 g compared to 75 g for effluent fruit. The effluent treatment produced a greater percentage of grade 1 fruit (33%) compared to the commercial treatment (26% grade 1 fruit). Thus, 74% of the commercial harvest was grade 2 or cull fruit compared to only 66% of the effluent harvest. Correlating grade with average fruit weight analysis identified statistical differences between treatments for the grade 1 fruit, but not the grade 2 or the culls. While effluent from thermophilic anaerobic digestion shows promise as an alternative hydroponic fertilizer, it is not better than the commercial fertilizer regime.