Anaerobic digestion of animal by-products : effect of substrate concentration (original) (raw)
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Slaughterhouse by-products treatment using anaerobic digestion
Waste Management, 2017
The objective of the present study is to evaluate the use of animal by-products (ABP) as substrates for anaerobic digestion, aiming at methane production. Specifically, four ABP of Category 2 and 3, namely (i) stomach and rumen, (ii) stomach contents, (iii) breasts and reproductive organs and (iv) bladders and intestines with their contents, were selected. The methane potential of each ABP was initially determined, while the feasibility of anaerobic co-digestion of ABP with two agroindustrial waste, i.e. orange peels and olive leaves was also studied. To this purpose, Biochemical Methane Potential (BMP), as well as semi-continuous assays were respectively conducted. In the latter, the effect of the variation in the organic loading rate (OLR) on methane production was investigated. Results obtained from BMP assays showed that the samples containing breasts and reproductive organs, bladders and intestine, and stomach and rumen, had higher methane potentials of 815, 787 and 759 mLCH 4,STP /gVS, respectively. Moreover, according to the results of the semi-continuous assays, maximum methane yields between 253 and 727 mLCH 4 /gVS fed were obtained at an OLR of 0.8 gVS/L/d. The only case in which methanogenesis inhibition phenomena, due to increased ammonia concentrations, were observed, was the assay being fed with a mixture of breasts and reproductive organs and orange peels, at the highest OLR. This inhibition phenomenon was attributed to an inappropriate C/N ratio.
2015
Animal manure constitutes a nuisance to the environment. This work aimed at tackling environmental problem as well dealing with energy demand crisis. This work evaluated and compared the energy produced from anaerobic digestion of Cow Slurry (CS), Pig Slurry (PS) and Chicken Waste (CW) by batch experiment at mesophilic temperature (37 ◦ C). The study was carried out in a laboratory scale batch digester. The digestion bottles were fed with 44.20, 105.70 and 11.21 g, respectively, which were calculated. The digestion took place for a period of about 40 days after which the gas production was noticed to be below 1% of the total gas produced till that time. The biogas yields from organic dry matter (oDM) of CS, PS and CW were found to be 441.33 l. kg -1 oDM, 277.35 l.kg -1 oDM and 493.08 l. kg -1 oDM respectively after 40 days digestion time. Methane yields (oDM) of CS, PS and CW were also found to be 296.50 l.CH4 kg -1 oDM, 216.90 l.CH4kg -1 oDM and 328.19 l.CH4kg -1 oDM respectively. ...
Biogas Production Potential from Anaerobic Co-Digestion of Food Waste and Animal Manure
Bulletin of the Chemical Society of Nigeria, 2024
The potential of biogas production by the anaerobic codigestion (AcoD) of canteen food waste and animal manure was investigated using the biochemical methane potential assay (BMP). The BMP assay was conducted under thermophilic temperature of 35 °C in a batch process at digestion time of 40 d. Waste substrate mixture was digested at a fixed proportion of 1:1 with different animal manure as co-substrate. Maximum cumulative biogas production (418 ml g-1 VS) was achieved during codigestion of food waste with pig manure > chicken manure (408 ml g-1 VS) > goat manure (319 ml g-1 VS). Generally, all manure codigested reactors produced 1.01 to 1.34 times more biogas than food waste alone indicating the synergistic effect of codigestion on overall biogas productivity. With analogous increase in biogas production, manure amendment produced significant (p<0.05) substrate biodegradation in terms of total and volatile solids loss. The microbial load profile prior and post-AD revealed significant reduction (p<0.05)in microbial species suggestion that anaerobic digestion can be adopted as a method of waste treatment and hygienization.
Enhancement of Anaerobic digestion of cow manure through inoculation under mesophilic conditions
Now a days, anaerobic digestion (AD) systems are using a wide range of techniques to improve their performance, including co-digestion, inoculation, and addition of various accelerants. The AD of cow-manure (CM) was inoculated with ruminant intestinal waste (IW) in this study. It was hypothesized that methanogens present in intestinal waste will enhance anaerobic digestion, which will result in increased methane production. Five different CM/IW ratios (1:0, 9:1, 7:3, 1:1, 0:1) of wet weight were introduced in AD systems at mesophilic environmental (37 ◦C) to find the best combination of CM and IW. All of the mixture CM/IW ratios (9:1, 7:3, and 1:1) demonstrated a good synergistic effect and yielded a higher cumulative biogas yields than CM and RIW alone. The CM/IW (9:1) had the maximum cumulative biogas yield (239 mL/g VS), COD removal rate (40%), VS removal rate (27%), and total solid (TS) removal rate (24%). In the current study fertility status (nitrogen, N; phosphorus, P and pot...
Evaluation of Biochemical Factors from Mixed Animal Wastes Feedstock in Biogas Production
Journal of Advanced Agricultural Technologies
Animal wastes can serve as the feedstock for biogas production that could be used as alternative energy source. The green energy derived from animal wastes is considered to be carbon neutral and offsetting those generated from fossil fuels. In this study, an evaluation of methane production from animal wastes with different nitrogen and carbon sources was carried out. Anaerobic batch reactors containing different mixtures of animal wastes and potential inhibition sources were set up to evaluate methane potential. The results showed that methane productions increased as the solid concentrations, temperature and total carbon increased. However, biogas production decreased substantially when ammonia concentrations in the feedstock were high. The addition of carbon to the feedstock provided a better substrate for methane production during anaerobic digestion of animal wastes. Methane productions were more than several times greater from reactors with feedstock amended with additional source of carbon than the ones with just animal wastes (e.g., swine, poultry or just dairy) or acclimated microbes. Thus, it appears that additional carbon source is necessary to increase methane production from animal waste anaerobic digester. Inhibitor such as ammonia appears to hinder the biomethanation in the anaerobic digestion of animal wastes for optimum methane production.
The objective of this research is to compare dry anaerobic digestion of cow dung for methane production with wet anaerobic digestion under mesophilic and thermophilic temperatures in batch cultures for 63 days. The results showed that a specific methane yield of 0.333 and 0.345 LCH4/gVSr was obtained at 35 o C in the fermentation systems for a dilute ratio of 1:1 and 1:0, with a VS removal of 50.01%, and 56.33%, a COD removal of 54.99%, and 61.35%, respectively. When the fermentation systems was performed under 55 o C, the specific methane yield was increased to 0.351 and 0.374 LCH4/gVSr, with a VS removal of 53.43% and 60.52%, and a COD removal of 58.37% and 65.36%, respectively. Though addition of water could promote start-up process and biodegradability of the substrate to some extent, the methane yields in the dry anaerobic digestion process were found comparable to the conventional wet anaerobic digestion process. Furthermore, the volume of the reactor was increased twice in the wet fermentation process (7.68% TS) of cow dung compared to the dry fermentation (15.18% TS) at the same loading rate. It was suggested that dry methane fermentation process was superior in energy recovery, saving resources and engineering investment compared with wet fermentation process.
Jurnal Ilmu dan Teknologi Hasil Ternak, 2021
Organic waste has high COD and BOD content, so it is dangerous if disposed of directly into the environment. Organic waste processing, such as waste from livestock manure and liquid tofu waste, requires a process that can reduce COD and BOD levels as well as produce valuable products. Anaerobic digestion method is the proper process to convert complex compounds in waste into simpler compounds with methanogenic bacteria into a renewable energy product, namely biogas. On the other hand, the anaerobic digestion process can reduce COD and BOD levels in the biogas formation process. This study uses raw materials such as cow manure and chicken manure, and liquid tofu waste. The variables that produced the largest biogas were those with a ratio of 70% cow dung, 15% chicken manure, and 15% tofu liquid waste with a total of 3,251.5 mL. Then, the COD and BOD levels decreased significantly with more than 98% COD removal, and more than 95% BOD removal in all variables at the end of the anaerobi...
Anaerobic Digestion of Meat Wastes
2020
Abstract. Many meat processing industries use dissolved air flotation (DAF) to treat the wastewater generated onsite before it is discharged or further treated and ending up with large volumes of sludge, usually of 20% TS. The aim of this study was to evaluate the biogas production potential (BPP) from meat processing DAF-sludge for different organic loadings. An associated objective was to compare BPP using acclimatised and non acclimatised seed. Batch reactors operated at mesophilic conditions and loadings of 5, 3.8, 2.5 and 1.2 gCOD/gVS acclimatised seed, and 3.4, 2.6, 1.7 and 0.8 gCOD/gVS non-acclimatised seed were monitored for biogas production on a daily basis. The highest biogas production for non-acclimatised seed was 1930 mL at 3.4 gCOD/gVS, whereas for acclimatised seed 1358 mL was obtained at 3.8 gCOD/gVS. It was observed that using acclimated seed, higher CBP was achieved at a lower loading compared to the non-acclimatised seed.