scholarly journals Digested residue as a fertilizer after the mesophilic process of anaerobic digestion

2011 ◽  
Vol 51 (No. 6) ◽  
pp. 262-266 ◽  
Author(s):  
N. Voća ◽  
T. Krička ◽  
T. Ćosić ◽  
V. Rupić ◽  
Ž. Jukić ◽  
...  

The aim of this paper is to determine the difference in quality of the digested residue after the process of anaerobic digestion by using different input raw materials. The research was conducted in the Republic of Austria on four facilities for biogas production. The raw materials used for biogas production were chicken manure, pig manure, Sudan grass and organic household waste. The research included chemical analysis and bacteriological tests of the samples taken. It was found that the digested residue in all of the samples, all of which are mildly alkaline, contains a low level of dry matter, 70% of which is organic matter. Biogenic elements were present in moderate concentration; the values of heavy metals were within approved limits. This analysis leads to the conclusion that the digested residues of all input materials can be used in agricultural production, especially so in plant production and grassland cultivation. Mesophilic and thermophilic microorganisms were found in the digested residue samples, but there were no cryophilic microorganisms and no pathogenic bacteria.

2021 ◽  
Vol 286 ◽  
pp. 02010
Author(s):  
Penka Zlateva ◽  
Angel Terziev ◽  
Krastin Yordanov

The focus of the present study is a small biogas power plant for anaerobic fermentation of several types of animal waste raw materials used for biogas production. The impact of some of the characteristics of substances such as composition, temperature, humidity, and pH of the mixture in the bioreactor has been considered. The above is vital for optimizing the fermentation process, and also to improve the biogas production process. The plant is located in Northeastern Bulgaria and the raw liquid manure is supplied by several neighboring small farms. The annual quantities of raw waste are as follows: cow manure - 1252 t / a; chicken manure - 427 t / a and pig manure - 639 t / a. The manure is collected in a preliminary tank and then pumped to the bioreactor. The fermenter itself is a hermetically sealed and thermally insulated tank where constant temperature is maintained. It is equipped with a stirring system, which helps the mixing and homogenization of the substrate. The tests were performed during three charges of the installation. The fermentation takes approximately 23 up to 25 days. The experiments were performed during the summer and autumn seasons when the ambient air temperature varies from 28 to 45 °C. The biogas can be used as an energy carried as the obtained organic fertilizer is suitable for agriculture purposes.


2019 ◽  
Vol 118 ◽  
pp. 03022
Author(s):  
Hongguang Zhu ◽  
Jing Yang ◽  
Cheng Xiaowei

The dead pig is an organic waste rich in oil and protein, and is an ideal anaerobic digestion raw material. This study based on single factor ANOVA and Modified Gompertz model. It investigated the effects of the ratio of dead pigs on biogas production by middle temperature co-digestion of pig manure and dead pigs. And the biogas production potential was determined. The results showed that there was no significant correlation between the ratio of dead pigs and the biogas production. The ratio would significantly affect the average methane content and degradation rate. When the addition ratio was in the range of 3 to 15%, the biogas production was between 191.39 and 202.44 (L/kg VS). The average contents of methane were 50.67%, 50.35%, 41.83%, 45.53% and 44.57%, respectively. The time required to reach 80% of the biogas production was 28, 34, 36, 65 and 63 days, respectively. The degradation rate of the raw materials was generally decreased with the increase of the addition ratio. The results of Modified Gompertz model fitting showed that the mixed raw materials had a fully anaerobic digestion with high utilization rate and short hysteresis in the range of 0 ~ 9%. Therefore, a hydraulic retention time (HRT) of 30 days and the addition ratio was in the range of 0 to 6% could be recommended for a continuous digester. It could get a better gas production and higher raw material utilization.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karol Postawa ◽  
Jerzy Szczygieł ◽  
Marek Kułażyński

Abstract Background Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 590
Author(s):  
Aiban Abdulhakim Saeed Ghaleb ◽  
Shamsul Rahman Mohamed Kutty ◽  
Gasim Hayder Ahmed Salih ◽  
Ahmad Hussaini Jagaba ◽  
Azmatullah Noor ◽  
...  

Man-made organic waste leads to the rapid proliferation of pollution around the globe. Effective bio-waste management can help to reduce the adverse effects of organic waste while contributing to the circular economy at the same time. The toxic oily-biological sludge generated from oil refineries’ wastewater treatment plants is a potential source for biogas energy recovery via anaerobic digestion. However, the oily-biological sludge’s carbon/nitrogen (C/N) ratio is lower than the ideal 20–30 ratio required by anaerobic digestion technology for biogas production. Sugarcane bagasse can be digested as a high C/N co-substrate while the oily-biological sludge acts as a substrate and inoculum to improve biogas production. In this study, the best C/N with co-substrate volatile solids (VS)/inoculum VS ratios for the co-digestion process of mixtures were determined empirically through batch experiments at temperatures of 35–37 °C, pH (6–8) and 60 rpm mixing. The raw materials were pre-treated mechanically and thermo-chemically to further enhance the digestibility. The best condition for the sugarcane bagasse delignification process was 1% (w/v) sodium hydroxide, 1:10 solid-liquid ratio, at 100 °C, and 150 rpm for 1 h. The results from a 33-day batch anaerobic digestion experiment indicate that the production of biogas and methane yield were concurrent with the increasing C/N and co-substrate VS/inoculum VS ratios. The total biogas yields from C/N 20.0 with co-substrate VS/inoculum VS 0.06 and C/N 30.0 with co-substrate VS/inoculum VS 0.18 ratios were 2777.0 and 9268.0 mL, respectively, including a methane yield of 980.0 and 3009.3 mL, respectively. The biogas and methane yield from C/N 30.0 were higher than the biogas and methane yields from C/N 20.0 by 70.04 and 67.44%, respectively. The highest biogas and methane yields corresponded with the highest C/N with co-substrate VS/inoculum VS ratios (30.0 and 0.18), being 200.6 mL/g VSremoved and 65.1 mL CH4/g VSremoved, respectively.


2015 ◽  
Vol 787 ◽  
pp. 803-808 ◽  
Author(s):  
A. Deepanraj ◽  
S. Vijayalakshmi ◽  
J. Ranjitha

The present research paper describes about the anaerobic digestion of vegetable (Banana, Cauliflower, potato, and sweet potato) and flower wastes (Rose, sambangi, gulmohar, marigold, golden shower tree, silk tree mimosa) in a 1L capacity of anaerobic digestor using pig manure as an inoculums. The digester was operated in the ratio of 1:1 of substrate to inoculums at RT. The substrate concentrations are varied such as 5%, 7%, and 10% was used and amount of gas produced was analysed using digital pressure gauge. The results obtained showed that, marigold flower had given higher yield of biogas than vegetable wastes and the digestion period was less. The average biogas production potential of withered flowers was observed as 14.36 g/kg in 5 days, where in case of vegetable wastes it was 10.0234 g/kg in 6 days. The study showed that flowers which are available in abundant in India is thrown away within a day, in the environment. These feedstocks are good feed stock for the production of biogas. The generation of biogas from flowers and vegetable waste upholds the concept of waste to wealth in enhancing sustainability of development. The future research work is mainly focused on the characterization of the main component present in the bio-gas using sophisticated instruments.


Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 539 ◽  
Author(s):  
Renfei Li ◽  
Wenbing Tan ◽  
Xinyu Zhao ◽  
Qiuling Dang ◽  
Qidao Song ◽  
...  

Wood waste generated during the tree felling and processing is a rich, green, and renewable lignocellulosic biomass. However, an effective method to apply wood waste in anaerobic digestion is lacking. The high carbon to nitrogen (C/N) ratio and rich lignin content of wood waste are the major limiting factors for high biogas production. NaOH pre-treatment for lignocellulosic biomass is a promising approach to weaken the adverse effect of complex crystalline cellulosic structure on biogas production in anaerobic digestion, and the synergistic integration of lignocellulosic biomass with low C/N ratio biomass in anaerobic digestion is a logical option to balance the excessive C/N ratio. Here, we assessed the improvement of methane production of wood waste in anaerobic digestion by NaOH pretreatment, co-digestion technique, and their combination. The results showed that the methane yield of the single digestion of wood waste was increased by 38.5% after NaOH pretreatment compared with the untreated wood waste. The methane production of the co-digestion of wood waste and pig manure was higher than that of the single digestion of wood waste and had nonsignificant difference with the single-digestion of pig manure. The methane yield of the co-digestion of wood waste pretreated with NaOH and pig manure was increased by 75.8% than that of the untreated wood waste. The findings indicated that wood waste as a sustainable biomass source has considerable potential to achieve high biogas production in anaerobic digestion.


Author(s):  
Fei Wang ◽  
Mengfu Pei ◽  
Ling Qiu ◽  
Yiqing Yao ◽  
Congguang Zhang ◽  
...  

Poultry manure is the main source of agricultural and rural non-point source pollution, and its effective disposal through anaerobic digestion (AD) is of great significance; meanwhile, the high nitrogen content of chicken manure makes it a typical feedstock for anaerobic digestion. The performance of chicken-manure-based AD at gradient organic loading rates (OLRs) in a continuous stirred tank reactor (CSTR) was investigated herein. The whole AD process was divided into five stages according to different OLRs, and it lasted for 150 days. The results showed that the biogas yield increased with increasing OLR, which was based on the volatile solids (VS), before reaching up to 11.5 g VS/(L·d), while the methane content was kept relatively stable and maintained at approximately 60%. However, when the VS was further increased to 11.5 g VS/(L·d), the total ammonia nitrogen (TAN), pH, and alkalinity (CaCO3) rose to 2560 mg·L−1, 8.2, and 15,000 mg·L−1, respectively, while the volumetric biogas production rate (VBPR), methane content, and VS removal efficiency decreased to 0.30 L·(L·d)−1, 45%, and 40%, respectively. Therefore, the AD performance immediately deteriorated and ammonia inhibition occurred. Further analysis demonstrated that the microbial biomass yield and concentrations dropped dramatically in this period. These results indicated that the AD stayed steady when the OLR was lower than 11.5 g VS/(L·d); this also provides valuable information for improving the efficiency and stability of AD of a nitrogen-rich substrate.


2020 ◽  
Vol 14 (4) ◽  
pp. 571-578
Author(s):  
Jian Zheng ◽  
Chuanyuan Zhu ◽  
Xingyun Qi ◽  
Peng Xiang ◽  
Yongchun Li ◽  
...  

This study aimed to investigate the material composition and transformation during composting of different kinds of livestock and poultry manures. Fresh cow manure (R1), pig manure (R2), and chicken manure (R3) were used as raw materials, and 10% corn stalk was selected as the leavening agent for aerobic static composting. The following results were obtained. After 30 days of aerobic composting, the mass reduction index of the R1, R2, and R3 piles was 48.94%, 47.94%, and 52.94%, respectively. Especially in the first stage (0–10 days) of the composting reaction, the mass reduction indices of the R1, R2, and R3 piles were significant, which were 21.45%, 22.73%, and 23.73%, respectively. During the composting process, the percentage of dissolved organic carbon in TC showed a downward trend, decreasing to 51.33% ± 1.25%, 57.35% ± 3.21%, and 52.34% ± 2.15%, for R1, R2, and R3, respectively. The percentage of ammonia nitrogen (AN) in total nitrogen (TN) in the piles R1, R2, and R3 first showed an increasing trend and then decreased, showing the highest values of 7.38%, 8.11%, and 9.22%, respectively.


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