Computer and Experimental Simulations of the Production of Methane Gas from Municipal Solid Waste

1993 ◽  
Vol 27 (2) ◽  
pp. 225-234 ◽  
Author(s):  
J. J. Lee ◽  
I. H. Jung ◽  
W. B. Lee ◽  
J.-O. Kim

Prediction of quantity and quality of gas produced after landfilling is not easy because it is strongly dependent on the hydrological and biological parameters. The objective of this study was to develop the LEAGA-I model by combining a hydrological module of unsaturated flow theory with a biological decomposition module in order to predict methane gas production, even carbon dioxide gas production, using a pilot scale lysimeter. For a biological module, especially, three-step procedures, i.e., hydrolysis of refuse, acid formation, and methane formation were applied. As a result of this study, the LEAGA-1 model, developed by combining a hydrological module with a biological module, not only provided more reasonable prediction of gas production during landfill stabilization, but also turned out to be a useful model, as a result of comparison of the simulated values with the observed values of lab-reactor.

2021 ◽  
Vol 14 (1) ◽  
pp. 1-14
Author(s):  
Abdul Mukhlis Ritonga ◽  
Masrukhi Masrukhi ◽  
Ahmad Mafrukhi

Abstrak. Biogas merupakan gas yang dihasilkan dari bahan organik melalui proses fermentasi. Energi yang terkandung dalam biogas tergantung dari konsentrasi metana (CH4). Semakin tinggi kandungan metana maka semakin besar kandungan energi pada biogas. Salah satu cara untuk meningkatkan kandungan gas metana pada biogas serta dapat menurunkan gas-gas pengotor seperti CO2, dan gas-gas lain yang tidak terpakai dengan pemurnian menggunakan purifier yang telah di isi adsorben, pada penelitian ini adsorben yang digunakan yaitu arang aktif dan zeolit. Variabel yang diukur dalam penelitian ini yaitu C/N rasio, pH, suhu, total solid (TS), volatile solid (VS), Biochemical Oxygen Demand (BOD) dan Chemical Oxygen Demand (COD) yang berpengaruh dalam produksi gas metan. Kadar  CH4 dan CO2 setelah dimurnikan, dan waktu optimal untuk proses pemurnian biogas, perlakuan yang diberikan menggunakan 3 waktu pengujian, yaitu 30, 60, dan 90 menit. Percobaan dilakukan pengulangan sebanyak tiga kali. Hasil penelitian menunjukkan bahwa rasio C/N sebesar 20,36 dengan suhu rata-rata 25,1oC dan pH rata-rata 6. Nilai BOD awal dan akhir masing-masing sejumlah 77800,86 mg/l dan 53002,42 mg/l dan COD awal dan akhir masing-masing sejumlah 59800 mg/l dan 36000 mg/l. TS dan VS masing masing mengalami penurunan sebesar 20,99% dan 17,93%. Penggunaan adsorben arang aktif dan zeolit dapat meningkatkan kandungan gas CH4 sebesar 136,5% dan menurunkan kandungan gas CO2 sebesar 64% pada biogas. Lama waktu pengujian mampu meningkatkan konsentrasi CH4 dan menurunkan kandungan gas CO2 dengan waktu paling optimal yaitu 30 menit.Increasing Quality Of Biogas With Purification Proses On Double Arranged Series Purifier Using Activated Charcoal And Zeolit AdsorbentAbstract. The quality of biogas is determined by the methane (CH4) content in the biogas. A good biogas is indicated by its high methane content. One way to increase the methane gas content in biogas is by purification using a series-level purifier that has been filled with adsorbents. In this study, the adsorbents used were activated charcoal and zeolite. The variables measured include CN ratio, pH, temperature, total solid (TS), volatile solid (VS), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) which influential in methane gas production. CH4 and CO2 levels, before and after purification. Biogas was purified for a duration of 30, 60, 90 minutes and was repeated three times. The results showed that the C/N ratio was 20.36 with an average temperature of 25.1 °C and an average pH of 6. The initial and final BOD values were 77800.86 mg/l and 53002.42 mg/l and the initial and final COD values were 59800 mg/l and 36000 mg/l. TS and VS experienced a decrease of 20.99% and 17.93%. The use of activated charcoal and zeolite adsorbents was able to increase the CH4 gas content by 136.5% and reduce the CO2 gas content by 64%. The optimal purification time is 30 minutes.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 179-188 ◽  
Author(s):  
K. F. Janning ◽  
X. Le Tallec ◽  
P. Harremoës

Hydrolysis and degradation of particulate organic matter has been isolated and investigated in laboratory scale and pilot scale biofilters. Wastewater was supplied to biofilm reactors in order to accumulate particulates from wastewater in the filter. When synthetic wastewater with no organic matter was supplied to the reactors, hydrolysis of the particulates was the only process occurring. Results from the laboratory scale experiments under aerobic conditions with pre-settled wastewater show that the initial removal rate is high: rV, O2 = 2.1 kg O2/(m3 d) though fast declining towards a much slower rate. A mass balance of carbon (TOC/TIC) shows that only 10% of the accumulated TOC was transformed to TIC during the 12 hour long experiment. The pilot scale hydrolysis experiment was performed in a new type of biofilm reactor - the B2A® biofilter that is characterised by a series of decreasing sized granular media (80-2.5 mm). When hydrolysis experiments were performed on the anoxic pilot biofilter with pre-screened wastewater particulates as carbon source, a rapid (rV, NO3=0.7 kg NO3-N/(m3 d)) and a slowler (rV, NO3 = 0.3 kg NO3-N/(m3 d)) removal rate were observed at an oxygen concentration of 3.5 mg O2/l. It was found that the pilot biofilter could retain significant amounts of particulate organic matter, reducing the porosity of the filter media of an average from 0.35 to 0.11. A mass balance of carbon shows that up to 40% of the total incoming TOC accumulates in the filter at high flow rates. Only up to 15% of the accumulated TOC was transformed to TIC during the 24 hour long experiment.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 105
Author(s):  
Tae Young Kim ◽  
Seong Bin Jo ◽  
Jin Hyeok Woo ◽  
Jong Heon Lee ◽  
Ragupathy Dhanusuraman ◽  
...  

Co–Fe–Al catalysts prepared using coprecipitation at laboratory scale were investigated and extended to pilot scale for high-calorific synthetic natural gas. The Co–Fe–Al catalysts with different metal loadings were analyzed using BET, XRD, H2-TPR, and FT-IR. An increase in the metal loading of the Co–Fe–Al catalysts showed low spinel phase ratio, leading to an improvement in reducibility. Among the catalysts, 40CFAl catalyst prepared at laboratory scale afforded the highest C2–C4 hydrocarbon time yield, and this catalyst was successfully reproduced at the pilot scale. The pelletized catalyst prepared at pilot scale showed high CO conversion (87.6%), high light hydrocarbon selectivity (CH4 59.3% and C2–C4 18.8%), and low byproduct amounts (C5+: 4.1% and CO2: 17.8%) under optimum conditions (space velocity: 4000 mL/g/h, 350 °C, and 20 bar).


2021 ◽  
Vol 13 (3) ◽  
pp. 1109
Author(s):  
Edgar Ricardo Oviedo-Ocaña ◽  
Angélica María Hernández-Gómez ◽  
Marcos Ríos ◽  
Anauribeth Portela ◽  
Viviana Sánchez-Torres ◽  
...  

The composting of green waste (GW) proceeds slowly due to the presence of slowly degradable compounds in that substrate. The introduction of amendments and bulking materials can improve organic matter degradation and end-product quality. However, additional strategies such as two-stage composting, can deal with the slow degradation of green waste. This paper evaluates the effect of two-stage composting on the process and end-product quality of the co-composting of green waste and food waste amended with sawdust and phosphate rock. A pilot-scale study was developed using two treatments (in triplicate each), one being a two-stage composting and the other being a traditional composting. The two treatments used the same mixture (wet weight): 46% green waste, 19% unprocessed food waste, 18% processed food waste, 13% sawdust, and 4% phosphate rock. The traditional composting observed a higher degradation rate of organic matter during the mesophilic and thermophilic phases and observed thermophilic temperatures were maintained for longer periods during these two phases compared to two-stage composting (i.e., six days). Nonetheless, during the cooling and maturation phases, the two treatments had similar behaviors with regard to temperature, pH, and electrical conductivity, and the end-products resulting from both treatments did not statistically differ. Therefore, from this study, it is concluded that other additional complementary strategies must be evaluated to further improve GW composting.


Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 227 ◽  
Author(s):  
Camila Favaro ◽  
Ilton Baraldi ◽  
Fernanda Casciatori ◽  
Cristiane Farinas

Soluble coffee offers the combined benefits of high added value and practicality for its consumers. The hydrolysis of coffee polysaccharides by the biochemical route, using enzymes, is an eco-friendly and sustainable way to improve the quality of this product, while contributing to the implementation of industrial processes that have lower energy requirements and can reduce environmental impacts. This work describes the production of hydrolytic enzymes by solid-state fermentation (SSF), cultivating filamentous fungi on waste from the coffee industry, followed by their application in the hydrolysis of waste coffee polysaccharides from soluble coffee processing. Different substrate compositions were studied, an ideal microorganism was selected, and the fermentation conditions were optimized. Cultivations for enzymes production were carried out in flasks and in a packed-bed bioreactor. Higher enzyme yield was achieved in the bioreactor, due to better aeration of the substrate. The best β-mannanase production results were found for a substrate composed of a mixture of coffee waste and wheat bran (1:1 w/w), using Aspergillus niger F12. The enzymatic extract proved to be very stable for 24 h, at 50 °C, and was able to hydrolyze a considerable amount of the carbohydrates in the coffee. The addition of a commercial cellulase cocktail to the crude extract increased the hydrolysis yield by 56%. The production of β-mannanase by SSF and its application in the hydrolysis of coffee polysaccharides showed promise for improving soluble coffee processing, offering an attractive way to assist in closing the loops in the coffee industry and creating a circular economy.


2009 ◽  
Vol 29 (1) ◽  
pp. 78-85 ◽  
Author(s):  
R. Valencia ◽  
W. van der Zon ◽  
H. Woelders ◽  
H.J. Lubberding ◽  
H.J. Gijzen

2013 ◽  
Vol 690-693 ◽  
pp. 378-389 ◽  
Author(s):  
Feng Lan Han ◽  
Qi Xing Yang ◽  
Lan Er Wu ◽  
Chun Du

The present authors have utilized, for the first time, H3BO3as an additive in pilot scale experiments of Mg production using Pidgeon process. The results from the experiments revealed positive effects of H3BO3on both quantity and quality of the Mg metal crowns. Besides acting as a catalyzer for MgO reduction, H3BO3stabilized also β-Ca2SiO4in the Mg slag. Based on these results, H3BO3may be adopted as an innovative additive replacing fluorite in the Mg production, to enhance sustainability and environmental soundness for the Pidgeon process in China.


1992 ◽  
Vol 271 ◽  
Author(s):  
Charles D. Gagliardi ◽  
Dilum Dunuwila ◽  
Beatrice A. Van Vlierberge-Torgerson ◽  
Kris A. Berglund

ABSTRACTTitanium alkoxides modified by carboxylic acids have been widely studied as the molecular precursors to ceramic materials. These alkoxide complexes have also been very useful in the formation of stable, porous, optically clear films having many novel applications such as chemical sensors, catalytic supports, and ion-exchange media. To improve the processing of these materials, it is essential to better understand the kinetics of the chemical transformations which occur.The kinetics of the hydrolysis reaction are studied for selected carboxylic acids using Raman spectroscopy to probe the chemistry of the process. The study has a special emphasis on the titanium isopropoxide-valeric acid system due to the superior quality of these films over other carboxylates. Greater knowledge of the hydrolysis kinetics allows increased control over the quality of the film materials and should be of general interest to those working with modified metal alkoxides.


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