scholarly journals Biochar Promotes Methane Production During Anaerobic Digestion of Organic Waste

Author(s):  
Leilei Xiao ◽  
Eric Lichtfouse ◽  
Senthil Kumar ◽  
Quan Wang ◽  
Fanghua Liu

Abstract Climate change and energy demand are calling more sustainable fuels such as biomethane produced by anaerobic digestion of organic waste. Biochar addition to waste is presumed to enhance the efficiency of methane production, yet individual reports disclose contradictory results. Therefore, we performed a meta-analysis of 27 selected publications containing 156 paired measurements of control and biochar-amended treatments to assess the impact of biochar on methanogenic performance. Results show that biochar promotes biomethane production substantially with a high Hedge's d value of 5.7 ± 1.04, yet sporadic publications report a methane decline. Methanogenic performance is statistically controlled by feedstock type, pyrolysis temperature and biochar concentration, but not controlled by pH, size, surface area and methanogen species. Our findings should help to tune the parameters of anaerobic digestion with biochar to optimize biomethane productions.

Author(s):  
Leilei Xiao ◽  
Eric Lichtfouse ◽  
P. Senthil Kumar ◽  
Quan Wang ◽  
Fanghua Liu

2020 ◽  
Vol 13 (1) ◽  
pp. 27
Author(s):  
Hatem Mahmoud ◽  
Ayman Ragab

The density of building blocks and insufficient greenery in cities tend to contribute dramatically not only to increased heat stress in the built environment but also to higher energy demand for cooling. Urban planners should, therefore, be conscious of their responsibility to reduce energy usage of buildings along with improving outdoor thermal efficiency. This study examines the impact of numerous proposed urban geometry cases on the thermal efficiency of outer spaces as well as the energy consumption of adjacent buildings under various climate change scenarios as representative concentration pathways (RCP) 4.5 and 8.5 climate projections for New Aswan city in 2035. The investigation was performed at one of the most underutilized outdoor spaces on the new campus of Aswan University in New Aswan city. The potential reduction of heat stress was investigated so as to improve the thermal comfort of the investigated outdoor spaces, as well as energy savings based on the proposed strategies. Accordingly, the most appropriate scenario to be adopted to cope with the inevitable climate change was identified. The proposed scenarios were divided into four categories of parameters. In the first category, shelters partially (25–50% and 75%) covering the streets were used. The second category proposed dividing the space parallel or perpendicular to the existing buildings. The third category was a hybrid scenario of the first and second categories. In the fourth category, a green cover of grass was added. A coupling evaluation was applied utilizing ENVI-met v4.2 and Design-Builder v4.5 to measure and improve the thermal efficiency of the outdoor space and reduce the cooling energy. The results demonstrated that it is better to cover outdoor spaces with 50% of the overall area than transform outdoor spaces into canyons.


Author(s):  
Kai Schumüller ◽  
Dirk Weichgrebe ◽  
Stephan Köster

AbstractTo tap the organic waste generated onboard cruise ships is a very promising approach to reduce their adverse impact on the maritime environment. Biogas produced by means of onboard anaerobic digestion offers a complementary energy source for ships’ operation. This report comprises a detailed presentation of the results gained from comprehensive investigations on the gas yield from onboard substrates such as food waste, sewage sludge and screening solids. Each person onboard generates a total average of about 9 kg of organic waste per day. The performed analyses of substrates and anaerobic digestion tests revealed an accumulated methane yield of around 159 L per person per day. The anaerobic co-digestion of sewage sludge and food waste (50:50 VS) emerged as particularly effective and led to an increased biogas yield by 24%, compared to the mono-fermentation. In the best case, onboard biogas production can provide an energetic output of 82 W/P, on average covering 3.3 to 4.1% of the total energy demand of a cruise ship.


2018 ◽  
Vol 199 ◽  
pp. 651-658 ◽  
Author(s):  
Amudha Thanarasu ◽  
Karthik Periyasamy ◽  
Kubendran Devaraj ◽  
Premkumar Periyaraman ◽  
Shanmugam Palaniyandi ◽  
...  

2016 ◽  
Vol 23 (1) ◽  
pp. 99-115 ◽  
Author(s):  
Agnieszka A. Pilarska ◽  
Krzysztof Pilarski ◽  
Kamil Witaszek ◽  
Hanna Waliszewska ◽  
Magdalena Zborowska ◽  
...  

Abstract The results of anaerobic digestion (AD) of buttermilk (BM) and cheese whey (CW) with a digested sewage sludge as inoculum is described. The substrate/inoculum mixtures were prepared using 10% buttermilk and 15% cheese whey. The essential parameters of the materials were described, including: total solids (TS), volatile solids (VS), pH, conductivity, C/N ratio (the quantitative ratio of organic carbon (C) to nitrogen (N)), alkalinity, chemical oxygen demand (COD). The potential directions of biodegradation of the organic waste types, as used in this study, are also presented. Appropriate chemical reactions illustrate the substrates and products in each phase of anaerobic decomposition of the compounds that are present in buttermilk and cheese whey: lactic acid, lactose, fat, and casein. Moreover, the biogas and biomethane production rates are compared for the substrates used in the experiment. The results have shown that buttermilk in AD generates more biogas (743 m3/Mg VS), including methane (527 m3/Mg VS), when compared with cheese whey (600 m3/Mg VS, 338 m3/Mg VS for biogas and methane, respectively).


2015 ◽  
Vol 17 (3) ◽  
pp. 40-46
Author(s):  
Kateřina Chamrádová ◽  
Jiří Rusín

Abstract A laboratory experiment of two-stage mesophilic, low-dry mass, anaerobic digestion was carried out, focused on verifying the benefit of processing the biscuit meal EKPO-EB instead of triticale silage Agostino (GPS) and corn silage LG3266 in a regular batch for the agricultural biogas station in Pustějov. While anaerobic digestion of ensilages is largely difficult due to the content of lignocellulose, biscuit meal provides a high yield of biogas or methane, respectively, thanks to its high content of simple saccharides and lipids. When the original GPS (or the replacement EKPO-EB, respectively) represented 0.81% of weight of the daily input mixture dose for the first stage, the rise in volumetric methane production was 20% which is significant. The biscuit meal EKPO-EB decomposes almost completely in the first stage. Later, when the EKPO-EB represented 1.63% of weight of the daily input mixture dose for the first stage, the rise in volumetric methane production was 54% in the first stage and 16% in the second stage.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Timothy King Avordeh ◽  
Samuel Gyamfi ◽  
Alex Akwasi Opoku

Purpose The purpose of this paper is to investigate the impact of temperature on residential electricity demand in the city of Greater Accra, Ghana. It is believed that the increasing trend of temperatures may significantly affect people’s lives and demand for electricity from the national grid. Given the recurrent electricity crisis in Ghana, this study will investigate both the current and future residential energy demands in the light of temperature fluctuations. This will inform future power generation using renewable energy resources mix to find a sustainable solution to the recurrent energy demand challenges in Ghana. This study will help the Government of Ghana to better understand the temperature dependence of residential energy demand, which in turn will help in developing behavioral modification programs aimed at reducing energy consumption. Monthly data for the temperature and residential electricity consumption for Greater Accra Region from January 2007 to December 2018 obtained from the Ghana Meteorological Service (GMS) and Ghana Grid Company (Gridco), respectively, are used for the analysis. Design/methodology/approach This study used monthly time series data from 2007 to 2018. Data on monthly electricity demand and temperature are obtained from the Ghana Grid Company and GMS. The theoretical framework for residential electricity consumption, the log-linear demand equation and time series regression approaches was used for this study. To demonstrate certain desirable properties and to produce good estimators in this study, an analysis technique of ordinary least squares measurement was also applied. Findings This study showed an impact on residential electricity requirements in the selected regions of Greater Accra owing to temperature change. The analysis suggests a substantial positive response to an increase in temperature demand for residential electricity and thus indicates a growth of the region’s demand for electricity in the future because of temperature changes. As this analysis projects, the growth in the electricity demand seems too small for concern, perhaps because of the incoherence of the mechanisms used to regulate the temperature by the residents. However, two points should be considered when drawing any conclusions even in the case of Greater Accra alone. First, the growth in the demand for electricity shown in the present study is the growth of demand due only to increasing temperatures that do not consider changes in all the other factors driving the growth of demand. The electricity demand will in the future increase beyond what is induced by temperature, due to increasing demand, population and mechanization and other socioeconomic factors. Second, power consumption understated genuine electricity demand, owing to the massive shedding of loads (Dumsor) which occurred in Ghana from 2012 to 2015 in the analysis period that also applies in the Greater Accra region. Given both of these factors, the growth in demand for electricity is set to increase in response to climate change, which draws on the authorities to prepare more critically on capacity building which loads balancing. The results also revealed that monthly total residential electricity consumption, particularly the monthly peak electricity consumption in the city of Accra is highly sensitive to temperature. Therefore, the rise in temperature under different climate change scenarios would have a high impact on residential electricity consumption. This study reveals that the monthly total residential electricity demand in Greater Accra will increase by up to 3.1%. Research limitations/implications The research data was largely restricted to only one region in Ghana because of the inconsistencies in the data from the other regions. The only climate variable use was temperature because it was proven in the literature that it was the most dominant variable that affects electricity demand, so it was not out of place to use only this variable. The research, however, can be extended to capture the entire regions of the country if sponsorship and accurate data can be obtained. Practical implications The government as the policy and law-making authority has to play the most influential role to ensure adaptation at all levels toward the impact of climate change for residential consumers. It is the main responsibility of the government to arrange enough supports to help residential consumers adapt to climate change and try to make consumers self-sufficient by modification of certain behaviors rather than supply dependent. Government bodies need to carefully define their climate adaptation supports and incentive programs to influence residential-level consumption practices and demand management. Here, energy policies and investments need to be more strategic. The most critical problem is to identify the appropriate adaptation policies that favor the most vulnerable sectors such as the residential sector. Social implications To evaluate both mitigation and adaptation policies, it is important to estimate the effect of climate change on energy usage around the world. Existing empirical figures, however, are concentrated in Western nations, especially the USA. To predict how electricity usage will shift in the city of Greater Accra, Ghana, the authors used regular household electricity consumption data. Originality/value The motivation for this paper and in particular the empirical analysis for Ghana is originality for the literature. This paper demonstrates an adequate understanding of the relevant literature in modern times.


2012 ◽  
pp. 75-98
Author(s):  
Rosaria Viscecchia ◽  
Antonio Stasi ◽  
Maurizio Prosperi

Modern lifestyle is one among the most relevant causes of alimentary disorder and environmental problems. Preventing both of them implies a win-win strategy for the improvement of social wellness (i.e. health and environmental benefits). A suitable strategy could be addressed to the partial substitution of caloric food (e.g. beef meat), which is also responsible for a large amount of greenhouse gas (ghgs) emissions, with less caloric food (e.g. vegetables), which is proved of exerting a lower impact on climate change. The analysis is referred to the Italian case study, based on data from the Italian Statistical Institute (istat). The relationship between obesity and ghgs emissions is here explained experimentally through a 5-stage methodology. In the first step, a regression model (ols method) is adopted to explain obesity rate in terms of ratio of people consuming meat more than once a week, and the ratio of people consuming vegetables less than once a day. The outcome of this analysis allows simulating a policy target in terms of obesity abatement, provided by a reasonable change in food demand. In the third step, a meta-analysis of Life Cycle Assessment (lca) studies has been performed in order to calculate the CO2 emissions of the food types we considered. In the fourth step, the observed change in food demand from the previous step is combined with lca indicators, in order to evaluate the impact of food industry on climate change. Finally, in the fifth step, the benefits of the obesity reduction are calculated considering the cost saving for health care of the obesity, which amounts to 1.700 Eur per person. In addition, the value of the CO2 emission have been compared with the value of the European Union Allowance (eua) of CO2 emissions, which was evaluated in 2009 in terms of 21.45 eur/t CO2. Consequently, we found that the effect of the policy can be estimated in terms of 1,032 Million eur, of which the impacts on human health is the most important (about 1.020 Million eur). The study shows the evidence that the consumption of food with low content of calories has a most relevant effect in the reduction of obesity, but very limited economic effect in terms of CO2 emissions.


2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Thales H. F. Costa ◽  
Vincent G. H. Eijsink ◽  
Svein Jarle Horn

Abstract Background The recent discovery that LPMOs can work under anaerobic conditions when supplied with low amounts H2O2 opens the possibility of using LPMOs as enzyme aids in biogas reactors to increase methane yields from lignocellulosic materials. We have explored this possibility by studying anaerobic digestion of various lignocellulosic materials: Avicel, milled spruce and birch wood, and a lignin-rich hydrolysis residue from steam-exploded birch. The digestions were added LPMOs and various cellulolytic enzyme cocktails and were carried out with or without addition of H2O2. Results In several cases, enzyme addition had a beneficial effect on methane production, which was partly due to components present in the enzyme preparations. It was possible to detect LPMO activity during the initial phases of the anaerobic digestions of Avicel, and in some cases LPMO activity could be correlated with improved methane production from lignocellulosic materials. However, a positive effect on methane production was only seen when LPMOs were added together with cellulases, and never upon addition of LPMOs only. Generally, the experimental outcomes showed substrate-dependent variations in process efficiency and the importance of LPMOs and added H2O2. These differences could relate to variations in the type and content of lignin, which again will affect the activity of the LPMO, the fate of the added H2O2 and the generation of potentially damaging reactive-oxygen species. The observed effects showed that the interplay between cellulases and LPMOs is important for the overall efficiency of the process. Conclusion This study shows that it may be possible to harness the power of LPMOs in anaerobic digestion processes and improve biogas production, but also highlight the complexity of the reaction systems at hand. One complicating factor was that the enzymes themselves and other organic components in the enzyme preparations acted as substrates for biogas production, meaning that good control reactions were essential to detect effects caused by enzyme activity. As also observed during regular aerobic enzymatic digestion of lignocellulosic biomass, the type and contents of lignin in the substrates likely plays a major role in determining the impact of LPMOs and of cellulolytic enzymes in general. More work is needed to unravel the interplay between LPMOs, O2, H2O2, and the multitude of redox-active components found in anaerobic bioreactors degrading lignocellulosic substrates.


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