scholarly journals Co-Digestion of Salix and Manure for Biogas: Importance of Clone Choice, Coppicing Frequency and Reactor Setup

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3804
Author(s):  
Jonas A. Ohlsson ◽  
Ann-Christin Rönnberg-Wästljung ◽  
Nils-Erik Nordh ◽  
Anna Schnürer

Animal manure represents a major source of renewable energy that can be converted into biogas using anaerobic digestion. In order to most efficiently utilize this resource, it can be co-digested with energy dense, high biomethanation potential feedstocks such as energy crops. However, such feedstocks typically require pretreatments which are not feasible for small-scale facilities. We investigated the use of single-stage and the sequential co-digestion of comminuted but otherwise non-pretreated Salix with animal manure, and further investigated the effects of coppicing frequency and clone choice on biomethanation potential and the area requirements for a typical Swedish farm-scale anaerobic digester using Salix and manure as feedstock. In comparison with conventional single-stage digestion, sequential digestion increased the volumetric and specific methane production by 57% to 577 NmL L−1 d−1 and 192 NmL (g volatile solids (VS))−1, respectively. Biomethanation potential was the highest for the two-year-old shoots, although gains in biomass productivity suggest that every-third-year coppicing may be a better strategy for supplying Salix feedstock for anaerobic digestion. The biomethane production performance of the sequential digestion of minimally pretreated Salix mirrors that of hydrothermally pretreated hardwoods and may provide an option where such pretreatments are not feasible.

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3477
Author(s):  
Navodita Bhatnagar ◽  
David Ryan ◽  
Richard Murphy ◽  
Anne-Marie Enright

Anaerobic digestion (AD) of chicken litter (CL) is a viable alternative to disposal. However, methane yields from this primarily organic waste are quite low when mono-digested. This paper discusses the effect of an enzyme cocktail, trace element (TE) supplementation and selenium (Se) addition in small-scale batch biomethane potential (BMP) assays to enhance the AD of CL. Eleven different assays were set up in triplicate including assays containing only inoculum (blank), only CL (negative control) and cellulose and inoculum (positive control). The results indicate that both enzyme treatment and trace element supplementation enhanced the biogas and methane yield. The highest specific biogas and methane yields were noted for 1% enzyme-treated CL of 835.2 L/kg volatile solids (VS) and 460.8 L/kg VS, respectively. Usually, mono-digestion of CL is low due to high nitrogen content and the presence of recalcitrant lignocellulosic material from the bedding material. Enzyme treatment performed better than the addition of the TE mix and Se.


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).


2019 ◽  
Vol 50 (3) ◽  
pp. 127-133 ◽  
Author(s):  
Ester Scotto di Perta ◽  
Elena Cervelli ◽  
Maria Pironti di Campagna ◽  
Stefania Pindozzi

Anaerobic digestion (AD) is a mature technology commonly used for manure treatment, both for the stabilisation of waste and for the production of energy. The introduction of new incentives could represent an opportunity for biogas production, when the current feed-in-tariffs, which improved the financial feasibility of AD plants producing electricity will end. This paper examines the feasibility of reconverting an existing AD biogas production plant into a biomethane production plant. The AD plant, in this case study, is a two-stage reactor situated in the centre of Italy and mainly fed with livestock manure from both cows and buffaloes. The economic analysis of two hypotheses is provided: i) continuing the electricity production from biogas after the end of the current incentives (2025); ii) considering the new incentives program for the biomethane and reconverting the plant, using hollow-fibre membranes for the purification of the raw biogas (SEPURAN® Green modules, EnviTec). For this purpose, investment and operating costs, based on plant monitoring data (2105.3 m3 d–1, Biogas production; 4432.9 kWh d–1, electricity production) as well as on market analysis for costs evaluation were considered. The mean biogas production for the considered year was about 30% less than the expected production, indicated by producer, highlighting the need for the optimisation of the management of the reactors. Moreover, based on the averaged methane production (June 2017-June 2018), results show that: i) plant conversion for the biomethane production is not suitable for small-scale plants, due to the high investment costs of upgrading technology (1.2 M€); ii) when current incentives end, the electricity production from biogas in the current plant may not be self-sufficient, due to the highly expensive operating costs. This paper provides a first analysis of the possible fate of the biogas plants under the new incentives.


2020 ◽  
Vol 14 (2) ◽  
pp. 258-264
Author(s):  
Caiyan Liu ◽  
Baocheng Wei ◽  
Zhuangqiang Dai ◽  
Chang Chen ◽  
Guangqing Liu

Due to an approaching energy crisis, new energy sources with low pollution and high energy density are being urgently sought. Energy plants, as a new option, were widely studied and considered. In this work, the characteristics and biomethane production performance of giant grasses (Pennisetum giganteum z.x.lin) with different harvest times were studied. The results implied that the solid content and lignin content in giant grasses both increased with growth time. The anaerobic digestion (AD) of giant grasses harvested in December initiated faster. Cumulative methane yield of the giant grass harvested in July was higher, reaching 267.9 mL/gVS at an organic loading of 15 gVS/L. A first-order model and a modified Gompertz model were used to fit and evaluate the AD process of these two giant grasses, and the results showed that both models can describe the process well. The results of this study indicated that the harvest time of the giant grass had a large impact on the biomethane production, which also provided a theoretical basis for the future utilization of giant grass and other energy plants.


2020 ◽  
Vol 7 (8) ◽  
pp. 200443
Author(s):  
Ming Gao ◽  
Shuang Zhang ◽  
Xinxin Ma ◽  
Weijie Guan ◽  
Na Song ◽  
...  

Food waste contains numerous easily degradable components, and anaerobic digestion is prone to acidification and instability. This work aimed to investigate the effect of adding yeast on biogas production performance, when substrate is added after biogas production is reduced. The results showed that the daily biogas production increased 520 and 550 ml by adding 2.0% (volatile solids; VS) of activated yeast on the 12th and 37th day of anaerobic digestion, respectively, and the gas production was relatively stable. In the control group without yeast, the increase of gas production was significantly reduced. After the second addition of substrate and yeast, biogas production only increased 60 ml compared with that before the addition. After fermentation, the biogas production of yeast group also increased by 33.2% compared with the control group. Results of the analysis of indicators, such as volatile organic acids, alkalinity and propionic acid, showed that the stability of the anaerobic digestion system of the yeast group was higher. Thus, the yeast group is highly likely to recover normal gas production when the biogas production is reduced, and substrate is added. The results provide a reference for experiments on the industrialization of continuous anaerobic digestion to take tolerable measures when the organic load of the feed fluctuates dramatically.


2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
R. Oberti ◽  
A. Tenca ◽  
F. Perazzolo ◽  
E. Riva ◽  
A. Finzi ◽  
...  

Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg) can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices), afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55􀀀 2 °C) without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous laboratory results, with a typical hydrogen and methane specific productivity of 2.2 and 0.5 Nm3/m3reactor per day, in the first and second stage of the plant respectively. At our best knowledge, this plant is one of the very first prototypes producing biohydrogen at farm scale, and it represents a distributed, small scale demonstration to obtain hydrogen from renewable waste-sources.


2019 ◽  
Vol 26 (14) ◽  
pp. 14250-14258 ◽  
Author(s):  
Lyu Li ◽  
Ruolin Wang ◽  
Zhenlai Jiang ◽  
Wanwu Li ◽  
Guangqing Liu ◽  
...  

2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2561
Author(s):  
Furqan Muhayodin ◽  
Albrecht Fritze ◽  
Oliver Christopher Larsen ◽  
Marcel Spahr ◽  
Vera Susanne Rotter

Rice straw is an agricultural residue produced in abundant quantities. Open burning and plowing back the straw to the fields are common practices for its disposal. In-situ incorporation and burning cause emissions of greenhouse gas and particulate matter. Additionally, the energy potential of rice straw is lost. Anaerobic digestion is a technology that can be potentially used to utilize the surplus rice straw, provide renewable energy, circulate nutrients available in the digestate, and reduce greenhouse gas emissions from rice paddies. An innovative temperature phased anaerobic digestion technology was developed and carried out in a continuous circulating mode of mesophilic and hyperthermophilic conditions in a loop digester (F1). The performance of the newly developed digester was compared with the reference digester (F2) working at mesophilic conditions. Co-digestion of rice straw was carried out with cow manure to optimize the carbon to nitrogen ratio and to provide the essential trace elements required by microorganisms in the biochemistry of methane formation. F1 produced a higher specific methane yield (189 ± 37 L/kg volatile solids) from rice straw compared to F2 (148 ± 36 L/kg volatile solids). Anaerobic digestion efficiency was about 90 ± 20% in F1 and 70 ± 20% in F2. Mass fractions of Fe, Ni, Co, Mo, Cu, and Zn were analyzed over time. The mass fractions of Co, Mo, Cu, and Zn were stable in both digesters. While mass fractions of Fe and Ni were reduced at the end of the digestion period. However, no direct relationship between specific methane yield and reduced mass fraction of Fe and Ni was found. Co-digestion of rice straw with cow manure seems to be a good approach to provide trace elements except for Se.


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