scholarly journals Enhancing waste degradation and biogas production by pre-digestion with a hyperthermophilic anaerobic bacterium

2021 ◽  
Vol 8 (3) ◽  
pp. 1433-1443
Author(s):  
Jaron C. Hansen ◽  
Zachary T. Aanderud ◽  
Lindsey E. Reid ◽  
Carson Bateman ◽  
Conly L. Hansen ◽  
...  

The hyperthermophilic anaerobic bacterium, Caldicellulosiruptor bescii, is effective in degrading and solubilizing lignocellulosic materials. Laboratory studies have characterized the chemistry of the process for crystalline cellulose and switchgrass, but the data are insufficient for engineering commercial plants to use C. bescii for pre-digestion of waste streams. The purpose of this study is three-fold: 1) to identify any potential toxicities in C. bescii pre-digestion and biogas production from several wastes; 2) to determine the potential enhancement of biogas production by anaerobic digestion of pre-digested dairy manure and waste activated sludge; and 3) to identify variables that must be quantified and controlled for engineering commercial, continuous-flow systems for waste disposal and biogas production incorporating C. bescii pre-digestion. Tests were run at lab-, bench- and pilot plant-scale with C.bescii pre-digestion and controls run at 75°C and pH 7-8 followed by mesophilic anaerobic digestion at 37-41°C. The lab- and bench-scale tests demonstrate that C. bescii is capable of growing on several organic wastes and pre-digestion with C. bescii increases conversion of waste into biogas, typically by a factor of 2 or more. Incorporation of C. bescii pre-digestion in an optimized commercial system is predicted to provide 75-85% volatile solids conversion to biogas with 75% methane when digesting dairy manure and sewage sludge. Achieving these results at a commercial scale requires further work to quantify C. bescii growth and enzyme production rates, as well as rates of base- and enzyme-catalyzed hydrolysis of the polymeric materials, e.g., lignocellulose, in the waste in order to optimize retention times.

2021 ◽  
Vol 11 (7) ◽  
pp. 3064
Author(s):  
Roberta Mota-Panizio ◽  
Manuel Jesús Hermoso-Orzáez ◽  
Luis Carmo-Calado ◽  
Gonçalo Lourinho ◽  
Paulo Sérgio Duque de Brito

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and inoculum (digested sludge from a wastewater treatment plant (WWTP)), with a ratio of inoculum/substrate (Ino/CBW) of 1:1 and 2:1 on the basis of volatile solids (VSs); the codigestion with food waste (FW) had a ratio of 2/0.7:0.3 (Ino/CBW:FW) and the codigestion with cow manure (CM) had a ratio of 2/0.5:0.5 (Ino/CBW:CM). Biogas and methane production was proportional to the inoculum substrate ratio (ISR) used. BMP tests have proved to be valuable for inferring the adequacy of anaerobic digestion to treat wastewater from the cork industry. The results indicate that the biomethane potential of CBWs for Ino/CBW ratios 1:1 and 2:1 is very low compared to other organic substrates. For the codigestion tests, the test with the Ino/CBW:CM ratio of 2/0.7:0.3 showed better biomethane yields, being in the expected values. This demonstrated that it is possible to perform the anaerobic digestion (AD) of CBW using a cosubstrate to increase biogas production and biomethane and to improve the quality of the final digestate.


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.


2015 ◽  
Vol 10 (3) ◽  
pp. 532-537 ◽  
Author(s):  
Yumika Kitazono ◽  
Ikko Ihara ◽  
Kiyohiko Toyoda ◽  
Kazutaka Umetsu

This study evaluated antibiotic degradation and biogas production during anaerobic digestion of dairy manure contained two common veterinary antibiotics at 37 °C. After 18 days of digestion, the concentration of chlortetracycline (CTC) decreased more than 80% regardless of the initial CTC concentration. The concentration of cefazolin (CEZ) decreased from 10 to 0.08 mg/L in 6 days. Less than 50 mg/L CTC and 10 mg/L CEZ had negligible impact on biogas production during anaerobic digestion process. The result showed that the anaerobic digestion has a potential to degrade antibiotic residues in livestock manure.


2005 ◽  
Vol 52 (1-2) ◽  
pp. 487-492 ◽  
Author(s):  
Y. Shang ◽  
B.R. Johnson ◽  
R. Sieger

A steady-state implementation of the IWA Anaerobic Digestion Model No. 1 (ADM1) has been applied to the anaerobic digesters in two wastewater treatment plants. The two plants have a wastewater treatment capacity of 76,000 and 820,000 m3/day, respectively, with approximately 12 and 205 dry metric tons sludge fed to digesters per day. The main purpose of this study is to compare the ADM1 model results with full-scale anaerobic digestion performance. For both plants, the prediction of the steady-state ADM1 implementation using the suggested physico-chemical and biochemical parameter values was able to reflect the results from the actual digester operations to a reasonable degree of accuracy on all parameters. The predicted total solids (TS) and volatile solids (VS) concentration in the digested biosolids, as well as the digester volatile solids destruction (VSD), biogas production and biogas yield are within 10% of the actual digester data. This study demonstrated that the ADM1 is a powerful tool for predicting the steady-state behaviour of anaerobic digesters treating sewage sludges. In addition, it showed that the use of a whole wastewater treatment plant simulator for fractionating the digester influent into the ADM1 input parameters was successful.


2016 ◽  
Vol 75 (4) ◽  
pp. 775-781 ◽  
Author(s):  
J. A. Barrios ◽  
U. Duran ◽  
A. Cano ◽  
M. Cisneros-Ortiz ◽  
S. Hernández

Anaerobic digestion of wastewater sludge is the preferred method for sludge treatment as it produces energy in the form of biogas as well as a stabilised product that may be land applied. Different pre-treatments have been proposed to solubilise organic matter and increase biogas production. Sludge electrooxidation with boron-doped diamond electrodes was used as pre-treatment for waste activated sludge (WAS) and its effect on physicochemical properties and biomethane potential (BMP) was evaluated. WAS with 2 and 3% total solids (TS) achieved 2.1 and 2.8% solubilisation, respectively, with higher solids requiring more energy. After pre-treatment, biodegradable chemical oxygen demand values were close to the maximum theoretical BMP, which makes sludge suitable for energy production. Anaerobic digestion reduced volatile solids (VS) by more than 30% in pre-treated sludge with a food to microorganism ratio of 0.15 g VSfed g−1 VSbiomass. Volatile fatty acids were lower than those for sludge without pre-treatment. Best pre-treatment conditions were 3% TS and 28.6 mA cm−2.


2014 ◽  
Vol 1008-1009 ◽  
pp. 121-126
Author(s):  
Lin Jun Shi ◽  
Wen Lan Liu ◽  
Hui Fen Liu ◽  
Wei Yu Zhang ◽  
Li Tong Ban

Anaerobic digestion of single dairy manure, single vegetable waste, mixture of dairy manure and vegetable waste was conducted to produce biogas. Startup characteristic, leachate parameters and inoculation amount were investigated. The experimental results showed that anaerobic digestion can start up quickly with acclimated thickening sludge as inoculation sludge and 30% was appropriate inoculation percentage. Digestion of single dairy manure and mixture of dairy manure and vegetable waste appeared better buffering ability with higher alkalinity than single vegetable waste. Compared to single digestion of dairy manure or vegetable waste, mixture of dairy manure and vegetable waste is more suitable for anaerobic digestion. Under the conditions of TS=10% and T=(36±1)°C, cumulative biogas production of mixture of dairy manure and vegetable waste is 5281 mL during the period of 30 days and average daily gas production is about 176 mL. These results could provide theoretical data for practical biogas engineering.


Author(s):  
Peter E. Zemke ◽  
Byard D. Wood ◽  
Christopher R. Rohleder

Many modern anaerobic digesters in developed countries consist of a digestion process in which solids are reduced to biogas, followed by mechanical separation that removes the majority of the remaining solids from the effluent. Experience has shown that such systems are often plagued with plugging due to excessive solids in the digester influent. Moreover, the mechanical separation equipment is prematurely degraded due to the elevated temperatures and corrosive compounds in the digester effluent. Reversing the order of separation and digestion offers a proven method of eliminating these problems, but at the expense of lower biogas production. The work presented in this paper quantifies this difference in biogas production by comparing the biogas yields of dairy wastewater feedstocks with and without prior mechanical solids separation through a 0.75-mm screen. Laboratory-scale batch digesters were operated up to 40 days at 35–40 °C and monitored for mass of volatile solids consumed and biogas production. Although the initially separated influent contained only half as much volatile solids, the ultimate biogas yield was only 25% less than that obtained with non-separated influent, demonstrating some tradeoff between higher energy production and system reliability.


2019 ◽  
Vol 9 (13) ◽  
pp. 2703
Author(s):  
Hui Wang ◽  
Horacio A. Aguirre-Villegas ◽  
Rebecca A. Larson ◽  
Asli Alkan-Ozkaynak

Manure characteristics change through processing, including anaerobic digestion (AD). These changes can alter handling of manure during downstream operations. This study analyzed the density, total solids (TS) content, and volatile solids (VS) content of pre-digested and anaerobically digested dairy manure from seven dairy farms in Wisconsin. The density of pre-digested manure increased from 990 to 1065 kg m−3 as the TS level increased from 1.5% to 13.0%. Density and TS for pre-digested manure from facilities using separated solids as bedding were related with a linear model for TS ranging from 1.5% to 13.0% and with a polynomial model for TS ranging from 1.5% to 50%. The model shows that density decreases with an increasing TS content when TS is greater than 8.0%. Manure from dairy facilities that used sand bedding had a VS/TS ratio of 0.87. This ratio was higher than the ratio when manure solids were used as bedding (0.81) and when food waste was incorporated into the digester (0.77). This study also provides a simple methodology to estimate biogas yield by using the density of pre- and post-digested manure.


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.


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