scholarly journals In Situ Sonification of Anaerobic Digestion: Extended Evaluation of Performance in a Temperate Climate

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5349
Author(s):  
John Loughrin ◽  
Stacy Antle ◽  
Jason Simmons ◽  
Karamat Sistani ◽  
Nanh Lovanh
Keyword(s):  
Control System ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Low Frequency ◽  
Sine Wave ◽  
Temperate Climate ◽  
Anaerobic Digesters ◽  
Environmental Consequences ◽  
The Cost ◽  
Wave Induced

Increasing the efficiency of anaerobic digesters and improving sludge breakdown is vital to reducing the cost of biogas production and reducing the environmental consequences of sludge disposal. The performance of two unheated anaerobic digestion systems, one exposed to sound at <20 kHz by waterproofed speakers and one acting as a control, were compared for over a year. The digester systems were both composed of primary (11.4 m3) and secondary (3.8 m3) anaerobic tanks, facultative tertiary (3.0 m3) tanks and an aerobic holding tank from which effluent was mixed with feed and recirculated back to the system. Exposure of the gas saturated digestate to a low frequency sine wave induced numerous bubble harmonics up to, and presumably beyond, ultrasonic range, showing that sonification of a highly gaseous liquid might be used to accomplish low power ultrasonication of digestate at greater distances than is possible with conventional ultrasonic technology. Through the summer of 2019, the sound-treated system produced 27% more biogas than the control system, and 74 times more during the winter when biogas production by the control systems essentially ceased. Afterwards, the control system produced more biogas due to depletion of volatile solids in the sound-treated digester. Results show that sound can be used for faster digester startup and substitute for a share of heating requirements during cool months.

Application of the IWA Anaerobic Digestion Model (ADM1) for simulating full-scale anaerobic sewage sludge digestion

2005 ◽  
Vol 52 (1-2) ◽  
pp. 487-492 ◽  
Author(s):  
Y. Shang ◽  
B.R. Johnson ◽  
R. Sieger
Keyword(s):  
Wastewater Treatment ◽  
Steady State ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Biochemical Parameter ◽  
Full Scale ◽  
Anaerobic Digesters ◽  
Biogas Yield ◽  
Volatile Solids

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.

scholarly journals Anaerobic Digestion of Cassava (Manihot Esculenta) Waste: Effects of Inoculum on Biogas Production Rate

2020 ◽  
Vol 4 (2) ◽  
pp. 411-420
Author(s):  
B.E. Eboibi ◽  
K.O. Adiotomre ◽  
F. Onobrudu ◽  
E. Osioh
Keyword(s):  
Anaerobic Digestion ◽  
Production Rate ◽  
Manihot Esculenta ◽  
Decay Constant ◽  
Biogas Production ◽  
Cow Manure ◽  
Anaerobic Digesters ◽  
First Order ◽  
Cassava Peel ◽  
Biogas Production Rate

In this paper, cow manure fluid was used as inoculums to investigate biogas production rate from anaerobic digestion of cassava peel at mesophilic temperature (280C). The anaerobic experiment was conducted using six batch digesters (D1, D2, D3, D4, D5 and D6) each of 20L capacity for 40-day hydraulic retention. Each digester, was loaded with 5kg of cassava peel (CP) and 0%, 10%, 20%, 30%, 40% and 50% of inoculum to CP. Hashimoto model was used to obtain the digestion kinetic parameters. The results of the study showed that inoculums influenced the rate of biogas production, showing variations in biogas production, correlation coefficient (R2) and in first-order decay constant (k). The average cumulative biogas production was in the range of ~2358 to 4010ml/kgVS for 10% to 50% inoculum. The R2 and k for D1 was 0.959 and 0.359 D1 (without inoculum), 0.990 and 0.371 for D2 (10% inoculum) and 0.991 and 0.371 for D3 (20% inoculum), 0.951 and 0.356 for D4 (30% inoculum), 0.992 and 0.372 for D5 (40% inoculum), and 0.990 and 0.371 was obtained for D6 loaded with 50% inoculum. Despite variation in biogas yields from different inoculums, biogas production obtained from anaerobic digesters loaded with inoculums were still lower compared with that without inoculum.

scholarly journals Potentials and Costs of various Renewable Gases: A Case Study for the Austrian Energy System by 2050

Detritus ◽  
2021 ◽  
pp. 106-120
Author(s):  
Daniel Cenk Rosenfeld ◽  
Johannes Lindorfer ◽  
Hans Böhm ◽  
Andreas Zauner ◽  
Karin Fazeni-Fraisl
Keyword(s):  
Anaerobic Digestion ◽  
Biomass Gasification ◽  
Energy System ◽  
Production Costs ◽  
Anaerobic Digesters ◽  
Synthetic Natural Gas ◽  
Technical Potential ◽  
Methane Potential ◽  
Power To Gas ◽  
The Cost

This analysis estimates the technically available potentials of renewable gases from anaerobic conversion and biomass gasification of organic waste materials, as well as power-to-gas (H2 and synthetic natural gas based on renewable electricity) for Austria, as well as their approximate energy production costs. Furthermore, it outlines a theoretical expansion scenario for plant erection aimed at fully using all technical potentials by 2050. The overall result, illustrated as a theoretical merit order, is a ranking of technologies and resources by their potential and cost, starting with the least expensive and ending with the most expensive. The findings point to a renewable methane potential of about 58 TWh per year by 2050. The highest potential originates from biomass gasification (~49 TWh per year), while anaerobic digestion (~6 TWh per year) and the power-to-gas of green CO2 from biogas upgrading (~3 TWh per year) demonstrate a much lower technical potential. To fully use these potentials, 870 biomass gasification plants, 259 anaerobic digesters, and 163 power-to-gas plants to be built by 2050 in the full expansion scenario. From the cost perspective, all technologies are expected to experience decreasing specific energy costs in the expansion scenario. This cost decrease is not significant for biomass gasification, at only about 0.1 €-cent/kWh, resulting in a cost range between 10.7 and 9.0 €-cent/kWh depending on the year and fuel. However, for anaerobic digestion, the cost decrease is significant, with a reduction from 7.9 to 5.6 €-cent/kWh. It is even more significant for power-to-gas, with a reduction from 10.8 to 5.1 €-cent/kWh between 2030 and 2050.

scholarly journals Evaluation of Microaeration and Sound to Increase Biogas Production from Poultry Litter

Environments ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 62
Author(s):  
John Loughrin ◽  
Stacy Antle ◽  
Michael Bryant ◽  
Zachary Berry ◽  
Nanh Lovanh
Keyword(s):  
Feeding Rate ◽  
Fine Particles ◽  
Biogas Production ◽  
Poultry Litter ◽  
Sine Wave ◽  
Aerobic Bacteria ◽  
Anaerobic Digesters ◽  
Wastewater Quality ◽  
Complex Polymers ◽  
Sound Treatment

Microaeration, wherein small amounts of air are introduced into otherwise anaerobic digesters, has been shown to enhance biogas production. This occurs by fostering the growth of facultatively aerobic bacteria and production of enzymes that enhance the degradation of complex polymers such as cellulose. The treatment of anaerobic digestate with sound at sonic frequencies (<20 kHz) has also been shown to improve biogas production. Microaeration at a rate of 800 mL day−1, treatment with a 1000-Hz sine wave, and combined microaeration/sound were compared to a control digester for the production of biogas and their effect on wastewater quality. Poultry litter from a facility using wood chips as bedding was used as feed. The initial feeding rate was 400 g week−1, and this was slowly increased to a final rate of 2400 g week−1. Compared to the control, sound treatment, aeration, and combined sound/aeration produced 17%, 32%, and 28% more biogas. The aeration alone treatment may have been more effective than combined aeration/sound due to the sound interfering with retention of aeration or the formation of free radicals during cavitation. Digesters treated with sound had the highest concentrations of suspended solids, likely due to cavitation occurring within the sludge and the resulting suspension of fine particles by bubbles.

scholarly journals Inter-stage thermophilic aerobic digestion may increase organic matter removal from wastewater sludge without decreasing biogas production

2017 ◽  
Vol 77 (3) ◽  
pp. 721-726
Author(s):  
Sasha D. Hafner ◽  
Johan T. Madsen ◽  
Johanna M. Pedersen ◽  
Charlotte Rennuit
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Aerobic Digestion ◽  
Anaerobic Digesters ◽  
Stage System ◽  
Thermophilic Aerobic Digestion ◽  
Pre Treatment

Abstract Combining aerobic and anaerobic digestion in a two-stage system can improve the degradation of wastewater sludge over the use of either technology alone. But use of aerobic digestion as a pre-treatment before anaerobic digestion generally reduces methane production due to loss of substrate through oxidation. An inter-stage configuration may avoid this reduction in methane production. Here, we evaluated the use of thermophilic aerobic digestion (TAD) as an inter-stage treatment for wastewater sludge using laboratory-scale semi-continuous reactors. A single anaerobic digester was compared to an inter-stage system, where a thermophilic aerobic digester (55 °C) was used between two mesophilic anaerobic digesters (37 °C). Both systems had retention times of approximately 30 days, and the comparison was based on measurements made over 97 days. Results showed that the inter-stage system provided better sludge destruction (52% volatile solids (VS) removal vs. 40% for the single-stage system, 44% chemical oxygen demand (COD) removal vs. 34%) without a decrease in total biogas production (methane yield per g VS added was 0.22–0.24 L g−1 for both systems).

Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge

2004 ◽  
Vol 50 (9) ◽  
pp. 17-23 ◽  
Author(s):  
B. Park ◽  
J.-H. Ahn ◽  
J. Kim ◽  
S. Hwang
Keyword(s):  
Control System ◽  
Microwave Irradiation ◽  
Biogas Production ◽  
Irradiation Time ◽  
Oxygen Demand ◽  
Volatile Solid ◽  
Anaerobic Digesters ◽  
Secondary Sludge ◽  
Working Volume ◽  
Soluble Chemical Oxygen Demand

This work elucidates the effects of pretreatment of secondary sludge by microwave irradiation on anaerobic digestion. The soluble chemical oxygen demand (COD) concentration increased up to 22% as microwave irradiation time increased, which indicated the sludge particles disintegrated. Three identical automated bioreactors with working volume of 5 l were used as anaerobic digesters at mesophilic temperature (35°C). The reactors were separately fed with sludge with microwave pretreated- and controlsludge at different hydraulic retention times (HRT). The volatile solid (VS) reduction in the control operation was approximately 23.2 ± 1.3%, while it was 25.7 ± 0.8% for the reactors with the pretreated sludge. The average biogas production rate with the pretreated sludge at 8, 10, 12, and 15 days HRTs was 240 ± 11, 183 ± 9, 147 ± 8, and 117 ± 7 ml/l/d respectively, while those with the control sludge were134 ± 12 and 94 ± 7 ml/l/d at 10 and 15 days HRTs. Maximum rates of COD removal and methane production with the pretreated sludge were 64% and 79% higher than those of the control system, respectively.

scholarly journals Effect of Solids Concentration on the Kinetic of Biogas Production from Goat Droppings

2020 ◽  
pp. 25-33
Author(s):  
K. Eden Luboya ◽  
Mélissa Kusisakana ◽  
W. Gaston Luhata ◽  
K. Balthazar Mukuna ◽  
M. Justine Monga ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Laboratory Scale ◽  
Anaerobic Digesters ◽  
Average Temperature ◽  
Solids Concentration ◽  
C 30 ◽  
Time Required ◽  
The Relationship ◽  
Plastic Containers

This experiment was conducted at the Bioenergy laboratory of Groupe de Génies Congolais (GGC) at the Université Loyola du Congo in Kinshasa, D.R.Congo. The experiment started on May 23, 2019 and ended on July 17, 2019. The study focused on the relationship between solids concentration and the kinetic of anaerobic digestion of goat droppings in the methanation process. The feedstock consisted of goat droppings waste made into slurry of four solids concentration (SC); A=50%, B=38%, C=30% and D=25%. Each SC was repeated three times. Feedstocks were inserted in laboratory scale anaerobic digesters constructed from 5L plastic containers. The results revealed clearly that the time required for the production of biogas depends on SCs. The ratio D (1/3), i.g. 75% of water and 25% of biomass produced the biogas in 3 weeks (±22 days) and the ratio A (1/1), 50% of water and 50% of biomass, in 7 weeks and a few days (±53 days). The ratio C (1/2), 66.6% of water in the mixture, provided the biogas in ± 26 days (approximately 4 weeks) and finally, it took ±30 days (4 weeks and a few days) for ratio B to produce biogas rich in CH4 (<50%). The equation f(x)= 1.1x + 1 can be used to predict the approximative number of days to produce a biogas containing more than 50% of CH4. The average temperature inside the reactors was found to be 28.5 ± 0.8°C during the combustion testing process implying that the reactors designed at the GGC were operating in a mesophilic regime. Finally, the pH of the digestates obtained from reactors had an average of 9.0 ± 0.2.

scholarly journals Portable Biodigester System for Household Use – A review

2020 ◽  
Author(s):  
Muhammad Badrul Amin Mohamed Zaki ◽  
Rosnah Shamsudin ◽  
Mohd Zulkhairi Mohd Yusoff
Keyword(s):  
Anaerobic Digestion ◽  
Organic Waste ◽  
Review Paper ◽  
Biogas Production ◽  
Plug Flow ◽  
Value Added ◽  
Large Area ◽  
A Value ◽  
Alternate Source ◽  
The Cost

Biogas is a value-added product comes from anaerobic digestion of organic compounds. The most common biogas production is done in large capacity which required large area and high cost to be operated. In order to benefits the consumer on the biogas production, varieties of innovated household biodigester machines were introduced.This portable household biodigesterappeals to the rural to provide economical and alternate source of energy apart reducing the organic waste dumping to landfill. Biogas produce consists of methane gas which can act as an alternative for cooking gas at home. In the meantime, effluent obtained at the end of anaerobic digestion can be used as fertilizer. Moreover, the cost of production is cheaper and easier to be operate. The size of portable household biodigesters varies in range of 1 to 150 m3 with common designs such as fixed dome, floating drum, plug flow type, and balloon type.This review paper aims to bring a further understanding on the design, capabilities and limitation from different type of household biodigester that have been used.

Assessment of the state of the art of technologies for the processing of digestate residue from anaerobic digesters

2013 ◽  
Vol 67 (9) ◽  
pp. 1984-1993 ◽  
Author(s):  
W. Fuchs ◽  
B. Drosg
Keyword(s):  
Anaerobic Digestion ◽  
Large Scale ◽  
State Of The Art ◽  
Biogas Production ◽  
The State ◽  
Anaerobic Digesters ◽  
Adequate Treatment ◽  
Biogas Plants ◽  
Treatment Technologies ◽  
Digestate Processing

Anaerobic digestion is widely used as an important source of renewable energy. With the increasing number and capacity of biogas plants also, adequate treatment technologies for whole digestate – the residue from anaerobic digestion – are gaining attention. In this study the state of the art of digestate processing is analysed, and currently used treatment schemes and the various technological processes involved are evaluated. The study combines data and experiences from existing large-scale digestate processing facilities in Austria, Germany, Switzerland and Italy, as well as know-how from technology providers and relevant research projects. However, the field of digestate processing is still quite new and little detailed information about the performance of different technologies at industrial scale is available. Digestate processing is gaining importance since digestate utilisation can become an important bottleneck when increasing biogas production. In addition, the production of renewable fertiliser from digestate is increasingly of interest to replace fossil fertilisers. This study is the first profound attempt to establish an assessment of the state-of-the-art technologies in use.

scholarly journals Anaerobic Digestion of Food Waste, Brewery Waste, and Agricultural Residues in an Off-Grid Continuous Reactor

2021 ◽  
Vol 13 (12) ◽  
pp. 6509
Author(s):  
Kimberley E. Miller ◽  
Tess Herman ◽  
Dimas A. Philipinanto ◽  
Sarah C. Davis
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Biogas Production ◽  
Agricultural Residues ◽  
Temperate Climate ◽  
Continuous Reactor ◽  
Small Scale ◽  
Seasonal Temperature ◽  
Full Time ◽  
Time Operation

Small-scale anaerobic digestion (AD) can be an effective organic waste management system that also provides energy for small businesses and rural communities. This study measured fuel production from digestions of single and mixed feedstocks using an unheated, 2 m3 digester operated continuously in a temperate climate for over three years. Using local food waste, brewery waste, grease waste, and agricultural residues, this study determined that small-scale AD co-digestions were almost always higher yielding than single feedstocks during psychrophilic operation and seasonal temperature transitions. Agricultural residues from Miscanthus x giganteus had the greatest impact on biomethane production during co-digestion (4.7-fold greater average biogas %CH4), while mesophilic digestion of brewery waste alone produced the most biogas (0.76 gCH4 gVS−1 d−1). Biogas production during the transition from mesophilic to psychrophilic was temporarily maintained at levels similar to mesophilic digestions, particularly during co-digestions, but biogas quality declined during these temperature shifts. Full-time operation of small-scale, unheated AD systems could be feasible in temperate climates if feedstock is intentionally amended to stabilize carbon content.

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