scholarly journals Quantification of leakage in batch biogas assays

2018 ◽  
Vol 13 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Sasha D. Hafner ◽  
Charlotte Rennuit ◽  
Palle J. Olsen ◽  
Johanna M. Pedersen
Keyword(s):  
Methane Production ◽  
Biogas Production ◽  
Additional Research ◽  
Wastewater Sludge ◽  
Potential Importance ◽  
Mass Measurements ◽  
Simple Method ◽  
Independent Estimate

Abstract Avoiding leaks is essential for accurate measurement of biogas production by batch assays. Here we present a simple method for detecting leaks and correcting results, based on the change in bottle mass during incubation. Three experiments were carried out using pure chemicals, wastewater sludge, and other complex substrates to test and demonstrate the method, and leaks were detected in all three. The frequency and magnitude of leakage was related to headspace pressure and the number of times bottle septa had been punctured. Comparison to an independent estimate of leakage in two experiments showed that the proposed method is accurate. This mass-based approach can generally be used to detect leaks as small as 20% of total biogas or methane production, or lower when biogas production is high relative to the precision of mass measurements. Additional research is needed to improve the sensitivity of the method and to better understand the causes of leakage. Given the potential importance of leaks and the simplicity of leakage measurements, we recommend that this method is always used in batch biogas assays.

scholarly journals Addition of Different Biochars as Catalysts during the Mesophilic Anaerobic Digestion of Mixed Wastewater Sludge

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1094
Author(s):  
Marco Chiappero ◽  
Francesca Cillerai ◽  
Franco Berruti ◽  
Ondřej Mašek ◽  
Silvia Fiore
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Chemical Properties ◽  
Principal Component ◽  
Gompertz Model ◽  
Wastewater Sludge ◽  
Total Carbon ◽  
Lag Phase ◽  
Working Volume

Biochar (BC) recently gained attention as an additive for anaerobic digestion (AD). This work aims at a critical analysis of the effect of six BCs, with different physical and chemical properties, on the AD of mixed wastewater sludge at 37 °C, comparing their influence on methane production and AD kinetics. AD batch tests were performed at the laboratory scale operating 48 reactors (0.25 L working volume) for 28 days with the addition of 10 g L−1 of BC. Most reactors supplemented with BCs exhibited higher (up to 22%) methane yields than the control reactors (0.15 Nm3 kgVS−1). The modified Gompertz model provided maximum methane production rate values, and in all reactors the lag-phase was equal to zero days, indicating a good adaptation of the inoculum to the substrate. The potential correlations between BCs’ properties and AD performance were assessed using principal component analysis (PCA). The PCA results showed a reasonable correlation between methane production and the BCs’ O–C and H–C molar ratios, and volatile matter, and between biogas production and BCs’ pore volume, specific surface area, and fixed and total carbon. In conclusion, the physic-chemical properties of BC (specifically, hydrophobicity and morphology) showed a key role in improving the AD of mixed wastewater sludge.

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).

Biogas Production from Fruit and Vegetable Solid Waste Co Digested with Sugar Mill Waste Sludge

2019 ◽  
Vol 1 (6) ◽  
pp. 582-587
Author(s):  
Velayutham T ◽  
Karthikeyan G
Keyword(s):  
Solid Waste ◽  
Methane Production ◽  
Room Temperature ◽  
Biogas Production ◽  
Sugar Industry ◽  
Wastewater Sludge ◽  
Fruit And Vegetable ◽  
Volume Weight ◽  
Working Volume ◽  
Industry Wastewater

Biogas (methane) production from batch anaerobic digesters containing varying concentration of sugar industry wastewater sludge as inoculums and organic fruit and vegetable market solid waste as a substrate was experimentally studied in this research. It was observed that biogas production was optimized with batch anaerobic digestion of fruit and vegetable solid waste. It was carried out for 60 days at room temperature with untreated sugar industry wastewater sludge as an inoculums with the varying concentration 10%, 20% and 30% of the working volume (Weight) of substrate. The performance of reactors was evaluated by measuring the daily biogas production at the room temperature and pH was maintained in the range of 6.8 to7.3 respectively. The maximum cumulative methane production is 597.66 ml/gVS. The biogas yields at the end of the 60days total cumulative biogas for R1, R2 and R3 was obtained as 382.48ml/gVS, 552.66ml/gVS and 597.66ml/gVS respectively from the reactors. At the end of the 60 days total cumulative biogas for Rc(control) was obtained as 196.85ml/gVS. It was observed that the methane content of the biogas generated from the reactors was in the range of 47–56% in control reactor and that forR1, R2and R3 were 56-61%, 60-67% and 65-74% respectively.

Potential of Palm Oil Empty Fruit Bunch as Biogas Substrate

2019 ◽  
Vol 2 (1) ◽  
pp. 59-64
Author(s):  
Vincentius Vincentius ◽  
Evita H. Legowo ◽  
Irvan S. Kartawiria
Keyword(s):  
Palm Oil ◽  
Fermentation Process ◽  
Biogas Production ◽  
Wastewater Sludge ◽  
Empty Fruit Bunch ◽  
Alternative Source ◽  
The Earth ◽  
The One ◽  
Wet Fermentation ◽  
Water Ratio

Natural gas is a source of energy that comes from the earth which is depleting every day, an alternative source of energy is needed and one of the sources comes from biogas. There is an abundance of empty fruit bunch (EFB) that comes from palm oil plantation that can become a substrate for biogas production. A methodology of fermentation based on Verein Deutscher Ingenieure was used to utilize EFB as a substrate to produce biogas using biogas sludge and wastewater sludge as inoculum in wet fermentation process under mesophilic condition. Another optimization was done by adding a different water ratio to the inoculum mixture. In 20 days, an average of 6gr from 150gr of total EFB used in each sample was consumed by the microbes. The best result from 20 days of experiment with both biogas sludge and wastewater sludge as inoculum were the one added with 150gr of water that produced 2910ml and 2185ml of gas respectively. The highest CH 4 produced achieved from biogas sludge and wastewater sludge with an addition of 150gr of water to the inoculum were 27% and 22% CH 4 respectively. This shows that biogas sludge is better in term of volume of gas that is produced and CH percentage.

Anaerobic thermophilic digestion of sewage sludge with a thickened sludge recycle

2012 ◽  
Vol 65 (3) ◽  
pp. 403-409 ◽  
Author(s):  
A. Ya. Vanyushina ◽  
Yu. A. Nikolaev ◽  
A. M. Agarev ◽  
M. V. Kevbrina ◽  
M. N. Kozlov
Keyword(s):  
Retention Time ◽  
Municipal Wastewater ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Wastewater Sludge ◽  
Recycling Process ◽  
Digested Sludge ◽  
Volatile Solids ◽  
Solids Retention ◽  
Thermophilic Digestion

The process of anaerobic thermophilic digestion of municipal wastewater sludge with a recycled part of thickened digested sludge, was studied in semi-continuous laboratory digesters. This modified recycling process resulted in increased solids retention time (SRT) with the same hydraulic retention time (HRT) as compared with traditional digestion without recycling. Increased SRT without increasing of HRT resulted in the enhancement of volatile substance reduction by up to 68% in the reactor with the recycling process compared with 34% in a control conventional reactor. Biogas production was intensified from 0.3 L/g of influent volatile solids (VS) in the control reactor up to 0.35 L/g VS. In addition, the recycling process improved the dewatering properties of digested sludge.

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