scholarly journals Increased biogas production by anaerobic co-digestion of wastewater sludge with fruit and vegetable waste, and by sludge pre-treatment.

2012 ◽  
Author(s):  
Nathan D. Park
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.


2011 ◽  
Vol 64 (9) ◽  
pp. 1851-1856 ◽  
Author(s):  
Nathan D. Park ◽  
Ronald W. Thring ◽  
Randy P. Garton ◽  
Michael P. Rutherford ◽  
Steve S. Helle

Anaerobic digestion is a well established technology for the reduction of organic matter and stabilization of wastewater. Biogas, a mixture of methane and carbon dioxide, is produced as a useful by-product of the process. Current solid waste management at the city of Prince George is focused on disposal of waste and not on energy recovery. Co-digestion of fresh fruit and vegetable waste with sewer sludge can improve biogas yield by increasing the load of biodegradable material. A six week full-scale project co-digesting almost 15,000 kg of supermarket waste was completed. Average daily biogas production was found to be significantly higher than in previous years. Digester operation remained stable over the course of the study as indicated by the consistently low volatile acids-to-alkalinity ratio. Undigested organic material was visible in centrifuged sludge suggesting that the waste should have been added to the primary digester to prevent short circuiting and to increase the hydraulic retention time of the freshly added waste.


2017 ◽  
Vol 77 (3) ◽  
pp. 721-726
Author(s):  
Sasha D. Hafner ◽  
Johan T. Madsen ◽  
Johanna M. Pedersen ◽  
Charlotte Rennuit

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).


2017 ◽  
Vol 228 ◽  
pp. 362-367 ◽  
Author(s):  
Suelen Pavi ◽  
Luis Eduardo Kramer ◽  
Luciana Paulo Gomes ◽  
Luis Alcides Schiavo Miranda

2019 ◽  
Vol 1 (6) ◽  
pp. 582-587
Author(s):  
Velayutham T ◽  
Karthikeyan G

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.


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