List of Titles

Authors: Belaid, Mohamed , Matheri, Anthony Njuguna , Lelosa, Itumeleng Constance , Muzenda, Edison , Ramatsa, Ishmael
Date: 2019
Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature
Language: English
Type: Conference proceedings
Identifier: http://hdl.handle.net/10210/403887 , uj:33862 , Citation: Belaid, M. et al. 2019. Optimization of Biogas Production from sewage sludge.
Description: Abstract: It is widely known that the degradation of waste activated sludge is a slow process with a low extent of degradation. Improvement methods with regards to bio-methane yield were investigated in this study using a laboratory batch anaerobic digester. Mono-digestion of sludge with a C: N ratio of 15.47 resulted in a lower accumulation of gas volume than co-digested sludge even though the pH decreased rapidly in both cases. The thermophillic anaerobic digestion of sludge and co-digested sludge also produced higher bio-methane yield than mesophillic digestion of waste water sludge. Gas accumulation volume in the digesters during thermophillic digestion increased from 50 Nml to 100 Nml, 200 Nml to 600 Nml and 600 Nml to 750 Nml for sludge, cow dung and sludge and sludge and food waste respectively as the temperature was increased from 37o C to 45o C.
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Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane
Date: 2016
Subjects: Anaerobic , Co-digestion , Kinetics , Mesophilic temperature , Modified gompertz
Language: English
Type: Conference proceedings
Identifier: http://hdl.handle.net/10210/93635 , uj:20372 , Citation: Matheri, A.N. et al. 2016. Modelling the kinetic of biogas production from co-digestion of pig waste and grass clippings.
Description: Abstract: This work investigated the use of laboratory batch anaerobic digester to derive kinetics parameters for anaerobic co-digestion of pig waste and grass clippings. Laboratory experiment data from 10 litres batch anaerobic digester operating at ambient mesophilic temperature of 37 0C and pH of 6.9 was used to derive parameters for modified Gompertz model. The carbon/nitrogen (C/N) ratio of Pig waste was found to be 16.16 and grass clippings to be 20.54. Through co-digestion in ratio of 1:1, the C/N ratio settled at 17.28. The actual biogas yield was found to be 7725 ml/g COD. In the model of biogas production prediction, the kinetics constants of A (ml/g COD), μ (ml/g COD. day), λ (day) was 7920.70, 701.35, 1.61 respectively with coefficient of determination (R2) of 0.9994. Modified Gompertz plot showed better correlation of cumulative biogas production and these results show biogas production can be enhanced from co-digestion of substrates.
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Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Ntuli, Freeman , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine , Njenga, Cecilia Kinuthia
Date: 2017
Subjects: Anaerobic digestion , Bio-digester , Mesophilic temperature
Language: English
Type: Article
Identifier: http://hdl.handle.net/10210/250904 , uj:26157 , Citation: Matheri, A.N. et al. 2017. Waste to energy bio-digester selection and design model for the organic fraction of municipal solid waste.
Description: Abstract: Please refer to full text to view abstract
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Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
Date: 2016
Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature , Trace elements
Language: English
Type: Conference proceedings
Identifier: http://hdl.handle.net/10210/93628 , uj:20371 , Citation: Matheri, A.N. et al. 2016. The role of trace elements on anaerobic codigestion in biogas production.
Description: Abstract: In this study, we investigated the concentration of trace elements in the digestates in a laboratory batch anaerobic digester. Many of these trace elements are important macro and micro nutrients. The availability of these nutrients for microbes responsible for anaerobic digestion and substrate toxicity have to be controlled in biogas production. The analyzed substrates were characterized at various concentrations in the following trace elements; potassium, phosphorus, manganese, copper, calcium, molybdenum, zinc, cobalt, iron, aluminum, silver, nickel and cadmium. Trace elements like copper, silver, nickel, cadmium, zinc have been reported to be inhibitory and toxic under certain conditions in biochemical reaction depending on their concentrations. These trace elements lower biogas production above threshold concentration due to accumulation of organic acid as a result of methanogenic bacterial inhibition. There was no deficit of nutrients detected in the anaerobic digesters analysis.
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Authors: Matheri, Anthony Njuguna , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Catherine Jane , Mbohwa, Charles
Date: 2016
Subjects: Anaerobic digestion , Co-digestion , Mesophilic temperature
Language: English
Type: Conference proceedings
Identifier: http://hdl.handle.net/10210/214105 , uj:21240 , Citation: Matheri, A.N. et al. 2016. Mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings.
Description: Abstract: The main focus of this study was mesophilic anaerobic co-digestion of cow dung, chicken droppings and grass clippings using pilot bio-digesters. The biochemical methane potential (BMP) works under batch anaerobic digester operating in ambient mesophilic temperature of 35 oC and 37 0C and pH of 7 to generate biogas. The carbon/nitrogen (C/N) ratio for cow dung and chicken droppings was found to be 17.70 and 63.67 respectively and grass clippings to be 20.54. Through co-digestion in a ratio of 1:1, the C/N ratio for cow dung and grass clippings settled at 19.19 while that for chicken droppings and grass clippings settled at 20.49. The conversion rate of the reaction and biogas production increased with the increase in temperature and hydraulic retention time until an equilibrium state was achieved. At the temperature 37 OC, it was observed to be the suitable mesophilic temperature for anaerobic digestion due to high dissociation and collision leading to high rate of biogas production.
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