Technical evaluation and standardization of Biogas Plants in Ghana
Loading...
Date
2009-08-17
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Biogas plants are noted for improving sanitation, generating energy, and supplying organic fertilizer. Despite the numerous benefits derived from biogas technology, Ghana is yet to develop a major programme that will promote the dissemination of biogas plants on a large scale. This research work conducts a technical review of biogas installations in Ghana and looks into challenges facing the design, construction, and operation of biogas plants. It further proposes standardized biodigester models for use in future large-scale dissemination programmes. The study was done by surveying fifty (50) biogas plants, and conducting interviews with both plant users and service providers. Majority of the digesters were fixed- dome (82 %); water-jacket floating-drums (8 %) ranked second. From the survey, sanitation was the main motivational reason for people using biogas plants. Most sanitary plants treating blackwater from flushing toilets discharge their effluent into public drains. Of the 50 plants surveyed, 22 (44 %) were functioning satisfactorily, 10 (20 %) were functioning partially, 14 (28 %) were not functioning, 2 (4 %) were abandoned and the remaining 2 (4 %) were under construction. Reasons for non-functioning include non-availability of dung, breakdown of balloon gasholders, absence of maintenance services, lack of operational knowledge, gas leakages, and bad odour in toilet chambers of biolatrines. Design problems observed involved the wrong orientation of inlet pipes of biolatrine digesters and the faulty interconnection between tandem (series) digesters. This thesis recommends the development of a national programme focussing on three major areas - sanitation, energy, and agricultural fertilizer production. A minimum retention time of 60 days for nightsoil and slaughterhouse waste, and 30 days for livestock waste under mesophilic conditions is recommended for the design of biogas plants. Standardized household, dung-digesting plant volumes of 4, 6, 8, and 10 m3, and nightsoil-digesting volumes of 10, 30, 50, and 60 m3 are proposed for dissemination. The correct design layout of tandem systems is also proposed.
Description
A Thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology, in partial fulfilment of the requirements for the degree of Master of Science in Mechanical Engineering