Abstract
Problem statement: Concentrated livestock production is a major contributor to environmental problems through the production of large quantity of husks on relatively small land area. Anaerobic digestion represents a valuable means of cover by these husks into methane while reducing manure pollution problems. Methodology: An experimental apparatus, including data acquisition and control system, was developed and used to investigate the effects of two diurnally cyclic temperature ranges (20-40 and 15-25°C) and four levels of hydraulic retention times (25, 20, 15 and 10 d) on the performance of anaerobic reactors operated on screened dairy manure. Results: The reactor temperature exhibited a lag relative to the chamber temperature. For the 20-40°C temperature cycles, the average lag at the maximum chamber temperature was 3.75 h while the lag at the minimum chamber temperature was 4.37 h. For the 15-25°C temperature cycle, the average lag at maximum chamber temperatures was 3.61 while the lag of the minimum chamber temperature was 4.34 h. The effluent solids content, total Kjeldahl nitrogen and ammonium nitrogen concentrations were not adversely affected by the reactor diurnally cyclic temperature. The observed values of these parameters compared fairly well with the values obtained by other researchers. The effluent total solids, volatile suspended solids, TKN, NH4-N and methane content of the biogas diurnally cyclic patterns were out of phase with the diurnally cyclic pattern of the reactor temperature by about 12 h under most of the investigated operating conditions. The pH and the carbon dioxide content of the biogas all exhibited a diurnally cyclic pattern which was in phase with the reactor diurnally cyclic temperature. The reductions in total solids, total suspended solids, fixed suspended solids, total Kjeldahl nitrogen, ammonium nitrogen and methane yield were all significantly affected by the diurnal temperature range and hydraulic retention time. Conclusion: The measured reactor pH followed a diurnally cyclic pattern which was in phase with the reactor temperature. At the operating temperature cycle of 20-40°C, the reactor pH ranged from 6.80-7.54 while VFA concentration ranged from 44.7-154.8 mg L-1. At the operating temperature cycle of 15-25°C, the pH ranged from 6.30-6.60 while the VFA concentration ranged from 151.0-1187.0 mg L-1.
Highlights
Concentrated livestock production is a major by obnoxious odorous compounds causing widespread contributor to environmental pollution problems health problems (Bradford et al, 2009)
It was not until the energy crises, caused by the wars in the Middle East in the 1970s and 1990s which clearly dramatized the vulnerability of a fossil-fuel based economy, that serious awareness was created over the need for intensified effort at finding alternative energy sources (Cleveland, 1995)
The process requires the concerted actions of a symbiotic population of three groups of facultative and Despite these advantages, anaerobic digestion has not enjoyed widespread acceptance among many farmers due to the relative instability of the system resulting from the sensitivity of anaerobic bacteria to adverse environmental conditions (Ghaly et al, 2000)
Summary
Concentrated livestock production is a major by obnoxious odorous compounds causing widespread contributor to environmental pollution problems health problems (Bradford et al, 2009). Efforts to increase the Oxygen Demand (BOD) and causing an ecological quantity of food produced, to meet the needs of a imbalance (Dieu, 2009), (c) high pathogen content growing population, have led to large mechanical. Among the various alternative energy sources, biomass (a general term that refers to plant and animal materials) is perhaps the only Fig. 1: Three stage anaerobic digestion process energy source which is available and affordable to the third world population (Legros et al, 2009). Anaerobic digestion is a biological process in which organic materials are decomposed in the absence of free oxygen to yield methane (CH4), carbon dioxide (CO2) and small quantities of other gases (H2S, N2 and H2O ). The effect of gradual variation in obligate anaerobic bacteria to: (a) degrade temperature in a diurnal cycle is yet to be investigated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: American Journal of Biochemistry and Biotechnology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
