| dc.description.abstract | Depletion of fossil fuels and environment deterioration has led to extensive research and development activities to explore renewable energy such as biogas generation from anaerobic digestion of waste for power generation. Anaerobic digestion of waste to generate methane (CH4) has been proven to be a very promising alternative to waste disposal and a valuable technology for renewable energy recovery. Although anaerobic digestion is not proven to be a feasible and economically viable technology for renewable energy generation of wastes in countries like Uganda, it calls for attention for its wide adoption throughout the country. The potential of using the biogas as energy source has long been widely recognized and current techniques are being developed to upgrade quality and to enhance energy use. Biogas is composed of methane (55–75%), carbon dioxide (25–45%), nitrogen (0–5%), hydrogen (0–1%), hydrogen sulfide (0–1%), and oxygen (0–2%). The sewage sludge contains mainly proteins, sugars, detergents, phenols, and lipids. Sewage sludge also includes toxic and hazardous organic and inorganic pollutants sources. The digestion of municipal sewage sludge (MSS) occurs in three basic steps: acidogen, methanogens, and methanogens. This research extensively reviews the principles and current optimization techniques associated with anaerobic digestion and suggests possible areas where improvements could be made, the process parameters and their interaction, the design methods, the biogas utilization. Here The batch type of reactor was operated at room temperature varying from 25 to 38 ◦C with a fixed hydraulic retention time (HRT) of 30 days. The digesters were operated at different organic feedings of domestic sewage inoculum and sludge. The maximum biogas production of 430 ml. The maximum reduction of total solids (TS) (13.84%), VS (3.69%) and chemical oxygen demand (COD) (11803.57 mg/L). The DSS contains low nitrogen and has carbon- to-nitrogen (C/N) ratios of around 40–70. The optimal C/N ratio for the AD should be between 25 and 35. C/N ratio of sludge in small-scale sewage plants is often low, so nitrogen can be added in an inorganic form (ammonia or in organic form) such as livestock manure, urea, or food wastes. Having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognized as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids, and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical, and biological interventions to the feedstock. | en_US |
