Anaerobic digestion for biogas

There are numerous options for food waste valorization technologies available around the world, such as composting, animal feed production, incineration for energy production and anaerobic digestion for biogas... 

Anaerobic digestion for biogas production was commonly carried out in continuously stirred tank reactor (CSTR) [137,138]. 

TABLE V Energy Inputs Using Anaerobic Digestion for Biogas Production from 1001 wet (131 dry) using Cattie Manure (Pimentel et al., 1988) 4>... 

Lehtomaki, A., Feedstocks for anaerobic digestion, in Biogas from Energy Crops andAgro Wastes, Jyvaskyla Summer School, Jyvaskyla, Finland, August 2005, http //www.cropgen.soton.ac.uk/publication/ AL%20Feedstocks.pdf. 

Shen F, et al. Improving the mixing performances of rice straw anaerobic digestion for higher biogas production by computational fluid d5mamics (CFD) simulation. Appl Bio-chem Biotechnol 2013 171(3) 626-42. 

Tilche A., De Poli F., Ercoli L., Tesini O., Cortellini L., Piccinini S. An improved plug-flow design for the anaerobic digestion of dairy cattle waste paper presented to the International Conference State of the art on biogas technology transfer and diffusion , Cairo, November 17-24, 1984. 

Environmental pollution is the subject of many political and social discussions in the Netherlands. This is mainly caused by the concentration of the animal husbandry farms close to the villages and cities. There are technical treatments of air and slurry to decrease the odour of it. Anaerobic digestion is one of these. This technology is known from biogasproduction. Most countries in the western world have studied this possibility for renewable energy. A lot of technical problems are solved but on most places it is not possible to produce biogas from farm waste to a competitive price. What is the feasibility for biogas production if there is a need for reduction of the odour emission on the farm ... 

If there is a need for odour reduction on an animal husbandry farm anaerobic digestion is one of the real possibilities. The investment and running costs of the methods, mentioned in table 3, are indicated in previous chapters. An economic calculation for the feasibility of an anaerobic digestion is open for discussion. For our purpose we must valuate the nett output of biogas. 

Biogas can be used after appropriate gas cleanup as a fuel for engines, gas turbines, fuel cells, boilers, industrial heaters, other processes, or for the manufacturing of chemicals. Before landfilling, treatment or stabihzation of biodegradable materials can be accomplished by a combination of anaerobic digestion followed by aerobic composting. 

Biogas is considered a clean, cheap and versatile gaseous fuel that is also environmentally friendly. It is mainly a mixture of methane and carbon dioxide obtained by anaerobic digestion of biomass, sewage sludge, animal wastes, and industrial effluents. Anaerobic digestion occurs in the absence of air and is typically carried out for a few weeks. 

Most often, the rates for feedstock destruction in anaerobic digestion systems are based upon biogas production or reduction of total solids (TS) or volatile solids (VS) added to the system. Available data for analyses conducted on the specific polymers in the anaerobic digester feed are summarized in Table II. The information indicates a rapid rate of hydrolysis for hemicellulose and lipids. The rates and extent of cellulose degradation vary dramatically and are different with respect to the MSW feedstock based on the source and processing of the paper and cardboard products (42). Rates for protein hydrolysis are particularly difficult to accurately determine due the biotransformation of feed protein into microbial biomass, which is representative of protein in the effluent of the anaerobic digestion system. 

---