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Effluents from many food processing industries, slaughterhouses, edible oil processing industries,

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Effluents from many food processing industries, slaughterhouses, edible oil processing industries, and dairy product industries contain high lipid. These lipid-rich wastes content lipids as a main ingredient and causes problems during the anaerobic treatment of waste. One of the operational problems associated with lipid is clogging. Besides clogging, it also causes the mass transfer limitation forming a layer on the surface of granules by absorbtion. Due to adhesion of fat, biomass wash out is another problem in anaerobic reactors treating any lipid-based wastewater (Cirne et al., 2007). All these operational problems restrain the efficiency of anaerobic reactors. To overcome these operational problems, generally the lipid content in …show more content…

Liquefaction of lipid was indicated as the process-controlling factor due to their low bioavailability in the presence of high amounts of suspended solids (Petruy and Lettinga, 1998; Sayed, 1988).
LCFA exert an acute inhibitory effect on acetoclastic and hydrogenotrophic methanogens, acetogens, and to the β-oxidation itself (Kim et al., 2004; Lalman and Bagley 2000, 2001, 2002; Templer et al., 2006). Moreover, LCFA degrading bacteria have a very slow growth rate (Mackie et al., 1991). As a consequence, during anaerobic digestion of lipid-rich wastes, accumulation of LCFA is most likely phenomenon and subsequently, inhibition of the biomethanation occurs. Oleic acid is the major LCFA in various kinds of industrial and domestic lipid-rich wastewaters (Pereira et al., 2002). It was also reported as the most toxic LCFA (Cirne et al., 2007). Adsorption of LCFA to the cell wall (Koster and Cramer, 1987), and binding of LCFA to cell membranes, changing their surface property with interference in transport functions (Hook et al., 2010), have been suggested as potential mechanisms underlying inhibition by LCFA. Nevertheless, Pereira et al. (2004, 2005) observed mineralization of biomass-associated LCFA up to 5 g COD-LCFA g-1 volatile solids, and concluded that LCFA inhibition is reversible which is primarily caused by physical transport

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