ABSTRACT
Dumping of lipid-rich wastewater will certainly cause accumulation inside the sewer networks, creating serious environmental problems. Anaerobic digestion (AD) of lipid-rich wastewater is a promising technique and produces energy in the form of methane. Lipid-rich wastewater could be used to generate organic acids via an anaerobic process. Lipids represent the major organic fraction in agro-industrial effluents. Hydrolysis of fats and oils proceeds rapidly in the sewerage network, resulting in an increase of long chain fatty acids (LCFAs) in wastewater, which adversely affects the subsequent AD process. The AD process is efficient for methane production from lipid-rich wastewater. However, the process is a failure, particularly at high lipid concentrations and in the presence of inhibitory compounds such polyphenols, and lack of nutrients. Calcium is an essential element for the growth of methanogens and the formation of microbial aggregates in anaerobic digesters. The pulse feeding sequence of anaerobic digesters represents an essential operation mode to overcome the accumulation of LCFAs.
