Application of lactic acid derived from food waste on pathogen inactivation in fecal sludge: a review on the alternative use of food waste

Food waste generation and disposal have led to several environmental problems, especially in developing countries. This phenomenon is partly because most cities rapidly urbanize, which results in population increase, urban settlement and waste generation. Improper management of waste has continued to create environmental problems. These problems have indeed interfered with the inadequate measures in managing other organic waste such as food waste. Food waste can be fermented and used for pathogen inactivation in fecal sludge (FS). The continual decrease in global crop production due to soil erosion, nutrient runoff and loss of organic matter has generated interest in using FS for soil amendment. However, due to the high number of pathogens in FS that are harmful to humans, FS must be treated before being used in agriculture. Thus, given the high amounts of food waste generated globally and the lactic acid potential of fermented food waste, several researchers have recently proposed the use of fermented food waste to suppress pathogens in FS. This review presents the various approaches in pathogen inactivation in FS using different types of food waste. On the basis of the literature review, the major problems associated with the generation, collection and application of food waste in pathogen inactivation in FS are discussed. Moreover, the trends and challenges that concern the applicability of each method are critically reviewed.