Food waste accounts for a substantial portion of the organic waste generated at an increasing rate worldwide. Organic waste, including food waste, is largely subjected to landfill disposal, incineration, and anaerobic digestion; however, more sustainable methods are needed for treating it. Treatment of organic waste using black soldier fly (Hermetia illucens) larvae is an environmentally safe and cost-efficient method that has been attracting increasing attention worldwide. Black soldier fly decomposes various types of organic waste and converts them into high-value biomasses such as oils and proteins. This review introduces the trends in research related to the treatment of organic waste by black soldier fly (Hermetia illucens) larvae (BSFL) and their bioconversion efficiencies in Asian countries. Perspectives on the growth of BSFL during waste treatment operation and optimal rearing conditions are provided. The trends in studies related to the application of BSFL as biofuel and animal feed are also discussed. Such use of BSFL would be beneficial in Asia, especially in countries where the technology for processing organic waste is not readily available. This review may provide further directions of investigations including culture techniques for industrial scale applications of BSFL in food waste treatment and resource production in Asian countries.

In this study, cattle and pig slaughterhouse wastes (SHWs) were hydrothermally carbonized at 150–300 °C, and the properties of SHW-derived hydrochar were evaluated for its use as a solid fuel. The results demonstrated that increasing the hydrothermal carbonization (HTC) treatment temperature improved the energy-related properties (i.e., fuel ratio, higher heating value, and coalification degree) of both the cattle and pig SHW-derived hydrochars. However, the improvements of cattle SHW-derived hydrochars were not as dramatic as that of pig SHW-derived hydrochars, due to the lipid-rich components that do not participate in the HTC reaction. In this regard, there was no merit of using HTC treatment on cattle SHW for the production of hydrochar or using the hydrochar as a solid fuel in terms of energy retention efficiency. On the other hand, a mild HTC treatment at approximately 200 °C was deemed suitable for converting pig SHW to value-added solid fuel. The findings of this study suggest that the conversion of SHWs to hydrochar using HTC can provide an environmentally benign method for waste treatment and energy recovery from abandoned biomass. However, the efficiency of energy recovery varies depending on the chemical composition of the raw feedstock.

In this study, two types of sewage sludge (primary sludge and waste activated sludge) were hydrothermally treated at 125–250 °C to enhance the lipid extraction efficiency and obtain a higher biodiesel yield. The enhanced efficiency of the lipid extraction method was compared with the efficiency of the organic solvent extraction method. The results confirmed that a hydrothermal reaction could be an appropriate option for disrupting sludge cell walls and increasing the lipid extraction from sewage sludge. The highest lipid recovery efficiency was observed at 200 °C, and the lipid recovery efficiency of primary sludge and waste activated sludge increased from 7.56% and 5.35% to 14.01% and 11.55% by weight, respectively. Furthermore, transesterified lipids, such as biodiesel from sewage sludge, mostly consist of C16 and C18 methyl esters, and have features similar to those of jatropha oil-based biodiesel. During the hydrothermal treatment, the carbon content in the sludge decreased as the carbon transformed into lipids and the lipids were extracted. The volatile matter and fixed carbon content in the solid residue decreased and increased, respectively, through chemical dehydration and decarboxylation reactions under hydrothermal reaction conditions.

The study investigated the performance of the pre-denitrification membrane bioreactor (MBR) process to treat high-strength wastewater generated from food waste disposals. Extracellular polymeric substances (EPS) as membrane foulant and microbial community profiles were analyzed under different hydraulic retention time (HRT) operation conditions. The pre-denitrification MBR was effective for treating food wastewater with high chemical oxygen demand (COD)/N resulting in high total nitrogen (TN) removal efficiency. The operational data showed that effluent qualities in terms of COD, TN, and TP improved with longer HRT. However, membrane fouling potential as shown by specific membrane fouling rate and specific resistance to filtration (SRF) increased as HRT increased. The longer HRT conditions or lower influent loading led to higher levels of bound EPS while HRT did not show large effects on the level of soluble microbial products (SMP). The restriction fragment length polymorphism (RFLP) analysis showed similar microbial banding patterns from the sludges generated under different HRT conditions, indicating that HRT had minimal effects on the composition of microbial communities in the system. All these results suggest that the MBR with pre-denitrification is a feasible option for treating high-strength food wastewater and that different HRT conditions could affect the operational performance and the fouling rate, which is governed via changes in microbial responses through EPS in the system.