The increase in solid waste generation is caused primarily by the global population growth that resulted in urban sprawl, economic development, and consumerism. Poor waste management has adverse impacts on the environment and human health. The recent years have seen increasing interest in using black soldier fly (BSF), Hermetia illucens, as an organic waste converter. Black soldier fly larvae (BSFL) feed voraciously on various types of organic waste, including food wastes, agro-industrial by-products, and chicken and dairy manure, and reduce the initial weight of the organic waste by about 50% in a shorter period than conventional composting. The main components of the BSFL system are the larvero, where the larvae feed and grow, and the fly house, where the adults BSF live and reproduce. It is essential to have a rearing facility that maintains the healthy adult and larval BSF to provide a sufficient and continuous supply of offspring for organic waste treatment. The BSF organic waste processing facility consists of waste pre-processing, BSFL biowaste treatment, the separation of BSFL from the process residue, and larvae and residue refinement into marketable products. BSFL digest the nutrients in the wastes and convert them into beneficial proteins and fats used to produce animal feed, and BSFL residue can be used as an organic fertilizer. This review summarizes the BSFL treatment process to provide an in-depth understanding of the value of its by-products as animal feed and organic fertilizer.

The disposal of large amounts of food waste has caused serious environmental pollution and financial losses globally. Compared to alternative disposal methods (landfills, incineration, and anaerobic digestion), composting by black soldier fly larvae (BSFL) is a promising alternative for food waste management. Despite extensive research into larval biomass, another valuable by-product generated from BSFL composting is BSFL frass. However, limited information is available for its potential application. The applications of BSFL frass can be intensified by understanding its physicochemical characteristics, benefits, and challenges of BSFL frass derived from food waste. BSFL frass is harvested after 9–23 days of the experiment, depending on the substrate used in the composting process. The generated BSFL frass could exceed 33% of the original weight of the substrate. The physicochemical characteristics of BSFL frass are as follows: the temperature after harvest is 24 °C to 27 °C, pH is 5.6–8.0, moisture content is 30 to 72%, C/N ratio is 8:1 to 27:1, high nitrogen, phosphorus, and potassium (NPK) content, and low heavy metal content. This paper reviews the characteristics, benefits, and application of BSFL frass. It will also investigate the challenges of using food waste substrates to produce BSFL frass, as well as the best way to pre-treat the food waste substrate and post-treat the BSFL frass.

The increase in the global population has led to a rise in organic waste generation and landfill sites. Consequently, there has been a global shift in focus towards the utilization of BSFL to address these challenges. This study aims to design, develop, and test a user-friendly BSFL bin and identify the optimal MCCM for treating organic waste using BSFL. The four BSFL bins have a dimension of 330 mm (width) × 440 mm (length) × 285 mm (height). This study uses mixtures of food waste added with different MCCMs, including chicken feed, rice bran, and garden waste. We add the mediums to the BSFL bins every third day and measure the humidity, ambient temperature, pH, medium temperature, and BSFL weight and length. The measurements show that the fabricated BSFL bins can fulfill the BSF lifecycle requirements. Wild BSFs lay eggs in the medium of BSFL bins, and the hatched larvae decompose it. When they reach the prepupae stage, they climb the ramp into the harvesting container. The results show that the food waste without MCCM produced the heaviest (0.228 g) and longest (2.16 cm) larvae; the prepupae are 2.15 cm long and weigh 0.225 g; and the growth rate is 53.72%. However, the high moisture content of 75.3% makes the maintenance work challenging. The medium with MCCM has a markedly lower moisture content of 51-58%. A comparison of the three MCCMs shows that the chicken feed produces the larvae and prepupae with the highest growth rate (the larvae are 2.10 cm long and weigh 0.224 g, the prepupae are 2.11 cm long and weigh 0.221 g, and the growth rate is 72.36%) and the frass with the lowest moisture content (51.2%). An effective BSFL composting system is easy to manage and produces the biggest larvae. In summary, food waste mixed with chicken feed is the most suitable MCCM for treating organic waste using BSFL.