Researchers at BITS, Pilani Hyderabad campus have developed a low-cost system that uses black soldier fly larvae to convert food waste into protein-rich animal feed. According to the Institute the developed system costs Rs 2500 a unit and offers an innovative solution to resource-efficient, food waste management. Beyond waste reduction, the developed system also recovers economically useful products from organic waste.
Black soldier fly larvae contain approximately 20 per cent protein and 25 per cent fat, making them a potential alternative feed ingredient for the poultry, pig and aquaculture sectors. In addition to this, the residual organic material, known as frass, can also potentially be used as a soil amendment.
The system uses the natural waste-consuming ability of the black soldier fly. The larvae feed on vegetable, fruit and cooked food waste, converting the organic material into nutrient-rich biomass during a feeding cycle of approximately two weeks.
This approach provides a faster alternative to the conventional composting process, which takes multiple weeks or months says, Prof. Sankar Ganesh Palani of the Department of Biological Sciences, who along with his research graduate, Dr. Atun Roy Choudhury developed it at the Hyderabad camps of the Birla Institute of Technology and Science (BITS Pilani).
As India focuses on strengthening its efforts towards sustainable waste management and resource recovery, the developed innovation can be used in hotels, educational institutions, hospitals, residential societies and other similar places to process segregated wet waste closer to its source while recovering usable by-products, the Institute says.
The Process:
“The black soldier fly is a harmless insect whose larvae feed on vegetable and fruit waste, cooked food and manure. They do most of their eating in a two-week larval stage, converting waste into body mass far more efficiently than warm-blooded animals,” says Dr Atun Roy.
Designed using easily available materials from hardware shops, the system consists of an egg-laying and hatching vessel paired with a harvesting bucket. A 7-8 cm layer of coconut coir and sand acts as a filter for leachate. The filtered liquid is recirculated to maintain moisture levels of 50-60 per cent and facilitate the movement of mature larvae into the harvesting bucket, thereby reducing manual handling.
Based on the initial trials, the researchers have recorded a yield of approximately 2 kg of larvae per day over a 20 day period. The system is affordable and space-efficient. Its enclosed design also addresses the challenge of unpleasant odour, one of the major concerns associated with on-site organic waste processing, the Institute says.