The problem of resources and environment is an important problem that beset the sustainable development of our economy and society in the 21th century. How to treat livestock wastes to minimize the amount of sewage and maximize the utilization of resources is a headache for enterprises and governments. The black soldier fly manure management system is a hot spot in the world. This project is based on the practical production application, and develops a set of process flow from faecal disposal, black water gadfly culture, prepupae processing to product application to maximize the benefit of multi-module. It can set an example for the treatment and application of solid waste in a pig farm, create certain economic benefits for enterprises, reduce the pollution of carbon emissions to the environment, and realize the sustainable development.

Black soldier fly, also known as Hermetia illucens (Linnaeus), is a kind of saprophytic insect. It belongs to diptera and stratiomyidae in the taxonomy of insects. The larvae are known as "phoenix worm ", a kind of resource insect with the same name as the fly maggot, yellow mealworm, superworm. The life cycle of black soldier fly includes eggs, larvae, prepupa, pupa and adults (Figure 1). The larvae live in saprophytic life. The larvae feed on the decomposed organic matter such as kitchen garbage, animal manure, animal and plant carcasses in nature, which can transform food into their own nutrients, which is an important part of the natural detrital food chain.

The resource utilization of black soldier fly is mainly concentrated in two aspects, one is to dispose of garbage, and the other is to produce resources. The cost is low and the efficiency is high in dealing with livestock feces. The biggest advantage is that the degree of resource utilization is high, and no secondary waste is produced during the whole process. It is an excellent method of feces treatment. Black soldier fly has high conversion efficiency to the treatment of feces. A ton of feces can produce 100-150 kg of fresh insect. While producing high quality protein insects, it can also deodorize and sterilize very well. At the same time, the amount of excrement is reduced by more than 50%. The feeding of black soldier fly is equivalent to the process of rapid composting. After treatment, the residue of feces is a good organic fertilizer. The advantages lie in the following aspects:

First of all, the black soldier fly treatment is very efficient. The normal composting process takes about 2 months, while the black soldier fly takes only 10-14 days.
Secondly, after the feces was disposed of by black soldier fly, high protein body formation with high economic value. The larvae are the best feed for raising chicken, duck, fish, turtle and so on. After processing, the larvae can replace the fish meal as protein feed additive.
Third, after the feces was disposed by black soldier fly, the remaining fecal residue is odorless, puffed and breathable, and can be sold as a commercial organic fertilizer.
Fourth, the cost of using black soldier fly to treat feces was low. Compared with the biogas treatment in our country, the construction cost of using by black soldier fly to treat livestock feces could be reduced by nearly 80%.
Using black soldier fly to treat livestock waste and resource utilization technology:
The ecological breeding system of black soldier fly consists of three modules: breeding, the large-scale transformation of livestock wastes, ecological cycle application, the breeding of insect eggs, the large-scale production and transformation of livestock wastes. A large number of the larvae were obtained as animal feed, and insect manure was applied as high-quality organic fertilizer to melon, fruit and vegetables to realize the ecological cycle development of planting and breeding. The overall technical route (Figure 3) and breeding process (Figure 4) are as follows:

Preliminary Analysis of Economy:

Taking the manure treatment of ten thousand pig farms as an example, it can produce about 4000 tons of excrement every year, and can produce about 200 tons of dry powder of insect protein feed and 1000 tons of microbial fertilizer by combined transformation of black soldier fly and microorganism. The manure of ten thousand pig farms was treated with black soldier fly and microorganism: the profit was about 1 million yuan per year, and to a large extent, it was used as a resource to realize low-carbon green.

Recycling treatment of livestock wastes by black soldier fly. On the one hand, it can reduce the secondary pollution in the process of storing livestock wastes, effectively protect the environment, reduce the possible environmental pollution and epidemic spread caused by the unreasonable disposal of livestock feces, improve the environmental quality and promote the improvement of agricultural recycling economy level. On the other hand, we will turn livestock waste into treasure. We will introduce advanced and mature experience technology to combine with the actual situation of China. We can truly realize the harmlessness, recycling and reduction of livestock manure, improve the ecological environment, ensure food safety, and promote the development of low-carbon green agriculture.