Garbage classification is a reform of traditional garbage collection and disposal methods and a scientific management method for effective garbage disposal. People are facing the situation of increasing garbage output and deteriorating environmental conditions. How to make the best use of garbage resources, reduce the amount of garbage disposal and improve the quality of living environment through garbage classification management is one of the urgent problems that all countries in the world pay attention to.

Walnut shell is dry garbage, which is classified as dry garbage because it is not easy to corrode, break and damage the terminal treatment equipment of wet garbage.

In the "Guidelines for the Classified Delivery of Domestic Waste in Shanghai", hard fruit shells such as coconut shells, durian shells, walnut shells, corn husks and sugarcane husks, and hard fruits such as durian kernels and jackfruit kernels are classified as dry garbage. Their similarity is hard or full of toughness. If these wastes are mixed with other wet wastes and enter the end of wet garbage treatment, it may cause damage to the equipment, such as blocking the cutter head and winding parts.

Wet garbage: Wet garbage is not wet garbage, but perishable garbage. Such as leftovers, expired food, melon seeds, flowers and green plants.

Dry garbage: Dry garbage refers to all garbage except recyclable garbage, harmful waste and wet garbage. Some places are also called non-recyclable garbage.