蚯蚓-蚯蚓粪分离-收获工艺与关键部件试验

蚯蚓堆肥是实现农业有机固体废弃物减量化、无害化、资源化和增值化的生物处理技术之一。蚯蚓堆肥结束后，如何将成熟活体蚯蚓从大量堆肥物料中快速分离收获，是目前规模化蚯蚓堆肥亟需解决的难题之一。为实现蚯蚓体快速、高效、稳定的分离和收获，该研究提出了蚯蚓堆肥产物3步分离收获工艺方法，并针对此工艺中的动态斜面分离收获关键部件和工艺参数开展了试验研究。在此基础上，结合力学分析、EDEM离散元仿真模拟揭示了蚯蚓分离关键过程中的动力学机制。结果表明：本研究所提出的分离工艺可较好实现蚯蚓、蚯蚓粪的分离和集中收获，动态斜面在蚯蚓-蚯蚓粪分离过程中起关键作用，利用了蚯蚓体表液膜接触粘附摩擦特性强，易粘附于斜面，而动态斜面作用下蚯蚓粪滚动摩擦力小的特性，蚯蚓与蚯蚓粪抛落于动态斜面后因受力差异导致两者呈相反方向运动，实现分离。蚯蚓-蚯蚓粪分离收获的最优参数组合为安装锥形分离器下，分离收获斜面速度50 mm/s、倾角为30°。基于此工艺方法处置蚯蚓粪-蚯蚓混合物料10 kg耗时55.36 s，在蚯蚓收获区的蚯蚓收获率为（81.50±5.55）%，蚯蚓粪含杂率接近于0，物料总收获率为（96.56±1.79）%。研究结果可提高蚯蚓堆肥产物分离收获的速度与效率，为规模化蚯蚓堆肥机械装备化、减少人工作业和降低成本提供借鉴与参考。

Separation and harvest technology for earthworm-vermicompost and key component experiments

Abstract: Vermicomposting is a widely accepted, clean, and sustainable technology to dispose of the solid organic wastes, such as livestock manure, plant straw, garden wastes, and food residues. There is an ever-increasing demand for live earthworms for waste resource utilization in recent years, as the vermicomposting industry grow rapidly. It is necessary to harvest the live earthworm from the large scale vermicompost at the end of vermicomposting. However, the traditional earthworm separation is labor-intensive, costly and time-consuming, depending mostly on manual or simple tools. It is also a high demand to rapidly, high-efficiently separate and harvest the live earthworm from the mature vermicompost, as the vermicomposting scale expands constantly. In this study, a three-step earthworm separation was developed to obtain the optimal harvest parameters and the key kinetic mechanism. The third key step technology named dynamic inclined plane separation was studied in terms of experiment, theory, and simulation. The earthworm separation experiment was carried out to harvest the live earthworm from the resulted vermicompost using Earthworm-Vermicompost Rolling Screen (EVRS) and harvest conveyor. The separation mechanism of dynamic inclined plane was investigated from the kinetic analysis and Electronic Discrete Element Method (EDEM) simulation on the key process. The results indicated that the earthworm dynamic inclined plane separation was effective and feasible. Most adult earthworms and vermicompost were separated and collected independently in the specific harvest area. The optimal parameters were achieved in the earthworm inclined harvest plane for the conical separator in the EVRS, particularly with the conveying velocity of 50 mm/s and the inclined angle of 30°. The earthworm harvest rate was approximately (81.50±5.55)% with almost no vermicompost impurity. Consequently, the harvest system was run the 10 kg mixture in 55.36 s with a total material harvest rate of (96.56±1.79)%. The core separating between the earthworm and vermicompost was attributed to their difference in characteristics and surface properties, resulting in the different force and motion states in the earthworm harvest area. Specifically, the earthworms were carried and moved with the dynamic inclined plane during the key harvest process, due to the wet adhesion behavior. The vermicompost was directly rolled down under the effect of a moving and inclined plane, where the spherical shape led to the decrease in the rolling friction force. A full separation was finally realized, where the earthworm and vermicompost were moved in the opposite direction on the dynamic plane. Therefore, the effective solution can be expected to improve the harvest speed and efficiency of earthworm and vermicompost products. The finding can also greatly contribute to shortening the harvest time and saving the separating expense in the vermicomposting field.