蚯蚓对电刺激的响应及其与蚯蚓粪胁迫分离的参数量化

蚯蚓与蚯蚓粪快速高效分离是规模化蚯蚓生物消解农业废弃物的关键技术环节。针对目前电刺激分离蚯蚓方法在实际生产应用中缺乏相关定量参数等问题,该研究探讨了蚯蚓分离率对电刺激方式、强度、通断电循环周期时长、通电时长及电刺激耦合物料含水率、物料厚度等因子的响应关系,并分析了电刺激对蚯蚓生理生化指标的影响。结果表明,电刺激可促进蚯蚓与蚓粪分离,间歇式电刺激方式较持续式电刺激具有更好的分离效果;间歇式电刺激方式下,蚯蚓分离率与电刺激强度、通断电循环周期时长、通电时长均呈显著的开口向下一元二次抛物线关系,蚯蚓生长的物料含水率适宜值为52.60%,物料厚度越小,越有利于电刺激分离率的提高;电刺激处理对蚯蚓体内过氧化氢酶、超氧化物歧化酶、乙酰胆碱酯酶、纤维素酶、可溶性蛋白含量无显著影响,但显著提高了丙二醛含量,蚯蚓经过5 d的恢复性驯养后,丙二醛含量可恢复至对照处理水平;综合蚯蚓分离率、技术参数易操作性等,采用间歇式电刺激方式分离蚯蚓,设计电刺激强度2 mA、通断电周期时长30 s、通电时长1 s,控制物料含水率50%左右、物料厚度20～25 cm,辅助210 lx白光光照,电刺激作业时间30 min,蚯蚓分离效率可达85%左右。研究可为快速高效分离蚯蚓活体与蚯蚓粪的设备研发与应用提供参考。

Responses of earthworm to the electric stimulation and the parameter quantification of its stress separation from earthworm dung

Abstract: Earthworm composting can serve as one type of agricultural waste treatment to combine with conventional composting with biological digestion. The earthworms can be selected to decompose the organic matter. The ''ecological interface'' of earthworm composting has been utilized to optimize the earthworm culture using the large-scale breeding equipment, particularly for the harmless, reduction and recycling of agricultural wastes. However, a perfect balance needs to be gained between the short mature period of earthworms, and the large output of earthworm and earthworm dung. The separation can be the key link to harvesting the earthworm products and earthworm dung organic fertilizer. Electric stimulation can be used to separate using the instinctive reaction of earthworms with less harm. Once the electric stimulation is directly applied to the material carrier where earthworms are, the earthworms can be actively driven to leave the growing environment. There was no harm to the health of earthworms, and no secondary pollution to the environment, synergistically coupled with the breeding equipment in practice. Therefore, it is a high demand to clarify the separation process for the rapid design of the separation facility. In this study, a systematic investigation was conducted to determine the response of the separation rate of earthworms to the mode, intensity, and duration of electric stimulation, the water content of the carrier, and the material thickness. An evaluation was made to clarify the effects of electric stimulation on physiological and biochemical indexes of earthworms. The results show that electrical stimulation promoted the separation of earthworm and dung, where the intermittent electrical stimulation presented a better separation performance than the continuous. The earthworm separation rate was significantly correlated with the intensity of electrical stimulation under the intermittent mode, the circulation cycle time of power-on and power-off, as well as the times of power-on. The optimal moisture content of the material carrier was 52.6% for the earthworm growth. The smaller the material carrier thickness was, the better the earthworm separation rate was. Electrostimulation treatment had no significant effect on the contents of catalase, superoxide dismutase, acetylcholinesterase, cellulase and soluble protein in earthworms, but significantly increased the content of malondialdehyde. After 5 days of recovery domestication, the content of malondialdehyde could be restored to the level of control treatment. Consequently, the earthworm can be separated by intermittent electrical stimulation, in terms of the separation rate and the technical parameters. An optimal combination was achieved, where the intensity of electrical stimulation was 2mA, the on-off cycle time was 30 s, and the power-on time was 1s. The earthworm separation efficiency reached about 85% after 30 minutes of electrical stimulation, where the water content of the material carrier was about 50%, the material thickness was 20-25 cm, and the auxiliary 210 lx white light. The finding can provide strong support to the equipment application for the rapid and efficient separation of earthworm and earthworm dung during agricultural waste treatment