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Earthworms have been shown to effectively process biodegradable organic waste and increase the availability of nutrients to plants in the final product, vermi-compost, compared to the raw material. After processing earthworms are mechanically separated from the vermi-compost and used for processing more waste or sold. This study investigated whether an electric field could be used to separate earthworms from vermi-compost, since it is known earthworms are repelled by an electric field. The effectiveness with which an earthworm is repelled depends on the voltage created across the earthworm. Select variables affecting this voltage were varied in a set of experiments using earthworms placed in a 2.8 x 2.8 x 7.5 cm soil slab at a density corresponding to 150 earthworms per liter. The variables were the level of electric current at the threshold of the soil slab (the point beyond which earthworms were to be repelled), earthworm diameter and resistance (species-dependent), soil electrode depth and spacing. Effectiveness of the electric field was calculated as a function of the number of earthworms that exited the soil slab. Spatial voltage values were evaluated in each replicate in order to identify the voltage drops in the soil slab and derive the corresponding threshold electric current. Results showed that the effectiveness of the electric field was logarithmically proportional to the voltage generated across earthworms, at a given electrodes spacing, up to the point where earthworm mortality started to occur. At higher voltages the electric field effectiveness decreased exponentially due to mortality. The time where all potential earthworms exited a soil slab increased exponentially up to peak effectiveness, and decreased exponentially after that. The resulting mathematical models can be used to aid in the design of an array of soil rods connected to a power source to repel earthworms from the compost medium.