Farmland Soil Remediation: A Novel Mechanical Approach for Efficiently Separating Residual Film from Ploughed Soil

This study investigates the incomplete separation caused by the adhesion and bonding between residual film and soil, examines its adverse impacts on farmland soil remediation and environmental pollution, and proposes a multistage sieving roller device to achieve residual Film–Soil separation in the plough layer. The overall structure and working principle of the device were described, and the sieving process during operation was analyzed. The fragmentation characteristics of the film–soil composite under impact loading were investigated using an analytical approach. Based on the characteristic parameters of soil and residual film in the plough layer, the key structural parameters of the sieving rollers were determined. A test platform of the multistage sieving roller film–soil separation device was constructed, and physical experiments were conducted using the Box–Behnken response surface methodology. The rotational speed, gap, and inclination angle of the sieving rollers were selected as experimental factors, with the soil removal rate and film leakage rate as evaluation indices. Analysis of variance revealed high coefficients of determination (R2) for the soil removal rate (0.9909) and the film leakage rate (0.9927), demonstrating an excellent fit of the model. The optimal combination of parameters was determined as follows: a sieving roller rotational speed of 450 r·min−1, a gap between the sieving rollers of 21.48 mm, and an inclination angle of 10° for the sieving rollers. Under these conditions, the soil removal rate reached 92.08%, and the film leakage rate was 5.74%, meeting the requirements for separating soil and residual film. This study presents a novel method and provides a technical reference for the efficient separation of residual film and soil in the plough layer, thereby contributing to an improved recovery rate of residual film. The growing urgency to mitigate farmland soil pollution has necessitated the advancement and widespread adoption of mechanized technologies and equipment for residual film recovery.