Circular Economy Approach for Utilizing Organic Waste in Cat Litter and Compost to Support Plant Growth

This study introduces a novel two-stage circular economy model to transform organic waste materials—bean dregs and coffee grounds—into functional products: eco-friendly cat litter and organic fertilizer. The hypothesis was that integrating vermicompost and diatomaceous earth with these waste materials would enhance the functional properties of cat litter while ensuring its recyclability into high-quality fertilizer. In the first stage, a combination of bean dregs, coffee grounds, vermicompost, and diatomaceous earth was optimized using the Taguchi method, achieving cat litter with superior water absorption and clumping performance. In the second stage, the spent cat litter was rapidly composted, producing a nutrient-rich organic fertilizer. The fertilizer’s efficacy was validated through a potting experiment with lettuce, where a 10% application rate promoted optimal growth without causing nutrient toxicity. This innovative approach offers a sustainable solution to waste management challenges while contributing to environmentally friendly agricultural practices. Future research could investigate incorporating additional waste streams and enhancing composting efficiency for broader implementation.