Design and fabrication of rice hull pelletizer for cat litter production/ Angel Gift B. Carabal, Dave Mathew O. Collado, Christine Joyet I. De Guzman, Kenneth Vincent O. Ocsillos, and Elijah C. Testor.--

Bachelor's thesis

College Of Engineering.--
Bachelor of science in mechanical engineering: Technological University of the Philippines,
2025.

Includes bibliographic references and index.

Along with the rising population of domestic cats in households and shelters comes the
growing concern of maintaining healthy living conditions of such beloved felines which
includes proper waste management often with the use of cat litter. Conventional cat litter
often contains non-biodegradable materials like clay, which contribute to landfill waste and
environmental pollution. This study presents the design and fabrication of a rice hull
pelletizer aimed at transforming agricultural waste—specifically rice hulls—into eco-friendly
cat litter pellets. The machine features interchangeable circular die plates with hole diameters
of 4 mm and 6 mm, producing pellets with output sizes ranging from 2–3 mm and 4–5 mm,
respectively. It is capable of processing up to 7 kilograms of material per hour. The optimal
pellet formulation consists of 60% rice hull, 18% starch, 12% water, and 10% charcoal.
Performance tests showed promising results, with an absorption rate of 70.175 mL/min,
adsorption capacity of 254%, hydration capacity of 2.54 g/g, and a deodorizing ability rated
as “noticeable.” These findings support the viability of rice hull-based cat litter as a
sustainable, cost-effective alternative to commercial products, with potential for widespread
use in shelters and households alike.