Coconut Husks and Sugarcane Bagasse with Limestone in Greywater Treatment for Non-potable Uses

Abstract: Greywater recycling is an important approach in sustainable water management, particularly for non-potable applications such as irrigation and toilet flushing. This study investigates the use of coconut husks and sugarcane bagasse, combined with limestone, as low-cost filtration media for greywater treatment. The vertical flow filtration system was tested under four conditions: (i) coconut husks with limestone, (ii) coconut husks alone, (iii) sugarcane bagasse with limestone, and (iv) sugarcane bagasse alone. Parameters measured included turbidity, colour, pH, and heavy metals (Cu, Zn, Fe). Results showed significant improvement, with coconut husks + limestone achieving the highest removal efficiency (turbidity 86%, RScolour 52%, Cu 66%, Zn 70%, Fe 84%). The findings indicate that agro-waste combined with limestone can provide an effective, eco-friendly, and affordable method for greywater treatment at the domestic scale. Future studies should explore microbial removal, cost analysis, and pilot-scale applications.