Use of naturalized coagulants in removing laundry waste surfactant using various unit processes in lab-scale

•We identify the most efficient natural coagulant in treating laundry rinsing water.•Nirmali seed and pectin extracted from Orange peel were used as coagulant.•GAC adsorption was found to be effective in removing anionic surfactant.•Treatment system using orange peel pectin as coagulant was found to be efficient.

This lab-scale experiment is aimed at demonstrating a treatment system for purification and reuse of laundry rinsing water generated from households. The main objective of the study is to compare the efficiencies of various natural coagulants in removing laundry waste surfactants and other major pollutants from the laundry rinsing water. The treatment system consists of Coagulation–Flocculation, Sand filtration and Granular Activated Carbon (GAC) adsorption. Four experiments were conducted in batch process by varying the coagulants (Nirmali seed and Pectin extracted from pith of Orange peel). Coagulants have been selected due to their local availability at affordable cost and technical feasibility. From the study it is concluded that laundry rinsing water polluted with high turbidity and anionic surfactant treated with Nirmali seeds as coagulant at a retention time of 24 h gives the best results. The treatment system where Orange peel pectin is used as coagulant at a retention time of 24 h is found to be the most efficient one based on the weighted factor. Hence the treatment of laundry rinsing water by aforesaid combination results in better water quality.