An approach for analysis and selection of ideal natural coagulants for the treatment of synthetically prepared turbid water

Abstract

The volume of research on natural coagulants has expanded significantly in recent years, driven by increased awareness of environmental sustainability and the excellent characteristics and efficiency that natural coagulants offer, thereby minimising environmental effects. The present study aimed to select the most suitable natural coagulants among banana peel, coconut fibre, groundnut shell, onion peel, sawdust, and lemon peel, necessitating a systematic approach, such as a screening test. The experimental runs were conducted using a standard jar test apparatus having synthetic turbid water to assess the efficiency of coagulants. The physicochemical properties were examined using the standard methods recommended by APHA (2017). Color, turbidity, pH, electrical conductivity, total solids, and sludge dewaterability were chosen as the primary indicators for this study. The results revealed encouraging insights into the efficacy of the tested natural coagulants, with rice husk removing the least amount of turbidity (83.3%) at 1gm/500ml and onion peel removing the most at 96.4%. The sludge formed after treatment with natural coagulants demonstrated outstanding dewaterability, with tamarind seeds having the lowest dewaterability at 29.17% and coconut fibre having the highest at 90.2% at a dosage of 1 gm/500 ml. The findings suggest that tested natural coagulants are effective for water treatment. Furthermore, sludge dewaterability, another critical measure in analysing feasibility and sustainability, was reported to be the greatest by coconut fibre (90.2%) and the least by onion peel at 46.71%.The screening strategy used in the study appears to be quite effective in expediting the selection process by systematically examining the influence of coagulant type and dose. The study not only identified the most effective coagulants but also saved time and effort by eliminating less effective choices.