Development of an integrating coagulation and reverse osmosis system to treat highly turbid water using synthesized coagulants

Abstract

In the present study coagulation process was used as pretreatment for the RO membrane with turbid raw water collected from Bisalpur Dam, Rajasthan, India. To optimize coagulation performance, three kinds of coagulants, namely, Alum (commercially available), synthesized inorganic polymeric coagulant-medium basicity (IPC-M), and inorganic polymeric coagulant-ultra high basicity (IPC-UH) were examined for turbidity removal with varying operating parameters. It was observed that in the optimum pH range of 6–7, the IPC-UH resulted as the best performing coagulant with 0.99 mg/L equivalent Al2O3 dose revealing 2 NTU residual turbidity and residual aluminium of 0.001 mg/L. Moreover, Langelier saturation index and Ryznar stability index values were evaluated at optimum conditions of all the three coagulants proclaiming negligible scaling potential. Furthermore, the coagulant-treated water (100 L) was fed to the RO membrane, and the performance was noted in terms of flux, pressure, and TDS. It was observed that IPC-UH has the lowest reduction in permeate flux of 0.78 L/min/m2 compared to commercially available coagulant alum (0.90 L/min/m2). Also, the increased feed pressure was observed for all the coagulants treated water with the lowest value of 2.3 kg/cm2 for IPC-UH, which was 2.5 kg/cm2 for Alum (commercially available coagulant). Henceforth, integration of coagulation before the RO system resulted in effective pretreatment of turbid water with very minute scaling.

A Comparative Study of Removal of Acid Red 27 by Adsorption on Four Different Chitosan Morphologies

“…The dye molecules in textile wastewater are stable for oxidants and microorganisms that pose challenges to elimination [2]. Consequently, various techniques have been developed to treat wastewater contaminated with dyes, including adsorption [3], membrane filtration [4,5], electrochemical treatment [6], advanced oxidation processes [7], enhanced biotechnology methods [8], and so on. Among them, adsorption has been a subject of extensive studies, due to its operational convenience and high efficiency, with a central focus on achieving high adsorption rates and capacities [9].…”