Preparation and characterization of Azadirachta indica A. Juss. plant based natural coagulant for the application of urban sewage treatment: Modelling and cost assessment

Abstract The aim of the present study was to investigate the efficiency of Azadirachta indica A. Juss. plant based natural coagulation (NC) and chemical coagulation (CC) to treat urban sewage. Aluminium sulphate​ (Al2(SO4)3 ⋅ 6H2O) was used as a chemical coagulant. NC was examined using Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and X-ray emission spectrometry (EDX). The effects of rotation speed, mass of coagulant and settling time on the removal of colour, turbidity and COD were investigated using Box–Behnken design (BBD) of experiments. The results showed that NC could be effectively reduced the colour, turbidity and COD at the optimum conditions compared to CC. The operating cost were 1.73 US $/m3 and 0.56 US $/m3 for CC and NC, respectively.