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 sulfate (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.

本研究的目的是调查Azadirachta indica A. Juss的功效。基于植物的自然混凝（NC）和化学混凝（CC）处理城市污水。硫酸铝 (Al ₂ (SO ₄ ) ₃ .6H ₂O)用作化学混凝剂。使用傅里叶变换红外光谱 (FT-IR)、扫描电子显微镜 (SEM) 和 X 射线发射光谱法 (EDX) 检查 NC。使用 Box-Behnken 设计 (BBD) 实验研究了转速、混凝剂质量和沉降时间对颜色去除、浊度和 COD 的影响。结果表明，与CC相比，NC在最佳条件下可以有效降低颜色、浊度和COD。CC 和NC的运营成本分别为1.73 美元/m ³和0.56 美元/m ³。