Performance Assessment of Descurainia Sophia Seed Extract as a Natural Coagulant in Combination with Aluminium Sulfate for Turbidity Removal in Water

Background: The combined use of plant-based and chemical coagulants, such as aluminium or iron salts can reduce the use of chemical coagulants while providing sufficient efficiency in removing suspended solids. This experimental research investigated the effect of Descurainia sophia seed extract (DSSE) in conjunction with the aluminium sulphate (alum) on turbidity removal efficiency.  Methods: D-Optimal design using Response Surface Methodology (RSM) was used for experimental design to investigate the effects of operating factors on responses and the potential interactions between these factors. Results: The results showed that, when starting with  an initial turbidity of 200 NTU, the maximum achieved turbidity removal efficiency of 91.45% (Run 1) was attained by using only alum at an optimized concentration of 59.5 mg/L and a pH 6. However, when the initial turbidity was 200 NTU, pH 7, and the alum concentration was reduced to 40 mg/L, and the DSSE/water ratio was increased to 16 mL/L, a turbidity removal efficiency of 93.45% (Run 35) was obtained. Conclusion: DSSE can be used as a plant-based coagulant along with alum to reduce alum consumption and improve the coagulation and flocculation of suspended solids in water. By incorporating this extract, the removal of impurities and reduction of turbidity can be effectively promoted.