اعظم مکائیلی - Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.
Mazyar Peyda - Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.

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 ۲۰۰ NTU, the maximum achieved turbidity removal efficiency of ۹۱.۴۵% (Run ۱) was attained by using only alum at an optimized concentration of ۵۹.۵ mg/L and a pH ۶. However, when the initial turbidity was ۲۰۰ NTU, pH ۷, and the alum concentration was reduced to ۴۰ mg/L, and the DSSE/water ratio was increased to ۱۶ mL/L, a turbidity removal efficiency of ۹۳.۴۵% (Run ۳۵) 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.

Alum, Coagulation, Descurainia Sophia, Natural Coagulant, Turbidity