Turbidity removal from aqueous environments by Pistacia atlantica (Baneh) seed extract as a natural organic coagulant aid

Abstract

Coagulation/flocculation, as an important step in water treatment processes, is applied for turbidity removal of raw water coming from suspended particles and colloidal material. In this study, the ability of Pistacia atlantica seed extract, as a natural organic coagulant aid along with ferric chloride for turbidity removal from synthetic solutions, was investigated. Coagulation ability of this coagulant was assessed by the use of standard jar test measurement. The influence of several operating parameters such as, pH (2–12), coagulant dose (2–35 mg/L), natural coagulant aid dose (0.1–5.0 ml/L), and initial turbidity (20–200 NTU), were investigated. The optimum pH for removal of turbidity by coagulation process using P. atlantica seed extract was found 9–10 with coagulant dose 1 ml/L (in combination with FeCl3 at dose 2 mg/L). The results obtained with synthetic solutions revealed that the most effective removal efficiency of turbidity (97.43%) was achieved with natural coagulant dose 0.4 ml/L and FeCl3 10 mg/L at pH 9. In addition, the highest removal efficiency was obtained at higher initial turbidities. According to the results of this study and with respect to the abundance of this tree in various regions of Iran, especially in mountain areas, its use as a natural coagulant for turbidity removal from aqueous environments is possible and viable specifically for rural areas and small communities.