Treatment of the pistachio processing wastewater using Fenton’s, ultrasound with Fenton’s, and coagulation processes

Pistachio processing wastewater was characterized and the treatability of wastewater using Fenton’s process, the combination of Fenton’s process with ultrasonic irradiation and coagulation processes was investigated. [Fe²⁺] = 27.6 mg/dm³, [H₂O,sub>2]= 30 mg/dm³ and 75 min of reaction time were determined as the optimum conditions for Fenton’s process. Then, the combined treatment (ultrasound with Fenton’s process, was applied to the pistachio processing wastewater and 45% of COD removal efficiency was obtained. For the coagulation process, the optimum removal efficiencies of 60% and 45% were achieved for FeCl₃ dosage of 2000 mg/dm³ and Al₂(SO₄)₃ dosage of 3000 mg/dm³, respectively. The results demonstrate that higher COD removal efficiencies could be obtained from the combined ultrasound and Fenton’s process with respect to Fenton’s process alone. Besides, applying the coagulation process using FeCl₃and Al₂(SO₄)₃ also presents high COD removal efficiencies.