Mineralization of olive mill wastewater under hydrothermal conditions

Abstract

Olive mill wastewater (OMW) is highly dangerous for land and aquatic environments because of its high phenolic content, acidity, and salinity. Hence, hydrothermal degradation of OMW in subcritical water medium with and without using external oxidizer (H 2 O 2 ) was studied to decrease its total organic carbon (TOC), total phenolic content (TPC), and color. Effects of reaction temperature (150°C–250°C), reaction time (30–120 min), and H 2 O 2 content (0–100 mM) on TOC and TPC of OMW were investigated. Box-Behnken-type experimental design and statistical analysis (analysis of variance) were practiced by Design Expert 11. According to statistical analysis, effect of reaction temperature significantly affected TOC removal efficiency. The best TOC reduction (31.65%) was achieved without using H 2 O 2 at 250°C for 120 min.