Abstract
Olive oil mill wastewater is a strong pollutant with low pH (4.63) and high salinity (2.70 dS m−1), organic matter (chemical oxygen demand (COD) = 7910 mg L−1), total phosphorus (1049.7 mg L−1), total phenols (540.4 mg L−1) and turbidity (280.1 NTU). This study provides the first application of precipitation processes using HCl, H2SO4, HNO3, NaOH and Ca(OH)2 to olive oil mill wastewater in order to reduce COD, total phosphorus, turbidity, calcium, total phenols and absorbances at 220, 254, 410 and 600 nm. Application of HCl was capable of reducing initial COD (11.4%), turbidity (87.8–98.4%), calcium (100%), total phosphorus (22.1%) and absorbances at 254 nm (12.5–23.5%), 410 nm (46.1–57.9%) and 600 nm (47.4–63.6%) due to the destabilization of suspended and colloidal matter. H2SO4 process allowed removals of turbidity (82.5–97.4%), total phosphorus (14.3–26.9%), calcium (100%) and absorbances at 254 nm (10.9–22.9%), 410 nm (43.4–56.6%) and 600 nm (94.2–96.8%). Experiments conducted using HNO3 showed a positive effect on the removal of COD (10.5–23.6%), total phosphorus (18.9%), turbidity (78.3–94.3%), total phenols (4.6–24.6%) and absorbances at 254 nm (40.5–72.0%), 410 nm (59.1–70.3%) and 600 nm (82.5–91.4%). The advantages of the application of Ca(OH)2 precipitation constituted the removals of COD (11.4–17.8%), total phosphorus (23.6–42.2), turbidity (60.9–100%), total phenols (25.9–48.0%) and absorbances at 220 nm (10.3–33.5%), 254 nm (18.5–45.9%), 410 nm (34.2–81.6%) and 600 nm (22.1–77.3%) owing to formation and precipitation of calcium and magnesium carbonates, magnesium hydroxide and phosphates. Similar results were obtained for NaOH precipitation: COD (19.9–21.5%), total phosphorus (5.9–22.7%), turbidity (80.3–99.4%), total phenols (32.9–55.4%) and absorbances at 220 nm (2.8–11.9%), 410 nm (10.4–44.5%) and 600 nm (24.4–91.9%).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: International Journal of Environmental Science and Technology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.