Assessment and Classification of Liquids Wastes Quality from a Food Processing Factory in the Korhogo Region Using a Combination of Water Quality and Pollution Indices

Abstract

Background: Liquid wastes from the food-processing factory are a major source of environmental pollution. There is a need to investigate the compliance of wastewater discharged from food-processing factories with regulatory standards. Aim: To assess the physicochemical quality and pollution status of liquid effluents from a food-processing factory in Korhogo that operates without a wastewater treatment plant. Study design: A total of 06 liquid-waste samples were collected from a food-processing factory in Korhogo. Methodology: The samples were analysed in the laboratory in accordance with the standards in force at the Sub-Directorate for the Inspection of Classified Installations (SDIIC). Parameters assessed included temperature (T), turbidity (Tur), pH, biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), total suspended solids (TSS), electrical conductivity (EC), nitrates (NO₃⁻), nitrite (NO₂⁻), phosphates (PO₄³⁻), total phosphorus (TP), ammonium (NH₄⁺), and total nitrogen (TN). Results: The parameters were measured. The mean values of TSS, T, Tur, TP, TN, and pH in the effluents were 77.8 mg/l, 27.21°, 93.73 NTU, 37.99 mg/l, 36.966 mg/l, and 7.21, respectively. The reported average values for dissolved oxygen (DO), biological oxygen demand (BOD₅), and chemical oxygen demand (COD) were 2850 mg/l and 4750.16 mg/L, respectively. The average electrical conductivity (EC) was 7987.5 μS/cm, and the concentrations of anions and cations, including NO₃⁻, NO₂⁻, and NH₄⁺, were 1.63, 0.12, and 39.17 mg/L, respectively. Therefore, these results indicated elevated pollution levels, particularly for organic matter, ammonium, phosphorus, and suspended solids. BOD₅ and COD concentrations exceeded national discharge limits. The effluents showed high biodegradability, as reflected by the COD/BOD₅ ratio (0.6). The Comprehensive Pollution Index (CPI) ranged from 1.472 to 6.940, with 83.3% of effluents classified as heavily polluted. The Nemerow index identified all stations as seriously polluted. The Wastewater Quality Index (WWQI) ranged from 36.535 to 198.922, with 66.7% of effluents rated as very bad (Grade E). Conclusion: These results underscore the need for effective wastewater treatment before discharge into receiving waters.