Numerical Optimization of the Physico-chemical Process Used in the Treatment of Real Poultry Slaughterhouse Wastewater for Water Quality Improvement

• Published in: International Journal of Environmental Research 2022-10, Vol.16 (5), Article 78
• Main Authors: Masmoudi Jabri, Khaoula, Hakimi, Rania, Akrout, Hanene, Bousselmi, Latifa
• Format: Article
• Language: English
• Subjects: Abattoirs; Agribusiness; Agricultural production; Calcium chloride; Chemical oxygen demand; Coagulants; Coagulation; Design optimization; Earth and Environmental Science; Environment; Environmental Engineering/Biotechnology; Environmental Management; Ferric chloride; Flocculation; Food industries wastewaters; Food industry; Geoecology/Natural Processes; Germination; Iron chlorides; Lactuca sativa; Landscape/Regional and Urban Planning; Magnesium chloride; Mathematical analysis; Natural Hazards; Optimization; pH effects; Phytotoxicity; Poultry; Quality control; Research Paper; Response surface methodology; Seeds; Sewer systems; Turbidity; Wastewater treatment; Water quality
• ISSN: 1735-6865; 2008-2304
• DOI: 10.1007/s41742-022-00451-4

The coagulation–flocculation process is widely used as a pretreatment step in the agri-food industry, particularly in oily wastewater such as that produced by poultry industry, to remove oil particles, organic, and nutrient fractions. The optimization of the operating conditions of this treatment process is a crucial step, which affects the performance of the treatment and the design of the other treatment steps. In this study, different coagulants were tested mainly Al 2 SO 4 , FeCl 3 , MgCl 2 , CaCl 2 , and NH 4 SO 4 . It was found that iron chloride presented the highest removal efficiency for the turbidity and the chemical oxygen demand (COD). The response surface methodology investigated the interaction of three factors: the coagulant concentration ( X 1 ), flocculent dosage ( X 2 ), and initial pH ( X 3 ), and the responses were COD removal ( Y 1 ) and residual turbidity ( Y 2 ). The determined optimal operating conditions were FeCl 3 dose = 400 mg L −1 , flocculent dose = 46 mg L −1 , and pH = 5.88. Under the optimal conditions, a COD removal of 79% and turbidity removal of 94% were achieved with high variance coefficient ( R 2 ) values of 0.942 and 0.964 for COD and turbidity removals, respectively. Moreover, the Germination Index (GI) of the poultry slaughterhouse wastewater (PSWW) evaluated with Lactuca sativa was improved from 22.35 to 64.65% in the treated wastewater. Article Highlights Common coagulants used in agri-food industry were tested for the treatment of poultry slaughterhouse wastewater. FeCl 3 was identified as the most efficient coagulant in terms of turbidity and COD removal. Response surface methodology through central composite design was used for the optimization of the coagulation flocculation process. The phytotoxicity assessment was investigated through the germination index of Lactuca sativa seeds. The treated poultry slaughterhouse wastewater fits with the Tunisian norm of discharge into the sewer system. Graphical Abstract