University of Tehran Journal of Natural Environment 2008-7764 78 Monitoring and Management of Natural Environmental Pollutants 2025 07 01 Optimization of COD and BOD removal from dairy plant wastewater using the Fenton process Optimization of COD and BOD removal from dairy plant wastewater using the Fenton process 127 139 99900 10.22059/jne.2024.386319.2734 FA Mahtab Babajani Marzenaki Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. Hassan Rezaei Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. Hajar Abyar Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. Journal Article 2024 12 02 The dairy industry is considered as one of the top industries in the field of food production, which consumes a lot of water during the manufacturing and processing of dairy products. Dairy wastewater contains mineral particles, organic substances, heavy metals, and suspended substances, which affect the aquatic ecosystems and biodiversity if not treated properly. The purpose of this research is to treat dairy wastewater and reduce COD using the Fenton process, and to evaluate the effect of different operational parameters by the response surface methodology. At first, the characteristics of dairy wastewater such as pH, COD, TSS, TDS, phosphate, and nitrate were determined. The design of the experiment was carried out using the response surface methodology by Design-Expert software to optimize operational parameters such as H₂O₂, Fe²⁺, pH, and contact time. The efficiency of Fenton process in dairy wastewater treatment was investigated during 30 experiments and finally the optimal conditions were determined. The results of dairy wastewater quality investigation showed that the initial COD concentration of wastewater was 1400 mg/L. In addition, pH and H₂O₂ concentration had the most effect on the maximum reduction of COD. The highest COD and BOD removal efficiency under optimal conditions (pH= 3.5, H₂O₂ equal to 54 ml, 4 g of Fe²⁺ and reaction contact time of 10 minutes) was 93% and 88%, respectively. Despite the high efficiency and potential of the Fenton process in removing COD and BOD from dairy wastewater, the use of this approach on an industrial scale requires a comprehensive environmental and economic evaluation. The dairy industry is considered as one of the top industries in the field of food production, which consumes a lot of water during the manufacturing and processing of dairy products. Dairy wastewater contains mineral particles, organic substances, heavy metals, and suspended substances, which affect the aquatic ecosystems and biodiversity if not treated properly. The purpose of this research is to treat dairy wastewater and reduce COD using the Fenton process, and to evaluate the effect of different operational parameters by the response surface methodology. At first, the characteristics of dairy wastewater such as pH, COD, TSS, TDS, phosphate, and nitrate were determined. The design of the experiment was carried out using the response surface methodology by Design-Expert software to optimize operational parameters such as H₂O₂, Fe²⁺, pH, and contact time. The efficiency of Fenton process in dairy wastewater treatment was investigated during 30 experiments and finally the optimal conditions were determined. The results of dairy wastewater quality investigation showed that the initial COD concentration of wastewater was 1400 mg/L. In addition, pH and H₂O₂ concentration had the most effect on the maximum reduction of COD. The highest COD and BOD removal efficiency under optimal conditions (pH= 3.5, H₂O₂ equal to 54 ml, 4 g of Fe²⁺ and reaction contact time of 10 minutes) was 93% and 88%, respectively. Despite the high efficiency and potential of the Fenton process in removing COD and BOD from dairy wastewater, the use of this approach on an industrial scale requires a comprehensive environmental and economic evaluation. https://jne.ut.ac.ir/article_99900_16bcab142a8c63ff260b641ebbe959d5.pdf