Research on the treatment of meat industry wastewater by filtration combined with coagulation

Abstract

Meat processing enterprises generate significant volumes of fatty wastewater with high fat content (600–2000 mg/L), suspended solids (600–2000 mg/L) and chemical oxygen demand (COD 1000–2600 mg/L). Traditional local treatment methods (grease traps, sedimentation tanks, flotation) do not always ensure compliance with regulatory requirements for discharge into municipal sewers (fats ≤ 20–100 mg/L, suspended solids ≤ 500 mg/L, COD ≤ 1000 mg/L), which complicates the operation of municipal treatment facilities. The paper investigates the effectiveness of treating such effluents by pressure filtration through elastic polyurethane foam (EPU) in combination with chlorine iron coagulation and sedimentation. A two-stage scheme is proposed: preliminary filtration through EPPU – coagulation (FeCl₃ dose 100–200 mg/L, optimally 150 mg/L) with polyacrylamide flocculation (3–5 mg/L) – settling for 30 minutes – repeated filtration through EPPU. Experiments have shown that at a filtration rate of 5–15 m/h, a bed height of 2 m and a density of 50 kg/m³, the fat content is reduced by 97.3–99.1%, suspended solids by 94.1–96.6%, COD by 52.0–74.6%. After a full treatment cycle, the wastewater parameters are as follows: fats 19 mg/L, suspended solids 54 mg/L, COD 630 mg/L, BOD5 470 mg/L, which meets the requirements for discharge into the municipal sewerage system. Based on experimental design and regression analysis, mathematical dependencies were obtained that allow predicting the concentration of contaminants in treated water and the duration of the filter cycle depending on the initial parameters (filtration rate, concentrations of fats, suspended solids, COD). The proposed technology ensures high efficiency, compact equipment and the possibility of repeated use of EPPU after mechanical regeneration, which makes it promising for local treatment systems of meat processing enterprises.