The goal of this study was to elucidate the interaction of complex feed solutions under modified membrane fouling models for constant flux operation. The polyvinylidene fluoride membrane (PVDF) was tested for three types of solutions containing inorganic foulants (Al, Mn, and Fe), organic foulants, and suspended solids at 0.5 mM Ca²⁺ ionic strength. The membrane’s performance was evaluated by measuring the increase in transmembrane pressure (TMP) during two different filtration scenarios: continuous filtration lasting 1 h and cyclic filtration lasting 12 min, with 3 min backwashing cycles included. Statistical analysis (linear regression results (R²), p-value) was used to verify the fouling model propagation along with the determination of the contributing constant of each fouling model. An increasing TMP percentage of 164–302%, 155–300%, and 208–378% for S1 (HA + Ca²⁺), S2 (inorganics + kaolin + Ca²⁺), and S3 (HA + inorganics + kaolin + Ca²⁺) was recorded for 1 h filtration, respectively. Furthermore, a five percent increase in irreversible resistance was noted for the S3 solution due to the strong adsorption potential of foulants for the PVDF membrane caused by the electrostatic and hydration forces of foulants. In addition to that, the participation equation elucidated the contribution of the fouling model and confirmed that complete blocking and cake layer contribution were dominant for the S1 and S3 solutions, while standard blocking was dominant for the S2 solution with a high significance ratio. Moreover, R² and cyclic filtration analysis also confirmed the propagation of these fouling models. The statistical confirmation and regression results analysis of the modified model gave comparative results and satisfied the filtration mechanism and can be used for the constant flux dead filtration analysis of water treatment.

Industrial wastes in the form of chromium, generated by leather industries, commonly contaminate soil, affecting its geotechnical properties. The present study examines the impact of trivalent chromium Cr(III) on the soil’s mechanical, physiochemical, and microstructural properties. The soil and Cr(III) were collected from an industrial area in Sheikhupura, Pakistan, and are mixed in various proportions ranging from 0% to 50% by weight to simulate various contamination levels. A detailed experimental program that included index and strength testing, in addition to physiochemical analysis, was carried out. Modifications in microstructure and mineralogical composition were also examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The results showed an increase in the soil strength characteristics, with maximum dry density (MDD) and cohesion enhanced up to 15% and 12%, respectively, with an addition of Cr(III) up to 20% contamination concentration. Notable reduction in the soil pH was also observed, indicating the acidic impact of Cr(III). Microstructural examination affirmed significant mineralogical rearrangement, with quartz remaining the dominant mineral. The results provided useful insights into the geotechnical implications of Cr(III) contamination in clayey soils and will contribute to improved assessment of the soil behavior in industrially contaminated zones.