In this experiment, a variety of inorganic materials were simply compounded with Polysilicate Aluminum Ferric Sulfate (PSAFS) to treat emulsified oil-contaminated water. Manganese sulfate (MnSO₄), magnesium sulfate (MgSO₄), and zinc sulfate (ZnSO₄) were selected as the materials to modify PSAFS in order to obtain a coagulant with good flocculation performance. During the preparation of modified PSAFS, metal manganese, magnesium, and zinc were introduced for modification, and four factors were used to optimize the best proportion of modifiers and PSAFS. The results showed that the order of demulsification and oil-removal ability is as follows: Mn-PSAFS (Mn-modified PSAFS) > Zn-PSAFS (Zn-modified PSAFS) > Mg-PSAFS (Mg-modified PSAFS) > PSAFS. Modified PSAFS was characterized by infrared spectroscopy (IR) and a Scanning Electron Microscope (SEM). In the range of 604 cm⁻¹ to 1200 cm⁻¹, due to the complexation reaction between metal ions and polysilicic acid, the absorption peaks of the modified PSAFS and PSAFS were significantly different. SEM results revealed that the particles of the spatial network structure were fibrous and arranged more closely (0.5 mm × 50.0 mm) than others. This study provided that the modified PSAFS had good potential application in treating emulsified oily wastewater in the future.

The aim of this work was to develop bacterial communities to effectively degrade petroleum hydrocarbons (PHs). We investigated the biotic and abiotic contributors to differences in PHs degradation efficacy between two bacterial strains, Klebsiella pneumoniae (Kp) and Pseudomonas aeruginosa (Pa), screened out from the activated sludge of a petroleum refinery. We characterized the temporal variations in degradation efficacy for diesel and its five major constituents as a sole carbon source and identified more constituents they degraded. The growth characteristics, surface tension, hydrophobicity and emulsifiability of these two strains were measured. We further estimated the relationships between their degradation efficacy and all the biotic and abiotic factors. Results showed that the Pa strain had higher diesel degradation efficacy (58% on Day 14) and utilized more diesel constituents (86%) compared to Kp. Additionally, the growth of the Pa strain in diesel medium was faster than that of the Kp strain. The Pa strain had a lower surface tension and higher hydrophobicity and emulsifiability than Kp, while the surfactant produced by Pa was identified as rhamnolipids. Degradation of PHs was positively related to bacterial growth, hydrophobicity and emulsification but negatively related to surface tension. Overall, differences in degrading capacity for diesel constituents, relative growth rate, and biosurfactant production contributed to the variation in the PHs degradation efficacy of these two bacterial strains.