جستجوی مقالات مرتبط با کلیدواژه « oily wastewater » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

The increasing pollution of water and soil in today›s industrial activities becomes a real problem in the world. In the meantime, oily wastewater has adverse effects on surface and underground waters, agricultural products and soil quality. The purpose of this study was to reduce or eliminate pollutants present in the effluent of one of the vegetable oil plants to prevent the accumulation of oily materials in environment. In this regard, effectiveness of using coagulants and coagulant aids as water and oil separation process has been investigated. This method is based on the changing of operational variables such as pH, alkalinity and concentrations of coagulant and coagulant aids. Thus, optimal conditions for effective water and oil separation were determined. Test samples were prepared from a vegetable oil plant. Poly aluminum chloride as coagulant and different coagulant aids have been used. The basic method was jar test in which, the different concentrations of coagulant, coagulant aids, pH and Alkalinity were considered. The best results were achieved at 10 ppm for poly-aluminum chloride as coagulant, 0.3 ppm for Gfloc-C125 as a coagulant aid with alkalinity amount of 75 ppm. The results showed that at optimal condition, the quantities of turbidity, oil, COD and Total Suspended Solids (TSS) for wastewater was decreased 89.4%, 98.8%, 62.6% and 97.9% respectively. The results were in a good accordance with environmental standards for plant irrigation.

In this study four types of ceramic microfiltration membranes were fabricated by extrusion and sintering method; Mullite, mullite-alumina, mullite-alumina-zeolite and mullite-zeolite membranes. In order to ensure the correct fabrication of membranes, fabricated membranes were subjected to characterization tests such as scanning electron microscopy (SEM), X-ray diffraction (XRD), porosimetery, mechanical strength and mean pore size calculation. Synthetic oily wastewater were treated by these membranes in microfiltration-adsorption hybrid process. Effect of Powdered Activated Carbon (PAC) concentration on the membrane permeation flux, oil removal efficiency, turbidity and COD removal were investigated. Results showed that in mullite, mullite-alumina and mullite-alumina-zeolite membranes, highest permeate flux obtained in 800 mg L-1 of PAC concentration. For mullite-zeolite membranes addition of 200 mg L-1 PAC concentration lead to highest permeate flux. Addition of PAC with any concentration in all membranes increased oil removal, turbidity and COD removal percent significantly.

In this paper, results of the oily wastewater treatment by ceramic membranes in microfiltration process are simulated using neural network and hermia model. The process simulation by neural networks is written using MATLAB software program. The network input consisted of oil concentration (Coil), cross-flow velocity (CFV), temperature (T), trans-membrane pressure (TMP), and filtration time (t) and the network output consisted of permeation flux. The operational data is divided in three categories: training, validation and testing. In this study, three modes (20-20-60 and 15-15-70 and 10-10-80) are investigated for training the network. Also formation of precipitate is modeled using hermia model includes four different behavior in obstruction. In all states are observed prediction of permeation flux using neural network is better than hermia model.

Oily wastewaters and oil-in-water emulsions are two major environmental pollutants. However, industrial oily wastewaters, though they may be lower in volume, contain much higher concentrations of pollutants. Treatment of the oily and greasy wastewater of Tehran refinery was experimentally studied using an ultrafiltration (UF) system. In the experiments, a UF membrane Polysulfone (PS) 30 kDa and sample from Tehran refineryoutlet wastewater of the API unit were used as feed. Effects of different operating parameters such as transmembrane pressure (TMP), cross flow velocity (CFV), and temperature on permeation flux, fouling resistance and UF rejection were studied. According to the results, permeation flux was found to improve with increasing TMP, CFV and temperature at constant feed concentration. Fouling of the membrane completely follows Hermia’s model (filtration cake mechanism). Analysis of the UF process showed 99.2, 75.4, 63.3, 42.3, 23.1, 100 and 97.9 % decreases in oil and grease content, total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD5), total dissolved solids (TDS), total suspended solids (TSS) and turbidity, respectively. A comparison of the results shows that UF performs better than conventional biologicalmethods. The results showed that refinery wastewater treatment by using UF process is possible. The obtained UF permeates are suitable to discharge into the environment, even in the special regions in accordance with international requirements.