Membrane separation activated sludge for residual organic removal in oil wastewater

Abstract

A hybrid membrane separation activated sludge process was investigated for treatment of residual organic matter in oily wastewater from an automobile engine manufacturing plant. A bench scale experiment was conducted to identify the biodegradability of the residual organic matter in activated sludge reactors at various HRT (equal to SRT), such as 5, 10, 20, 30 days. Removal efficiency of higher than 90% was obtained in terms of SCOD at more than 10 day HRT showing the possibility of biological treatment. Ultrafiltration test was also carried out for the residual organics using cross-flow membrane filtration system at transmembrane pressure (TMP) of 2.0 kg/cm2. The membrane used for this experiment was polysulfone hollow fiber membrane with 30,000 molecular weight cut off. The rejection rate was around 10% in terms of TCOD. This low rejection rate explains that the residual organics in the oil wastewater are soluble and their MWCO size distribution might be less than 30,000. However the combined membrane activated sludge process could maintain significantly high removal efficiency more than 95% for the residual organics in the oily wastewater. The enhancement in organic removal was estimated to be contributed to the increased biomass in the system resulting in the reduction of the organic loading.

Performance of a Submerged Membrane Bioreactor System for Biological Nutrient Removal

“…This suggests that MBR systems operated with a long SRT condition can effectively prevent nitrifying bacteria from being washed out. Similar improvements on nitrification capability of MBRs were also reported by Engelhardt et al (1998) , Fan et al (1996) , Mouthon‐Bello et al (2002) , Roberts et al (2000) , Rosenberger et al (2002) , and Seo et al (1997) . Furthermore, total nitrogen in the effluent appears to be proportional to its concentration in the influent.…”

Break-up of oil-in-water emulsions by electrochemical techniques

“…Different processes have been described in the literature for the treatment of these wastes, but the most commonly used are the chemical destabilization (conventional coagulation) [2][3][4][5][6], the electrochemical destabilization (electrocoagulation) [6][7][8][9] and the ultrafiltration [10][11][12][13][14]. Less expensive biological processes [15][16][17] are rarely used since the effluents generated in this kind of processes usually contain biocides to prevent degradation of the industrial fluids.…”

Evaluation of a simple batch distillation process for treating wastes from metalworking industries

“…Appropriate treatment of these wastewaters is necessary in order to reduce the impact of the discharge of such materials into municipal sewage treatment plants. Several processes have been described in the literature for the treatment of such waste, but the most commonly used are chemical de‐emulsification,1, 2 electrocoagulation3 and ultrafiltration 4–8…”