Abstract: Synthetic oily wastewaters were prepared from metal working fluids (MWF). Electrocoagulation experiments were performed under constant voltage application. The current, conductivity, pH, dissolved oxygen concentration and temperature were recorded on line at every 5 seconds during the experiments. Effects of applied voltage differences, electrode materials and distance between electrodes on removal efficiency have been investigated. According to the experimental results, the treatment of MWF wastewaters by iron electrodes rather than aluminum and stainless steel was much quicker; and the distance between electrodes should be less than 1cm. The electrocoagulation process was modeled by using block oriented approach and found out that it can be modeled as a single input and multiple output system. Modeling studies indicates that the electrocoagulation process has a nonlinear model structure.
Abstract: This study is aimed to investigate feasibility of the
aerobic biological process to treat oily wastewater from palm oil food
industry. Effect of aeration and sludge concentrations are studied.
Raw sludge and raw wastewater was mixed and acclimatized for five
days in a stirred tank reactor. The aeration rate (no aeration, low;
1.5L/min and high rate; 2L/min) and sludge concentration (3675,
7350, and 11025mg/L of VSS) were varied. Responses of process
were pH, COD, oil and grease, VSS, and PHB content. It was found
that the treatment can remove 85.1 to 97.1 % of COD and remove
12.9 to 54.8% of oil & grease. The PHB yield was found to be within
0.15% to 2.4% as PHB/VSS ratio and 0.01% to 0.12% as PHB/COD
removed. The higher aeration results a high COD removal and oil &
grease removal, while experiment without aeration gives better PHB
yield. Higher sludge concentrations (11025mg/L VSS) give higher
removal of oil & grease while moderate sludge concentration
(7350mg/L VSS) give better result in COD removal. Higher PHB
yield is obtained in low sludge concentration (3675mg/L).
Abstract: The coalescer process is one of the methods for oily water treatment by increasing the oil droplet size in order to enhance the separating velocity and thus effective separation. However, the presence of surfactants in an oily emulsion can limit the obtained mechanisms due to the small oil size related with stabilized emulsion. In this regard, the purpose of this research is to improve the efficiency of the coalescer process for treating the stabilized emulsion. The effects of bed types, bed height, liquid flow rate and stage coalescer (step-bed) on the treatment efficiencies in term of COD values were studied. Note that the treatment efficiency obtained experimentally was estimated by using the COD values and oil droplet size distribution. The study has shown that the plastic media has more effective to attach with oil particles than the stainless one due to their hydrophobic properties. Furthermore, the suitable bed height (3.5 cm) and step bed (3.5 cm with 2 steps) were necessary in order to well obtain the coalescer performance. The application of step bed coalescer process in reactor has provided the higher treatment efficiencies in term of COD removal than those obtained with classical process. The proposed model for predicting the area under curve and thus treatment efficiency, based on the single collector efficiency (ηT) and the attachment efficiency (α), provides relatively a good coincidence between the experimental and predicted values of treatment efficiencies in this study.