TREATMENT OF OILY WASTE

Abstract

Oil water emulsion such as cutting oil in water emulsion used as lubricant and coolant in engineering for metal working industry. The temperature of oil water emulsion is usually maintained in the range of 45 °C to 90°C due to heat removal from metal surface. In Oil water emulsion anaerobic microbial growth occurs therefore 0/W emulsion is replaced periodically. - Since the CPCB, Delhi has prescribed a maximum permissible limit for oil/grease : 10 mg/1 in the wastewater sewers. So it is necessary that the oil water emulsion, before it discharge, treated to remove/recover oil. Various technologies are available to removal of oil from oily wastewater. Most economical technique for removal of oil from oily wastewater is electrocoagulation. The efficiency of electrocoagulation technique depends on various parameters like pH, current density, inter-electrode spacing, fraction of electrodes submerged, number of electrodes etc. The present dissertation reports the work on batch & continuous process for the removal of oil and turbidity from oily wastewater have been experimentally investigated by using Al and Fe electrodes systems. Electrocoagulation for continuous process by using Fe electrodes system. The reactor voltage was maintained 4V for both Al and Fe electrodes systems, it was found that the optimum condition for the removal of oil from oily wastewater as pH 6.5, current 3.5A (current density 138.8 A/m2), inter-electrode spacing 0.5 cm and electrodes are fully submerged condition for Al electrodes system and pH 6.8 , current 6.0A (current density 238.09 A/m2), inter-electrode spacing 0.5 cm and electrodes are fully submerged condition for Fe electrodes system. 0/W emulsion tested with the different percentage oil, it was found the maximum removal when oil concentrations are 1V(Ifor Al and 0.75% for Fe electrodes system respectively. For constant current density 65 A/m2 system it was found that as the increases number of electrodes, the oil removal from oily wastewater increases and the electrolysis time reduces. The removal efficiency decreases with increase in temperature after a certain value of temperature, removal efficiency increases with increase in temperature above 50°C for both type of electrodes systems.