Metal working fluids are widely used as coolants in the industries for machining purposes. These coolants when discarded increase the oil and grease and chemical oxygen demand of the effluent. Excess oil and grease content affects the biological effluent treatment and hence, must be separated from the effluent in the primary treatment stage itself. Free oil is easy to separate and can be easily removed by physical oil & grease separators but emulsified oil present in the coolants is difficult to remove unless the emulsion bond is broken. This study explores the option of treatment of waste coolant (metal working fluid) by acid cracking. With reference to the study conducted, use of hydrochloric acid for emulsion bond breaking results in COD by 46.4%, BOD by 41.4% and Oil & Grease by 39.4%