In order to find suitable oily sludge treatment equipment for a produced water treatment station of an oilfield in Iraq,the widely used mechanical dewatering equipments overseas including plate and frame filter,belt press filter,centrifugal filter and screw press filter were compared and analyzed,and the application situation of screw press filter was investigated at site. The site survey showed that,screw press filter was an integrated equipment combined with functions of concentrating and dewatering,which was characterized by low water content of filter cake,small occupied area,easy to separate,no blocking and can realize self-cleaning,which is suitable to low concentration sludge. Screw press filter can simplify oily sludge treatment process,and save engineering construction and operation cost,which is a better choice for oily sludge dewatering. The design of screw press filter adopted in the produced water treatment station of an oilfield in Iraq was introduced here. In order to find suitable oily sludge treatment equipment for a produced water treatment station of an oilfield in Iraq, the widely used mechanical dewatering equipments overseas including plate and frame filter, belt press filter, centrifugal filter and screw press filter were compared and analyzed, and the application situation of screw press filter was investigated at site. The site survey showed that, screw press filter was an integrated equipment combined with functions of concentrating and dewatering, which was characterized by low water content of filter cake, small occupied area, easy to separate, no blocking and can realize self-cleaning, which is suitable to low concentration sludge. screw press filter can simplify oily sludge treatment process, and save engineering construction and operation cost, which is a better choice for oily sludge dewatering. screw press filter adopted in the produced water treatment station of an oilfield in Iraq was introduced here.