6.6 Coalescing bed-type oily water separators The coalesce is capable of forming oil globules up to 12 mm diameter and the heavier fuel oils usually form long 'stalagmites' which grow to a considerable size before they are released Because of the low velocities employed the collected oil can flow past the water screen without becoming re-entrained and carried through into the outlet6.6 Coalescing bed-type oily water separators • The coalesce is capable of forming oil globules up to l2 mm diameter and the heavier fuel oils usually form long 'stalagmites' which grow to a considerable size before they are released. Because of the 1ow velocities employed the collected oil can flow past the water screen without becoming re-entrained and carried through into the outlet