Free non-dissolved and non-emulsified oils can be removed efficiently and cost effectively from a watery main phase using coalescing plate separators. The CPS system can completely remove oil droplets of 20 micron and above. CPS systems have no replacement elements and are completely cleanable. Patented Mpak coalescing plates are designed to separate oil and solids from water using the differences in their specific gravities. They are provided with integral moulding that ensure the spacing's are accurately controlled while at the same time promoting the transfer of solids to the bottom of the installation. The plates can be assembled into packs which are securely held together by moulded polypropylene supports with either stainless steel wire or rods. The pack modules are designed to be supported in such a way as to provide integral sumps for solids retention. This construction makes them eminently suitable for use in retrofit as well as new applications.