A drain system that collects liquids that spill on the deck is an “atmospheric,” “gravity,” or “open” drain. Liquid gathered in an open drain system is typically rain water or wash-down water contaminated with oil. This liquid is usually contaminated with oils, solids, and/or any other liquid that is used on production sites. These liquids are typically directed to a sump or skim pile for separation prior to being disposed. Sumps are atmospheric tanks which utilize gravity separation in removing lighter density fluids, usually hydrocarbon based. In some cases, the addition of coalescing material can have a positive influence on the quality of the discharge water. These tanks come in many different configurations and sizes.


PWS offers a complete line of Tertiary treatment options ranging from Adsorption Filters such as Walnut Shell Filters to Absorption Filters such as Cartridge and Multimedia Filters.  In an industry where stricter water discharge qualities are expected, the capacity to treat water to below 10 PPM is critical. We are uniquely positioned to meet your tertiary needs to any discharge criteria.
How low can you go is no longer the question with our walnut shell technology. You should now be asking yourself, how low DO YOU want to go? Walnut shell filters have been installed for the removal of oil and suspended solids from produced water, refinery effluent and waste / re-circulation streams for many years. Utilizing the perfect size walnut shells with the perfect bed depth and finishing off with a backwash system that is user friendly, considering this technology for offshore applications is at your fingertips.