After more and more accidents, also the sea environmental protection comes to PEOPLE's sense, now offshore projects taking care more about the drilling waste disposal. Maybe before it is just a screw conveyer, or a channel for washing to the ship's rail, then slicking to the sea.
So the bentonite, the polymer, cuttings, or whatever you may bring up from the mixture of drilling prodution, go to the sea.
For land rigs, now normally the drilling mud service company, or the contract might handle this with driling waste management system, like the one we just sent to West Africa. It contains Drilling waste management unit equipment list

• One Centrifuge high configuration centrifuge GNLW363BG-VFD.
• One set Cuttings Dryer GNCD930C, fixed speed (800rpm), high configuration dryer, equipped with air line, upgrade scraper and basket screen.
• One set Vertical slurry pump GN50YZ20A-18 for feeding Decanter Centrifuge
• One set Netzsch Brand NEMO pump for flushing cuttings dryer
• One set skid, flexible legs, accessories and electrical control panel system
  Offshore drilling waste normally also contains such equipment, giant contractors for offshore projects normally are solving these problems. While for the design of such systems, different engineers have different ideas. Just like solids control, we also have construction engineering difference. What GN Solids Control insist is simple is beautiful, make everything just simple. Less equipment, more work, which makes the system more powerful.
  There also many differences, between designing onshore projects, the limit space, the whole consturcture, the ambient, sometimes we even have to consider where is it located, as the PH different, then have to use high config stainless steel.
  GN Solids just went to SCIPPE in Shanghai, which is for oil & gas, showed the latest update decanter centrifuge, speed upto 3900rpm. Also more and more good news regarding cuttings dryer feedback to us.