CETCO Oilfield Services, a pioneer in the treatment of oilfield wastewater, has developed NEMOH – a nomadic environmental media operated host – that acts as a hosting treatment vessel for processing and retaining polluted fluids in a subsea environment.
CETCO Oilfield Services’ first venture into the subsea sector, NEMOH is a new
technology that can treat and retain chemically contaminated water without the
need for a topside facility. The technology, described by CETCO as an equalized
underwater media vessel, is capable of operating at depths of up to 6,000
Developed in response to an operation where project delays meant there were no
topside facilities available, this technology is flexible and portable. It is
proving very effective as a temporary installation that can operate at varying
sea levels and in all types of marine environments, including fresh, salt or
brackish water. The treatment of potentially hazardous chemicals, including
corrosion inhibitors and biocides, at subsea level can be more time-efficient
when compared to traditional topside methods.
The technology itself is a medium-sized container fitted with a protective cage
and lifting frame. Initially, NEMOH is
operated by topside technicians, however, following its immersion in the water,
it is controlled by remotely operated vehicles (ROVs).
Particularly useful where no permanent topside facility is available, NEMOH is
landed at the bottom of the ocean, and is communicated, via a device known as a
“hot stab,” into the inlet and connected at the other end of the line to the
out, or pipeline end termination. To prevent backflow or release of contaminated
fluids to the surrounding marine environment, the NEMOH equalization valves are
closed, and treatment then is able to begin.
When the treatment process is complete, NEMOH either can be recovered in a
reverse process and disconnected, or it can be guided by an ROV along the
seabed to another location.