Microbac has recently delivered two offshore wastewater treatment plants (WWTP's) for Sakhalin Energy Investment Corporation (SEIC). The plants, designed to treat grey and black waters from platform personnel, have been installed on the Lunskoye A (LUN-A) and Piltun (PAB) platforms that operate offshore Sakhalin Island, Far East Russia. Offshore winter temperatures can be as low as -39C and the area is prone to high seismic activity. The Microbac Bioreactors (MBR's), which have IMO approval, are designed to meet the extremely strict discharge standards imposed by the Russian Authorities in terms of organic load, BOD, Suspended Solids, Ammonia and Phosphate. The stringent discharge requirements have been imposed to reduce any adverse impact on the feeding ground of the critically endangered Western Grey Whales, that spend four to five months a year feeding off Sakhalin’s Piltun Bay and to protect the wild salmon stocks that are of great importance to Sakhalin Island economy.
The plants have been provided to withstand the lowest winter temperatures and to remain structurally intact under severe seismic accelerations. Prior to building the plants, the design was validated using Finite Element Analysis.
The WWTP's comprise a compartmentalised tank to provide equalisation of the influent wastewater, biological treatment using a fixed film bioreactor, solids settlement and a clean water chamber. The tank, pipework and associated components are trace heated and insulated to provide frost protection down to -39C, ambient.
Both plants are skid mounted and controls for the operation of the ancillary equipment are based on the use of SMART transmitters to measure process parameters. The subsequent signal outputs, which are relayed to the Local Control Panel mounted on the skid, provide all indications, alarms and control functions for the WWTP's.