The International Convention for the Prevention of Pollution from Ships (MARPOL) states that bilge water cannot be pumped directly into the sea unless for the purposes of securing the safety of a ship or saving life at sea. Instead, it must first be treated to reduce the level of suspended oil particles to a permissible limit of 15 ppm or less and can only be discharged when the ship is at sea.

Vessels in violation of this legislation are fined heavily and in some cases crew members may even face prison sentences. 

Accumulated bilge water from the bilge wells is pumped into bilge water holding tanks by a bilge pump. The contents of the bilge holding tank are then passed through treatment equipment to reduce the oil content to below 15 ppm. If the oil content is still above 15 ppm after treatment, the bilge water is recirculated back to the holding tank.

Keeping an accurate record of discharges and the location of discharges is very important for vessels to prove that they adhere to MARPOL legislation. ABB’s Recording and Control products offer a world-class solution for management of shipboard bilge water.

ABB’s ScreenMaster RVG200 recorder offers a versatile and secure solution for data recording in marine bilge water discharge applications.

The RVG200 is ideal for recording bilge well level, holding tank level, bilge alarm status, bilge pump status, bilge discharge and GPS coordinates of discharge. The recorder provides a visual representation of the whole process (see diagram) with the convenience of fingertip control of the screen.

Furthermore, to help satisfy MARPOL requirements for logging of the location and content of discharges, the RVG200 can be connected to a GPS via serial communications using NMEA protocol. This enables the ship’s GPS co-ordinates to be logged alongside data on discharge volume and water quality.