Effluent Management

Effluent Management refers to the methods that we use to dispose of our liquid effluent produced from our processes. The water we use may become contaminated as it passes through our processes. Through the correct treatment and disposal of our waste water we can prevent pollution of our environment.

GRI 103-01, 103-02, 103-03, 303-02: Management approach

Bapco has developed company standards for its effluent management that comply with Ministerial Order No. 3 of 2021 with respect to Environmental Standards (Air and Water). The existing Refinery discharges comprise cooling water, process waste water, site drainage and domestic type effluent (from offices). Bapco uses a state-of-the-art advanced membrane bioreactor technology for the treatment of its effluent, combining membrane ultra-filtration of solids with biological waste water treatment. The technology is recognised internationally as offering superior energy efficiency compared to other biological waste treatment processes. The membrane bioreactor technology is used within our WWTP and Sewage Treatment Plant (STP).

The WWTP is a 19,108 m3 per day facility for treating process waste water to meet discharge limits prescribed by the SCE. Process effluents and drainage water that may contain oil or other contaminants are routed, through a dedicated oily water sewer network, to a primary treatment system comprising oily water separation and induced air flotation. The effluent then passes through the WWTP that uses membrane bioreactor technology, which in turn reduces the organic loading and nitrogen content and removes the dissolved contaminants from the process effluents before discharge to sea via the main outfall.

The STP is a 1,000 m3 per day facility for treating effluent from offices and accommodation blocks. The STP uses dissolved air flotation, the membrane bioreactor biological treatment and a sludge treatment system before discharge to the sea via the main outfall.

GRI 303-04: Water discharge

Treated effluent is returned to the sea via the discharge flume in compliance with discharge limits as prescribed by the SCE. Cooling water and ‘reject water’ from the desalination plants is returned to the sea at a controlled temperature and salinity that does not exceed the parameters set by SCE.

Groundwater discharge volume is calculated based on the approximate circulation rates, considering evaporation and windage losses within the cooling towers. Seawater discharge volume is calculated by deducting the sea water consumption volume from the withdrawal.