Sungai Bera Holding Basins

As a partner in a joint venture company called Sungai Bera Remediation J.V. Sdn. Bhd, Jacques Whitford, consulting engineers of Dartmouth, Nova Scotia, completed the highly successful remediation of the Sungai Bera Holding Basins in December 2003.

The holding basins are owned by Brunei Shell Petroleum Sdn. Bhd and located in Seria, Brunei Darussalam in Southeast Asia. Consisting of three unlined, shallow pits, they cover an area of approximately six hectares. The site is located adjacent to the Sungai Bera River, which flows into the South China Sea immediately to the north.

In the 1990s the owners decided that the site was a priority for remediation. The basins had been used for disposing oilfield wastes from 1982 to 1996 due to the lack of locally available resources for treating the waste. The stored material included tank bottom sludges, oil based muds and other petroleum wastes generated from normal oilfield operations. By 1999, the basins held a total of approximately 62,000 cubic metres of oily sludge. In addition, since the basins were unlined, petroleum had migrated into the surrounding and underlying sandy soils, creating an additional 42,000 cubic metres of contaminated soils that needed excavation and treatment. The basins gave off strong odours and contained floating oil that was a risk to birds and wildlife in the area.

To clean up the site, a contract was awarded to the SBRJV joint venture, which consisted of three Canadian companies: Jacques Whitford, Envirosoil and Inland Technologies, as well as a local Brunei Company, Haji Adinin & Sons. The joint venture had a design-build, performance-based contract that included the selection of remedial technology, detailed design, mobilization, site excavation, waste treatment, oil recovery and complete site re-vegetation. As an equal 25% owner in the SBRJV partnership, Jacques Whitford’s role included: conceptual and detailed engineering design, tendering, project management, engineering management, cost control, construction oversight, environmental site assessment, site remediation design and supervision, air monitoring and emissions control, health and safety, quality assurance and client reporting.

Work began in 2000 and successfully treated 104,000 cubic metres of material and recovered approximately 85,000 barrels of oil from the waste. The area is now completely restored and re-vegetated with local native grasses, trees and wild flowers. Wildlife has returned and there is no visual evidence of the past waste disposal operations.

In addition the project provided a transfer of technology to the local people. Staff were obtained from the Brunei joint venture partner and trained by the Canadian partners. None had been previously exposed to environmental remediation services, nor to the advanced remedial technologies employed on the project. The local partner company has expanded its services to pursue environmental remediation projects in the region, as well as in the Middle East.

Post tender release of sludge

The project included many logistical, technical and management challenges.

For example, the major treatment equipment, which was a low temperature thermal desorption (LTTD) plant, was transported from North America. During the shipping, the load was dropped, creating damage to approximately 25% of the plant. Replacement parts and service personnel were quickly ordered and there was only an eight week delay in commissioning the plant.

In 1999, an emergency at Brunei Shell Petroleum’s facilities required the release of approximately 10,000 cubic metres of oily sludge to the Sungai Bera basins. This incident occurred after the tenders had been received for the remediation project and the material was not included in the original scope of work. The sludge released was unique, consisting of oil with a high paraffin and solids content. It formed a layer of “floating product” on the basins. The treatment methods had to be revised and facilities had to be added to recover and deal with this additional waste.

Further technical challenges were encountered in operating the LTTD plant. Significant sediment was building up in the gas condensing system, reducing production rates and raising safety concerns over a possible blockage of the gas-condensing stream. Jacques Whitford designed a system that was fabricated on site to enable the removal, separation and treatment of the sediments. The system worked flawlessly, enabling the plant to achieve the designed production rates with minimal downtime.

Targets exceeded

The remediation was a success and exceeded the client’s expectations in many areas.

For example, a treatment target of 5,000 mg/kg total petroleum hydrocarbons (TPH) was specified for the treatment of sludge and contaminated soil. The project exceeded this target by achieving an average of 1,350 mg/kg TPH. The treatment standard established for wastewater was 18 mg/L TPH, whereas the project achieved an average concentration of 4 mg/L TPH.

The original project schedule was for completion within 146 weeks, based on the original estimated waste volume of 52,000 cubic metres. The final waste volume treated (including offsite waste transported to the treatment facility) was approximately 115,000 cubic metres. Despite a 120% increase in the waste volumes, the site remediation schedule only had to be extended by 46%.

Furthermore, the original budget estimate was increased by only 25% to accommodate the 120% increase in waste volumes.

Name of project: Remediation of Sungai Bera Holding Basins, Brunei

Award-winning firm: Jacques Whitford, Dartmouth, Nova Scotia (Dan Morehouse, P.Eng., Suther Yuill, P.Eng., Bill Sutherland, P.Eng., Don Elder, P.Eng.)

Owner/client: Brunei Shell Petroleum Company

Joint Venture Partners: Envirosoil/Inland Technologies/ Haji Adinin & Sons

Other key players: CIC Environmental Services (laboratory analysis), ESP (recycled oil treatment), V-Con Engineering Enterprise (civil), Phillips Analytical Services (laboratory set-up and training)