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Bechtel’s Impact Report

Environmentally Safe Dredging and Circular Economy Practices

  • By
    portrait of Tam Nguyen
    Tam Nguyen, General Manager,
  • 09 November 2017

Securing More Than Gas Supplies

The Chevron-operated Wheatstone LNG Plant on the coast of Western Australia is one of the continent’s biggest natural resource projects. It will have the capacity to supply 8.9 million metric tons of liquefied natural gas per year—equal to 5 percent of Asia’s 2017 use—to meet the soaring demand for cleaner energy in the Asia-Pacific market. Wheatstone will also deliver 200 terajoules per day (2.2 billion cubic meters per year) of gas to Western Australian consumers.

Bechtel is performing the engineering, procurement, construction, construction management, and commissioning of facilities to process and liquefy the gas, the tanks that store the fuel at -260 Fahrenheit (-162 Celsius), and the export terminal.

Wheatstone worker

Using Data for Dredging

One of the most ecologically sensitive tasks Chevron and Bechtel performed involved some of the most advanced data analytics used at the project. To dredge the plant’s 10-mile (16-kilometer) channel, Bechtel participated in a program that used sensors to continually monitor water quality between work zones and sensitive areas such as coral reefs and seagrass communities. Meanwhile, engineers used real-time models of winds, tides, currents, and other weather information to predict how sediment kicked up by the work would disperse.

Before dredging began, Bechtel and Chevron conducted extensive studies of marine habitats and developed a comprehensive dredge management and monitoring plan that was approved by both state and federal governments.

Throughout the dredging, engineers used waterlogging instruments to measure sediment in the water and satellites to transmit data in near real-time to the monitoring team. Remote-operated vehicles took high-resolution images of marine life to assess any changes. Workers continually refined the model and responded to any environmental changes. The timing and location of dredging activities were also managed very closely to reduce impacts on the surrounding environment and ecologically important events such as coral spawning.

Reef areas closest to the dredging activity showed no negative impact from the dredging, and water-quality levels continuously remained within the strict parameters required by environmental regulators.

Applying the “Circular Economy”

The Wheatstone Construction Village, a camp of more than 7,000 people, employs a “circular economy” approach where recycling and reusing is encouraged. In addition to paper, cardboard, glass, and household metal being separated and recycled, other organic waste from the camp, such as food, is turned into compost. These initiatives have prevented 450 metric tons of trash from ending up in landfill and more than 1,000 cubic meters of nutrient-rich compost donated to local schools, parks, and farms for agriculture and landscaping.

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