Harmony in Industry and Nature



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Green architecture provides benefits for humans and wildlife.


To the average passerby, the 640-acre wetlands adjacent to Andeavor’s Mandan, North Dakota refinery might simply look like part of the landscape where the refinery was built. However, it’s very much a part of the refinery itself – the successful partnering of industry and nature.  


These wetlands are lovingly called the “North 40” by workers at the site, although no one really knows why the name stuck.


The North 40 is made up of an 11-pond system that treats waste water and serves as a wildlife habitat. More specifically, the ponds are a surface flow engineered wetland system. Five ponds are actively used in a filtration process to treat waste water from the refinery, while the other six are there for additional water storage capacity and wildlife habitats.


These habitats are home to more than 200 different species like deer, wild turkey, rabbits and pheasants. More than 2,000 goslings have hatched there, 800 of which were transplanted to start flocks in 20 different locations all over North Dakota. Other wildlife also frequents the area, like coyotes, foxes, skunks, minks, badgers, and birds like partridges, grouse, ducks, herons and pelicans.


The ecosystem has been enhanced and expanded over the years with islands and platforms to provide safe nesting areas. More than 60,000 trees and shrubs were planted (half of which bear fruit) to provide further food and shelter for wildlife. About 11,000 of these were planted over the past 25 years with Boy and Girl Scouts on Arbor Day. Additionally, fields of corn, alfalfa, millet and other forage crops were planted for the wildlife.


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However, the North 40 wasn’t just an environmental success when it was built in 1974 – it made the Mandan refinery an industrial example of best practices for water treatment.


First, Mandan utilizes water from the Missouri River for various refinery operations. Then any water that isn’t consumed in those processes, or not converted to steam, ends up back in the river or recycled back into the refinery. However, before it can return, that waste water must be filtered. Mandan’s solution for this filtration, or ‘bioremediation’, was to turn to nature.


Naturally occurring wetlands host vegetation like cattails and reeds. As water moves through this vegetation, pollutants in the water get absorbed and neutralized by the plants or broken down through chemical reactions and microbial activity. That microbial activity requires oxygen, which is created by the plants as well as any aeration of the water on the surface. Mandan’s North 40 wetland system was engineered to copy these natural processes. The cascading nature of its ponds also helps create extra aeration in the water.


In general, engineered wetland systems can operate up to 50 – 100 years. And the costs of building and maintaining them are significantly cheaper than mechanical processes to treat water. The North 40 has been a big part of proving this out for others around the world.


The refinery was one of the first to embrace engineered wetland solutions when they were first being pioneered in Germany in the early 1970’s. And in 1985, the refinery received the National Blue Heron Environmental Achievement Award, sponsored by the National Wildlife Federation and supported by the U.S. Fish and Wildlife Service.


For the last four decades, cities and industry alike have looked to Mandan as a successful example of how to treat water in a sustainable, affordable and lasting way. This is just one of the many ways Andeavor embraces and realizes a shared value approach to doing business.


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