Mike Christensen strides among rows of gleaming steel tanks, pointing to pipelines that arrive from miles around to this corner of former farmland near Midland, Texas, the heart of the largest oil patch in the United States. His company is one of dozens opening sites like this one that handles, not the lucrative oil, but the shale industry’s dirty secret: wastewater. While U.S. oil production has reached record levels on account of the shale revolution of the last decade, much of the supporting infrastructure has failed to keep up, including how to transport the large quantities of water used in the hydraulic fracturing process and the water that is produced from wells alongside oil and […]