The technology of hydraulic fracturing has played a major role in oil and natural gas production in the US. A group of researchers have been studying the wastewater produced from this process in order to gain a better understanding of the impact of possible contaminants released in the environment.
Penn State environmental engineering professor Bill Burgos and his colleagues have studied sediment samples collected from a reservoir in western Pennsylvania. The study was published in the most recent issue of Environmental Science & Technology
“There wasn't a water keeper who was sitting in these rivers collecting these samples at a great continuous clip, so in a way, a lot of information just flowed by,” Burgos said. “But in certain reservoirs, where sediments collect over time, there are layers of sediment that are like rings of a tree; you can look into the sediments and capture time and spatially composite samples.”
The objective of the study was to use the sediments that had built up to reconstruct the industrial oil and gas activity that was happening during the boom of the Marcellus Shale development in Pennsylvania, from roughly 2008 to 2015, in order to gain a better understanding of the historical impact of oil and gas wastewater disposal.
“You need a lake or a reservoir that allows sediments to lay down undisturbed in those layers,” said Burgos. “The words we use are a 'coherent temporal record.' You only get a coherent temporal record if it's a lake that continuously accumulates sediments and isn't subject to a flood or scour.”
Xiaofeng Liu, assistant professor of civil engineering, developed a computer model to reconstruct the layers of sediment in order to identify the best sampling location. The researchers chose the Conemaugh River Lake in western Pennsylvania. This site offered high wastewater concentration and low wastewater dilution, as well as a dam-controlled reservoir.
To read the full article, please go to Penn State News