Determination of the Toxicity of Spent Fracturing Water from Energy Exploration

摘要

The determination of toxicity of industrial wastewater prior to its disposal has focused on in the past utilization of indicator organisms, Ceriodaphnia dubia and Pimephales promelas found in the U.S. Environmental Protection Agency (EPA) Whole Effluent Toxicity (WET)test. The concerns with this type of indicator test are: the extended period of time (up to 96 hours) required for completion of the test; the sensitivity of the indicator organisms to variations in pH and low concentrations of dissolved metals; the lack of comparability between indicator organism acute toxicity and the synergistic effects seen with toxic chemicals in the wastewater activated sludge process. Oxygen uptake rate, OUR, is an analytical test that has a long history of use in wastewater testing, which traditionally relied on the standard biochemical oxygen demand (BOD) equipment with oxygen depletion being measured either manually or automatically. More recent updates have utilized respirometry or microchip bacteria assays. Though these instruments showed promise, they did not truly represent the conditions that the biomass encountered in a wastewater process nor were they cost effective. The use of the GreenLight® instruments for measuring OUR presented in this paper have optimized the conditions that the biomass will encounter in the presence of wastewater from hydraulic fracturing or fracking water and will determine toxicity and generate results in a rapid timeframe.