James S. Rosenblum

Temporal characterization of flowback and produced water quality from a hydraulically fractured oil and gas well

This study examined water quality, naturally-occurring radioactive materials (NORM), major ions, trace metals, and well flow data for water used and produced from start-up to operation of an oil and gas producing hydraulically-fractured well (horizontal) in the Denver-Julesburg (DJ) Basin in northeastern Colorado. Analysis was conducted on the groundwater used to make the fracturing fluid, the fracturing fluid itself, and nine flowback/produced water samples over 220days of operation. The chemical oxygen demand of the wastewater produced during operation decreased from 8200 to 2500mg/L, while the total dissolved solids (TDS) increased in this same period from 14,200 to roughly 19,000mg/L. NORM, trace metals, and major ion levels were generally correlated with TDS, and were lower than other shale basins (e.g. Marcellus and Bakken). Although at lower levels, the salinity and its origin appear to be the result of a similar mechanism to that of other shale basins when comparing Cl/Br, Na/Br, and Mg/Br ratios. Volumes of returned wastewater were low, with only 3% of the volume injected (11millionliters) returning as flowback by day 15 and 30% returning by day 220. Low levels of TDS indicate a potentially treatment-amenable wastewater, but low volumes of flowback could limit onsite reuse in the DJ Basin. These results offer insight into the temporal water quality changes in the days and months following flowback, along with considerations and implications for water reuse in future hydraulic fracturing or for environmental discharge.

Importance of Recovery of E. coli in Water Following Ultraviolet Light Disinfection

AbstractEscherichia coli photorepair and dark recovery was investigated in two different water sources. Sterilized drinking water and wastewater effluent treated for reuse were spiked with either wild E. coli isolate or a laboratory-purchased E. coli strain and ultraviolet (UV)-irradiated at fluences from 40 to 120  mJ/cm2. Although no threshold UV fluence was established after which E. coli photo and dark repair did not proceed, the extent of repair was generally low, not exceeding 0.5 log. Contrary to the repair results, the 48-h regrowth of E. coli disinfection survivors reached up to 3 log, likely due to the remaining inactivated E. coli cells that served as a source of biodegradable carbon postdisinfection. Although it is proposed that concerns regarding bacterial repair under drinking and reuse water UV disinfection conditions are overestimated based on experiments at low UV fluences, the long-term postdisinfection safety of water may be underestimated for conditions of low or no disinfection residu...

Low-energy hydraulic fracturing wastewater treatment via AC powered electrocoagulation with biochar.

Produced and flowback waters are the largest byproducts associated with unconventional oil and gas exploration and production. Sustainable and low cost technologies are needed to treat and reuse this wastewater to avoid the environmental problems associated with current management practices (i.e., deep well injection). This study presents a new process to integrate AC-powered electrocoagulation (EC) with granular biochar to dramatically reduce energy use and electrode passivation while achieving high treatment efficiency. Results show achieving a 99% turbidity and TSS removal for the AC-EC-biochar system only used 0.079 kWh/m(3) or 0.15 kWh/kg TSS, which is 70% lower than traditional DC-EC systems and orders of magnitude lower than previous studies. The amount of biochar added positively correlates with energy saving, and further studies are needed to improve organic carbon and salt removal through system integration.

Organic Chemical Characterization and Mass Balance of a Hydraulically Fractured Well: From Fracturing Fluid to Produced Water over 405 Days

A long-term field study (405 days) of a hydraulically fractured well from the Niobrara Formation in the Denver-Julesburg Basin was completed. Characterization of organic chemicals used in hydraulic fracturing and their changes through time, from the preinjected fracturing fluid to the produced water, was conducted. The characterization consisted of a mass balance by dissolved organic carbon (DOC), volatile organic analysis by gas chromatography/mass spectrometry, and nonvolatile organic analysis by liquid chromatography/mass spectrometry. DOC decreased from 1500 mg/L in initial flowback to 200 mg/L in the final produced water. Only ∼11% of the injected DOC returned by the end of the study, with this 11% representing a maximum fraction returned since the formation itself contributes DOC. Furthermore, the majority of returning DOC was of the hydrophilic fraction (60-85%). Volatile organic compound analysis revealed substantial concentrations of individual BTEX compounds (0.1-11 mg/L) over the 405-day study. Nonvolatile organic compounds identified were polyethylene glycols (PEGs), polypropylene glycols (PPG), linear alkyl-ethoxylates, and triisopropanolamine (TIPA). The distribution of PEGs, PPGs, and TIPA and their ubiquitous presence in our samples and the literature illustrate their potential as organic tracers for treatment operations or in the event of an environmental spill.

Succession of toxicity and microbiota in hydraulic fracturing flowback and produced water in the Denver–Julesburg Basin

Hydraulic fracturing flowback and produced water (FPW) samples were analyzed for toxicity and microbiome characterization over 220 days for a horizontally drilled well in the Denver-Julesberg (DJ) Basin in Colorado. Cytotoxicity, mutagenicity, and estrogenicity of FPW were measured via the BioLuminescence Inhibition Assay (BLIA), Ames II mutagenicity assay (AMES), and Yeast Estrogen Screen (YES). Raw FPW stimulated bacteria in BLIA, but were cytotoxic to yeast in YES. Filtered FPW stimulated cell growth in both BLIA and YES. Concentrating 25× by solid phase extraction (SPE) revealed significant toxicity throughout well production by BLIA, toxicity during the first 55 days of flowback by YES, and mutagenicity by AMES. The selective pressures of fracturing conditions (including toxicity) affected bacterial and archaeal communities, which were characterized by 16S rRNA gene V4V5 region sequencing. Conditions selected for thermophilic, anaerobic, halophilic bacteria and methanogenic archaea from the groundwater used for fracturing fluid, and from the native shale community. Trends in toxicity echoed the microbial community, which indicated distinct stages of early flowback water, a transition stage, and produced water. Biota in another sampled DJ Basin horizontal well resembled similarly aged samples from this well. However, microbial signatures were unique compared to samples from DJ Basin vertical wells, and wells from other basins. These data can inform treatability, reuse, and management decisions specific to the DJ Basin to minimize adverse environmental health and well production outcomes.