Thirteen states in the United States allow the spreading of O&G wastewaters on roads for deicing or dust suppression. In this study, the potential environmental and human health impacts of this practice are evaluated. Analyses of O&G wastewaters spread on roads in the northeastern, U.S. show that these wastewaters have salt, radioactivity, and organic contaminant concentrations often many times above drinking water standards. Bioassays also indicated that these wastewaters contain organic micropollutants that affected signaling pathways consistent with xenobiotic metabolism and caused toxicity to aquatic organisms like Daphnia magna. The potential toxicity of these wastewaters is a concern as lab experiments demonstrated that nearly all of the metals from these wastewaters leach from roads after rain events, likely reaching ground and surface water. Release of a known carcinogen (e.g., radium) from roads treated with O&G wastewaters has been largely ignored. In Pennsylvania from 2008 to 2014, spreading O&G wastewater on roads released over 4 times more radium to the environment (320 millicuries) than O&G wastewater treatment facilities and 200 times more radium than spill events. Currently, state-by-state regulations do not require radium analyses prior to treating roads with O&G wastewaters. Methods for reducing the potential impacts of spreading O&G wastewaters on roads are discussed.

Combining horizontal drilling with high volume hydraulic fracturing has increased extraction of hydrocarbons from low-permeability oil and gas (O&G) formations across the United States; accompanied by increased wastewater production. Surface water discharges of O&G wastewater by centralized waste treatment (CWT) plants pose risks to aquatic and human health. We evaluated the impact of surface water disposal of O&G wastewater from CWT plants upstream of the Conemaugh River Lake (dam controlled reservoir) in western Pennsylvania. Regulatory compliance data were collected to calculate annual contaminant loads (Ba, Cl, total dissolved solids (TDS)) to document historical industrial activity. In this study, two CWT plants 10 and 19 km upstream of a reservoir left geochemical signatures in sediments and porewaters corresponding to peak industrial activity that occurred 5 to 10 years earlier. Sediment cores were sectioned for the collection of paired samples of sediment and porewater, and analyzed for analytes to identify unconventional O&G wastewater disposal. Sediment layers corresponding to the years of maximum O&G wastewater disposal contained higher concentrations of salts, alkaline earth metals, and organic chemicals. Isotopic ratios of RaRa and SrSr identified that peak concentrations of Ra and Sr were likely sourced from wastewaters that originated from the Marcellus Shale formation.

A rapid batch extraction method was evaluated to estimate potential for total dissolved solids (TDS) release by 65 samples of rock from coal and gas-bearing strata of the Appalachian Basin in eastern USA. Three different extractant solutions were considered: deionized water (DI), DI equilibrated with 10% CO 2 atmosphere (DI þ CO 2 ), or 30% H 2 O 2 under 10% CO 2 (H 2 O 2 þCO 2 ). In all extractions, 10 g of pulverized rock (<0.5-mm) were mixed with 20 mL of extractant solution and shaken for 4 h at 50 rpm and 20-22 � C. The 65 rock samples were classified as coal (n¼3), overburden (n ¼ 17), coal refuse that had weathered in the field (n ¼ 14), unleached coal refuse that had oxidized during indoor storage (n ¼ 20), gas-bearing shale (n ¼ 10), and pyrite (n ¼ 1). Extracts were analyzed for specific conductance (SC), TDS, pH, and major and trace elements, and subsequently speciated to determine ionic contributions to SC. The pH of extractant blanks decreased in the order DI (6.0), DI þ CO 2 (5.1), and H 2 O 2 þCO 2 (2.6). The DI extractant was effective for mobilizing soluble SO 4 and Cl salts. The DI þ CO 2 extractant increased weathering of carbonates and resulted in equivalent or greater TDS than the DI leach of the same material. The H 2 O 2 þCO 2 extractant increased weathering of sulfides (and carbonates) and resulted in the greatest TDS production and lowest pH values. Of the 65 samples, 19 had leachate chemistry data from previous column experiments and 35 were paired to 10 field sites with leachate chemistry data. When accounting for the water-to-rock ratio, TDS from DI and DI þ CO 2 extractions were correlated to TDS from column experiments while TDS from H 2 O 2 þCO 2 extractions was not. In contrast to column experiments, field SC was better correlated to SC measured from H 2 O 2 þCO 2 extractions than DI extractions. The field SC and SC from H 2 O 2 þCO 2 extractions were statistically indistinguishable for 7 of 9 paired data sets while SC from DI extractions underestimated field SC in 5 of 9 cases. Upscaling comparisons suggest that (1) weathering reactions in the field are more aggressive than DI water or synthetic rainwater extractants used in batch or column tests, and (2) a batch extraction method utilizing 30% H 2 O 2 (which is mildly acidic without CO 2 enrichment) could be effective for identifying rocks that will release high amounts of TDS.

The escalating global energy demand, driven by heavy reliance on fossil fuels, worsens environmental degradation and triggers socio-economic shifts in extraction and refinery hubs. In Colombia, the energy matrix is predominantly fossil-based (76%), with hydroelectric power accounting for 70% of electricity generation. However, renewable energy sources only contribute 2% to the national energy mix. To reduce emissions by 20% by 2030, Colombia has presented an energy transition roadmap. The need for bioenergy production in Colombia arises from the residual biomass availability, the potential to provide sustainable energy access, and the potential to mitigate climate change impacts, while addressing energy poverty and enhancing energy security. This study presents an overview of biogas production in Colombia, emphasizing the need for financial resources to overcome barriers. Policy incentives, awareness campaigns, and research and development play a vital role in fostering social acceptance, technology adoption, and optimizing biogas production processes. Collaborative efforts among the government, private sector, and local communities are recommended to ensure wide-scale adoption of biogas, promoting economic, social, and environmental sustainability. By enabling informed decision-making, this research supports the transition to renewable energy sources and the achievement of sustainable development goals (SDGs), with a particular focus on bioenergy. The aim of this study is to explore the challenges and opportunities associated with biogas production in Colombia, including technical, economic, social, and environmental aspects, and provide recommendations for promoting its sustainable implementation and widespread adoption in the country.