Flowback water after completion of hydraulic fracturing is one of major waste streams generated during the lifespan of a well so its beneficial reuse is crucial. The application of treated flowback is not limited to stimulation processes but also may include drilling operations and secondary oil recovery. The flowback water used in this work is characterized by high salinity reaching up to ~295 g/L caused mainly by NaCl. The presence of suspended solids, mainly corrosion products, prompts the use of coagulation and filtration as treatment methods. Among tested coagulants the most effective one was the SAX18 (NaAlO₂) commercial coagulant applied at concentration of 12 mL/L which reduces the water turbidity from over 400 FTU to 23 FTU. The applied treatment greatly reduces the concentration of scaling ions and so the concentration of SiO₂ is reduced by 64%, Ba²⁺–66%, Fe²–36%, Mn²⁺–65%, SO₄²⁻–66%. The treated flowback fluid can be reused in surfactant flooding for enhanced oil recovery where achieves 7% higher displacing efficiency than fresh water. The drilling muds which were prepared using the untreated flowback water exhibit good rheological properties. The obtained results show that recycling of flowback water in future drilling and exploitation operations is technically feasible.

Boron minerals are a sought-after raw material. The European Union’s total dependence on imported borates means that this has been a critical material since 2014. Due to the increased use of borates in modern economies, data on the predicted boron demand in the coming years indicate that it may become a critical element on a global scale. Formerly, the high boron content in groundwater was the basis for qualifying it as medicinal water (boric water). Nevertheless, the current information on the potential toxicity of boron and the narrow margin between deficiency and toxicity of boron in the human body has caused a tightening of the limits of this element in water intended for human consumption. For this reason, metaboric acid has lost its position as a specific component of curative waters. However, despite the fact that boron is not currently a specific component of curative waters, it is found in measureable concentrations in Polish medicinal water considered therapeutic based on other valuable specific components. High boron content in curative water may be the cause of the problems in some spas when obtaining certificates confirming the therapeutic properties of waters. Literature data indicate that waters with high boron content (above 25 mg/L) should not be freely available for drinking in pump rooms and other places in health resorts. To identify the situation with Polish health resorts, the content of boron in 248 curative water samples was analyzed. In 154 of these samples, the boron concentration was relatively low and did not exceed 5 mg/L. However, in the remaining 94 samples, the boron content exceeded 5 mg/L, and 38 samples had boron content exceeding 30 mg/L. Ten of the 248 samples of curative water had a boron concentration above 100 mg/L, which may be a potential source of boron for industrial recovery. The highest concentration of boron was noticed in a water sample from the Wysowa health resort and was 187.6 mg/L. Unfortunately, most of water intakes with a high concentration of boron (above 100 mg/L) are low-yielding wells. Based on the data collected, Rabka appears to be the best candidate for small-scale boron production in terms of boron content and water resources values.