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A pilot-scale plasma reactor installed into an 8 × 20 ft 2 mobile trailer was used to rapidly and effectively degrade poly-and perfluoroalkyl substances (PFAS) from liquid investigation-derived waste (IDW; development and purge water from monitoring wells) obtained from 13 different site investigations at Air Force installations. In the raw water, numerous PFAS were detected in a wide concentration range (∼10−10 5 ng/L; total oxidizable precursors (TOP) ∼10 2 −10 5 ng/L, total fluorine by combustion ion chromatography ∼10 2 to 5 × 10 6 ng F/L). The concentration of total PFAS (12 perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonates (PFSAs)) in the 13 samples ranged between 2.7 and 1440 μg/L and the concentration of perfluorooctane sulfonate (PFOS) plus perfluorooctanoic acid (PFOA) ranged between 365 and 73700 ng/L. Plasma-based water treatment resulted in rapid perfluoroalkyl acids (PFAAs) removal from 4 L individual IDW samples with faster rates for longer-chain PFCAs (C ≥ 8) and PFSAs (C ≥ 6) than for PFCAs and PFSAs of shorter chain length. In 9 of the 13 IDW samples, both PFOS and PFOA were removed to below United States Environmental Protection Agency's (USEPA's) health advisory concentration level (HAL) concentrations in <1 min, whereas longer treatment times (up to 50 min) were required for the remaining four IDW samples due to either extremely high solution electrical conductivity, which decreased the plasma−liquid contact area (one IDW sample) or high concentrations of PFAAs and their precursors; the latter was found to be converted to PFAAs during the treatment. Overall, 36−99% of the TOP concentration present in the IDWs was removed during the treatment. There was no effect of non-PFAS co-contaminants on the degradation efficiency. Overall, the results indicate that plasma-based water treatment is a viable technology for the treatment of PFAS-contaminated IDW.

Dialogue has become a pivotal concept within contemporary humanstudies, yet few theorists explore its temporal dimension. Is dialogue an extended state of high quality mutuality? Or does it exist in important yet ephemeral moments of human meeting? This article reports on the contributions to communication theory that emerge from a close reading of a metadialogic conversational "text "-the landmark 1 957 meeting of Martin Buber and Carl Rogers. Although most commentators have described Buber and Rogers as disagreeing sharply, we argue that a coherent Buber-Rogers position emerged from their dialogue. Buber and Rogers, in their informal theoretical collaboration, theorize that mutuality-and, by extension, dialogue-is possible in role-unequal relationships in moments of meeting. We then discuss how this Buber-Rogers position prefigured the contemporary cultural tenor of postmodernism. Although not postmodernists themselves, Buber and Rogers helped to shape an intellectual climate in which key postmodern themes could flourish.Dialogue must be understood as something taking part in the very historical nature of human beings. . . . Dialogue is a moment where humans meet to reflect on their reality as they make and remake it. Something else: To the extent that we are communicative beings who communicate to each other as we become more able to transform our reality, we are able to know that we know, which is something more than just knowing. . . . Knowing is a social event with nevertheless an individual dimension. What is dialogue in this moment of communication, knowing and social transformation? Dialogue seals the relationship between the cognitive subjects, the subjects who know, and who try to know.Paulo Freire (Shor & Freire, 1987, pp. 98-99) The Brazilian educator and dialogic theorist Paulo Freire shows how dialogue is a relation of co-constituted mutuality that exists in a matter of moments. Although dialogue necessarily involves separate persons, it is not an individualistic process. Although its 63

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