Neuer Zeitschriftenbeitrag von Silva et al. 2020

Hydrogen sulfide (H₂S) is a volatile, toxic and malodorous compound, which presence causes corrosion, damages to the environment, health and safety problems. Thus, the removal of H₂S present in wastewaters is important, especially in the context of wastewater reclamation. In this work, a modified direct contact membrane distillation (M-DCMD) process with receiving NaOH solution in permeate side, flowing in counter-current mode, was evaluated for accelerating dissolved H₂S removal from a two-stage anaerobic membrane bioreactor (2S-AnMBR) treating vinasse, rich in organic matter and sulfate. The H₂S concentration in the 2S-AnMBR permeate was 166 ± 15 mg L⁻¹. The effect of pH and temperature and the interference of the organic and inorganic compounds on the H₂S removal were investigated. The results demonstrated the application potential of a M-DCMD process for the H 2 S removal from permeate of a 2S-AnMBR treating vinasse. The DCMD process is favored at lower pH values, where all the sulfide species are present as H₂S. High temperature can be used to increase the M-DCMD process performance, mainly in neutral pH, and so, to reduce the chemicals demand. The highest removal efficiency of H₂S was achieved at pH 4.2 and temperature of 44 °C, referring to the optimal condition, after 20 min. Repeated H₂S removal tests of the 2S-AnMBR effluent caused a decrease of 23% of the mass transfer coefficient likely attributed to membrane fouling. Tests were also carried out by inverting the flow configuration, i.e., lumen-side feed and shell-side feed. The more effective contact of hot feed and membrane in the lumen-side feed, favored by the flow conditions as the larger contact area, resulted in a higher permeate flux.

Silva et al. 2020