Svovlbrinte Oxidation og Kloak Korrosion: Med artiklerne: Beskrivelse af svovlbrinte forårsaget korrosion af kloaksystemer – en ny tilgang. Svovlbrinte optagelses rater and biomasse koncentrationer af mikroorganismer fra korroderet beton.
Translated title
Hydrogen Sulfide Oxidation and Sewer Corrosion: Including the articles: Description of the hydrogen sulfide induced corrosion of concrete sewer systems - a new approach. Hydrogen sulfide uptake rates and biomass concentrations of microorganisms from corroded concrete.
Author
Kalhøj, Mark
Term
10. term
Publication year
2009
Pages
40
Abstract
I kloaksystemer bliver svovlbrinte (H2S) i gasfasen absorberet og oxideret på blottede betonoverflader, hvilket fører til betonkorrosion. Vi undersøgte forholdet mellem faktisk og potentiel korrosion og beskrev det som en korrosionsreduktionsfaktor. Vi undersøgte også skæbnen for delvist oxideret H2S, som bliver immobiliseret i korroderet beton. Disse immobiliserede svovlforbindelser har fortsat et betydeligt korrosivt potentiale: når H2S-niveauet er lavt, kan de oxideres til svovlsyre og fortsætte med at korrodere kloakken. Derudover undersøgte vi, hvordan luftstrømmens hastighed i kloakken påvirker fjernelsen af H2S; stigende hastigheder gav en markant stigning i fjernelsen. For at belyse den biologiske oxidation gennemførte vi forsøg i en bioreaktor i laboratorieskala med korroderet beton i suspension. H2S- og iltkoncentrationer blev målt kontinuerligt, og der blev løbende taget prøver til proteinanalyse. Resultaterne viser, at forskellige H2S-oxiderende mikroorganismer varierer i aktivitet. For at berige de mest aktive H2S-oxiderende mikroorganismer blev reaktoren inokuleret fra et kørende system. I takt med at kulturen nærmede sig en dominans af Acidithiobacillus, blev sammenhængen mellem H2S-fjernelseshastighed og proteinkoncentration bedre. Som delstudie blev kinetikken for oxidation af methylmercaptan undersøgt i samme reaktor. Den blandede mikrobielle diversitet i korroderet beton kunne oxidere methylmercaptan, mens den Acidithiobacillus-dominerede kultur opnået ved inokulation ikke kunne. Samlet viser arbejdet, at luftstrøm og mikrobiologisk sammensætning påvirker fjernelse af svovlforbindelser og betonkorrosion i kloakker, og at lagret svovl i korroderet beton kan opretholde korrosion, når H2S falder.
In sewer systems, hydrogen sulfide (H2S) in the gas phase is absorbed and oxidized on exposed concrete surfaces, leading to concrete corrosion. We examined how actual corrosion compares to the maximum potential corrosion and expressed this link as a corrosion reduction factor. We also studied the fate of partly oxidized H2S that becomes immobilized in corroded concrete. These trapped sulfur compounds still have substantial corrosive potential: when H2S levels are low, they can further oxidize to sulfuric acid and continue to corrode the sewer. In addition, we investigated how the speed of air movement in sewers (atmosphere velocity) affects H2S removal; higher velocities produced a significant increase in removal. To explore biological oxidation, we ran bench-scale bioreactor experiments with corroded concrete in suspension. H2S and oxygen were measured continuously, and samples for protein analysis were taken throughout. The results show that different H2S-oxidizing microorganisms vary in activity. To enrich the most active H2S oxidizers, we inoculated the reactor from a running system. As the culture shifted toward Acidithiobacillus, the relationship between H2S removal rate and protein concentration improved. As a sub-study, we investigated the kinetics of methyl mercaptan oxidation in the same reactor. The mixed microbial community from corroded concrete was able to oxidize methyl mercaptan, whereas the Acidithiobacillus-dominated culture obtained by inoculation could not. Overall, the work highlights how airflow and microbial composition influence sulfur compound removal and concrete corrosion in sewers, and shows that stored sulfur in corroded concrete can sustain corrosion when H2S levels drop.
[This abstract was generated with the help of AI]
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