Hydrogen sulfide laden wastewater end-of-pipe treatment
Author
Ignacz, Reka
Term
4. term
Publication year
2023
Submitted on
2023-06-09
Pages
77
Abstract
This thesis investigates end-of-pipe removal of hydrogen sulfide (H2S) by oxidizing total sulfide in wastewater. The work is motivated by H2S-driven corrosion, odor, and health risks in sewers, and by the difficulty of predicting H2S levels that can lead to overdosing and sustainability and safety concerns when using chemicals. Two oxidation strategies were evaluated: simple aeration and a biofilm of sulfide-oxidizing bacteria (SOB). Experiments were performed in a laboratory reactor (1 L) and a pilot reactor (110 L). Pilot-scale tests showed rapid oxidation with an average total removal of 85% within 30 minutes. The SOB biofilm did not achieve faster removal than aeration, suggesting that biofilm-driven oxidation did not occur due to inconsistent H2S dosing. Measurements in both the water and air phases showed decreasing H2S concentrations, indicating oxidation in both phases. The findings suggest that treatment time could be further reduced by applying a trained SOB biofilm with a constant feed of H2S-rich wastewater, offering a more sustainable end-of-pipe option.
Denne afhandling undersøger, hvordan hydrogensulfid (H2S) kan fjernes ved end-of-pipe behandling ved at oxidere totalsulfid i spildevand. Motivationens baggrund er, at H2S i afløbssystemer forårsager korrosion, lugtgener og sundhedsrisici, mens uforudsigelige H2S-niveauer gør kemisk dosering vanskelig og kan føre til overdosering og bæredygtigheds- samt arbejdsmiljøudfordringer. To oxidationsstrategier blev afprøvet: simpel beluftning og anvendelse af en biofilm bestående af sulfidoxiderende bakterier (SOB). Forsøgene blev gennemført i laboratoriereaktor (1 L) og pilotreaktor (110 L). Pilotforsøgene viste hurtig oxidation med gennemsnitlig samlet fjernelse på 85 % inden for 30 minutter. SOB-biofilmen gav ikke hurtigere fjernelse end beluftning, hvilket tyder på, at biofilmoxidation ikke blev etableret i reaktorerne på grund af ujævn H2S-dosering. Målinger i både vand- og luftfase viste faldende H2S-niveauer, hvilket indikerer, at oxidation sker i begge faser. Resultaterne peger på, at behandlingstiden potentielt kan forkortes ved at anvende en trænet SOB-biofilm og en stabil, konstant dosering af H2S-rigt spildevand som en mere bæredygtig end-of-pipe løsning.
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