The Influence of Micro-Oxygen Addition on Desulfurization Performance and Microbial Communities during Waste-Activated Sludge Digestion in a Rusty Scrap Iron-Loaded Anaerobic Digester
The Influence of Micro-Oxygen Addition on Desulfurization Performance and Microbial Communities during Waste-Activated Sludge Digestion in a Rusty Scrap Iron-Loaded Anaerobic Digester
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In this study, micro-oxygen was integrated into a rusty scrap iron (RSI)-loaded anaerobic digester.Under an optimal RSI dosage sophie allport bee curtains of 20 g/L, increasing O2 levels were added stepwise in seven stages in a semi-continuous experiment.Results showed the average methane yield was 306 mL/g COD (chemical oxygen demand), and the hydrogen sulphide (H2S) concentration was 1933 ppmv with RSI addition.O2 addition induced the microbial oxidation of sulphide by stimulating sulfur-oxidizing bacteria and chemical corrosion of iron, which promoted the generation of FeS and Fe2S3.
In the 6th phase of the semi-continuous test, deep desulfurization was achieved without negatively impacting system performance.Average methane yield was 301.1 mL/g COD, and H2S concentration was 75 ppmv.Sulfur mass balance was described, with 84.
0%, 11.90% and 0.21% of sulfur present in solid, liquid and gaseous phases, respectively.The Polymerase Chain read more Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis revealed that RSI addition could enrich the diversity of hydrogenotrophic methanogens and iron-reducing bacteria to benefit methanogenesis and organic mineralization, and impoverish the methanotroph (Methylocella silvestris) to reduce the consumption of methane.
Micro-oxygen supplementation could enhance the diversity of iron-oxidizing bacteria arising from the improvement of Fe(II) release rate and enrich the sulphur-oxidising bacteria to achieved desulfurization.These results demonstrated that RSI addition in combination with micro-oxygenation represents a promising method for simultaneously controlling biogas H2S concentration and improving digestion performance.