Sulfate reduction behavior in pressure-bearing leachate saturated zone

Area of Science:

• Environmental Microbiology
• Geochemistry
• Waste Management

Background:

• Sulfate reduction is a key process in landfill leachate, influencing gas production and environmental impact.
• Understanding sulfate reduction under pressure is crucial for landfill management and safety.

Purpose of the Study:

• To investigate the impact of pressure on sulfate reduction rates and hydrogen sulfide (H2S) release in leachate-saturated zones.
• To analyze the effects of pressure on microbial community structure and functional genes involved in sulfate reduction.

Main Methods:

• Experiments were conducted in a pressure-bearing leachate saturated zone at varying pressures (0-0.6 MPa) and a constant temperature (50°C).
• Measurements included sulfate reduction rates, H2S concentration and release duration, and microbial community analysis (structure and dsrB gene abundance).

Main Results:

• Sulfate reduction rates potentially increase with pressure, but H2S release is significantly inhibited (highest concentration decreased by ~85%) and prolonged (duration doubled).
• Pressure significantly altered sulfate-reducing bacteria community distribution.
• A negative correlation was observed between disulfide reductase B (dsrB) gene abundance and the H2S release rate.

Conclusions:

• Pressure influences sulfate reduction dynamics in landfills, primarily by affecting H2S release rather than the reduction rate itself.
• Alternative sulfate reduction pathways independent of dsrA and dsrB genes may be dominant under pressure.
• Findings provide a theoretical basis for optimizing landfill operation and management under pressure conditions.