Enhanced phosphorus removal by microbial-collaborating sponge iron

Area of Science:

• Environmental Science
• Microbiology
• Materials Science

Background:

• Domestic wastewater contains significant phosphorus, contributing to eutrophication.
• Conventional phosphorus removal methods can be inefficient or costly.
• Sponge iron and microbial systems offer a novel approach to wastewater treatment.

Purpose of the Study:

• To investigate the synergistic phosphorus removal mechanisms in a sponge iron and microorganism system.
• To evaluate the effectiveness of this system at laboratory and pilot scales.
• To elucidate the roles of biochemical reactions and microbial activity in phosphorus removal.

Main Methods:

• Laboratory-scale experiments were conducted using a sponge iron and microorganism system.
• Pilot-scale experiments validated the findings from laboratory studies.
• Analysis of effluent total phosphorus concentrations and microbial activity.

Main Results:

• Achieved total phosphorus concentrations in the effluent below 0.5 mg/L.
• Demonstrated that biochemical reactions accelerate sponge iron electrochemical corrosion.
• Identified iron bacteria as key drivers for Fe(II) oxidation to Fe(III).
• Confirmed chemical precipitation of Fe(III) as the primary phosphorus removal pathway.
• Observed adsorption of phosphorus by phosphate-accumulating organisms.

Conclusions:

• The microbial-collaborating sponge iron system significantly enhances phosphorus removal from domestic wastewater.
• The enhanced removal is attributed to accelerated iron corrosion, Fe(III) precipitation, and microbial adsorption.
• This integrated approach offers an effective strategy for advanced wastewater phosphorus management.