Mixed culture hydrogenotrophic nitrate reduction in drinking water

Area of Science:

• Environmental microbiology
• Water treatment technologies
• Microbial ecology

Background:

• Denitrification is crucial for removing nitrates from drinking water.
• Hydrogenotrophic reactors utilize microbial processes for denitrification.
• Understanding microbial roles in denitrification is key to optimizing water purification.

Purpose of the Study:

• To identify key microorganisms involved in hydrogenotrophic denitrification.
• To elucidate the biochemical pathways of nitrate and nitrite reduction.
• To investigate the influence of organic growth factors and microbial interactions.

Main Methods:

• Bacterial isolation and identification from hydrogenotrophic sludge.
• Analysis of microbial metabolic pathways for denitrification.
• Assessing the impact of organic growth factors on microbial activity.

Main Results:

• Several bacterial species, including Acinetobacter sp., Aeromonas sp., Pseudomonas sp., and Shewanella putrefaciens, were identified as primary denitrifiers.
• Nitrate reduction to nitrite is performed by diverse microorganisms.
• Nitrite reduction to nitrogen gas is enhanced by organic growth factors, mixotrophic growth, and chemolithotrophic bacteria.

Conclusions:

• A mixed microbial community, supported by organic growth factors and mixotrophic activity, efficiently drives hydrogenotrophic denitrification.
• Chemolithotrophic bacteria play a significant role in the final conversion of nitrite to nitrogen gas.
• Optimizing reactor conditions to support these microbial consortia is essential for effective drinking water denitrification.