Temperature dependence for anammox bacteria enriched from freshwater sediments

Area of Science:

• Environmental microbiology
• Wastewater treatment technologies
• Biogeochemical cycles

Background:

• The anoxic ammonium oxidation (anammox) process is a promising technology for treating high-ammonium wastewater.
• Applying anammox at moderately low temperatures (<25°C) expands its applicability to diverse industrial wastewater scenarios.
• Establishing effective anammox cultures is crucial for optimizing nitrogen removal efficiency.

Purpose of the Study:

• To establish enrichment cultures of anammox bacteria from freshwater sediments under moderately low temperatures.
• To evaluate the nitrogen conversion rates of the established anammox cultures.
• To identify the phylogenetic diversity of anammox bacteria present and assess the influence of enrichment conditions.

Main Methods:

• Utilized an up-flow column reactor packed with porous polyester nonwoven fabric for bacterial enrichment.
• Employed moderately low temperatures (<25°C) as the operational condition.
• Conducted phylogenetic analysis using 16S rRNA gene sequencing to identify bacterial populations.

Main Results:

• Successfully established anammox enrichment cultures from freshwater sediments.
• Achieved significant nitrogen conversion rates ranging from 0.07 to 0.26 kg-N/m³/d.
• Identified diverse anammox bacteria, including known candidates (e.g., Ca. Kuenenia stuttgartiensis, Ca. Brocadia fulgida, Ca. Scalindua wagneri) and novel lineages.
• Demonstrated that enrichment conditions, specifically seed sediments and temperature, influenced anammox bacterial populations.

Conclusions:

• Anammox bacteria can be effectively enriched from freshwater sediments at moderately low temperatures.
• The established process demonstrates efficient nitrogen conversion, suitable for industrial wastewater treatment.
• Enrichment conditions play a critical role in shaping the composition of anammox bacterial communities.