2-Chlorophenol consumption and its effect on the nitrifying sludge

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Nitrifying sludge is crucial for removing ammonia from wastewater.
• 2-chlorophenol (2-CP) is a common industrial pollutant that can be toxic to microorganisms.
• The kinetic effects of 2-CP on nitrifying sludge require detailed investigation.

Purpose of the Study:

• To evaluate the kinetic behavior of nitrifying sludge exposed to 2-chlorophenol (2-CP).
• To assess the impact of prior 2-CP exposure on ammonium and nitrite oxidation processes.

Main Methods:

• Batch culture assays using stabilized nitrifying sludge.
• Controlled experiments with and without 2-CP addition.
• Evaluation of substrate consumption rates, efficiency, and product yield.
• Post-exposure assessment of ammonium and nitrite oxidizing processes.

Main Results:

• 2-CP addition reduced nitrifying efficiency to 10% and ammonium consumption rate by 95%.
• A 2-CP-induced intermediate was observed, but nitrate yield remained high.
• Pre-exposure to 2-CP increased ammonium and nitrite consumption times by 120 and 42 hours, respectively.
• Specific consumption rates decreased by 95% for ammonium and 83% for nitrite.

Conclusions:

• 2-CP significantly inhibits nitrifying sludge activity, particularly ammonium oxidation.
• Prior exposure to 2-CP causes long-term kinetic impairments in nitrifying sludge.
• Nitrifying sludge demonstrates resilience but requires extended periods for recovery after 2-CP exposure.