Denitrifying sulfide removal process on high-tetracycline wastewater

Area of Science:

• Environmental Science
• Microbiology
• Chemical Engineering

Background:

• Antibiotic production wastewater, particularly from tetracycline (TC) manufacturing, contains high concentrations of chemical oxygen demand, ammonium, sulfate, and TC.
• Conventional wastewater treatment methods may struggle to efficiently remove these complex pollutants.

Purpose of the Study:

• To investigate the efficacy of the denitrifying sulfide removal (DSR) process for the simultaneous removal of sulfur, carbon, and nitrogen from TC-contaminated wastewater.
• To assess the impact of varying TC concentrations on the DSR process performance and microbial community.

Main Methods:

• The DSR process was implemented to treat synthetic wastewater mimicking TC production effluent.
• Microbial community analysis was performed to identify key heterotrophic and autotrophic bacteria involved in the DSR reactions.
• TC tolerance was evaluated by monitoring removal rates of nitrate, acetate, and sulfide, as well as elemental sulfur (S(0)) accumulation at different TC concentrations.

Main Results:

• The DSR process demonstrated effective removal of nitrate and acetate even under TC stress.
• Sulfide removal and S(0) accumulation rates were moderately inhibited at TC concentrations exceeding 100 mg/L.
• The microbial consortium, including Thauera sp., Pseudomonas sp. (heterotrophs), and Sulfurovum sp. (autotroph), exhibited high tolerance to TC.
• Excess production of extracellular polymeric substances (EPS) by the microbial community was identified as a key mechanism for TC detoxification.

Conclusions:

• The DSR process is a viable technology for treating antibiotic wastewater from TC production.
• Microbial adaptation and EPS production contribute significantly to the resilience of the DSR process against TC toxicity.
• Further research can optimize DSR for enhanced TC removal and resource recovery.