Microbial transformation of thiocyanate.

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Coal carbonization wastewater contains significant thiocyanate concentrations alongside other hazardous substances like phenols, cyanide, sulfide, and ammonia.
• Effective treatment of this complex wastewater is crucial for environmental protection.

Purpose of the Study:

• To investigate the biodegradation of thiocyanate by a microbial consortium from a biological treatment plant.
• To assess the impact of secondary toxicants and growth stimulants on thiocyanate oxidation.
• To evaluate thiocyanate transformation in real and partially treated coal carbonization wastewater.

Main Methods:

• Isolation and utilization of a microbial consortium from a wastewater treatment plant.
• Batch culture experiments to determine thiocyanate degradation capacity.
• Testing the effects of varying concentrations of phenol, cyanide, sulfide, and ammonia on thiocyanate oxidation.
• Analysis of thiocyanate transformation in actual industrial wastewater.

Main Results:

• The microbial consortium effectively degraded thiocyanate up to 1400 mg/L within 6 days.
• Phenol (>500 mg/L) and cyanide (10 mg/L) completely inhibited thiocyanate oxidation.
• Sulfide (32 mg/L) and ammonia (4000 mg/L) significantly prolonged the degradation time.
• The consortium is dominated by bacteria from the genera Pseudomonas and Bacillus.

Conclusions:

• Pre-treatment to remove phenolics, cyanides, sulfides, and ammonia is essential for efficient thiocyanate bioremediation.
• The identified microbial consortium shows potential for treating thiocyanate in coal carbonization wastewater.
• Understanding the inhibitory effects of co-existing toxicants is key for optimizing biological treatment processes.