Performic acid for advanced wastewater disinfection

Area of Science:

• Environmental Science
• Microbiology
• Water Treatment

Background:

• Municipal secondary effluent requires effective disinfection for safe water reuse.
• Traditional disinfection methods like chlorination can produce harmful by-products.
• Alternative disinfection strategies are needed to meet stringent water quality standards.

Purpose of the Study:

• To evaluate the disinfection efficiency of performic acid (PFA) in municipal secondary effluent.
• To compare PFA's efficacy against various microbial contaminants with disinfection by-product formation.
• To determine PFA's suitability for agricultural water reuse applications.

Main Methods:

• Testing PFA disinfection efficiency against a range of microorganisms including bacteria, viruses, spores, and cysts.
• Assessing disinfection by-product formation (hydrogen peroxide, organic per-acids, AOX).
• Evaluating PFA's performance at low doses (0.5-1 mg L(-1)) and short contact times (10 min).

Main Results:

• PFA demonstrated rapid and efficient disinfection of bacteria and viruses, with MS2-coliphages being the most resistant.
• Low PFA doses (0.5-1 mg L(-1)) achieved required disinfection levels for agricultural reuse (≤3 log units for faecal coliforms) for up to 72 hours.
• PFA produced significantly lower adsorbable organically bound halogens (AOX) compared to chlorine, with minimal hydrogen peroxide and organic per-acids detected.

Conclusions:

• Performic acid is a highly effective and safe disinfectant for municipal wastewater.
• PFA meets microbiological criteria for unrestricted agricultural water reuse with a chlorine-free disinfection process.
• PFA offers a promising alternative for advanced water disinfection due to its efficiency and reduced by-product formation.