Peracetic Acid (PAA)
Peracetic Acid (PAA)
Wastewater Disinfection Solution
What is Peracetic Acid?
Peracetic Acid (PAA) is produced by combining Hydrogen Peroxide (HA)and a strong Acetic Acid (CHjCOOH), also known as vinegar. The catalyzed reaction between Hydrogen Peroxide and Acetic Acid creates Peracetic Acid and water as follows:
HA* CH.COOH <—> CHjCOO-OH . H:0
How does Peracetic Acid Work?
When Peracetic Acid is introduced to water the Hydroxyl Radical (-OH*) is spun off and destroys cell structure and ONA so that the cell dies. The Hydroxyl Radical is an extremely powerful oxidant. It is a broad-spectrum biocide that is effective on bacteria, viruses, mold, fungus and yeast.
Advantages of PAA
Cost advantages are:
- Minimum Capital Investment
- Most WWTPs can be Retrofitted
- Competitive Chemical costs
- Minimal or no electrical consumption {solar power)
O&M advantages are:
- Long shelf life (12-18 months)
- Broad Spectrum Disinfectant
- Small Footprint
- Feed as a Liquid in Neat Form
- Use of Existing Contact Basins
- Easy to test for
- No safety issues
- No transportation issues
Chemical advantages are:
- Stronger Oxidant than Chlorine
- Low Freezing Point
- No Toxic Disinfection By-Products
- Fast Acting (seconds to minutes)
- Very little Non-toxic Residual
- Non-persistent in the environment
- Breaks down into CO, & H,0
- No BOD interference
- Does not add Conductivity (TDS)
- Minimal affect by TSS 'shadowing'
- Not Temperature Dependent
- Performs Best at pH from 6-9
The most capital-cost effective system includes reusing the existing contact basin, a peristaltic pump and HDPE or Teflon tubing to introduce the PAA at the optimal feed point in the contact basin. The PAA can be stored in any existing chemical storage building on a pallet to provide required secondary containment. That’s it! The PAA dosage (ppm) can be entered by operator to maintain a minimum residual.
The system can also be automated to minimize chemical usage but requires the use of a PLC which many communities already own. The PLC will send a signal to the pump to vary the PAA pumping rate.
Measurements and flow control options that can be used with the PLC include:
- On-line residual measurement for loop feed control
- Level indicator, flow signal, run signal or proximity sensor used for loop feed control
- PAA pumping rate computed by set points and regulator flow rate.
- H-O-A equipped for manual, off and automatic operation.
Europe has used PAA for decades to disinfect wastewater and because of PAA’s high rate disinfectant ability it can be used for Wet Weather Flow Treatment Processes. However, PAA has been used in a number of other applications. Some of the more prevalent applications are:
- Used for Food Produce Disinfectant
- Medical, Pharmaceutical Disinfection
- Pulp and Paper industrial Processes
- Drinking Water Treatment Processes
- Control of Biological Growth on Screens, Filters and Membranes
- Food & Beverage Preparation
- Hydrofracking
- Control of Sulfur Reducing Bacteria
- Bleaching Agent
- Hard surface sanitization. No rinse.
- RO and UF membrane bio-fouling
- Paper mill water systems
- Cooling Tower treatment
- Irrigation water systems
- Decontamination studies
- Disinfection of Chlorine Resistant
