This page summarises laboratory testing evidence for Envirolyte anolyte against Legionella pneumophila and other waterborne microorganisms relevant to building water systems, process water and hygiene-sensitive installations.
The testing of anolyte against Escherichia coli, Salmonella spp., Pseudomonas aeruginosa and Legionella pneumophila was undertaken by IPROMA S.L.
The results are provided for technical and regulatory reference. Real-world Legionella prevention depends on system design, water age, temperature, biofilm, disinfectant residual, pH, flow conditions, monitoring frequency and the facility’s water management program.
Why Legionella Prevention Matters
Legionella pneumophila can grow in building water systems, especially where water becomes stagnant, disinfectant residual is low, biofilm is present or temperatures are favourable for bacterial growth. Effective prevention normally requires a complete water management approach: system assessment, temperature control, residual disinfectant monitoring, flushing, cleaning, sampling and corrective actions where required. Envirolyte anolyte can support Legionella control programs by providing on-site generation of a disinfectant solution containing active chlorine species, including hypochlorous acid, for controlled dosing into water systems. For application-specific information, see Legionella Prevention, On-site Water Disinfection and Cooling Towers.Test Protocol
The test evaluated anolyte contact with four microorganisms at initial concentrations of approximately 105 CFU/100 mL.| Microorganism | Initial concentration | Contact times |
|---|---|---|
| Escherichia coli | 1.5 × 105 CFU/100 mL | 1, 5, 10 and 30 minutes |
| Salmonella spp. | 1.3 × 105 CFU/100 mL | 1, 5, 10 and 30 minutes |
| Pseudomonas aeruginosa | 1.1 × 105 CFU/100 mL | 5, 10, 30 and 60 minutes |
| Legionella pneumophila | 1.5 × 105 CFU/100 mL | 5, 10, 30 and 60 minutes |
Test Results: Escherichia coli
In the reported test, Escherichia coli was reduced from 1.5 × 105 CFU/100 mL to 0 CFU/100 mL after 1 minute of contact time.
| Parameter | Units | Initial values | 1 min | 5 min | 10 min | 30 min |
|---|---|---|---|---|---|---|
| pH | pH unit | 8.1 | 8.1 | 8.1 | 8.1 | 8.0 |
| Residual chlorine | mg/L | — | 0.7 | 0.7 | 0.7 | 0.7 |
| Redox potential | mV | 825 | — | — | — | — |
| Escherichia coli | CFU/100 mL | 1.5 × 105 | 0 | 0 | 0 | 0 |
| Heterotrophic bacteria | CFU/mL | < 1 | — | — | — | — |
Test Results: Salmonella spp.
In the reported test, Salmonella spp. was negative after 1 minute of contact time.
| Parameter | Units | Initial values | 1 min | 5 min | 10 min | 30 min |
|---|---|---|---|---|---|---|
| pH | pH unit | 8.1 | 8.1 | 8.1 | 8.1 | 8.0 |
| Residual chlorine | mg/L | — | 0.7 | 0.7 | 0.7 | 0.7 |
| Redox potential | mV | 825 | — | — | — | — |
| Salmonella spp. | CFU/100 mL | 1.3 × 105 | NEG | NEG | NEG | NEG |
| Heterotrophic bacteria | CFU/mL | < 1 | — | — | — | — |
Test Results: Pseudomonas aeruginosa
In the reported test, Pseudomonas aeruginosa was positive at the first measured contact time and negative at the following contact times.
| Parameter | Units | Initial values | 1 min | 5 min | 10 min | 30 min |
|---|---|---|---|---|---|---|
| pH | pH unit | 8.1 | 8.1 | 8.1 | 8.1 | 8.0 |
| Residual chlorine | mg/L | — | 0.7 | 0.7 | 0.7 | 0.7 |
| Redox potential | mV | 825 | — | — | — | — |
| Pseudomonas aeruginosa | CFU/100 mL | 1.1 × 105 | POS | NEG | NEG | NEG |
| Heterotrophic bacteria | CFU/mL | < 1 | 150 | < 1 | < 1 | < 1 |
Test Results: Legionella pneumophila
In the reported test, Legionella pneumophila was reduced from 1.5 × 105 CFU/100 mL to 0 CFU/100 mL after 10 minutes of contact time.
| Parameter | Units | Initial values | 1 min | 5 min | 10 min | 30 min |
|---|---|---|---|---|---|---|
| pH | pH unit | 8.1 | 8.1 | 8.1 | 8.1 | 8.0 |
| Residual chlorine | mg/L | — | 0.7 | 0.7 | 0.7 | 0.7 |
| Redox potential | mV | 825 | — | — | — | — |
| Legionella pneumophila | CFU/100 mL | 1.5 × 105 | 1200 | 200 | 0 | 0 |
| Heterotrophic bacteria | CFU/mL | < 1 | 1200 | 200 | < 1 | < 1 |
Interpretation of the Legionella Test Results
The reported IPROMA results indicate that anolyte showed rapid antimicrobial activity under the test conditions. Escherichia coli and Salmonella spp. were reduced to zero or negative results after the first measured contact time.
For Legionella pneumophila, the reported result decreased from 1.5 × 105 CFU/100 mL initially to 1200 CFU/100 mL, then 200 CFU/100 mL, and then 0 CFU/100 mL at the following measured contact times.
These results support technical evaluation of Envirolyte anolyte for Legionella control and water system hygiene, but they should not be interpreted as a guarantee of performance in every installation. Field performance depends on water chemistry, hydraulic conditions, biofilm, system cleanliness, dosing control, residual disinfectant and monitoring.
Where This Evidence Is Relevant
- domestic hot and cold water systems;
- hospitals, care homes and healthcare facilities;
- hotels, spas and hospitality buildings;
- cooling towers and evaporative systems;
- industrial process water systems;
- rural and decentralised drinking water systems;
- maritime and offshore water treatment systems.
Customer Requirements and Monitoring
Customers should evaluate anolyte dosing as part of a complete Legionella risk management program. Important control points include temperature, pH, residual disinfectant, water age, flow, dead legs, storage tanks, biofilm, sampling points and maintenance procedures.
For compliance-related information, see Customer Requirements, ECHA / BPR Information and Microbiological Testing.
Frequently Asked Questions
Yes. The reported IPROMA test included Legionella pneumophila at an initial concentration of 1.5 × 105 CFU/100 mL.
Under the reported test conditions, Legionella pneumophila was reduced to 0 CFU/100 mL after 10 minutes of contact time.
No. Laboratory results depend on defined test conditions. Real building water systems require assessment of temperature, water age, biofilm, flow, residual disinfectant, pH and monitoring procedures.
Anolyte may be evaluated as part of a Legionella control strategy where on-site generation and controlled dosing of disinfectant solution are suitable for the system design and local regulations.
Envirolyte can provide available Legionella testing documentation and related technical information upon request for project evaluation, tenders or regulatory discussions.
Request Legionella Prevention Documentation
Envirolyte can support customers, distributors and OEM partners with Legionella prevention evidence, microbiological testing information and project-specific recommendations for water system disinfection.
