When Biocides Can’t Reach the Problem: Restoring Biological Control by Disrupting Biofilms in PVC Process Sumps

At a glance

Biofilms were blocking biocide performance in a PVC plant’s process-water system, increasing biological risk and under-deposit corrosion potential. Aquaguard 625, a biodispersant, was dosed, to restore biological control. Monitoring confirmed biofilm dispersal and increased biocide effectiveness, without shutdowns or disruption.

Key metrics

45.5% INCREASE IN ATP – BIOFILM RELEASED

IMMEDIATE BIOCIDE ENGAGEMENT

NO DOWNTIME OR DISRUPTION TO PROCESS

Why biocides alone struggle against established biofilm

Biofilm is a slime layer that bacteria build on wet surfaces. Once it forms, it shields the bacteria inside from biocides in the water. The system keeps using disinfectant, but the organisms on the surfaces are protected.

Left in place, biofilm also cuts heat transfer and creates conditions for under-deposit corrosion. In a process water system, that means more chemical demand, less efficient equipment, and a growing biological risk.

This PVC manufacturing plant was seeing those signs in its process water sumps. It needed to break down the biofilm so its existing oxidant program could work, without shutting down or creating new safety or process problems.

Challenges

Biofilms in the process water system at a PVC manufacturing facility were shielding bacteria from biocides, driving higher disinfectant demand, reducing heat transfer, and increasing under-deposit corrosion risk. The facility needed to remove biofilm barriers that were undermining biological control, without creating new safety or operational risks.

Solutions

Aquaguard 625, a bio-dispersant was dosed into the active sump system to disrupt and disperse biofilms so microorganisms were exposed and accessible to existing oxidant programs.

To validate performance, Guardian monitored system response using ATP testing, chlorine residual behaviour, and visual inspection.

Results

Biofilm barriers disrupted: Adenosine Triphosphate (ATP) levels increased, indicating biofilm-associated biomass release into the bulk water.

Biocide engagement increased: Free chlorine residual dropped rapidly after dosing, consistent with oxidant demand from newly exposed biomass.

Online cleanup without disruption: Foam and visual observations were consistent with active slime dispersal, with no odour complaints or process interruptions reported.

Data

After second dose of Aquaguard 625, ATP monitoring showed a 45.5% increase in Free ATP, indicating biofilm associated biomass release from system surfaces into the bulk water. Free chlorine residual dropped rapidly, consistent with oxidant demand from newly exposed biological material. Visual observations, including foam formation in the sump supported active slime dispersal. The system remained online throughout, with no odour complaints or operational disruption.

Aquaguard 625

AQUAGUARD 625 is designed to disrupt biofilm formation and optimize biocide performance, this smart cleaner-slash-penetrant supports both preventative maintenance and remediation.

Frequently asked questions

What is Aquaguard 625?

A biodispersant. It disrupts and disperses biofilm so the microorganisms inside are exposed to the existing oxidant program.

How was the result measured?

With ATP testing, free chlorine residual trends, and visual inspection of the sumps.

What did the monitoring show?

After the second dose, free ATP rose 45.5%, showing biomass released from surfaces into the water. Free chlorine residual dropped quickly, consistent with newly exposed biological material using up oxidant.

Did the system need to be shut down?

No. The system stayed online, with no odour complaints or process interruptions.