Case Study: Auto Manufacturer Proactively Controls Biological Fouling in Wastewater RO using BioFilmPro™

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Biological fouling is a major challenge in reverse osmosis (RO) membrane systems because it leads to increased maintenance and cleaning/replacement frequency, reduced productivity, high energy and chemical usage, and a high total cost of operation. This case study discusses how an auto ancillary company tackled problems caused by microbial growth on its RO membranes by implementing our BioFilmPro technology.

Challenge

An auto ancillary company faced problems with microbial growth on its RO membranes, causing reduced permeate flow and requiring frequent clean-in-place (CIP) to keep the system functional. This resulted in excessive chemical usage, reduced membrane lifespan, and constant operator involvement, leading to a high overall cost of operation.

The conventional method of injecting an oxidizing biocide (Sodium Hypochlorite) was used to maintain free chlorine between 0.3-0.5 ppm to address the biofouling. Despite maintaining residual chlorine and subsequent neutralization using Sodium Bisulfite, the treatment was ineffective, causing an increase in differential pressure (dP) and requiring cleaning every 36 hours on average.

The auto manufacturer sought a more cost-effective solution to address the biofilm growth and increase in differential pressure.

Solution

After evaluating the system’s performance, the implementation of BioFilmPro, Aquatech's proactive biofilm measurement and control technology, was recommended. The technology integrates bacteria deactivation, real-time sensing, and data-driven analytics to accurately predict and control biofilm before a problem occurs.

A sensor was installed downstream of the bacteria deactivator before connecting it to a control panel that controls the biocide dosing pumps for supplemental use if needed. Once in place, the sensor outputs were fed to the predictive analytics software in real-time, where the data was aggregated and analyzed.

Over the initial nine days, a baseline of biofilm signal was established, averaging 800 mV. After introducing bacteria deactivation, the biofilm signal level dropped to an average of 550 mV. Figure 1 shows actual test data collected during the BioFilmPro treatment, highlighting the increase in hours between clean-in-place (CIP).

Figure 1: Hours without CIP

Actual test data was collected during the following five phases after establishing the baseline.

Phase 1: Performance with bacteria deactivator in operation
Phase 2: Performance with bacteria deactivator and online biocide injection
Phase 3: Performance with only biocide injection

Phase 4: Performance with bacteria deactivator in operation
Phase 5: Performance with bacteria deactivator in operation

Customer Benefits

Using smart, data-driven decision-making to proactively manage biofilm growth in the system’s RO membranes, the facility was able to reduce its cleaning frequency, reducing plant downtime from every 36 hours to every 260 hours, an over 600% increase in uptime.

In addition to decreasing the site’s total cost of operations through reduced chemical consumption and membrane replacement, the auto manufacturer also:

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