WATER / WASTEWATER
FROM EFFLUENT TO EXCELLENCE:
MICROBIOLOGICAL ASSESSMENT OF A CONTAINERIZED MODULAR WATER REUSE PILOT SYSTEM
Introduction
Water is an invaluable resource for industries such as pharmaceutical manufacturing that require vast amounts of pure water for their operations. As global sustainability goals tighten, companies face increasing pressure to reduce water consumption and explore reuse strategies. In 2024, Ekopak installed a cutting-edge pilot system for a multinational biopharmaceutical company to meet these challenges head-on. The solution consisted of a best-in class treatment train and was equipped with an automated microbial analyser, BactoSense for additional microbiological monitoring capabilities.
Figure 2: Overview of the water reuse treatment train consisting of UF and 2-stage RO. The sampling points for total cell count measurements with the online fl owcytometer (BactoSense) are indicated with small sample tube images for manual samples and a BactoSense image for online monitoring.
recycled water met stringent drinking water standards, compliant with local legislation. Ensuring high microbiological water quality was paramount, but traditional microbiological testing methods were insuffi cient, as they are time-consuming and lack online monitoring capabilities.
Moreover, the client aimed to maximize the reuse of wastewater, ensuring that as much water as possible met quality specifi cations. Water outside these limits represented a loss in recovery. They also required an accurate assessment of the overall recovery potential, coupled with an estimate for the investment required for a full-scale implementation. Compounding these challenges was the highly variable composition of the water to be recycled, which requires clever system designs, testing and optimization.
Solution Figure 1: Example pictures of the inside and outside of a containerized pilot system Challenge
The biopharma client had clear objectives for this water reuse project. With ambitious sustainability targets, they sought to signifi cantly reduce their water consumption while ensuring the
An innovative pilot system was installed, consisting of a containerized ultrafi ltration (UF) and two-stage reverse osmosis (RO) process. This solution, housed in a standard shipping container, featured the whole treatment system and was controlled from a built-in Supervisory Control and Data Acquisition (SCADA) system with Human-Machine Interface (HMI). With this mobile test lab the most suitable technology for the client’s specifi c water quality requirements was determined. The solution also provided numerous sampling points for extensive water quality analysis throughout the whole pilot period. To address the strong requirement for tight microbiological control, an online fl ow cytometer as a rapid microbiological monitoring system was included. This complemented conventional cultivation-based tests and provided more precise data on bacterial levels all along the treatment train, further enhancing the client’s confi dence in the water reuse system.
Ekopak’s project support spanned the entire trial period, from commissioning to decommissioning. The team provided both
6 | AET MAY 2025 |
ENVIROTECH-ONLINE.COM
remote and on-site assistance, detailed performance analysis, and thorough reporting to help the client assess the feasibility and estimate the cost of a full-scale solution. The three-month pilot was conducted on-site, right next to the client’s production facility, ensuring data collection under realistic operational conditions.
Microbiological Findings
The Total Cell Count (TCC) can automatically and accurately be measured in as little as 20 minutes. This capability was utilized to assess the performance of the core treatment stages, UF and RO. A combination of manual sampling campaigns and online monitoring installations during the pilot phase yielded the following important fi ndings:
1. Membrane fi ltration and microbial regrowth shape the overall microbiological landscape
The microbiological quality of the water evolved signifi cantly during treatment. The membrane fi ltration steps achieved a reduction of approximately 1.5 log in total cell counts (fi gure 3). However, RO prefi lters and storage tanks emerged as potential hotspots for biofi lm formation and bacterial growth, compromising RO membrane performance and elevating microbial counts in the permeate. Replacing the RO 2 prefi lter immediately enhanced the quality of the RO 2 permeate.
2. Stagnation is a driver of biofouling and impacts fi nal water quality
Despite having nominal pore sizes orders of magnitude smaller than bacteria, UF fi ltrates and RO permeates are generally not sterile nor are their bacterial levels constant over time.
In this pilot, cell count variability could largely be attributed to interruptions of the treatment system, leading to water stagnation. Short-term stagnation triggered signifi cant but temporary TCC
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