NCEDA analysis of IDA World Congress technical sessions
Validation testing of a full scale RO system for pathogen removal
Authors: Mr Jim Lozier, Dr Greta Zornes, Ms. Emily Jansen
This paper focused on work done in validating the pathogen removal being achieved at the Gippsland Water Factory (GWF) in Victoria. The GWF produces two streams of recycled water. The plant receives 8ML/d municipal wastewater from the 50,000 residents in the local area. This wastewater is treated and subsequently used as feedwater for the nearby Australian Paper and Pulp Mill. The wastewater from this Plant is then again treated by GEWF to a standard suitable for agricultural reuse rather than a channel to the sea which has been the source of long term complaints from residents due to its poor quality and odours.
Key components of the plant at both stages are MBR technology followed by RO. Since the plant is producing recycled water , it is subject to regulation and qualified as a class A recycled water scheme. To secure approval for reuse, validation of GWF’s claims for removal of bacteria, viruses and protozoa to the required log removal criteria needs to be undertaken. The process and the standards achieve need to accord with the Australian Guidelines for Recycled Water.
The study reported here by Jim Lozier used a fluorescent dye (Rhodamine WT abbreviated R-WT) as a molecular marker for validating removal of viruses by the RO system. Results of the GWF’s testing showed that when dosed at a concentration of 100microgram/litre an intact 2 stage system can achieve approx.2.6 log dye removal with removal most likely limited by feed dye concentration. Limited on line TOC monitoring of RO feed and permeate generated >2.0 log removal at steady state operating conditions. These results have meant that the RO sysme has been awarded a 2.0 log virus removal credit as part of the quantitative microbial risk assessment that the whole of the plant generates (credits also come from the MBR, preliminary and post treatment components)
