Event Summary

The Queensland Branch of the Australasian Corrosion Association (ACA) invites all our members and those interested to attend our Annual General Meeting and a presentation on a MIC problem in an air-conditioning cooling system of a large residential building.

We are rejuvenating the ACA with new staff and now we need new Committee members to work with. It would benefit the branch to have some Regional QLD Committee members, so we can work on delivering events into regional QLD.

We encourage representation of all different sectors of corrosion on our Branch Committees. We also encourage young people or people that haven’t been involved with the ACA to help us make the changes and be part of the rejuvenated ACA.

We are also looking for members interested in joining the Committee and that are keen to actively contribute to events as Speakers, Organisers and or Sponsors. During the AGM, we will elect committee members and discuss general business for the upcoming year. Or, we encourage you just to come along to see what it’s all about. We hope to see you there!


  • Steven Nearhos (CEO); Baseline Australasia
  • Rowan Dann (Service Manager); Everything Water Australia
  • Steve Clark; Everything Water Australia

Title: Identification and Control of a Persistent Sulphate Reducing Bacteria (SRB) & Tuberculate Microbial Induced Corrosion (MIC) Consortium from a Mild Steel Closed Loop Building Cooling System by a Novel Combination Strategy Relying on Anti-Corrosion and Anti-Microbial Chemistry introduced by a Custom Built Treatment System.

Part A: Baseline -Report on the Chemistry and Microbiology including tracking of SRB, IRB & IPB. Dr Steven Nearhos Senior Scientist Baseline.

Part B: Everything Water – Construction and Features of the Dosing & Treatment System  Rowan Dann Construction & Service Manager Everything Water.


A Brisbane tower building with a closed loop air-conditioner cooling system was diagnosed in 2014 was diagnosed by Dr Alan Shey to have had corrosion in Victaulic joints between mild steel pipe segments. This corrosion at the time was identified as from Sulphate Reducing Bacteria (SRB)  No Iron reducing bacteria or Iron Precipitating bacteria were identified at the time and repairs were enacted. In 2021 when the joints again started leaking Baseline was engaged to investigate the bacteria associated with corrosion on the site and in addition to SRB IRB and IPB were also resolved. The IPB were producing large fist sized polyps on the walls of the vertical pipes. While the outside of these polyps were oxidized the inside were reduced and so able to actively corrode the pipe walls. It was observed that the historical management regime was focused on minimizing corrosion however the chemicals used including Phosphorus, Nitrite and Sulphite directly or indirectly could be seen to support the persistence of MIC. 

It was agreed by the building owners that a modified liquor based on recirculation of low mineral water might starve the problem microbes of many of their essential growth factors and so provide a more sustainable system. To this end a system which was based on these aspirations was designed and fabricated by Everything Water. We embarked on routine tests for Heterotrophic Plate Counts and plate based assays for Iron Precipitating bacteria and Minimal Inhibitory Concentration assays indicated the Benzisothiazolinone (BIT) would be an effective biocide. Initially almost the entire population of HPC were also IPB. However over time the proportion of IPB diminished and we acquired and adapted population of BIT degrading and Sulphate releasing microbes. Ultimately we used other biocides and anti-corrosion agents without Nitrite Sulphate and Phosphate and we reduced the microbial density by around 7 logs. We had some problems with microbes sheltering in dead-legs heater loops and the system expansion tank but those engineering aspects form part B of the talk. Recirculation water Turbidity is now less than 1 NTU.

Event Details

Date: Thursday 21st March

Time: 5.30pm

Location: Aspley Central Tavern – 1378 Gympie Road Aspley Queensland 4034


5.30pm – Arrival

6.00pm – Presentation from Steven Nearhos (Baseline), Rowan Dann and Steve Clark

6.45pm – AGM

7.00pm – Networking and close of evening


  • Registrations for this event close Thursday 14th March 3.00pm
  • Registration for this event includes light refreshments

For Committee nomination and proxy forms, please see the ‘Content’ tab above.



Baseline (Australasia) Pty Ltd


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