29 September 2009


Colin Mciver, Armidale Dumaresq Council, and a New England representative on the Executive Committee, recently attended the National Cyanobacterial Workshop in Parramatta. Below are the notes that Colin has kindly provided to the Executive Committee for distribution amongst Water Directorate members.

NOTES ON NATIONAL CYANOBACTERIAL WORKSHOP HELD AT PARRAMATTA ON 12 & 13 AUGUST 2009
The workshop was hosted by the NSW Office of Water, DECCW, NSW Health, Sydney Catchment Authority and Water Quality Research Australia. I attended the workshop to keep abreast of the current industry position as the water supply source for the city of Armidale, Malpas Dam has a significant history of blue green algae (bga) blooms and periodic problems with taste and odour.

The majority of the presentations related to research being carried out on testing and monitoring processes and the remainder related to descriptions of actual events and some practical information for managers responsible for the management of recreational waters and town water supplies. As a manager in the water supply industry, the latter presentations were the ones that I found most helpful and interesting. More information can be found in the Workshop abstracts which are now available on the WQRA website at www.wqra.com.au under Meetings and Workshops.

The following dot-point notes summarise what I got out of the workshop.

• The Keynote address by Brett Neilan Uni NSW talked about his research into the identification of toxin producing genes in cyanobacteria and how this may become a practical means of predicting toxicity in the future. As we know, only a small percentage of algae blooms are toxin producing. If the toxin producing gene is present, then the bloom is likely to become toxic. Subject to timeframes for production of results and costs of testing, this could be the way of the future to get early warning regarding toxicity
• Sydney Catchment Authority is trialling “Phoslok” in small storages. Phoslok locks up phosphate in sediment so that it is not available to blue green algae to support blooms. Note that Armidale Dumaresq Council has considered this option but for the scale of Malpas Dam, treatment costs are currently prohibitive. Requires an initial treatment followed by periodic top-up treatments as required.
• Ian Stewart Griffith Uni questioned current practice regarding closure of recreational lakes because of bga blooms and potential toxicity. Divergent accounts of risk perception and messages to the public leave managers vulnerable to claims for compensation. Effective and consistent communication of the health risks that drive decisions to close a recreational waterbody is needed. Two recent examples at Logan SE Queensland and Lake Burley Griffin in Canberra discussed. The latter in particular had a major impact on users like the AIS rowing squad who had to move to Sydney at considerable cost.
• Rita Henderson Uni NSW described research that has identified a monitoring system that will ensure optimum performance of the coagulation process to remove bga cells. “Zeta potential” monitoring works with the potential difference between the fluid associated with the surface of a particle and the surrounding solution to determine the correct coagulant dose. Has the potential to work automatically on-line with quick response to changes in particle concentrations.
• Daniel Hoefel talked about an incident at a WTP in South Australia which started having trouble with taste and odour in the water supply after an “upgrade” at the WTP. It was discovered that the key change was the change to chlorinated water from unchlorinated water in the sand filter backwash process. In the old system, the sand filters acted as biologically active filters and effectively removed MIB and geosmin from the water whereas the new chlorinated backwash process killed off the biofilm allowing breakthrough of geosmin. Current research is looking into identification of the effective bacteria and practical means of growing the bacteria so that filters can be quickly re-seeded with biofilm after backwashing. There may be a potential here to seed main storages also.
• Gayle Newcombe talked about the international working party that is working on the development of an international guidance manual for the management of cyanobacteria. It is to be constructed on three levels – 1) Novice (overview, issues and general management strategies); 2) More detail (on specific management strategies) and 3) Case Studies. First part expected to be published by the end of 2009.
• Ian Falconer Uni of Adelaide talked about his concerns that there is often a ‘grey” area between the Guidelines and the quality of water supply. The utility may not measure the contaminant at all whether it is a cyanobacterial toxin or a pesticide so a harmful event may not be reported. An adverse event may be well past before it is identified. He also has concerns about the new risk management approach to recreational water use as recreational users do not want to give up their fun and risks are taken.
• The Wrap-up discussion focused on how we might better co-ordinate and share what is going on with respect to cyanobacteria and its management. It was agreed that a website should be set up which could serve as a means of sharing information, seek advice etc. WQRA agreed that they would set up this website. It was also agreed that the workshop / conference should become an annual event to promote awareness and sharing of information.
• A personal thought that I have taken away from the workshop is that maybe we need to be looking at the management of recreational use and the management of town water supplies as two separate management issues instead of trying to incorporate both into a single set of WD Action Guidelines. We can still have a single document but separate into two parts to get rid of confusion.
  

For more information contact: