Centre for Plant & Water Science - Central Queensland University

Centre for Plant & Water Science 2008 Annual Report
THE MYCOLOGY OF THE ROCKHAMPTON TREATED WATER
SUPPLY
SUMMARY
A qualitative and quantitative study of the mycobiological population of all parts of the
water supply system was conducted over 18 months and has now been completed. This study
involved the collection and analysis of water samples monthly from nine mains stand pipes,
six storage reservoirs, and four sites within the Glenmore Treatment Plant.
Eleven physico/chemical parameters were also collected each month using a YSI multiparameter
water meter. Samples were processed by membrane filtration followed by plating
of the filter membranes on culture medium and subsequent enumeration and identification of
resulting microfungal colonies. Sixty three genera were identified. Treated water on exit
from the treatment plant was effectively devoid of microfungal contaminants but microfungi
were isolated from all other parts of the system. Those reservoirs which are secondarily
chlorinated on a regular and automatic basis yielded the lowest microfungal counts.
Multivariate statistical analysis will now be carried out to determine any relationships
between the microfungal population and the physico/chemical data collected.
The sources of microfungal contamination are currently being investigated. Possible sources
of microfungal propagules include airborne ingress to the pulse-filled reservoirs, and
sporulating fungal biofilm growing on the internal walls of reservoirs and pipes and in the
sediments accumulated in reservoirs and pipe dead ends. Coupons of glass, PVC and
concrete have been immersed in two reservoirs to study the formation of fungal biofilm.
Examination of surface deposits by micro-filtration and culture, fluorescent staining, and
microscopic examination using light, scanning electron, and fluorescent microscopy
techniques are being used. Preliminary results indicate that there is no sporulating
microfungal biofilm within the system or on the coupons. This work is continuing.
The possibility that microfungal spores survive the treatment plant processes, but in a
damaged state, and are subsequently capable of resuscitation is being investigated by
subjecting chlorinated fungal cultures to antioxidants known to protect spores of some
species. Preliminary results indicate that resuscitation does not occur.
Future work will include an examination of the role of coagulation/flocculation and sand
filtration at the treatment plant. Preliminary tests have shown that polyaluminium hydroxide
flocs are very efficient at entrapping microorganisms.
Fig. 1. Mains sampling standpipe Fig. 2. Fluorescent micrograph of floc Fig. 3. Coupons ready for immersion
showing entrapped microrganisms
PROJECT STAFF Principal Investigator: Noel Sammon
Co-Principal Investigator: A/Prof. K. Harrower
Others:
A/Prof. L. Fabbro & Prof. R. Reed
FUNDING Fitzroy River Water & CQUniversity
INCOME $8,879
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