Measurement of the Decay of Microbial Pathogens in South East Queensland
Reservoirs
Simon Toze, Leonie Hodgers, Andrew Palmer, Darren Morrow
Purified Recycled Water Project
18 August 2009
Urban Water Security Research Alliance
PRW Project
• Project aimed to research safety and sustainability of PRW
• Project is divided into three research components– Source– Reservoirs– Advanced Monitoring
Techniques
Introduction to Pathogens in SE QLD Freshwater
Multiple sources of pathogens– Purified Recycled Water– Wastewater treatment plants– Farm animals and activities– Wild animals
Experiment Research Aims
• To determine pathogen survival in SE QLD freshwater sources– Persistence, what drives decay, major potential
sources
• To assist predictive modelling and management of pathogen risks in SEQ freshwater
• Research is being undertaken in partnership with Seqwater
Norovirus
Target Pathogens and Indicators of Interest
• Indicator Microorganisms– E. coli, enterococci, bacteriophage
• Enteric microbial pathogens– Bacteria
• E. coli O157:H7, Campylobacter, Salmonella
– Protozoa• Cryptosporidium, (Giardia)
– Viruses• Rotavirus, adenovirus, (norovirus)
Cryptosporidium
Campylobacter
Measuring Pathogen Decay
• Decay is measured In-Situ• Diffusion chambers used to retain
pathogens• Conditions within chambers can
be modified or controlled– Presence/absence of native
microbiota– Sediment– Depth
O-rings
Main chamberSize exclusion membranes
End plate
Screws
End plate
Injection ports
Methodology
Day 7 Day 14 Day 21 Day 35
Initial Results of Microbial Attenuation Bacteria
0 5 10 15 20 25 30 350
1
2
3
4
5
6
Log
cfu
mL-1
Time (days)
T90 = 7 days
0 5 10 15 20 25 300
1
2
3
4
Log
cfu
mL-1
Time (days)
T90 = 8 days
0 5 10 15 20 25 300
1
2
3
4
5
6
Log
cfu
mL-1
Time (days)
T901 = 2 daysT902 = 86 days
0 5 10 15 20 25 30 350
1
2
3
4
5
6
7
Log
cfu
mL-1
Time (days)
T90 = 2.5 days
Campylobacter
Salmonella E. coli O157:H7
Enterococcus
Initial Results of Microbial Attenuation Viruses and Cryptosporidium
0 10 20 30 40 50 60100
101
102
103
104
105
106
Ooc
ysts
mL-1
Time (days)
T90 = 45 days
0 5 10 15 20 25 30 350
1
2
3
4
5
6
7
Log
pfu
mL-1
Time (days)
T90 = 5 days
Cryptosporidium oocysts MS2
CoxsackievirusAdenovirus
0 10 20 30 40 500
1
2
3
4
Log
PDU
mL-1
Time (days)
T90 = 12 days
0 10 20 30 400
1
2
3
4
Log
PD
U m
L-1
Time (days)
T90= 4 days
Microorganisms T90 (days)In-Situ Laboratory
Enterococcus 2.5E. coli O157:H7 2; 86Campylobacter 8Salmonella 7Cryptosporidium 45MS2 5Adenovirus 12Coxsackievirus 4
Microorganisms T90 (days)In-Situ Laboratory
Enterococcus 2.5 3E. coli O157:H7 2; 86 6Campylobacter 8 NDSalmonella 7 NDCryptosporidium 45 84 (Giardia)MS2 5 8Adenovirus 12 8Coxsackievirus 4 ND
Decay Rates From First Experiment
Next Stages of Research
• Re-examine decay of bacterial indicators and pathogens
• Determine influence of native microbiota• Impact of sunlight• Influence of sediment• Start to incorporate findings into Seqwater
hydrologic models
Thank you
www.urbanwateralliance.org.au
