Microbial Diversity and the Quality of Roof Harvested Rainwater

8/9/2019 Microbial Diversity and the Quality of Roof Harvested Rainwater

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Microbial Diversity and the Quality of

Roof-harvested Rainwater

C.A. Evans, P.J.C.A. Evans, P.J. CoombesCoombes, R.H., R.H. DunstanDunstan, T.L. Harrison, A. Martin,, T.L. Harrison, A. Martin,K.K. PigottPigott, J.N. Harris, J.N. Harris

School of Environmental and Life SciencesSchool of Environmental and Life Sciences

University of NewcastleUniversity of Newcastle

AustraliaAustralia


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Are nonAre non--pathogenic bacteria significant?pathogenic bacteria significant?

1. The treatment traineffect

Apparent improvements to the microbial and chemical qualityof water with passage through the collection system.


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Contaminatedrun-off

INLET

OUTLET

Improvedwater quality

Treatment train


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Are nonAre non--pathogenic bacteria significant?pathogenic bacteria significant?

1. The treatment traineffect

Apparent improvements to the microbial and chemical qualityof water with passage through the collection system.

2. Environmental bacteria comprise majority of organismspresent in rainwater tanks.

HPC >>> coliform counts - (orders of magnitude)

Bacterial composition influenced by wind patterns


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Wind direction/velocity & HPCWind direction/velocity & HPC

0

1000

2000

3000

4000

5000

6000

0 2 4 6 8

Wind velocity (m/sec)

HPC(cfu

/mL)

N

S

(r2 = 0.98, p


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Contaminatedrun-off

INLET

OUTLET

Improvedwater quality

Treatment train

Biofilm formation

Nutrient cycling

Chemical remediation

Competitive exclusionof pathogens


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OverviewOverview

1. Assessment of microbial diversity in 2 rainwater tanks.

Impact of hot water systems

Assessment of coliforms

2. Biofilm pilot studies

Biofilm development and the treatment train

In-vitro examination of Pb2+ uptake


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Microbial Diversity of 2 Rainwater TanksMicrobial Diversity of 2 Rainwater Tanks

Urban tank

Located in Newcastle (160kM Nth of Sydney) Duel 2.2kL galvanized iron tanks

Mains water top-up system

Hot water service set at 60C

Rural tank Located at Gulgong (250kM inland of Newcastle)

10kL aquaplate tank

Hot water service set at 50C.


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Table 1: Plate count and diversity summary

Tank Urban Rural

Sample type Cold Hot Cold Hot

Total no. of species identified 64 20 49 39

mean no. species/sample 23 3.4 8 1.2 16 2.3 14 4.3

Mean plate count (cfu/mL) 366 153 17 2.6 2263 1070 94 31


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Tank Urban Rural






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Tank Urban Rural






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Tank Urban Rural






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Tank Urban Rural






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Tank Urban Rural






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Tank Urban Rural






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Fig. 2: % composition of gram negative and gram

positive bacteria in samples from rainwater tanks.

0%10%

20%

30%

40%50%

60%

70%

80%

90%

100%

Ncle(cold) Gulg(cold) Ncle(hot) Gulg(hot)

Sample type

%c

om

position

G+ve

G-ve


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Fig. 1: Profiles of the Newcastle and Gulgong tanks basedon average counts of most abundant genera present.

0

50

100

150

200

250

300

350

400

450

Pseudom

onas

sp.

Serra

tiasp.

Delfti

asp

.

Janthino

bacte

rium

sp.

Yersini

asp

.

Bacillus

sp.

Unide

ntifie

d

Fungi

Herba

spirillum

sp.

Sphin

gomonas

sp.

Avge

count(cfu/ml

Gulg.

Ncle


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Faecal indicator presence and abundance relative to totalplate count

Sample type COLD HOT

Presence Avge % of Presence Avge % of

(% of samples) plate count (% of samples) plate count

E.coli 50 0.06 0.03 0 0

Enterococci 23 0.05 0.03 28 0.62 0.41

Faecal col. 77 0.52 0.27 28 0.62 0.41

Total col. 100 3.77 2.08 43 3.36 2.21


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BiofilmsBiofilms and the treatment trainand the treatment train

Location:Newcastle on east coast of Australia(approx. 160kM Nth of Sydney)

Tank Biofilm development Comment

A (G.I.) Advanced heavy slime layer with extensive clumping

B (Plastic) Moderate uniform slime layer around interior


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Table 3: Variation in bacterial counts between the tankwater column and tap outlet of tanks A and B.

Tank Sample type Bacterial count

E.coli HPC

(cfu/100ml) (cfu/mL)

A Tank water column 48 610Tap outlet 29 390

Improvement 34% 36%

B Tank water column 70 200

Tap outlet 60 160

Improvement 14% 20%


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Table 3: Variation in bacterial counts between the tankwater column and tap outlet of 2 tanks.

Tank Sample type Bacterial count

E.coli HPC

(cfu/100ml) (cfu/mL)

A Tank water column 48 610Tap outlet 29 390

Improvement 34% 36%

B Tank water column 70 200

Tap outlet 60 160

Improvement 14% 20%


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PbPb2+2+ uptake by inuptake by in--vitro cultivatedvitro cultivated biofilmbiofilm

E.colibiofilms cultivated in wells of perspex tissueculture plates for 72 hours.

Incubation broth replaced with sterile milli-Q waterspiked with Pb2+ (100ppb).

Pb2+ determined by ICP-MS at time = 0, 5, 10 and 20hours.


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Pb2+ uptake by in-vitro cultivated biofilm

40

50

60

70

80

90

100

110

0 5 10 15 20 25

Time (hrs)

Leadconc

.(ppb)

Biofilm

Control


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ConclusionsConclusions

Rainwater tanks harbour a wide diversity of microbial species.

Species composition may vary considerably between tanks atdifferent locations.

Species composition varies temporally at any given site.

Minimal evidence of faecal contamination.

Hot water systems deliver water of quality suitable for bathing.

Biofilms have capacity to chemically remediate water.

Class Order Family GenusPhylumSphingomonadaceae

Afi i

NovosphingobiumPorphyrobacter

SphingomonadalesB d hi bi


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Caulobacterales Caulobacteraceae Caulobacter

RhizobialesMethylobacteriaceae

Afipia

Methylobacterium

PorphyrobacterSphingomonas

BurkholderiaBurkholderiaceae

AcidovoraxComomonasDelftiaPolaromonasVariovorax

Comomonadaceae

Duganella

MassiliaNaxibacterHerbaspirillumJanthinobacterium

Oxalobacteriaceae

Ralstonia

Burkholderiales

AquaspirillumAquitaleaChromobacteriumIodobacterMicrovirgula

NesseriaceaeNesseriales

DechloromonasRhodocyclaceae

CitrobacterEnterobacter

ErwiniaEscherichiaHafniaKlebsiellaLeclerciaObesumbacteriumPantoeaProteusRahnellaRaoultellaSerratiaYersinia

Pseudomonadaceae

LuteibacterStenotrophomonasPseudoxanthomonas

Xanthomonadales

ClostridiumClostridia

Planococcaceae

BrevibacillusPaenibacillus

Paenibacillaceae

Staphylococcaceae

Bradyrhizobiaceae

RalstoniaceaeProteobacteria

Rhodocyclales

Enterobacteriales Enterobacteriaceae

Aeromonadales Aeromonadaceae Aeromonas

Chromatiales Chromatiaceae RheinheimeraMoraxellaceae Acinetobacter

MoraxellaPseudomonadalesPseudomonas

Xanthomonadaceae

ClostridiaceaeClostridiales

BacillaceaeBacillusExiguobacterium

Listeriaceae Listeria

Bacillales PlanococcusPlanomicrobiumSporasarcina

Staphylococcus

AerococcusAerococcaceae

CarnobacteriumDesemzia

Carnobacteriaceae

EnterococcusEnterococcaceae

LactococcusStreptococcaceae

Lactobacillales

Bacilli

FrigoribacteriumMicrobacterium

Microbacteriaceae

CorynebacteriumCorynebacteriaceae

ArthrobacterLeucobacterMicrococcus

Micrococcaceae

Gordoniaceae Gordonia

Mycobacteriaceae Mycobacterium

Nocardiaceae Rhodococcus

Streptomycetaceae Streptomyces

ActinomycetalesActinobacteria

Flavobacteriaceae ChryseobacteriumFlavobacterium

Flexibacteriaceae FlectobacillusHymenobacter

Sphingobacteriaceae Sphingobacterium

Flavobacteroidales

Sphingobacteriales

Flavobacteria

Sphingobacteria

Firmicutes

Actinobacteria

Bacteroidetes

Microbial Diversity and the Quality of Roof Harvested Rainwater

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