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Technical Report WRD93040

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Report No: 40/1993 A

/LREYONGA

BORE REHABILITATION

JOHN 1'ii7JSCHUSEN

nYDROGEOLOGIST

WATER RESOURCES BRANCH, ALICE SPRINGS

February 1994

!?)I j ~SO /0 77Y--

2 q l-., ~

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1. INTRODUCTION

Areyonga is situated 270 kIn west of Alice Springs (figure 1). Water supplies are

drawn from several bores drilled along rocky creeks. Technical details of these

bores are shmvTl in table 1. As operation problems associated 'With declining bore

yields were reported. Technical Support Branch of the Power and Water Authority

requested Water Resources Branch (WRB) of the same Authority, to investigate

remedial action to restore bore yields.

2. NAlURE OF PROBLEM

Since the last of the five production bores was drilled in 1974, all bores have been

proved to have decreased in yield. Although this problem was clearly identified in

1982 when all bores were retested, operating problems became significant when

several bores were decommissioned, and the highest yielding production bore (R1\l

10774) was susceptible to periodic failure due to fouling of pump components.

Available drawdown is over 90 metres in RN 10774, hence no major dewatering of

the aquifer was indicated. Similarly, monitoring records showed little or no decline

in regional groundwater level, hence decline in bore performance was assumed to

be associated 'With physical deterioration of bore casings andj or the aquifer, rather

than a shortage of water resources. Indeed, recent research (Jacobson and others

1989, Brown and others 1990) indicates groundwater \vithin the Hermannsburg

Sandstone to be a paleo resource with through flow maintained by head decay from

Tertiary recharge.

In 1992, it was reported that sludge like deposits were fouling the pump of the main

production bore, RN 10774, causing the bore to fail. The deposition qf sludge like

deposits are commonly associated 'With the precipitation of iron hydroxides,

particularly in areas of high iron groundwater such as Areyonga. The proliferation

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of iron bacteria and/or encrustation are commonly cited as the factors known to

cause iron hydrOxide precipitation. While Howsam (I990) notes iron bacteria may

be associated with deposition of a biofIlm (i.e. organic rich deposits) many iron

bacteria initiate/enhance the formation of iron deposits.

Thus it was not knovm exactly what caused the decline in bore performance at Areyonga but the recorded symptoms of:

* *

Sludge deposits on the low water pressure point at the pump intake on RN 10774,

The presence of oily fIlms on water pumped from the bores,

The voluminous nature of deposits needed to be cleaned from pump columns over the years

are consistent with contaJ:nillation by iron bacteria (WRB info sheet).

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3. TREATMENT

The normal (most cited) method of treatment for biofoul bores is dosage with acid

to bre~ down biofilm and iron deposits, then treatment with a biocide such as

sodium hypochlorite to kill bacteria (Driscoll 1986).

Howsam (1990) recommends physical cleaning of a bore before the application of

any chemicals as the majority of biofouling problems are associated wim large

amounts of insoluble iron compounds which can be reSistant to the action of

chemicals. McLaughlan (1993 pers. com.) also notes physical cleaning (e.g.

airlifting, brushing etc) of bores is often the most effective part of any remedial

action with up to 80% of biofilm mateIial commonly removed.

The use of acid (HCl) at Areyonga was originally planned as experiments by

McLaughlan (1992) showed HCl was the most effective reagent when compared to

five propIietary chemicals on iron biofoul depOSits, however as problems with

handling and waste disposal were antiCipated alternative treatment methods were

investigated. After consultation with several other state water Authorities, it was

decided to hire high pressure jetting (HPJ) equipment from the West Australian

Water AuthOrity (WAWA). Discussions with Bob Buwyer (1993) about the use of

HPJ in Western Australia were so positive that this method, which also conveniently

avoids most waste disposal problems, was adopted for use at Areyonga. The

effectiveness of HPJ as a cleaning process is confIrmed by Fountain and Howsam

1990. The treatment program for bore rehabilitation at Areyonga, which was based

on WAWA work practices, is presented in Appendix 1.

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4. RESULTS

Pre Rehabilitation

Flior t9 treatment, chemical properties of bore water were measured in the field by

Mike Law-ton of the Water Quality Section. These measurements were taken with

a small pump from around 50 m in each hole. These measurements and full

chemical analyses of samples taken along with typical analysis from the bores when

operating are shown in Appendix 2. Figures 4 and 5 show caliper logging of both

holes prior to treatment. Bore RN 10774 was shown to have Significant reduction

in internal diameter particularly around zones 2 and 3 as defined by McLaughlan

(1992) and annotated on the bore construction diagram (figure 3).

Rehabilitation

Plots of the bore specific capacity tests conducted after each stage of rehabilitation

works, as programmed in Appendix 1, are shown in figures 6 and 7.

On examination of figure 6 it can be seen Bore RN 10774 performance improved

after the high pressure jetting run while chlorination had little if any effect on bore

performance. From the 1981 test data also shown on figure 6 it can be seen that

Significant improvement of bore performance was gained after airlifting this bore

with bore performance subsequently further enhanced after high pressure jetting.

The plots of specific capacity tests conducted on bore RN 2830 after rehabilitation

treatments (figure 7) are in complete contrast to those for bore RN 10774 in that

bore performance is observed to have decreased after each rehabilitation treatment.

The decrease in bore performance after the HPJ run was, at the time, thought to be

a consequence of the difficulties encountered in operation. That is, excessive hole

crookedness did not allow simultaneous operation of both HPJ and airlifting as

reco=ended by WAWA. HPJ without simultaneous airlifting was found by

Packman (1990) to actually reduce well yield in some instances; reduction in well

yield being attributed to remobilised "fines" clogging aquifer outflow. However the

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further decrease in bore performance following chlorination and further airlifting of

this bore suggested some other factor may have affected bore performance.

The most plausible explanation is that heavy rain, which caused the adjacent creek

to flow at the start of operations. contrtbuted additional yield to this bore which

then progressively declined has overprinted the test results. This additional yield

may have been from creek subflow entering the bore down the annulus between

open hole and casing or through a set of perforations near the top of the hole

unrecorded on drillin.g records, but vaguely alluded to ill correspondence (WRB bore

me Rt'J 2830) at about the time of drilling 1961 and also possibly displayed by

caliper logging between 7 - 13m (see figure 5). Thus the detrimental affect, if any,

of not airlifting during the HPJ run is not discernible. Conclusions as to what, if

any, improvement of bore performance resulted from rehabilitation work is also not

discernible as historical data is not being readily comparable to the double rate

specific capacity tests conducted in response to a noted lack of drawdown during

the first test following airlifting. The similar yields and drawdowns of the 1961 test

compared to the after chlorination test (figure 6) indicates no dramatic improvement

in bore performance was obtained.

This eVidence that bore RN 10774 may have been more effectively rehabilitated than

RN 2830 is confirmed by examining the calliper logs of each bore pre and post

treatment, as shown in figures 4 and 5. From this data it can be seen that while

bore RN 10774 had significant reduction in bore internal diameter prior to

treatment (figure 4) bore RN' 2830 was apparently less clogged prior to treatment

(figure 5) hence potential improvements from rehabilitation may have been much

less (as indicated on performance data figure 7) for this bore.

Analysis

Samples of scale airlifted from each bore were analysed by the Northern Territory

University. The results of these analyses are shown in table 2. The composition of

these scale deposits is different for each bore, with the unexpected significant

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percentage of aluminium silicates in RN 2830 perhaps a consequence of the periodic

contamination by aluminium enriched surface flow water. The prescence of

anhydrite crystals in RN 10774 is also unexpected (table 2), it may be associated

with tJ:;l.e Parke Siltstone mineralogy at this depth.

The low percentage weight loss on ignition of these samples (table 2) is indicative

of a chemical encrustation origin of this scale and not a bacterial precipitation (Le.

McLaughlan 1992 found around 10% of organic matter could be expected in biofoul

deposits from Wakool NS\V).

The results of commercial bacteriological tests (BARIS) run pre and post treatment

shown in table 3 show iron related bacteria to also be present which, while not

obviously producing large volumes of clogging biofilm, may contribute to chemical

encrustation by acting as a catalyst to ferry hydrite precipitation as discussed by

Tuhelae and others (1993).

The presence of iron related bacteria both pre and post treatment COnTIrmS the

difficulty of eradicating bacteria by chlorination as noted in various case histories

presented in Howsam (1990). Consequently, as the analyses presented in table 2

indicate a "chemical" rather than a bacterial influence on scale build up in these.

bores, the continued presence of iron related bacteria (table 3) does not necessarily

mean the rehabilitation treatment were ineffective.

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5. DISCUSSION

Analyses of scale deposits removed from both bores during treatment indicates the

loss o~bore performance is probably due to chemically induced precipitation of iron

compounds rather than bacterial growths.

The existence of iron bacteria is noted by both Hem (1989) and Howsam and Tyrrell

(1990) to be eA"pected wherever high iron groundwaters are encountered. Thus the

positive identification of iron related bacteria by kits such as the BART system,

(Mansuy and others 1990) does not necessarily indicate the nature of any iron

related bore yield problem.

In fact, Walters (1994) notes that the first stage of any suspected iron fouling

problem should be microscopical exanrination of sludge/clogging material to

ascertain whether a biological or chemical problem is present. This approach to

determine the appropriate treatment was not available at Areyonga as no sample of

the reported clogging sludge was obtained for exanrination.

Hem (1985) notes iron problems (chemical or bacterial) occur when conditions are

suitable (i.e. Eh - Ph, iron source, figure 8) for the precipitation of ferry hydrites.

Thus any induced change to the chemical conditions within a bore that are

favourable to precipitation of ferric compounds should be avoided or minimised.

For example a change in bore operation that allowed less oxygenation of water

hence less likelihood of Fe3+ precipitation by decreasing drawdown may prove a

more economical long term strategy, as expensive short term iron related

rehabilitation works may be avoided.

The use of HPJ treatments at Areyonga was appropriate in that this physical

cleaning method was expected to be equally effective no matter what the origin of

the iron problem. However, the application of Sodium Hypochlorite as a disinfection

agent, which is \videly recommended at the first sign of iron problems, may not have

been appropriate as most of the free chlorine has the potential to combine with iron •

to fonn ferry chlOrides.

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The fOnTIation of ferry chlorides could then have the affect of discolouring water red,

using the free chlorine intended to kill any iron bacteria and potentially damaging

bore infrastructure due to its corrosive nature (Walters 1994). The above

consiqerations may explain the apparent ineffectiveness in reducing the presence

of iron bacteria following rehabilitation as indicated by the BART results. However

it should be noted that Walters (1994) states the amount of iron bacteria in any . - -

pumped sample can fluctuate widely with time during pumping, and by far the most

diagnostic time to sample for iron bacteria is immediately on starting the pump after

a long period (1 - 3 days) ofinoperation.

The potential for chemical conditions favourable to the precipitation of ferric iron

compounds to exist in these bores was recognised prior to treatment. RN 10774

which is constructed with perforations both above and below the pump setting

(figure 3 ) was immediately noted as having the potential to cause iron problems.

For instance, once drawdown exposed the upper perforations, cascading ox.ygenated

'.v-ater may then create conditions move favourable for dissolved ferrous (Fe 2+) ions

to be oxidised to the insoluble ferric (Fe 3+) state. Also, the potential e.xists for water.

derived from the underlying (de-ox.ygenated?) sandy units within the Parke siltstone.

shown on the ganuna log (figure 9), to mix with water from overlying (ox.ygenated?)

Hermannsburg Sandstone aquifer during pumping. Mixing of different aquifer

waters could then create chemical conditions favourable to the precipitation of iron

compounds.

Similarly. the upper perforations deduced to exist in bore RN 2830 could also cause

chemical conditions to change with cascading water and occasional mixing of

surface run-off not unexpected.

Consequently it appears both bores RN 2830 and R1\T 10774 are unfavourably

constructed in that chemical conditions for the precipitation of iron compounds are

easily envisaged during pump operation. [It should be noted that many iron

bacteria are an anaerobic and can thrive given an organic carbon source. Indeed

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the common autotrophic bacteria such as Gallionella that utilise inorganic carbon

(Co2 ,H2 CO,J are less suited to the high (27°C) temperature groundwater atAreyonga

than heterotrophic bacteria such as crenothrix that use an organic carbon source

(Walters, 1994). Thus rnixing of water from upper aquifers within a bore can in

some cases can supply organic carbon thereby also increasing the likelihood of iron

bacteria proliferation].

Several possible methods are available to reduce the amount of mixing of water in

different oxidation states. For instance McLaughlan (1993 pers comm) notes that

use of anoxic rubber blocks set above the pump may be one way of negating the

affects of cascading water. Infilling upper perforations by cementing between

packers then drilling out the plug could also reduce cascading water, however both

these remedies could not prevent water cascading down the casing annulus. The

most obvious effective remedy would be to reconstruct both holes with the upper

aquifers cemented off. Reconstruction which may not even be feasible as the old

casing may prove impossible to shift is, however, likely to be a very expensive

remedy.

Given the likely causes of excessive chemical precipitation in these bores has been

identified it may be possible to operate these bores in such a way as to limit, if not

remove, the amount of chemical precipitation occurring. Such a st'ategy may then

allow less maintenance (pump cleaning), which in turn may prove more cost

effective than reconstruction.

Thus the most immediate remedial action is to pump these bores at lower rates for

longer periods. This action should lower drawdowns and pump entrance velocities

and, as it may prove effective, would seem prudent before committing funds to

reconstruction works. The feasibility of this method has at least initially, been

confirmed by operational measurements taken at bore R!.'J 10774 in February 1994,

where drawdown in bore RN 10774 was noted to be 5 metres above the top

perforations after pumping this bore for several weeks at 1.5 Lis (R DecetAES pers

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comm). This demonstrated capability of operating RN 10774 with reduced

likelihood of chemical precipitation implies any decision on future work should be

delayed until the success or otherwise of this reduced pumping rate remedy is

assessed.

6. RECOMMENDATIONS

• Rl~ 10774 should be pumped. at rate no greater than 1.51/s.

• RN 2830 should be pumped at a rate no greater than 0.6 l/s.

• Should operation of bores at the above rates still require an unacceptable

frequency of maintenance, reconstruction/redrilling of production bores

should be considerd

•

•

The reasonable yields of potable water obtained from holes drilled in the

Mereenie Sandstone leg RN 6968 2.3 L/ s 670 IDS J and very high yield ofRN

10757 [10 L/s 1 suggest this aquifer should be further investigated,

particularly as better aquifer characteristics should limit Iron problems.

The possibility of an organic carbon source such as leaf or animal matter

entering the hole should be minimised by sealing the bores at the surface.

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7. CONCLUSIONS

• Chemical iron fouling of production bores RN 2830 and RN 10774 has

pccurred.

• HPJ rehabilitation has restored RN 10774 perfonnance. results of

rehabilitation at RN 2830 have been complicated by additional temporary

bore yield due to creek flow.

• HPJ is a viable rehabilitation method for some iron fouled bores.

•

•

Both bores are unfavourably constructed and should be operated at lower

yields for longer periods to reduce drawdown.

As iron related bacteria can be expected h. any high iron groundwater. the

nature of any iron fouling problem should be assessed by microscope

exaxnination prior to treatment.

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10. REFERENCES

BOWYER, R, 1993 - Supervising Engineer, Drilling Section, West Australian Water

Authority pers comm 18/6/93.

BRo\VN, D.M., LLOYD, J.W. & JACOBOSON, G. 1990. Hydrogeological model for - -Amadeus Basin aquifers, Central Australia. Australian Journal of Earth

Sciences 37, pp 215 - 226.

DECET, R, 1994. AES (Aboriginal Essential Services) NT Power and Water

Authority, Water Operations Supervisor, Alice Springs pers corom Feb. 1994.

DRlSCOLL, F.G., 1986 - Groundwater and Wells. 2nd edition. Johnson Division

St Paul, Minesota, USA, 1108 pp.

FOUNTAIN, J. & HOWSAlV1, P. 1990. The use of high pressure water jetting as a

rehabilitation technique. In Howsam, P. 1990 (Ed) Water Wells, Monitoring,

Maintenance, Rehabilitation. Chapman and Hall, London 422p, pp 180 -

194.

HEM, J.D. 1985 - Study and interpretation of chemical characteristics of natural

water 3rd Edition. U.S. Geological Survey Water - supply paper 2254, 263 pp.

HOWSAM, P., 1990 - Well performance Deterioration. An introduction to cure

processes. In Howsam , P. 1990 (Ed) Water Wells, Monitoring, Maintenance,

Rehabilitation. Chapman and Hall, London 422p. pp 151 - 157.

JACOBSON, G., CALF, G.E., JANKOWSKI, J. & MCDONALD, P.S" 1989.

Groundwater chemistry and Paleo recharge in the Amadeus Basin, Central

Australia. Journal of Hydrology 109, pp 237 - 266.

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MA.NS1JY, N., NUZMAN, C. & CULLIMORE, D.R 1990. Well problem identification

and its importance in well rehabilitation. In Howsam. P. 1990 (Ed). Water

wells, Monitoring. Maintenance. Rehabilitation. Chapman and Hall. London

422 p. pp 87 - 99.

MCLAUGHlAN. RG .. 1992 - Fouling and corrosion of Groundwater Wells in --Australia. Phd thesis. Department of Applied Geology. University of NSW

(unpublished) 209 pp.

MCLAUGHlAN, RG., 1993 - Researcher at the National centre for groundwater

management. University of Technology. Sydney. pers comm 16/7/93.

PACKMAN. M.J., 1990 - Borehole yield development techniques in an iron rich

aquifer. In Howsam. P. 1990 (Ed) Water Wells. Monitoring. Maintenance.

Rehabilitation. Chapman and Hall. London 422p. pp 195 - 208.

TUHELA, L.. SMITH. SA & TUOVINEN, O.H .. 1993. Microbiological analysis of

iron-related biofouling in water wells and flow cell apparatus for field and

laboratory investigations. Groundwater Vol 31 No.6 pp 982 - 988.

WALTERS. Reg. 1994 - Senior Microbiologist Engineering and Water Supply

Department. State Water Laboratory. Adelaide ,South Australia pers comm.

during several days of in-house PAW A seminars. Darwin.

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11. ACKNOWlEDGMENTS

I am indebted to the follov.ing people for their help during planning and reporting

of this project.

Bob Bowyer, WAWA, Rob McLaughlan UTS Sydney, Mike Lawton, Water Quality

Darwin, Mike Brennan SADME, Reg Walters E.W.S. SA

Thanks also to Avis Wiegele for drafting, diagrams, Caroline Towers for ty-ping and

the patience and cooperation of the WRB drilling crew during the project.

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Tables

Technical R

eport WR

D93040

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t" "'~"\ I" "" "II " ,.,

j

-BORE DEf'I'H YlI,W US 8WJ.} M'

(M) AlRLIFr RECOMMENDED RECOMMENDED IUlCOMMENDED ORIGINAL 1982 1994 ORIGINAL 1993

2830 108 1.7 2.5 1.5 0.6 0.6 1.92 .. .

10774 180 B 25 2.5 1.5 1.5 1.5 ._,-_ .... -. . . TABLE 1 TECHNICAL DETAILS AREYONGA PRODUCTION BonES

-. - . . % NOIlMAUSED 1'0 SUM OF 100% FOil OXIDES SHOWN

BORE SAMPLE DEPrn 8 1°2 AI20a F,O CnO . S03

10774 173 1B.B7 2.35 69.85 2.69 6.76

18.62 5.28 69.31 2.72 7.06

Pnmp Impeller 53.48 30.64 n.d. 2.9 13.08

162 (sludge) 9.99 1.06 66.fiB 2.22 20.15

Anhydrile cryslnls 11<1 0.68 0.83 37.46 61.12

2830 103 40.93 26.15 28.89 1.86 2.68

40.B2 25.36 28.68 1.67 8.67 ._.- _.

TABLE 2 XBAY -ANALYSIS RESULTS

BORE DEPTH LOSS ON IGNI1'lON @ 400'c

2830 103 2.8%

10774 162 1.3% ,

173 4,9%

TABLE2A LOSS ON IGNITION lmSULl'S

Technical R

eport WR

D93040

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!lORE

"

?1l30

10774

BORE

2830

'fABLE 3

I

1

------

I~'--'Ii , --"j I,"'''' ".

----

PRE REHABILITATION JJAO'fllRlAb AC'I'!VITY NO'l'ICED (DAYS)

mON SLIME

WlTHJN 3 DAYS WI'!'HlN 3 DAYS ,

Wfl'IIIN 3 DAYS WrrHJN 3 DAYS

P081' REIIABILI'l'A'l'ION BAC,"l'ERlAL AO'l'M'l'Y NOTICED (DAYS)

mON SLIME

2 3

2 2

------ -------

,

JNTElU'llETATION

SULPHUR Significant but not aggression population equivalent to 104

coliform in both bores

Wl1'HlN 3 DAYS

WlTIIJN 3 DAYS

IN'l'ERPRE'rATION

SULPHUR Significant population not nggrcsivo equivalent to 104

coliform in both bores

3

2

BACTERIAL AC'fM'l'Y RMGENT 'fESTS


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Figures

•


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---------- ....... --

L

-----........

Brnc,' H,II ~.n

• A!Tp,u Hili sn

SCALE 1:2 500 000 1<llomelles 100 50 0 100 200 KI(ometres

~====c=====~=I~==============1 ============~I

.NORTHERN

I TERRITORY

l I Tennant Creek

•

J . I '%

"'.,. J AREYONGA

L._. ALICE SPRINGS

I I I

.-._.J

AREYONGA

LOCATION MAP

FIGURE 1


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1 1

AREYONGA BORE LOCATIONS

~ W

100 0 100 1

metres

RN 2830 ~.

RN 10774'

FIGURE 2

3434-10-084


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, ,

,

\

-i ,

50m -

59m -

75m

85m

97m -

ZONE 3

ZONE 2

ZONE 1 T.O.180m -

AREYONGA RN 10774

ySWL

vv2 Lis C"-

o 0

~

Q)

E ... III

0 ~ 0 ~Cl

0": ... ~ 3 LIs 0 o III V\r

0 0

0 11');; 0

0 III 0

PUMP SETTING

ZONE -100m

0 0 vv4.5 Lis 0 4 0 0 0

0 0

c 0 0 c

0 0

c 0

0 0

0 0 c

0 0

0 0 0 0

0 0 203mm steel 0 0 casing 0 0 0

0 0,

0 0

0 0

0 0

0 0 0

0 0

0 0

vv8 Lis 0 0 0

ZONE 1 Near bottom of screen ZONE 2 Mid section of screen ZONE 3 Top section of well screen ZONE 4 Pump section inlet ZONE 6 Discharge side of pump

Zones from Mclaughlan (1992)

RN 2830

7m -

13m -

possible perforations

79m-

96.6m-

108m_ T.D.

0 0 0

0 0 0

0 0

PERFS RN 10774 RN 2830

" SWL

PUMP SETTING -80m

"'-"-2 Lis

152mm steel casing

- ~

50 to 59m 79 to 96.6m 75 to 85m 97 to 180m

V\r. = Airilft yield when drilled

FIGURE 3


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AREYONGA - RN 10774

I I CALIPER

I I I I 6.000 inches 10.00

, B.OOO

SCALE: 1 to 800 without depth correction I I J I I I

1"' - --f- - .. - .--. ---. -J-

1- Prior to treatment - ... "$- .-~

( --< ,

e-- h

L- --~-- --t~~ t

--I

e--

f-.

f-. t ;

I I

r --

I , ,- --...

I , I r I , L + I

~~ i -""--~ I

e--- -~..:",:'- -- ---.--.- '-'-'-1-<- --f-.- -~ ..... ~~:::..'--.- -- --.... - ... -- .... _- ... -.--. ---, - .. - ..

CALIPER I I I

inches 10.00

Log starts at: }I I '1 I ?---__________ ---1

r Post treatment -?~- - :--.. -._. --_ ... __ .-.,. ~"',~==~======~--------~ -->.-

<:~ .. ~ .. - _. -_ .. _._.- .. - .... ---, <;

< •

,,~

~ ,- ~~--- --_.- -.-.----~----~-,...-~-.;r=---------------?--

- ~.-------.. ---- -.--

t 0':; " __ C'_ . ________ . __ . __ .,: ~.

~f

? }'. ---r..---------~

"'-...... =-s------- .. ---.-.----1 === I ~

i----~ ------ .. --. -- ---' -- -:c~ ~- . - --_$- ---- --- - -. -- -e-....-.... -.- =

~

~ ... 'C ~ "'""f¥---

-" .. ---=~:::;;-~·5~-- ----- ------f-.-- .... ---'--=~--------1 ;:-~- ~ -<->.

---cf -<-.

C..H. ----. --'2:.- .- .------------... ----j .. - - ~ . i

~. -~: . . _ .... _._-,,""-=-._-----._----_._-

Log ends at:

O.g6m

40.00m

80.00m

120.00m

160.00m

180.g6m

FIGURE 4


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AREYONGA - RN 2830

CALIPER 1 •. 000

I 1 inches 8.000

14.000

SCALE: 1 to 600 without depth correction

! I 1 '.E:":. I r 1- 1 I ~ _ _I I -) Prior to treatment I J----. ---- ---1.--.- --... -. - - -r

~r t ~, -il I -{L 1 \ i

)~, .} .

--7"·' .. -. ~ - .---- -----7~----- --t.

- -. ~~-~ ---_. -,-

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-\ ,~

r ""t -. ~ .,

_I

1 '--1 .

···T ,

._i ,

CALIPER , inches

I 1 8.000

Log starts at: O.SSm I:;:: 1

,-s--I I

-~ - ..--~ -- ------_. _ .. _~l-~-~:t tre.atment

-- --t .------.--.--... -f ..... -.- .-- --';-or-

f . -.. '-'r-'-' -. -- --.-;-, j ; 1=-"--- . -. -. ---.. -.. --. ;>

__ J ______ . ___ . __ . ~-

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'.

t , .. f ,

J;. , %'<

.. ----... -_. ---

.--- ... -... _ .. -._---'

30.00m

60.00m

SO.OOm -' .1 -- -.-- _. :.;~-:-~= --._ .. - --_.- .-. - ! ----~----. - """3:--._------

" ", 0(- .:t. >: .--.--... ----1 ? ,

I _._---- .. _------- ._-.- --.. J , I

< I , I I I . !

Log ends at: 105.84m

FIGURE 5

Technical R

eport WR

D93040

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age 25 of 39.

o l I 1 1 I I 1 I I I I 1 'I' T~----.j, 1 1 1 1+1 I I +-I-H I· 1 1 1 1 1 1 tl

tl f-----~ I--~ t---eJ-f-f 'P <p q; '" J!I-------I I I 1-/--1 I H-t-+-H

tl lj

!------~--+--------+I -----+-1 ---1r!--±--t-+,~ 1 r--~--l--I---I----i I I I I -j I I 1 1 1 1 1 o

1.0 I -----1 I---I--I-+-~h-I '" X * ~ t 1-+~H 1 1 1 /-~ ...... I/)

<1> ... +" <1> E ~

z 5: o

tl 1 1 I 1 I I I 0 ---r~--"---r----I- -I---i t t ~ r 1 -j 1 1 1 I-H o tl

o 1----·-·-·----··--·-·····1·---·--·-1-·- +-+ --H-I-H'I o

X

'" - ---------,-----,------,.----,--. I I I --l-------I---~I----J_-I_--+-H-_j I --/-+---1 1 1 1 ,--- --~.--~--.----~.-----

tl

~ 2.0/ I : I r-'--'--" -~ lu __ ~+ I Iii / I 1---·-·---+ 1 / / / !--+-0:: Cl i---------~~_+___---+--+·--I--++-+-++------------ 1 ~ 1----1-+ 1 + 1 -I I I I 1 1 I

l- AREYONGA --"- --~-I 1 1 I~--' ·--'-tl-I--I-- j I I j 1 -I I - +--/ I I I-+-I

'" I--- RN 10774 --,---·,---,--,-t-++- - ·--t I II-H--j-~- - I--------j I H-t---H

3.0j.:.. LEGEND - 1 I I -++-++--1----/-/-1--+ / / / /-- l------t---l I I t--I o

I--- 1993 REHABILITATION PROGRAM ~

" Aller Airlill '1 st Test J I--- 0 After Jetting 2nd Test - at 0.9 Us f--- --/-- 1 I I H f-- I I I 1 1 I

X After Chlorination 3rd Tost 1981 TEST

--.-.,----,-----, I I I I I 1--- +-,1 I I I I I

I--- tl 1981 Tost at 0.7 IJs ------,-------+-----1 I I I H-+--------- - I I I I I~ I (NB: 100 min reading = 4.87m) I I I 1 I

4.0 1 I I I 1 1 I L........ 1000 1 10 100 ., -(j)

C :tJ m C1:>

TIME (minutes) tl

o

SPECIFIC CAPACITY TEST

FIGURE 6

Technical R

eport WR

D93040

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age 26 of 39.

0.5

1.0

1.5

c;:; 2.0 4l .... ..... <))

E ~

Z 2.5

~ Cl

~ a: 3.0 Cl

3.5

4.0

;,' ,,~

~.~ .. -- 1L- --- ~.~

0 0 -

x -- - .-- .

x & 1---- !-- '" -------... ' ___ 0 - -.-.

~~ I

.j 1---- -J:,. •

P< , tJ

!--..... _-- ... " .... ". ---,- - ........

x 0

--.. ~,--- --- --~.--~- - ----~ --, ........ --.. - f-X---.

x - . -,_.- ._-._"--

X tJ

X 1-.- - -~""- -- -_.-1- - - ... ~-'"~"- X· ---- --

~ 1---. .... -- ........ - --- .- .'-.---_.'- -,- ,--~ -_._-(J. __ .- ._-

1---.... X 1-. AREYONGA- --,--~ . . - ---'_.- ._-

I- RN 2830 --_.----- _ ... _-'----- -~--- .. -- ... _---- .1-

I- LEGEND -. ... ._---------_.-- ,-.---"--'-- ,-~

1-_ 1993 REHABILITATION PROGRAM - --~--... A After Airlift 0 After Jetting 2nd Test .. then 1.0 Us for --

--I---

" " -_. --

9 ---0

... .- - -

--'-- - ...

x

P

x After Chlorination

1st Test } 0.5 Us for 30 mins

3rd Test 90 mins _. ----- I--

4.5

" @ 1 ::x:J m "'-oJ

---1961 TEST

,

0 1961 Test at 1.1 Us

(N~: 120 mir~ readi~g = ~ .3~m) I I I I I

. 10

TIME (minutes)

- -.

to

.- _.

- _._ ..

0

_._- .-

X

--

...

-- -

"" _ ..

-. -- ~- -- -

... -

. .... -0

- - ... ---~~- --~---."-,-

0

..

Xx

100 1000

SPECIFIC CAPACITY TEST FIGURE 7


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()')

I--" 0 > z ~

'"

1.20

1.00 Fe3 + · • 2 +. :FeOH: · . · · 0.80 · -- ... -.. ~

.<

0.60

Fe 2 +

OAO

0.20

000

·0.20

·0.40 I

. .

Water oxidized

'-."'-

""'1'"",-

.. ~-~~-.. F,.(()H)3

! ""'-! '---

. ".--. - -.

FeO

-----~

·080

""' ""'-FeS -----

Water reduced

pH

Fe(OHJ~

--_J FeIOHI"31-

Fields of stability for solid and dissolved forms of iron as a function of Eh and pH at 25°C and 1 atmosphere pressure. Activity of sulfur species 96 mg/L as SO}-, carbon dioxide species 61 mg/L as HCO;, and dissolved iron 56 iJ.gJL.

(after Hem, 1985)

FIGURE 8


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» :0 m

" -< 0 - ~ z

" 5 G) c: » '" m

" -

GAMMA I I

0.000 'PO

1 j GAMMA

I I 1 1 0.000 200.0

SCALE: 1 to 500 wIthout depth correction Log starts.at: D.eOm

!;> 1-'; 1-;(-..... -.. --. - ..... ~ .

4 --.--- -'._--l . ·t -1: f .. ,

r~ • t , ~~

1 •. /

. _._._---_ ... _._-----

:i 25.00m

I . __ ... __ ._ .. _._. ___ J ~j '.,

_1 .. -... -.. -... -.----.-- .. _--- .--- I ". . ...••.. -- •.• --._--. --.----

! "¢ '" .. _. -+- ,,;:.- .. _. -- , .. _._- ----------~

it 50.00m

! 'k _. -. ..-:-{. - - --- . __ ._-------,;:

----- ~-... -.. -.-.----.------_'_l ~

- '~. /

-

-I ~: "

! ::~.-75.00m

10Q,QOm

- ._,-

T T

125.00m

t 150,OOm

- -_ .. _-.. _ ...... - .... -- .----------.--1

-_ ... __ ._------------j t . -. .. -.- ------ ---.,,-"---. 17S.00m


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I I I

Appendix 1

Bore Rehabilitation Work Program

- -


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I I r -

13/07/93

BACKGROUND

AREYONGA BORE REHABILITATION

REVISED WORK PROGRAM

92.3 P3

John Wischusen

The work program for this job has been revised following concern on the use of toxic

chemicals and in light of additional information obtained on biofouling treatment from

the Western Australia Water Authority (WAWA).

Rather than the use of large, volumes of acid as a reactive agent on biofilm deposits,

WAWA have found that physically cleaning biofouled bores by high pressure jetting

is a far superior method. The ease of operation and reduction in potential waste

disposal problems make this a safer option for use at Areyonga. In addition, the

suitability of this environmentally safer method will be assessed, which will be of

benefit when future decisions on appropriate biofouling treatments elsewhere in the

Northern Territory need to be made.

Consequently as Water Resources Branch (WRB) are not equipped to conduct high

pressure jetting it is proposed to hire the necessary equipment from WAWA. This well

necessarily confine the timing of this job to equipment availability.

PREPARATION WORK

To facilitate operations in the limited space available near production bores RN 10774

and RN 2830 at Areyonga, it will be necessary for Aboriginal Essential Services prior

to rehabilitation work to arrange for the following work.

1. Pull the pumps from both bores. The production submersible on flexible well

master column in RN 10774 should be left on site, however cleaning the pump ¥

1


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2.

3.

4.

I .. J

5 .

. ;-

and column or having the back up pump available is desirable. This period of

bore decommission, in anticipation of successful rehabilitation, should be used

to recondition the pumping equipment pulled from RN 2830. Ideally these

pumps would be pulled only 1 or 2 days prior to rehabilitation works, so

samples of any biofouling deposits can be taken by the PAWA water quality

section.

The wire mesh cages and tripods over these two bores will need to be removed

to allow drilling rig access.

For safety reasons the power lines to these bores should be turned off and

cables and plugs near the well heads be temporarily removed the power boxes

should then be moved out of the way.

Community supplies from alternative production bores will need to be arranged

for the duration of rehabilitation works.

The work program for this job has been planned and budgeted on the

assumption that drilling rig access to the bores was possible. However, a

recent site inspection has shown much of the levelled land around RN 2830

(P3) has now been washed away. Consequently extensive earth works will be

needed to provide rig access to RN 2830. As such work has not been

budgeted for, additional funds will be required to implement the work program.

WRB crew can undertake this work with in house equipment and the PAWA

(Alice Springs) tip truck, if available, for a cost of around $6,500. If however

no additional funds are available for earthworks, the program could be reduced

to only attempt rehabilitation of one bore (RN 10774: P#5). Alternatively if no

additional funds are available, the work program could be reduced to only

attempt rehabilitation of RN 10774 (P5) .

2


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1

• 1 ,

'.

WORK PROGRAM

Day 1

Day 2

Day 3

Drill crew arrive on site and set up their camp.

NB. Project manager and Water Quality scientist already on site to

obtain biofilm samples from pumps and caliper log both holes.

Set rig over RN 2830 and airlift hole till "fairly" clean water obtained.

Note this process aimed at removing large loose biofoul deposits. Airlift

from the bottom to the top of the hole. As water lifted may be red and

dirty, airlift returns should be directed to the creek through a blooie line.

Set up rig over RN 10774 and airlift as for RN 2830 above.

If not done Day 2, run a) the WRB Alice Springs sampling submersible

pump to 50 m (47 m available drawdown) in RN 2830 and b) the

production submersible pump on flexible well master column to 100 m

in RN 10774.

Conduct 2 hour specific capacity test in each production hole. Power

will be obtained from the camp generator jf possible ie camp not too fare

away. Otherwise an additional generator for this purpose will be

needed. Pump rates need not be high, say 0.5 Us for RN 2830 and 1.0

Us for RN 10774. Both pumps are then to be pulled and .disinfected

with a Sodium Hypochlorite (NaOCI) solution. This will be done by

running the pumps in a portable mud tank to flush the pump and

column. This work will probably than require a water truck to be

available to ensure water supply to mud tanks.

All rig equipment that was placed down hole or splashed by bore water

is also to be disinfected/cleaned with a Sodium Hypochlorite solution.

This could be done by adding NaOCI to the steam cleaner or pumping

from one of the portable mud tanks.

3


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Day 4

f

1 • 1

Day 5

- -Day 6

Caliper logging of both holes will be rerun this day.

Water truck to be filled in preparation for jetting RN 10774.

Run into RN 10774 with high pressure jetting tool (size determined by

calliper log) and airlift duo pipe to TO of 180 m.

Rotate jetting tool at less than 20 rpm and pull up at less than 1.8 m per

minute (ie 4 minutes per rod). Airlifting is to be at a rate greater than

the high pressure injection rate (about 5 Us) to maintain a negative head

in the aquifer during jetting. WAWA recommend airlift returns to be

through a T piece so as to gauge any increase in bore efficiency and to

compare different jetting runs. Thus airlift yield rate, water colour and

turbidity are to ·be noted on work sheets.

The jetting of clean water is also recommended, consequently the above

implies (5 Us x 120 minutes = 36000 L) 40,000 Iitres of clean water

should be available on site during this operation for each jetting run. NB

recirculating airlift returns is not desirable as clogging of jets may occur .

Two runs of the high pressure jetting tool are allowed for. A glass bottle

sample at the end of each jetting run will be taken. Water truck to be

filled for jetting RN 2830.

High pressure jetting of RN 2830 as for Rn 10774 to be run.

If time allows Rn 2830 to be airlifted to remove any loose debris.

NB. High pressure jetting equipment may be run back to town for return

to Perth this day or the next (0 Miller?).

Airlift clean RN 2830 if need be, and RN 10774 if no time was available

after jetting operations Day 4.

4


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Day 7

i

"0;:

Run in submersible pumps to both holes and run 2 hour specific capacity

tests. Rig equipment to be cleaned during these tests.

Pull pumps if need be.

As time is limited to one chlorination douse per bore, a large amount of

NaOel is to be tremmied into each bore, exact amount to be decided on

by Water Quality chemist, but in the order of 100 L NaOel is envisaged

tor RN 2830 and 250 L for RN 10774. A dispersant such as

tripolyphosphate may be mixed with NaOel before adding to the hole.

As pH of commercial NaOel solution is known to vary, sufficient

chemicals will be on site to ensure pH is kept in described range (6.5).

Safety procedures ie goggles and impervious gloves and overalls to be

observed. Drill string is to be run to 98 m in RN 2830 and clamped in

place on the surface. Rig is then to move to RN 10774 and drill pipe run

to around 140 m.

Both bores will then be agitated periodically through the day by moving

the compressor between the two with a Toyota, and surging with air for

5 minutes every 11:2 hour.

If surging by airlift is assessed to be impractical once on site because

of the high water levels in these bores (SWL less than 5 m). Two

alternative methods of agitation may be tried.

1) The WRB mono pump will be run in RN 2830 and returns

recirculated in the bore to agitate chemicals through the perforations.

The submersible production pump will be similarly operated in bore RN

10774.

2) Surging with swab blocks.

Both bores then left to stand overnight. Both submersibles to be

cleaned during the day if applicable.

5


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Day 8

Day 9

Day 10

Notes

1

Both bores to be agitated for another hour and a half, then RN 10774 to

be airlifted clean, ie run into TD and work up. Rig then moved to RN

2830 and this bore then airlifted clean. Submersible pumps will then be

run and specific capacity tests run again.

Finish any remaining tasks, e.g. maybe need to conduct one of the

specific capacity tests.

Pull and clean pump from RN 2830. Disinfect rig.

Pack up and return to Alice Springs.

High pressure jetting will require a large volume of clean water on site.

Handling procedures of Sodium Hypochlorite to be noted. (attached)

Waste disposal is planned to be in the creek adjacent to these bores.

This is because biofoul deposit contaminated water is not believed to be

toxic and NaOCI solutions toxicity should be negated by sunlight and

dilution by aquifer water.

As WAWA recommend glass sample bottles of the dirtiest water after

each treatment sequence be taken to help asses treatment effectiveness

such samples should be taken.

In the event of this program proceeding ahead of schedule, an additional

chlorination treatment may be conducted in one or both bores.

Therefore additional NaOCI should be available on site.

Sodium metabisulphite or sodium thiosulphate to be on site to neutralise

any large spills of undiluted NaOcl.

6


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-~

~ .

I I J r I

;;;"-

..

If more than 5% available chlorine is measured after chlorination of

bores, the above neutralising agents will need to be added before any

water is disposed of down creek, thus slow pumping to mud tanks for

neutralisation following chlorination treatment may be an unlikely

necessity: Chemist to be on site during chlorination or advise on

acceptable dose that will keep free chlorine below 5%. No problems

envisaged however as long as less than 40% by volume of bore casing

of NaOCI is added, free chlorine should be less than 5%.

Legal requirements for transport and storage of Sodium Hypochlorite will

be ascertained an complied with by drill crew.

A handling of loxic chemicals penalty rate will probably apply under

PAWA award conditions.

300 m of drill pipe to be on site, WRB mono pump to be on site.

Difficulties of shuffling vehicles and equipment about in the limited space

available may cause unavoidable hold ups to the flow or work.

The use of dispersants with the chlorination phase of work will not

proceed if safe disposal of these chemicals cannot be arranged ie

dispersants potentially not suitable for disposal along creek.

7


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I I I T 1

Appendix 2

Chemical Data

Technical R

eport WR

D93040

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age 38 of 39.

"

. _".rI 1 i_ .. --1 I ........... ' 'I ,

UNCORRECTED PHYSICAL DATA CORRECTED PHYSICAL DATA -TIMF! 'l'EMP oC pH D.O. CONI) TURB 'fEMP pI! % SAT COND D.O. mg/l

oC D.O

o MIN 24.82 G.95 0.12 871 ~G_19 6.95 1 871 0.10

10 MIN 24.92 6.98 0.10 870 26.29 6.98 1 870 0.08 -.. ~--

BORE RN 2830

I UNCORRECTED PHYSICAL DA'fA CORRECTED PHYSICAL DA1'A

1'IME TEMP oC pH D.O. CONIl 'rURB TEMP pH % SAT COND D.O. mg/l oC D.O

-5 MIN 24.76 6.83 0.35 8G8 26.13 6.83 4 868 0.33

10 MIN 24.87 6.R5 0.29 868 26.24 6.85 4 868 0.27 --

15 MIN 24.96 6.87 0.37 868 26.33 6.87 5 868 0.35 -

BORE RN 10774

Technical R

eport WR

D93040

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age 39 of 39.

------

:1,1 f;' ~ • n, i .,j ~ ~ ~-""'I ............ -'",I,

Atli:1Iy~1s ttl Olllllg~ms per r~ro - ruglL (urJes<; oll;,erwtsfl $I~~~rl)

BORE DATE SPECIFIC TOTAL SODIUM POTASS· CAlCIUM MMNES- IRON TOTAL TOTAL SILICA CHLORIOE SULPHATE tllTAATE BlCMB· FLUORIDE (CALC COMMENTS REGISTERED OF CONDUCT- DISSOLVED IUM IUM (TOTAL) IIAAD, ALKA· otfATE FAOM

NUMBER SA,,tPLING ANCE SOLIDS NESS UNITY CHlOFlIDE) .

R" uS/em TOS pH ". K C. Mg Fa C8C01 CIIC01 SIO, CI SO, NO, HCOj F "SCI

2830 14/1/85 820 480 7.7 34 10 77 32 0,6 324 288 16 70 43 1 351 0.4 114

8/10/93 817 443 6,9 39 11 81 37 8,6 355 290 13 77 45 1 353 0.4 127

I

10774 3/6192 840 460 7,3 40 13 66 39 1,3 325 293 17 78 47 1 357 0,3 129

8/10193 830 448 7,0 40 12 78 38 3,5 351 300 14 77 44 1 366 0,3 127

- - -

I

I

. - -

-- \-----

NHMRC GUIDELINES ---> 1500 6,5· 0,3 500 400 400 100 1,7 Maxima except pH range a,s

•... _._-- - --

WATER QUALITY DATA

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