Water:Water June 2005 - WIOApersonal computer, pocket sized mobile phones, electronics and such innovations as automatic control of treatment plants, CITECT, PLC’s and SCADA to name

JUNE 2005

WATERWORKS JUNE 2005 41

Editorial CommitteePeter Mosse, Editor [email protected]

Russell Mack [email protected]

George Wall [email protected]

Direct mail to: WaterWorks Editorc/-Peter Mosse, Gippsland WaterPO Box 348, Traralgon, Vic 3844

Advertising & ProductionHallmark EditionsPO Box 84, Hampton, Vic 318899 Bay Street, Brighton, Vic 3186Tel (03) 8534 5000 Fax (03) 9530 8911Email: [email protected]

WaterWorks is the publication of the Water IndustryOperators Association (WIOA). It is published twiceyearly and distributed with Water Journal. Neitherthe WIOA nor the AWA assume responsibility foropinions or statements of facts expressed by contrib-utors or advertisers. All material in WaterWorks iscopyright and should not be reproduced wholly orin part without the written permission of the Editor.

Contributions WantedWaterWorks welcomes the submission of articlesrelating to any operations area associated with thewater industry. Articles can include brief accountsof one-off experiences or longer articles describingdetailed studies or events. These can be e mailed toa member of the editorial committee or mailed tothe above address in handwritten, typed or printedform. Longer articles may need to be copied to CDand mailed also.experiences or longer articlesdescribing detailed studies or events. These canbe emailed to a member of the editorialcommittee or mailed to the above address inhandwritten, typed or printed form. Longerarticles may need to be copied to CD and mailedalso.

C O M M E N T

CONTENTSComment 41

“Operators - Who Cares” 42

Water Treatment Coagulants 44

Improved Float Removal at a DAFF 48

Cairns Water Treatment Alliance 52

Trade Waste Management Plans 55

Composting Biosolids 59

Whakapapa Alpine Sewerage Scheme 62

In Brief 65

Our Cover: Operation Manager TonyDavies checks the operation of the on lineCOD analyser at EarthTech’s new EchucaWater Reclamation plant. The CODanalyser is used to continuously monitorinfluent COD.

President’s MessageA National Operators AssociationAt Last!!

The 10th of February 2005 will berecorded in the history of the Australianwater industry as a ground breaking day,the start of the development of a trulyNational operators association. At ameeting in Melbourne betweenrepresentatives of WIOA, AWA andWSAA, agreement was finally reached on astructure that will allow WIOA to assumethe role of dedicated service provider tooperators throughout Australia.

As a result of this historic agreement,WIOA has appointed a full time ExecutiveOfficer, something the organisation hasdreamed about for many years. The fulltime appointment will support the rapiddevelopment of the many initiatives thatare being planned. We are pleased to report

that WIOA’s Secretary/Treasurer for thepast 11 years and one of only four LifeMembers, Mr George Wall has acceptedthe important role as the foundationExecutive Officer of WIOA. Georgecommenced his duties on 5 April 2005.

From now on and with the full supportof the other Associations, WIOA will beresponsible for duplicating the qualityservices and events that we have enjoyed inVictoria for many years in all the otherStates.

Apart from maintaining the existingservices, the key priorities for the ExecutiveOfficer in the short term will be to • develop an operator support network ineach State, • develop operator focused eventsincluding conferences, trade exhibitions,seminars and workshops

• publish newsletters and journals withtruly national content• further develop and maintain our existingwebsite• continue to assist in the development ofwater industry training packages.

No doubt over time there will beopportunities to diversify into other fieldsas well and this will bring additionalbenefits to all Members and the waterindustry in general.

The formalisation of this agreement isthe result of a lot of hard work over thepast five years. To reach this point therehave been many meetings, discussions and amountain of correspondence. Our thanksfor their patience, efforts and vision mustbe passed on to Rod Lehmann, BarryNorman, Chris Davis and Ian Jarman fromAWA, Peter Donlon from both AWA and

WSAA, and our own Committee but inparticular Ron Bergmeier and George Wall.Without their efforts this positivedevelopment for the WIOA and the waterindustry would not have been possible.

We look forward to working co-operatively in the future with the manyindividuals, companies and associationsthat have an interest in the delivery ofservices on a National basis to the“operators” in the Australian waterindustry.

Cynthia Lim, WIOA PresidentJune 2005

As a result of this historic agreement, WIOA hasappointed a full time Executive Officer, something

the organisation has dreamed about for manyyears. The full time appointment will support the

rapid development of the many initiatives that are being planned.

42 WATERWORKS JUNE 2005

“OPERATORS? - WHO CARES?”George Wall

A wise person once wrote - “the only twocertainties in life are death and taxes”? I’dlike to add a third - CHANGE.

The passage of time and the advent oftechnology brings with it new and excitingchallenges for us all. In our technology drivenworld we deal with change on a daily basis,probably without even noticing it. In ourpersonal life we have a choice to take it orleave it, but in our work environment we areexpected to embrace everything that has everbeen dreamed up, particularly by those “evilIT people”.

This introduction leads me into what thisarticle is all about - “the operators” and whatis expected of them. In the 1980’s the role ofthe operator was to look after their plant, beavailable 24/7 and to keep it going throughthick and thin and with little support.Specialist training was a luxury afforded to aselect few. For any newcomers, their trainingconsisted of a quick lesson by “Fred” becausehe had been the operator there for twentyyears and knew everything about the place.Generally, the operators were told exactly

what to do and when, and there wasn’t a lotof room for creativity. The engineeringfraternity were the “professionals” and brainsof the organisation and the operators mostlyprovided the brawn to get the job done.

In the 1990’s, the role of the operator tookon a massive transformation. Along came thepersonal computer, pocket sized mobilephones, electronics and such innovations asautomatic control of treatment plants,CITECT, PLC’s and SCADA to name a few.With all due respect to the previousgenerations, the operator “came of age”through this period and the skills requiredhave continued to evolve at a great pace eversince. Although the quick history lesson from“Fred” is still important, the operator oftoday’s systems needs to be much morehighly trained and skilled to keep up withcommunity and industry expectations.

“The operators of today and the future areprovided training and opportunities that werenot available just a few short years ago. Theyare highly paid, committed, motivated, oftenspecialised and innovative people and have

effectively taken on the role of industryprofessionals as well. As a result they perform ata much higher levels and meet all the industryexpects of them.”

So does every operator in the waterindustry fit this last description? I’d suggestfrom my observations and discussions aroundthe country that they definitely don’t. “Whynot?” you may well ask.

In my mind, there are a number ofreasons. The first is that believe it or not,there are vast areas of the country where theoperators are still treated as they were in the80’s but are expected to perform at a 21stcentury level. For example, many operatorsare rarely sent to do training because thebudget is a bit tight or there’s no-one toreplace them while they are away. Somedon’t receive much in the way of personalsupport from their boss because there are toomany reports to write or they are too busy inthe office. Some bosses don’t see any pointsending out magazines or literature as theoperators are too busy or won’t read themanyway. The operators in these cases suffer

C O M M E N T


from a severe case of isolation and effectivelyget left to their own devices. They miss outon chances to learn and grow in theirindustry role.

Many people do not recognise the needoperators have for gaining knowledge andcontacts or the benefits that this can bring. Itstill amazes me that someengineers/employers can go to an event suchas a conference or seminar to learn, updateskills and “network with their peers” but willnot allow an operator to attend a similarfunction because it is a junket. It is true thatthe operators know how to have a good timebut they are also receptive to ideas, love totalk about and solve their issues with otheroperators and are inquisitive about howtechnology can be updated or implemented.Adopting new ideas can save money and gainefficiency in the workplace into the bargain.

Another frustrating thing is that manyoperators have a low regard for the importantrole they personally play in the industry. Iwas talking to someone at an operator’s eventnot long ago and asked what he did. “I workat the shitworks” was his reply. When I askedthe same question in a different part of thecountry I got the response of “I am awastewater treatment technologist”. Thetechnologist even got shirty that I dared tocall him an operator!

Why did they answer the way they dideven though they perform the same role?

Possibly, it is to do with the way theemployer treats the employee and the valuethat each places on the person. Let’s not justblame the poor old boss entirely in this case.Professional is as professional acts. We needto help change the mindset of the operatorfirst and get across to him that if he looks athis role as a career rather than just a job bothhe and his employer will be better off. If wecan provide ways to help him do that, hemay then change the idea and the value hisboss places on him into the bargain.

I could go on with examples like this allday but I trust you get the picture.

So, where do you as an operator or anemployer fit into all these scenarios? If youare already committed or supportive, can youdo more? If you are not, what can you do tochange?

We’d like to think this is where WIOAcan assist nationally. Although we have alist of set goals and objectives, I’d like totry to summarise the essence of what we areabout in a few sentences. We are primarilyabout raising the profile and importance ofthe people we collectively call “operators”.We aim to source, develop and shareknowledge and resources with them and to

run informative events with an operatorflavour. We want to give opportunities tooperators to allow them to reach their truepotential and we want to make sure thataccess to the best and most relevanttraining is readily available. Ultimately, wewant to be a group that people are proud tobe associated with.

There are already 500 or so people whohave recognised the value of what WIOA hasto offer and have joined up as members. Wedon’t want our Association to be the nationsbest kept secret any more. Imagine howmany other people work in the waterindustry right across the country. Thesepeople are all potential members if each of uspromotes the association properly. We areexcited about the future and want you to beas well.

If you would like more info on WIOAplease contact me or visit our website atwww.wioa.org.au

The AuthorGeorge Wall is the Executive Officer of

WIOA and can be contacted on telephone03 5821 6744, mobile on 0407 846 001 orby e-mail on [email protected].

www.iwaki-pumps.com.auSYDNEY: 1/7 Salisbury Road, Castle Hill, NSW 2154

Phone: (02)9899 2411 Fax: (02)9899 2421Email: [email protected]

MELBOURNE: 5/54 Howleys Road, Notting Hill, VIC 3168 Phone: (03)9558 8053 Fax: (03)9558 8123

Email: [email protected]: 1/87 Kelliher Road, Richlands, QLD 4077

Phone: (07) 3375 1747 Fax: (07) 3375 1806Email: [email protected]

When pumping sodium hypochlorite for disinfectionin water treatment plants a common problem is lossof prime due to “gassing off”. These pumps whencoupled with Iwaki’s FCP-1 flow monitor can autobleed, automatically change to a standby pump/fastprime the standby pump and send a signal advisingof the change. For further details refer to thetechnical article on page 91 of this magazine.

C O M M E N T


There are a growing number ofcoagulants now being promoted in themarketplace and many appear to havesimilar and confusing names. Some havepeculiar terms used to specify theircharacteristics, such as “Al2O3” and“basicity”. And, importantly, when do youuse one chemical instead of another?

This paper is intended to provide anintroduction to using coagulants in watertreatment by providing an A to Z guide. A is for:• alkalinity: for most surface and groundwaters that we deal with, this is simply theconcentration of bicarbonate (HCO3

-) ionpresent in a water, expressed as mg/Lcalcium carbonate (CaCO3). It is a veryimportant parameter in water treatment. Ifraw water does not have sufficient alkalinityto start with, then you will most likely haveto add some when you dose a coagulant.Why? Because most coagulants, such asalum, consume alkalinity. In the process,the pH of the water will decrease,sometimes to unsatisfactory levels as theyactually behave like an acid when added towater. One of the benefits of usingcoagulants such as aluminiumchlorohydrate or polyaluminium chloride isthat they do not use up as much alkalinityin the coagulation process and so the pHwill not be affected as much as if alum wereused. • alum: the workhorse coagulant! It’schemical name is aluminium sulphate andhas the chemical formulaAl2(SO4)3.18H2O. When it is added to araw water, alkalinity is used up and the pHof the dosed water will drop• aluminium chlorohydrate (ACH,Al2(OH)5Cl): commonly but incorrectlycalled polyaluminium chloride is a highlyhydroxylated or prepolymerised aluminium-based coagulant. It has five OH moleculesincluded in its structure and as aconsequence has a very high basicity.B is for:• basicity: this gives a quantitativeindication of how many hydroxyl ions areincluded in the structure of a hydroxylatedor prepolymerised polyaluminium orpolyferric coagulant. The higher thebasicity of a coagulant, the lower the impactit will have on raw water pH. For example,aluminium chlorohydrate has the formula

Al2(OH)5Cl. You can see that there arefive OH ions in its structure. TypicallyACH will have a basicity of 83-85%,indicating that it will have less impact ondosed water pH than polyaluminiumchloride, which only has three OH ions inits structure and consequently has a typicalbasicity of 50-55%. Alum has no OH ionsin its structure and hence has zero basicity.C is for:• concentration: often it is necessary toexpress the concentration of a coagulant (orother chemical, for that matter) in the unitsgram per litre or some other related unit.To do this you need to know the % w/wstrength and specific gravity of thesubstance. The formula is: g/L = 10 X %w/w X SG. For example, consider ACHwith a strength of 23.5% Al2O3 and SG1.33. The actual concentration of ACH is40.2 % w/w expressed as 100% ACH.Then the concentration in g/L will be: 10 X40.2 X 1.33 = 535 g/L. Now, for alum withan Al2O3 content of 7.5% w/w and SG1.29. This is equivalent to 49.0% w/waluminium sulphate (as Al2(SO4)3.18H2O).Using the same formula as before: mg/L = 10 X 49.0 X 1.29 = 632 g/L.D is for:• DBP’s: Disinfection By-products. Theseare compounds, many of which aresuspected carcinogens that are formed as aresult of the chemical reaction between a

disinfectant and organics present in the rawwater. In the case of chlorine (orchloramine) DBP’s include trihalomethanesand haloacetic acids. In the case whereozone is used for disinfection, DBP’s ofconcern include bromates andformaldehyde. DBP’s now require regularassessment under the new Victorian SafeDrinking Water Guidelines. Coagulationneeds to be optimised to remove as much ofthe organic material in water as possible soas to minimise the formation of DBP’s (seeenhanced coagulation below).• DOC: Dissolved Organic Carbon. This isused as a measure of the possible THMprecursor components that may be presentin raw water. DOC comes from NaturalOrganic Matter (NOM) that is dissolvedinto the water as rain percolates throughdecaying plant material. Generally if a rawwater has a TOC > 10 mg/L, then caremust be paid to its removal to ensure thatdisinfection by-products in the finishedwater (THM’s and HAA’s) are below therequirements set out in the AustralianDrinking Water Guidelines (ADWG).Coagulation needs to be optimised toremove as much of the organic material inwater as possible so as to minimise theformation of DBP’s (see enhancedcoagulation below).E is for:• enhanced coagulation: this refers to thepractice of dosing a coagulant, typicallyalum at high concentrations and low pH toboost the removal of DBP precursors in thecoagulation process. Whilst there is stilldebate about the exact nature of themechanisms involved, it does appear that atlow pH (4.5-5.0), direct neutralisation ofnegatively charged organic compounds andcolloids by the aluminium, Al3+ ion takesplace, thereby allowing the organicmolecules to directly contribute to flocformation. The process is often moreeffective than conventional coagulation at ahigher pH, say 5.8-6.5, when thepredominant mechanism is adsorption oforganics and colloidal matter onto metalhydroxide hydrolysis products that areformed. Obviously coagulating at such alow pH will require careful attention toavoid corrosion of construction materialsincluding pipes in the distribution systemand possible high aluminium residuals.

W A T E R T R E A T M E N T

WATER TREATMENT COAGULANTS (OR HOW I LEARNED TO LOVE DOING JAR TESTS!)

Peter Gebbie



H is for:• HAA’s: Haloacetic acids. This is a familyof disinfection by-products formed by thechlorine/chloramine, the most commonand important being trichloroacetic acid.This group of DBP’s will now requirecloser scrutiny under the Victorian SafeDrinking Water Guidelines.J is for:• jar test: this really is one of the mostimportant tools a WTP Operator has forevaluating and optimising differentchemical dosing regimes, as well aschecking on the performance of his/herplant on a regular basis. The AmericanWater Works Association has updated itsM37, which includes a very comprehensivechapter on the proper conduct of jar testsand I can highly recommend it for purchaseby your Authority as an importantreference1. P is for:• pH: this gives an indication of how acidor alkaline a water is. It is a very importantparameter in water treatment, especially foreffective coagulation. Each coagulant has anarrow optimum operating pH range. Forexample, alum tends to work best at adosed-water pH of 5.8-6.5. If the pH islower or higher than this optimum, thenproblems of high residual colour,aluminium or DBP’s may be apparent inthe finished water. This can createproblems when the raw water has a highalkalinity when very high alum doses willbe required to achieve the right pH. Thealternative is to dose acid to decrease thepH to a lower value first before dosing thecoagulant. This is the opposite of the morecommon practice of dosing alkali (lime,soda ash or caustic soda) to raise the pH oflow alkalinity waters. • percent weight/weight or w/w: number ofkilograms of active chemical per 100kilograms of liquid chemical. For example,liquid alum is commonly delivered as 7.5%w/w Al2O3, thus for every 100 kg of liquidchemical there are 7.5 kg of Al2O3 present• percent Al2O3: common method forquoting strength of aluminium-basedcoagulants on w/w basis. Another methodof referring to concentration is to state thealuminium content, which is roughly halfthe Al2O3 content. For example, liquidalum is typically 7.5 w/w Al2O3, which isthe same as 4.0-w/w aluminium (Al).• polyaluminium chloride (PACl,Al2(OH)3Cl3): often incorrectly referred toas “PAC”. This abbreviation is now moreusually reserved for “Powdered ActivatedCarbon”. Another hydroxylatedaluminium-based coagulant with lower

basicity than ACH, and hence has moreimpact on raw water pH when used as acoagulant but less impact than alum.• polyDADMAC: an abbreviation for acationic (positively charged) polyelectrolyte(polymer) that is often used as a primarycoagulant in direct filtration watertreatment applications. It is sometimes usedin combination with ACH and this mix isoften sold as a proprietary blend, e.g.Ultrion series from Nalco/Ondeo and“1190” from Aluminates. PolyDADMACdoes not give as high true colour removaland hence TOC/DOC removal as doesmetal-based coagulants. S is for:• specific gravity (SG): this is the unitweight of a liquid chemical relative to waterat the same temperature. Strictly speaking,

SG has no units but you’ll often find it ordensity stated on laboratory reports as“g/mL” or as “kg/L”. For a given chemical,there is a direct relationship between itsstrength and its SG, and indeed chemicalmanufacturers use SG to measure thestrength of a chemical during themanufacturing process. As an example,liquid alum (49% w/w) typically has a SGof 1.310, whilst liquid caustic soda (46%w/w) has a SG of 1.498 at 20ºC. T is for:• THM’s: Trihalomethane compounds.These are a class of disinfection by-productsformed by chlorination and to a lesserextent chloramination. Under the newVictorian Safe Drinking Water Guidelines,THM’s will require more frequentmonitoring. The higher the raw water

1. AWWA, (2000), Operational Control of Coagulation and Filtration Processes, M37, 2nd Edition, Manual of Water Supply Practices, Denver, CO.

Table 1. summary of important coagulant details.


TOC/DOC, the higher will be the finishedwater THM levels. Coagulation needs to beoptimised to remove as much of the organicmaterial in water as possible so as tominimise the formation of THM’s andother DBP’s. • TOC: Total Organic Carbon. This is alsoused as a measure of the possible DBPprecursor components that may be presentin raw water. Generally if a raw water has aTOC > 10 mg/L, then attention must begiven to its removal to ensure thatdisinfection by-products in the finishedwater (THM’s and HAA’s) are below thelevels set out in the ADWG.

Table 1 summarises importantcharacteristics and supplier details forcommonly used coagulants, as well as somenotes on possible applications.

To finish off, a couple of tips aboutcoagulant selection may be of help.• Generally, alum is the first coagulant ofchoice because of its lower cost andavailability throughout Australia. Forcoloured, low turbidity, low pH/alkalinitysurface waters typical of South EasternAustralia, pre-treatment with lime, soda ashor caustic soda will be required to ensurethat the optimum coagulation pH isachieved.

These types of water however, also makethe use of ACH possible. It is often feasibleto coagulate at a relatively high pH (7.5-8.0) and so avoid the need to dose alkali forpH correction, something that is oftendifficult at small WTP’s. The need to addalkali can often be further reduced byreplacing gas chlorine with hypo fordisinfection. Recently ACH dosing wassuccessfully implemented at the MallacootaWTP. Finished water residual aluminiumand THM levels have both been belowADWG limits since changing over fromalum to ACH.

As a rule-of-thumb, ACH doses requiredfor a surface water will be approximately1/3rd of those required when using alum.The overall chemical cost increase whenchanging over to ACH from alum will betypically 15-20%. However, other benefitssuch as lower sludge production, avoidanceof post-treatment alkali dosing and reducedmaterials handling may still make the use ofACH attractive.

So if you have a water with a lowalkalinity and you are having difficultytreating it using alum, try one of the higherbasicity coagulants e.g. ACH or PACl.• Iron-based coagulants, such as ferricchloride, ferric sulphate and PFS®, are not

that popular in Australia and tend be moreexpensive than alum on an equivalent kgper metal dosed basis. They also consumemore alkalinity than alum, and hence tendto depress pH of the dosed water moredramatically. Opinions also differ as towhether they produce a fluffier floc, whichis more difficult to settle. Several WTP’s inNSW use PFS® in order to meet verystringent manganese limits in the finishedwater. Ferric-based coagulants are extremelycorrosive and produce highly visibleblood/rust-coloured stains when there arechemical spills and leaks.

Hopefully you have found this guide ofsome help. Please feel free to contact me ifyou have any particular concerns aboutcoagulant choice, properties, pre- or post-treatment pH adjustment, choice of alkali,or other related matters!

I’ll forward your queries and my repliesto WaterWorks for future publication sothat we can all participate in learning moreabout this challenging topic.

The AuthorPeter Gebbie (peter.gebbie@

earthtech.com.au) is a Senior ProcessDesign Engineer with Earth TechEngineering in Melbourne.



The South Gippsland Region WaterAuthority constructed its first DAFF(Dissolved Air Floatation Filtration)treatment plant at Lance Creek in 1997-98. The Lance Creek treatment plantsupplies water to the towns ofWonthaggi, Cape Paterson andInverloch, representing approximately50% of South Gippsland Water’scustomer base. The plant has a designcapacity of 19ML/day

DAFF was selected due to its ability toremove algae without damaging the cells.This was a priority as Lance CreekReservoir has been subject to frequent algalblooms due to the amount of nutrientsfrom the predominantly agriculturalcatchment.

The ProblemTraditionally, removal of the float in the

DAF process is achieved by mechanicalscrapers which require on-goingmaintenance or flooding and overflowingthe floatation tank, the method used atLance Creek.

The problems with this method of floatremoval is that it uses large amounts ofwater; results in a heavy loading of washwater systems in summer and there is a riskof environmental contamination from asludge spill.

The objectives in looking forimprovements to the float removal systemwere to reduce the amount of water usedfor float removal and to reduce the amountof sludge produced.

TrialsThe idea for the original trial was based

on the fact that if you could blow the frothof a beer why couldn’t the same processwork for a DAFF cell? So a number of trialswere set up.1. Water sprays based on the cutting spraysystem with jets facing into the tank. Theseonly proved effective within about a 1m ofthe sprays and made little difference to theoverall float removal time.

2. High Pressure compressed air. This wasbased on a making up a manifold usingthe plants compressed air system. Theresults were similar to the water sprays 3. Low Pressure high volume air. Twosmoke machine blowers were temporarilyinstalled in a cell. They immediatelyproved effective, removing the sludge in afraction of the time of the original system.The blowers are linked to the existing celllevel control. When a float is activated, therising level in the cell starts the blowers.

IMPROVED FLOAT REMOVAL AT A DAFF

Karl Williams

The Lance Creek WTP.

The Lance Creek Reservoir. A DAFF Cell.



The blower run time is controlled by atimer which is based on the total floattime.

The float removal system uses low costoff the shelf units with low power cost andminimal maintenance requirements.

OutcomesThe blower units have proved successful

in removing the float in a shorter timereducing water usage. Table 1 provides acomparison of float removal performanceusing the original system and the blowerassisted system. The time lapsephotographs below also show visually howthe system has been improved.

The more efficient float removal systemmeans that more potable water isproduced for the same raw water volume.There is also a reduced loading on thesludge handling system and shorter runtimes leading to lower powerconsumption.

As a result of the trials two blowermachines were installed on each of thethree floatation tanks at the Lance Creekplant at a total cost of $5000 and the newwater treatment plant at Yarram has hadblowers included at the design stage.

AcknowledgementsKevin Mitchell and Peter Bentick

assisted with installation of the equipmentand

Ravi Raveendran and Bryan Chatalierprovided technical assistance.

The AuthorKarl Williams is a Water Treatment

Plant operator with South GippslandWater, Victoria, and can be contacted [email protected]. This paperwas originally produced as a poster andwon Best Operator Poster at the 2004Victorian Conference.

The blower used in the initial trial.

Table 1. Performance Comparison Trials

With Blower Assistance Parameter Without Blower Assistance

432 kL/hr Plant Raw Water Flow Rate 432 kL/hr54 hours Plant Run Time 65 hours23138kL Total treated water produced 27161kL428.5kL/hour Average treated water production 417.9kL/hour190kL Water lost during float 919kL3.5kL/hr Average float water lost 14.1kL/hour

Saving of water using air assisted withdrawal 10.6 kL/hour (24.7 kL/ML produced)




CAIRNS WATER TREATMENT ALLIANCE

Brian Smyth and Chris Ormond

The Freshwater Creek Water TreatmentPlant (WTP) was commissioned in 1980 tosupply treated water to the City of Cairns.At that time Cairns had a population ofaround 75,000. Raw Water for the plant istaken from Freshwater Creek, a tributary ofthe Barron River. The catchment forFreshwater Creek consists of rainforest withgenerally low impact land. Storage is inCopperlode Dam, Lake Morris, where norecreational activities are allowed. Waterquality in the lake is consistently good withthe turbidity varying typically between 2NTU and 4 NTU, colour between 7 and15 Pt-Co and alkalinity between 9 mg/Land 12 mg/L. There are no iron,manganese or algal problems, however rawwater turbidity can peak at over 900 NTUduring Cyclone events!!

The original plant consisted of four up-flow clarifiers and four multi media filterswith a maximum capacity of 55 ML perday. The clarifiers proved difficult to runwith such clean raw water so they weredeactivated and straight gravity flows wentto the filters. The plant was expanded withan additional two filters in 1988 to a designcapacity of 120 ML per day. Cairnspopulation through the 80’s and 90’soutgrew projected increases. Populationserviced today is 130,000 residents and anaverage of 25,000 tourists on any given day.A new 150 ML treatment plant is currentlyin the design stage for constructionbeginning in 2006.

The plant now operates as a directfiltration plant with multi media filters andupstream alum and polyelectrolyte dosing.Soda ash is applied post filtration for pHcontrol. The water is disinfected withgaseous chlorine. The plant runs ondemand, and averages 18 to 22 hours perday with flows as required. The averageflow is approximately 800 L/sec. Nine staffwho are in attendance at the plant for 8hours per day operate the plant. Staff areresponsible for all operations andmaintenance of the plant. They also operateand maintain Copperlode Dam, a secondtreatment plant (Behana) which suppliesthe southern side of Cairns with a 44ML aday capacity and 2 in stream intakes. Theyalso service and maintain all high-pressuretrunk mains, (75 kms total of 406mm -1080mm, at 1200kpa).

The Water Treatment Alliance ProjectCairns Water became aware of the Water

Treatment Alliance at a workshop inSydney in August 2000 conducted by BillLauer from the American Water WorksAssociation.

The Water Treatment Alliance is acontinuous improvement program forWater Treatment Plants based on a

thorough self-assessment of the plantincluding design, operation andadministration. The Alliance is jointlysupported and administered in Australia bythe Water Services Association of Australia(WSAA), the Australian Water Association(AWA) and the Cooperative ResearchCenter for Water Quality and Treatment(CRCWQT).

Figure 1. Copperlode Falls Dam - source water for Freshwater Creek.

Figure 2. Freshwater Creek Intake - supplies raw water to the Plant.



At the initial stage Cairns Water wasinterested in the concept but no officialworks were commenced. However the basicideas were discussed and severalimprovements to the plant were identifiedand work commenced on theimprovements.

Cairns Water was approached in May2002 to formally participate in the Alliance.Cairns Water agreed to participate and inSeptember 2002 the Self AssessmentHandbook and early version of the datacollection software was delivered.

Project TeamOne of the first steps in the Alliance

program is the establishment of a projectteam. At Cairns Water the team consistedof the Water Supply Team Leader andthree Treatment Plant Operators. Thisteam formed the basis of the Allianceproject for 12 months. Base line turbiditydata was collected for 12 months on filteroperations. Monthly Alliance meetingswere included into the plants normalSafety/Staff/Team Brief/Operations/ToolBox, meetings. By combining the WTAactivities with the other normal plantactivities, the concept of the Allianceapproach was integrated with the normaloperation of the plant and minimised thenumber of separate meetings and time offthe job.

Team ProjectsAs the Freshwater Creek WTP was over

20 years old, many upgrade ideas were intrain for capital works and minor works forstaff. The plant process hadn’t beenreviewed for over 15 years. New ideas werethought about and several wereimplemented or trialled.

These included:• PLC replacement• Electrical wiring upgrades and Ratproofing of the control cabinets. (We havea major issue with an Australian Marsupialcalled a “White Tailed Rat”. They areferocious eaters of electrical cables).• Sludge removal process upgrade. ADehydrum was decommissioned and sludgepumped to sewer• SCADA system upgrade. Macroview tobe replaced by Citect.• Flow meter replacement program• Pre soda trial for low alkalinity water• Calibration and servicing upgrade for testequipment.

• Polyelectrolyte requirement trial• Filter ripening trials over the plants flowrange. Min 400 L/sec to 1200 L/sec.• Trialling a Streaming Current Detector(SCD) for process control• Total replacement of the water hydraulicvalve system with Rotork electric actuators.• Review of filter husbandry procedures.• Review of plant standard operatingprocedures.

Water Quality: Summary of ResultsThe WTA relies heavily on the collection

of turbidity data for both the raw and treatedwater. Turbidity is an excellent surrogatemeasure for the overall water quality but inparticular the risk of Cryptosporidium and

Figure 3. Freshwater Creek Water Treatment Plant.

Valves for Water Supply Valves for Wastewater Systems

• High Strength Ductile Iron/Stainless Steel

• High air flow design

• Compact Height and low weight

• Anti-Slam Water Hammer Retro-Fit capability

• 16-40 Bar models up to 200mm diameter

Air Release Valves

BERMADw w w. b e r m a d . c o m . a u

Vic: (03) 9464 2374 NSW: (02) 9746 1788 WA: (08) 9381 1986 Qld: (07) 3279 0093



Giardia in the finished treated water.The WTA strongly recommendsindividual on line turbidity meters foreach filter, however at the time ofparticipation, the Freshwater CreekWTP had a single on line turbiditymeter monitoring the combinedfiltered water quality. One of theprojects for the future is to installindividual turbidity meters.

Table 1 shows the raw water quality forthe period 2002 to 2004.

The raw water generally has a lowturbidity however higher turbidities dooccur during heavy rainfall. The standardoperating procedure is for the plant to shutdown at 30 NTU. Experience has shownthat the water is untreatable above thisfigure. Dirty water events are generally ofshort duration and there is sufficient waterstored in the treated water storages tosupply water during that period.Approximately 72 hours supply is held instorage, but with community awareness andsevere restrictions this could be extendedfurther.

The filtered water turbidity data iscollected daily and entered to the WTAsoftware. At the end of 12 months the datais analysed and produces a graph and also aturbidity spike count. Turbidity spikecounts are the number of times that theturbidity exceeds a certain value. This is auseful way to view the overall performanceof the filters and the spike count data for2002 to 2004 is shown in Table 2.

The table shows very similar treatedwater quality for the 2 years.

One of the other key objectives specifiedin the WTA is that filter ripening periodsbe <0.3 NTU and no longer than 15minutes. Filter ripening times at theFreshwater Creek WTP remained the samefor both years. Filtered water turbidityreturned to below 0.1 NTU within 12minutes at all plant flows between 400L/secand 1000 L/sec.

Benefits from the Alliance Project.While there has been no real

improvement in the treated water quality(Water from the Freshwater CreekWTP was already very high quality) anumber of other significant benefitshave been realised. These are listedbelow.• Polyelectrolyte system shut downfor 9 months of the year (Clean rawwater times). Cost saving of$2,500.00. No loss of finished waterquality, no breakthrough from filters,extended filter runs by approximately12%. The extended filter run timesresulted in reduced backwash water

demands by 2ML per week allowing thatwater to go to the distribution network.During December to April, polyelectrolyteis still required to assist with coagulation.• The pre soda ash trial proved successful.This facility is now a permanent fixture,which can be switched on as required. Theproblem was at certain times of the year wecouldn’t maintain a good floc because thealkalinity dropped below 8mg/L. • Occasional double backwashes. It wasfound that doubling up backwashes once amonth greatly improved the filter runtimes. More than that it was noticed thefilter ripening times started to creep up to15 minutes prior to the double backwashes.Also spelling a filter and drying it outprevented mud balling and algae growth onthe sidewalls. Filter walls are now hosedduring backwashing at least once per weekand twice a year the walls are pressure waterblasted. Filters are spelled for a period of 14days, on rotation at a time when demandsallow.• Sieve samples were taken from all filtersto ascertain media size and serviceability.Filters 1- 4 (older units) were all still withinthe 95% of original specifications and filter5&6 were 97%.• Maintenance costs on the plants valveactuators has been reduced by $15,000 perannum.• The Streaming Current Monitor test wassuccessful during the clean water period ofthe year but was not able to cope with wetseason variables. More tests on this unit willbe done during the current wet season,before a decision is made for the long term.• Review of the calibration and testing offlow meters and online instrumentationshowed up the requirement for an upgrade.Staff training and review of procedures now

gives a greater confidence in collecteddata.• With the implementation of thenew Citect program, operators havebeen able to view additionalinformation the previous program wasunable to provide. Based on thisadditional information, over a dozenchanges have been made to the PLC

program to optimise the treatmentprocess. These include:- Time between backwashes reduced by15 minutes by adjusting levels in theservice water reservoir and pump start/stop levels.- An additional 20kL of water beingtreated at the beginning of eachbackwash cycle instead of drainingthrough the sludge cycle.- Less floc carry over in supernatant waterreturning to Freshwater Creek by acombination of installation of an onlineturbidity meter in the settling tanks andadjustments to paddle stirrer times.- Quicker filter refilling times after abackwash by using raw water instead ofthe original backwash water, afterinstalling baffles to dissipate flowvolumes over a greater surface area. PVCair scour lines are situated directly underthe raw water inlet valve. These pipesneed to be covered by water before theheavy flows from the inlet valve cascadeover them. Several had cracked beforethis modification was installed.

ConclusionsThe Freshwater Creek WTP has always

produced very high quality water. Whilstthere hasn’t been any measurableimprovement in treated water quality overthe past 2 years, the approachrecommended by the WTA and the self-assessment of the plant has allowed CairnsWater to greatly improve operationalreliability and achieve considerable costsavings. Ongoing projects to continue theimprovement process include, installationof additional turbidity meters for theindividual filters, a Particle Counter on

outlet water, bulk handlingequipment for chemicals andchanging the plant from liquidchlorine gas to sodium hypochlorite.

The AuthorsBrian Smyth ([email protected].

gov.au) is General Manager at CairnsWater and Chris Ormond([email protected]) isWater Treatment Team Leader at theFreshwater Creek Water TreatmentPlant.

Table 2. Turbidity spike counts for finished waterat the Freshwater Creek WTP for the 12-monthperiods 2002/2003 and 2003/2004.

Turbidity Spike 2002/2003 2003/2004

0 - 0.1 NTU 305 3190.1 - 0.2 NTU 44 410.2 - 0.3 NTU 9 50.3 - 0.4 NTU 8 10.4 - 0.5 NTU 0 0

Table 1. Raw water turbidity for the 12-monthperiods 2002/2003 and 2003/2004.

2002/2003 2003/2004

Minimum Turbidity (NTU) 1.9 1.1Maximum Turbidity (NTU) 33.7 43.7Average 2.8 3.0


IntroductionThe Victorian Water Act 1989 requires a

Water Authority to “provide, manage andoperate systems for the conveyance,treatment and disposal of sewage and, if itso decides, of trade waste”. This providesthe incentive for an authority to developand maintain an effective trade wastemanagement system.

A typical trade waste management systemmay include: • a trade waste by-law developed inaccordance with the Water Act,• a trade waste policy set by the authority, • a trade waste agreement or consentwhich is issued to customers that dischargetrade waste into the authority’s sewers and • a set of criteria that prescribes limits forindividual contaminants based on safetyconsiderations, system integrity, treatmentcapacities and increasingly, re-usepotential.

Many trade waste customers are unableto comply with stringent quality limitswithout significant change, often leading toeither reluctance to sign a trade wasteagreement or non-compliance with anexisting agreement. Likewise, waterauthorities are limited in their ability torelax quality limits without compromisingsafety and/or system efficiency.

In addition, the basic business objectivesof the trade waste customer and that of thewater authority differ. The authority’s goalis to safeguard against risk, while invariably,the trade waste customer wishes tomaximise profitability. Historically this iswhere legislative methodology has failed tobridge the gap.

A Trade Waste Management Plan(TWMP) is an effective tool that hasproven successful in linking both the waterauthority and the trade waste customer toan agreed action plan in support of a tradewaste agreement.

The Victorian Water IndustryAssociation in partnership with theVictorian EPA has published and released aset of guidelines titled Trade WasteManagement Plans - A Guide And IndustryTemplate For Improving Trade Waste

Discharges. As the name suggests, thisguideline provides the framework fordeveloping a TWMP with a view toreducing trade waste related contamination.The guideline also provides some valuabletools such as a process flow diagramtemplate and root cause analysis template,for use in identifying the process steps androot cause associated with the priorityparameters.

A good TWMP will contain a minimumof three key ingredients:• a description of the customer’s tradewaste circumstances and compliancedeficiencies;• an agreed action plan with objectives andtimeframes designed to address compliancedeficiencies; and• a set of contingency plans for use in anemergency.

The TWMP should provide a pathwayfor continuous improvement as a conditionof the agreement. At every stage in theprocess, the TWMP must remain dynamicenough to cater for changingcircumstances.

Mutual AwarenessTWMPs provide a flexible joint in the

customer/authority relationship, linking thecustomer’s trade waste obligations withachievable milestones. It is thereforeimperative that at the outset, both thecustomer and authority agree to apartnership approach. The interests of bothcustomer and authority are best servedthrough cooperation and understanding.The term “partnership” implies awillingness to understand the other’sposition and to accommodate the other’sneeds where possible.

The water authority should take theopportunity to educate the customer of theissues and difficulties surrounding itsdischarge of trade waste. Only throughdeveloping the customer’s awareness canthe water authority hope to approachunderlying issues with the support of thoseresponsible. An informed customer is morelikely to take ownership of the issuessurrounding their company’s trade wastedischarge, particularly where the customercan see a benefit to themselves also.

The viability of the partnership needs tobe maintained by meeting regularly and

W A S T E M A N A G E M E N T

TRADE WASTE MANAGEMENT PLANS - COOPERATIVE COMPLIANCE

Jason McGregorPaper presented at the Annual Victorian

Water Industry Engineers and Operators Conference 2004

Part of CMI Operations’ metal pressing and finishing plant.

sharing information and discussingproblems.

Collection of Information andIdentification of Priorities

Collection of information and setting ofpriorities will help determine the scope of theTWMP. Efforts towards trade wasteimprovements must be properly focused inorder to maximise any likely benefits.

In all cases the volume discharged shouldbe targeted so that water conservation andpotable substitution receive due attention.The contaminants chosen for inclusion in theplan should be chosen for their relativeimportance with regard to the risk of non-compliance with the customer’s trade wasteagreement, risk to health and safety and riskto the sustainability of re-use projects. A riskassessment conducted on the characteristicsof the customer’s trade waste is a valuableaid.

To achieve reductions in the volume orstrength of the selected parameters, anunderstanding of the source of theseparameters is necessary. However, sharinginformation with the water authority can bedaunting for the customer, therefore thewater authority must exude an enthusiasm towork cooperatively. It is rewarding to therelationship to reinforce the aim of theexercise regularly. The aim is to implementcleaner production in partnership with thecustomer to the benefit of all concerned.

Goal SettingGoal setting should be based on expected

benefits, the financial impact on thecustomer, available technology and theconsequences of doing nothing. It isimportant that in setting these goals, bothparties agree that the goals are achievable.

Keeping goals to a minimum ensures that thefocus is maintained on the priorityparameters.

Identification of Options and PlanDevelopment

Based on the identified goals, the customerand water authority should brainstorm allpossible options to achieve the goals. It isimportant to think beyond treatmenttechnology and consider process changes, orproduct substitution to achieve cleanerproduction. Recycling is often an easy meansof waste minimisation, yet withoutsimultaneous reductions in priorityparameters, critical loads may not beimproved.

Since the customer will have an intimateknowledge of the processes and limitations ofits operations, the water authority will mostoften rely on the customer to suggest processchange. However the water authority willusually possess a greater awareness oftreatment options. This combination servesto provide a comprehensive list of optionsfrom which to choose. The next key step is toassess these options based on benefit, costand consequences. Section 6 of the TradeWaste Management Plan guidelines offers asystematic approach towards developing andassessing options. This is particularly usefulin providing structure when assessingoptions.

Once both parties have agreed to the plan,it can be appended to the trade wasteagreement.

Implementation and ReviewThe regular review of the customer’s trade

waste agreement and TWMP offers insightinto the customer’s compliance with theagreed action plan, while periodic



Figure 1. Reduced Monthly Trade Waste Discharge Volumes.

Figure 2. Increased Chemical Oxygen Demand at CMI Operations Due to Recycling.


consultation with the customer helps tomaintain both parties’ understanding ofchanging circumstances.

A Case Study - CMI OperationsCMI Operations is an international

company manufacturing pressed metalcomponents for the automotive industry.As an ISO 14001 accredited company,CMI Operations is committed toimproving its overall environmentalperformance.

Metal finishing is an integral part of dailyoperations, with components subjected toheat treatment, surface preparation andcoating with various rust inhibitors andmetal based surface veneers. These processeshave historically resulted in highconcentrations of zinc, chromium and oil inthe trade waste discharged to CentralHighlands Water’s sewers.

CMI, in partnership with CentralHighlands Water, embarked on a tradewaste management plan focused on

reducing heavy metal loads and total tradewaste flows to the sewer. Focusing attentionon these parameters allowed CMI staff toidentify a number of problem areas withinthe factory. A simple site visit helpedidentify the key processes and equipmentgenerating a large percentage of the tradewaste.

Working with Central Highlands Water,CMI Operations developed a range ofoptions including recycling of cooling waterand minimising heavy metal residue to


Part of CMI Operations’ metal pressing and finishing plant. Finished components.


sewer. To minimise the total volume oftrade waste discharged, a closed circuitrecovery and cooling system was installed torecycle gas furnace cooling water.

The approach taken by CMI to reduceheavy metal loads was surprisingly simple.Staff began by questioning the processesup-stream of the point of discharge tosewer and made some simple observations.

CMI staff discovered that hundreds oflitres of heavy metal laden wastewater wereregularly discharged from a large causticbath. As a result the caustic bath is nolonger used to clean equipment, instead asmall water efficient pressure cleaner is usedinside a purpose built spray booth. Thereduction of the volume discharged tosewers is shown in Figure 1. The associatedincrease in COD is shown in Figure 2. Thisincreased COD concentration has notpresented any difficulties to CentralHighlands Water treatment operations.

The much lower volume of concentratedwastewater generated is now transported offsite to an appropriate treatment facility.Work is also being done to reduce themetals at the source.

The recycling of cooling water reducedpotable water consumption and trade wastevolumes by 57,000 litres per day. Thismore than halved their total daily volume.This initiative provides an annual saving of

approximately $8,400 for potable wateralone and more than $2,000 in trade wastecharges.

By changing its cleaning processes, CMIcompletely eliminated its heavy metaldischarge to sewer. This resulted in afurther $1700 saving in trade waste charges.It also managed to reduce its use of causticsaving a further $600 per annum andreducing the discharge of sodium, alimiting factor in wastewater reuse.Compared to the cost of implementation ataround $12,000, the collective savingsprovide a payback period of little morethan 12 months.

This partnership built a strong workingrelationship between CMI and CentralHighlands Water which was an integralpart in the development of CMIOperations’ trade waste management planand in overcoming troublesome non-compliances with CMI’s trade wasteagreement.

For Central Highlands Water the keyachievement from this partnership was theelimination of heavy metals beingdischarged to sewer. The reductionsachieved by CMI will assist in improvingbiosolids quality and decreasing the risk tovarious re-use projects.

It should also be noted that an awarenessof the consequences of any actions is

necessary in order to plan for changingcircumstances. It is important to stay alertto the potential for increasingconcentrations when recycling, or fordeferring the problem rather thanminimising or eliminating it altogether.

Don’t over engineer a solution to aproblem that can be avoided or minimised.Remember the waste hierarchy; cleanerproduction provides a better solution thandisposal.

ConclusionsIntegrating a trade waste agreement with

a TWMP provides an avenue for flexibletrade waste minimisation. The constraintsassociated with prescriptive trade wasteagreements are softened and in doing so,the ability of the customer to improve itsperformance becomes measurable.

Regardless of the extent of trade wastecontamination or degree of compliancedeficiency, the TWMP offers a systematicapproach to implementing cleanerproduction and waste minimisation andencourages improvement from everycustomer within the customer’s means.

A significant demand on resources can beexpected when utilising a TWMP insupport of a trade waste agreement. Thenegotiation and monitoring of TWMPsacross a number of customers requires

significant effort. However thebenefits can be quantified to establisha rate of return.

AcknowledgementsThe efforts of Central Highlands

Water’s trade waste customers inworking with the Authority towardswaste minimisation and cleanerproduction through the developmentand use of trade waste managementplans is acknowledged with thanks.

ReferencesVictorian Water Industry Association andEnvironment Protection AuthorityVictoria, Trade Waste Management Plans -A Guide And Industry Template ForImproving Trade Waste Discharges, March2004.Environment Protection AuthorityVictoria and CMI Operations, CleanerProduction Case Study, May 2004.Victorian Legislation and ParliamentaryDocuments, Water Act 1989, Effectivedate - January 2004.

The AuthorJason McGregor (jmcgrego@chw.

net.au) is the Trade WasteCoordinator at Central HighlandsWater, Ballarat, Victoria.




COMPOSTING BIOSOLIDSDarren Key and Peter Mosse

Biosolids are one of the products ofwastewater treatment. Left in a stockpileafter dewatering they tend to slump andthus require a relatively large area forstorage. The piles tend to developunpleasant odours and are very difficult toapply to land using conventionalagricultural equipment. Composting is oneway to convert this relatively undesirableproduct into a friable, pleasant smellingearthy product in as little as 8 to 12 weeks.The final product is easy to handle for bothdomestic and agricultural applications.

Gippsland Water operates five activatedsludge Sewage Treatment Plants (STP). Atthe Warragul STP, waste activated sludge isthickened and dewatered using aconventional belt press. A cationic polymeris mixed with the Waste Activated Sludgeand then passes through a drum thickenerand on to a belt press. The resultantproduct is around 16% to 18% solids.Approximately 35m3 of product isproduced each week. This product has beentransported approximately 130km to anagricultural site and stockpiled for a periodprior to application to the land. Theapplication to the land has always been arelatively smelly and sticky job.

Consistent with the changing emphasistoward beneficial reuse of biosolids, adecision was taken to compost the biosolidswith green waste to produce a moreacceptable product for reuse.

Construction of a Composting PadA thick gravel pad consisting of a

compacted road base material,approximately 30m by 120m wasestablished for the composting operations.This pad was constructed so that anyleachate would be collected in an adjacentdrain and disposed of to a nearbywastewater lagoon.

After the first composting trials, the padarea was found to be too small to be able tocompost all of the biosolids beingproduced. The pad was therefore extendedby a further 120m by 45m.

A water supply main was installedaround the pad with multiple outlets toallow easy application of water to thewindrows when necessary to achieveoptimal moisture content.

CompostingThe starting point for the composting trial

was a basic mix of 2 parts of shredded green

waste to 1 part biosolids (2:1 v/v). This gavea carbon:nitrogen ratio of about 17:1. Ourtarget ratio was 20:1. The basic mix wastherefore changed to 2.5:1 to achieve therequired carbon to nitrogen ratio.

Shredded green waste has been obtainedfrom a number of local suppliers. Thegreen waste is delivered to site using Bdouble trucks (Figure 1). One of our mainproblems has been with the amount ofcontamination in the green waste. This hasincluded plastic of all types, metal,concrete, dolls heads, tennis balls, cans,shade cloth and other general garbage andlitter. You name it we’ve had it. There havealso been problems with the size of thewood chips with some large branches andlumps of wood getting through. Theselarger contaminants have damaged thewindrow turner on a regular basis.

The windrows were constructed by firstlaying out a long bed of green waste wideenough for a truck to drive along. Biosolids

were then deposited directly from thetrucks along the green waste bed (Figure 2).The sides of the bed were then folded overusing a backhoe bucket, any extra greenwaste added to make up the correct ratiosand then formed into a windrow smallenough for the windrow turner to fit over(Figure 3).

During the initial trials, the windrowturner was passed through the piles many

Figure 1 Figure 2

Figure 3

Figure 4



times. It was soon realised that too muchmixing produced a biosolids and greenwaste “paste” that then tended to form bigclumps which were hard to break up. The“paste” and clumps didn’t allow air to flowinto the windrow meaning these clumpsbecame anaerobic and odorous. When thepile was mixed initially with only threepasses of the turner, then left to dry for afew days, then mixed again, a wellhomogenised mixture was achieved whichwas still fairly porous, allowing better airflow through the pile. The mixture becameeasier to mix as the materials began tocompost. For this reason our procedure has now beenstandardised for 3 passes with the windrow turner (Figure 4).

The composting process, while simple, needs to be monitoredcarefully. The piles are monitored for temperature, moisture leveland initially, oxygen levels. Because of the tackiness of thebiosolids, oxygen sampling probes continually became blocked andso were found to be impractical for this application. Enough datawas collected though, to indicate that, as the oxygen level in thepile depleted, the microbial activity slowed and the temperaturebegan to fall. This meant that the piles could be managed andturned based on temperature (Figure 5). We aim to keep thetemperature between 55ºC to 65ºC.

Moisture tests are also carried out periodically (usually aboutonce per week depending on weather conditions) on the compostand, if needed, water added to maintain optimum moisture levelsin the piles. Our target is to keep the pile between 50% to 60%moisture. Moisture levels are determined by weighing out a sampleof compost then putting it in a microwave oven for approximatelyone minute. The sample is again weighed and the processcontinued until there is no weight change. The difference inweight can be used to determine the moisture as a percentage. Thisinformation can then be applied to the volume of the windrow tocalculate how much water needs to be added.

Open windrow composting requires the compost to be turned 5times during the composting stage of the process, with the piles ata temperature of > 55C for a total of 15 days. This is to make surethat all parts of the pile have been above 55C for 3 consecutivedays. Figure 6 and Figure 7 show temperature and oxygen profilesfor two windrows.

In our experience it takes around a day for the piles to return totemperature after being turned. This means that it actually takeslonger than 15 days to complete the active composting stage. Theeffect of turning can be clearly seen in Figures 6 and 7.

MaturationOnce the active composting is finished, the windrows are pushed

into bigger windrows for maturation. Temperatures are stillmonitored and the piles are turned regularly if the temperatureexceeds 65ºC to prevent charring of the materials. This iscontinued until the temperature decreases indicating that the fullcomposting process is complete. Without the maturation phase,the compost may be toxic to plants. Turning of the large windrowsis carried out using a loader with a four metre bucket

ScreeningOnce the piles have matured the product is screened. This has

been done using a shaker screen (Figure 8) with the wires set at10mm. The screen was hired from a nearby gravel pit. During thescreening process some of the contaminants are removed by thescreens themselves. If the screening is done on a windy day most of

the plastic is blown out. This makes a bit ofmess on the site and the adjacent paddocks.Some sort of fence would be useful to catchthe plastic.

Large wood chips that have been screenedout are used to seed new windrows since theyalready have white rot fungi developed onthem. This seems to activate a new windrowin as little as one day where as without theseeding chips it can take up to three or fourdays before temperatures in the pile begin torise as the microbes develop.

Depending on how well the green wastehas been shredded, the proportion of useable

product to reject materials varies quite a lot.

TestingApart from the testing of the windrows during the composting

process, another important test for the final product is to checkthat it isn’t toxic to plants. Plant phytotoxicity testing was doneusing radish seeds. Four groups of trays were prepared. One groupcontained a brand name seed raising mix purchased from the localhardware store, one a sandy soil from the site, one compost andone a 1:1 mixture of compost and sand (Figure 9).

A single seed was sown in each compartment of the tray makinga total of 12 seeds for each tray. The trays were kept moist and the

Figure 5

Figure 7. Compost oxygen levels measured at three sites alonga windrow. Note the periods of low oxygen levels. This wasassociated with some odour development and also decreasedtemperatures. The rise in oxygen levels after each low pointshows the effect of turning the pile. The recommended oxygenlevel for composting is >15%.

Figure 6. Compost temperatures taken at two sites along awindrow showing the temperature time relations to producecompost. There were three turnings of the windrow in theperiod shown.



seeds allowed to germinate and grow untilthe first true leaves had formed. This tookapproximately three weeks. The seedlingswere then removed from the trays and thesoils carefully cleaned from the rootsystems. The plants were then placed ongraph paper so that they could bephotographed and measurements taken todetermine plant and root growth (Figure10).

The most successful growth medium wasfound to be the compost and sand mixture,producing 100% strike rate and the bestplant growth and root development. Thecompost and the brand name seed raisingmixture also produced reasonable results.The trays with the sandy soil from the siteproduced poor results. The compost alonetended to shed the water and it took a longtime for water to soak into it. This waspossibly due to the flat shape of the smallwoody particles in the compost. In the trayswith the compost/sand mixture, the sandwould have made the compost more porousallowing good moisture penetration withthe compost helping to retain this moisture.

The important result from thephytotoxicity testing was that the compostdid not hinder growth in any way and infact promoted growth when mixed with thesand.

The final product has also been tested formetal and pesticide contaminants using thesame tests as those required for biosolids.This was done at a NATA accreditedlaboratory. While the biosolids Zinc andCopper levels were a bit high, the finalcompost product complied with all levelsrequired for unrestricted reuse.

Product UseAt this stage the intention is for the

product to be used in the agriculturaloperations at the site. The goal of theoperation is to produce a marketableproduct. To do this, particular attentionwill need to be applied to all steps in theprocess.

We have also conducted some informaltrials with Gippsland Water staff using theproduct for gardens, lawns and as a pottingmix, with good results.

Things We Have Learned• The compacted road base material hasproved to be unsuitable because some of thestones in the road base material end upcontaminating the piles due to the stonesbeing picked up by the loader bucket andbeing added to the piles.• The green waste needs to be clean and ofan even size with no logs or branches.While not all plastic can be removed, theless the better. If the green waste containedtoo much larger, woody material, the pilesstayed active for a lot longer as this largermaterial took a lot longer to break down. • Over mixing of the pile in the initialstages causes the biosolids and the greenwaste to mash into clumps and forms a sortof “paste” that tends to become anaerobicand is difficult to break up. If these clumpswere not broken up the centre did notcompost and when broken apart, containedraw biosolids.• Application of water can be difficult.Water had to be applied slowly or it wouldjust run off the surface of the pile with littlepenetration. The wind at the site alsocaused problems when adding water.• Wind also caused problems by blowingsmall stones and pebbles onto the surface ofthe windrows. To overcome this, compostwas allowed to build up on the gravel toform a new work surface and to stop thestones getting into the compost, howeverafter heavy rains this tends to becomesloppy.• Odour hasn’t been much of a problem.The biosolids themselves are very odorouswhen delivered to the site but once mixedin with the green waste the odourdisappeared fairly quickly, developing intojust an earthy smell in the first few daysafter mixing.• Open windrow composting can beaffected by weather conditions that can

cause difficulties in trying to control theprocess. High rainfall events caused highmoisture which can cause anaerobicconditions to develop in the windrows.High wind was also a problem, blowingunwanted debris and stones onto the pilesand drying the piles out in summer months.Time of year and daily temperatures hadlittle effect on the compost, with the pilesreaching composting temperatures nomatter what the air temperature was.• The final product is of a good quality andhas produced good results in trialapplications. Most of the compost producedso far meets the composting standards forreuse. Contamination of the green waste isthe main problem. It would be far better toremove the contaminants before the greenwaste is shredded and composted ratherthan doing the separation at the end whenthe shredding and compost turning hasbroken each piece of rubbish into lots ofsmaller ones.

ConclusionsComposting represents a way of value

adding to biosolids and can convert arelatively unpleasant, difficult to handleproduct, to a friable, pleasant smelling, easyto handle product that can be usedbeneficially and is environmentally friendly.Composting also represents a way ofturning other waste streams into a reusableand possibly marketable product.

The AuthorsDarren Key (darren.key@gippswater.

com.au) (0429 025 269) is the acting sitecoordinator at Gippsland Water’s DutsonDowns Resource Recovery Facility. DrPeter Mosse ([email protected]) (0428 941 013) works part timewith Gippsland Water on special projectsand part time providing specialist technicalsupport in water and wastewater treatmentto the broader water industry.

Figure 8 Figure 9 Figure 10



Mt Ruapehu and Mt Tongiriro, situatedon New Zealand’s north island, are sacredto the Maori, especially the tribes ofTuwharetoa and Ngati Rangi. In 1887 thechief of the Tuwharetoa, gifted thesummits of Tongariro and Ruapehu to thepeople of New Zealand so that their tapu or“intrinsic worth” may be protected for alltime.

Over the hundred years since this gift,Tongariro National Park has grown and hasdeveloped as New Zealand’s best knownand most used national park for skiing andtramping. The Tongariro National Park isconsidered to be an outstanding pristineenvironment which has significant culturaland spiritual values for Maori. Theseattributes have been recognisedinternationally with the Park holding dualWorld Heritage Status as a natural site andcultural landscape of outstanding universalvalue.

The most challenging task facing themanagers of Tongariro National Park liesin establishing a level of use at which publicaccess can be facilitated and commercialoperations permitted within the parkwithout compromising the tapu of thisprecious landscape.

Waste Water ManagementWhakapapa and Iwikau villages are the

two main sites of development andoccupation within the Park, and as suchthey pose the greatest challenge for sewagedisposal. Ski facilities and huts were firstconstructed on the mountain in the early1900s. Post-war development in the 1950sand 1960s saw the construction of manymore huts, something which the ParkBoard of the day encouraged with a view toassisting development and interest in theski field and promoting recreational use ofthe Park.

The Department of Conservation hasallowed the ski fields and club lodges toremain within the Park, recognising thatthey have had an historical and legalassociation in the history and developmentof the Park and are instrumental inproviding for public enjoyment. Theimpact and effects of such developmenthowever, must not compromise the naturaland cultural values and resources that havegiven the Park its high national andinternational status.

The Whakapapa Village sewagetreatment plant (STP) is located north ofthe Chateau Golf Course. Built in the1940’s, this plant has been upgraded overtime to handle increasing numbers ofpeople but in recent times has not metcontemporary environmental or culturalrequirements.

At Whakapapa ski field and Iwikauvillage the sewage from the 48 ski clublodges and lower ski field facilities has beentreated in approximately 50 separate orcombined septic tanks with deep disposalsoakage pits. The septic tanks are all withinthe upper catchment of the Whakapapanuistream. Ongoing problems with the

operation of these systems have beendocumented over time, together with thedifficulties of sludge removal from analpine environment. This is often carriedout by helicopter which has potential foraccidental spillage. There have also beenproblems with backflow of effluent leadingto surface discharge and odour problems atthe start of high-use periods.

To date the methods for treating anddisposing of sewage within theWhakapapa/Iwikau Area have beenconsidered to be creating a greater negativeimpact than is acceptable. Furthermore theissue of disposal of human sewage on asacred mountain or into the pristine

WHAKAPAPA ALPINE SEWERAGE SCHEME

Warren Furner



waterways that flow from the mountain isone of considerable cultural sensitivitywhich, in the past, has not been adequatelydealt with. The Department ofConservation has been working with thelocal community to address this since 1990.

A feasibility study confirmed that it waspossible to collect the sewage from themountain, upgrade the treatment at theWhakapapa STP and irrigate the finaleffluent by subsoil infiltration in an areaadjacent to the Chateau Golf Course. Theestimated price for the scheme was $3.75million. Importantly the study concludedthat the scheme could be developed whilepreserving the tapu of the area.

In June 2001 all parties including Maoriagreed and committed to the proposedscheme and resource consents were appliedfor and obtained mid 2002.

Project ChallengesOne of the major challenges in the

construction of the collection system wasthe vertical fall from the head ofreticulation at 2100 m to the treatmentplant situated at 1150 m, a fall of 950m.This required work to be carried out onsome quite steep slopes.

In addition, due to the seasonal snowcover, there was a limited time frame inwhich to construct the upper half of thereticulation.

Of particular importance was the need toensure that the construction processesminimised the impact on the environmentand to thereby protect the tapu of theheritage area. In the detailed design stages,attention was given to building a systemthat would also minimise the impact of anymaintenance activities at a later date.

How It Was DoneTo complete the construction within the

limited timeframe, three concurrentcontracts were tendered:1. Installing the buffer tank andreticulation system at Iwikau, usingconventional diggers and helicoptersupport. This was carried out fromNovember 2003 - June 2004.2. Laying of the reticulation pipe usingconventional methods along the BruceRoad corridor. This was conducted fromNovember 2003-May 2004.3. Upgrading the Whakapapa TreatmentPlant and installing the irrigation fieldusing conventional civil constructionmethods on site of existing disturbance.This was carried out from December 2003- May 2004.

In order to avoid freezing andmechanical damage during the wintermonths the conveyance pipe had to be

protected. This was done by burying it to adepth of 600-900mm.

Where the pipe was exposed such as atthe Whakapapanui Bridge, it was insertedinto another lined pipe for extra insulation.

All wastewater is collected at the point ofgeneration at each facility in both villages.All kitchen discharges pass through greasetraps before entering the reticulationsystem.

HDPE pipe sizes were selected to be inexcess of estimated peak flows to allow forfuture growth of day visitation toWhakapapa Ski Area and to take account oflarger flow volumes immediately followingsystem maintenance.

Potential blockage was minimised byrestricting the pipe size at each connectionto 80mm. This acts as a choke and ifblockage is to occur it will be at the sourcewhere the potential spill is minimal and canbe detected early.


The new sewers at Iwikau Village wereburied to avoid freezing damage and locatedto maximise ease of installation in hardvolcanic rock. The installation of thepipelines from some facilities requiredblasting to break up the hard volcanicbedrock. Inspection points were located atappropriate intervals and geocloth was usedto avoid the scour of bedding materials inthe trench

The skeletal nature of the mountain soilsand the very hard basaltic rock cover madedigging and excavation difficult in theIwikau village area. This was exacerbated insome parts along the pipeline route by thesteep cliffs and rocky outcrops.

To minimise disturbance of the naturalenvironment, the pipeline between the skifields and Iwikau village was laid where thenatural environment had been previouslydisturbed to establish ski runs. Wherepossible the opportunity was taken to co-locate snow-making pipes and power andtelecommunication cables in the sametrench. This meant that the need for furtherdisturbance was minimised and thesewerage pipe trench provided for long-term benefits beyond the sewerage scheme.As a result some of the pipe routes traversedslopes up to 28 degree in slope.

From Iwikau to the Whakapapa STP, thepipe was located and buried within the roadand shoulder of the Bruce Road andutilised existing structures to cross theWhakapapanui Stream. The road alsoprovides a reasonably consistent downhillgradient for the pipe. This design featureand location assisted matters such aspressure variation, air-locking, waterhammer surges and the deposition of solidsover time.

The contract team worked to aspecification which limited the disturbed

area to a 3.5 m wide access track. Thislimited trench methodology to a “once in”to clear access and working platforms,blasting rock to excavate a trench withcareful placement of excavated material onthe way out, importing and laying beddingsand by helicopter followed by hand laidpipe installation and bedding retention,then digger access again for finalreinstatement.

The final effluent is passed through anultraviolet disinfection system before beingpercolated through specially designedsubsurface irrigation tubes and trenches laidwithin a 7.0 hectare soakage field. Thesoakage field is located in a site formerlyused as an airstrip and pig farm, in thetundra area beside the Chateau GolfCourse.

The filtering/absorption qualities of thesoils, in particular the pumice in thesoakage field further reduces Coliformbacteria counts and phosphorus. Theirrigation journey ensures that a suitableloading of nitrogen per hectare of land isachieved.

In April 2004 the scheme wascommissioned with trials continuing withinthe irrigation field.

ConclusionContractors worked to achieve

approximately 15000 m of reticulation overa vertical elevation of 950m. Critical to thesuccess were contractors with a can-doapproach and willingness to work outsidespecifications to solve problems. Snow, ice,volcanic hazard and severe sun made up theenvironmental hazards along with strictsupervision from environmental officersand the general public who regard thislandscape as their own.

AcknowledgementsI would like to take this opportunity to

thank all those involved in the project andthe WIOA for their interest in taking thisstory to the Australian industry.

The AuthorWarren Furner ([email protected] )

is Program Manager for the Department ofConservation inNew Zealand.



BRAIN TEASER -Disinfection

1. Which disinfectionprocess uses thecombination ofChlorine andAmmonia?a. Chlorinationb. Chlorine dioxidec. Chloraminationd. Chloralkali

2. Which of thefollowing diseases canbe caused bypathogens?a. Typhoidb. Salmonellac. Cryptosporidiosisd. Diptheriae. All of the above

3. Chlorine in theform of solid tabletsis?a. Sodium hypochloriteb. Calcium hypochloritec. Elemental chlorined. Chlorine dioxide

4. When Chlorine gasis added to water itreacts with the waterto produce?a. Hypochlorous Acid& Hydrochloric Acidb. Hypochlorous Acid& Calcium Hydroxidec. Hypochlorous Acid& Sodium Hydroxide

5. The sum of Freeand CombinedResidual is called?a. Desired residualb. Total residualc. Best residual

6. Calculate the newChlorine feed rate inkg/day using thefollowing infor-mation.Current feed rate =3.2 kg/24hrFlow rate = 42.3 m3/hr

Current free residual =

0.9 mg/L

Desired free residual =

0.3 mg/L

7. When Chlorine gas

is added to water the

pH,

a. Increases

b. Stays as it is

c. Decreases

8. What is the recom-

mended ratio of

Chlorine to Ammonia

for Chloramination?

a. 2:1

b. 3:1

c. 4:1

9. A weak solution of

what can be used to

detect small gaseous

chlorine leaks?

a. Ammonia

b. Fluoride

c. Sodium hypochlorite

10. When Sodium

Hypochlorite is added

to water the pH,

a. Increases

b. Stays as it is

c. Decreases

11. Name one

advantage and one

disadvantage of using

full strength Sodium

Hypochlorite (Hypo

12.5%) for disin-

fection.

12. What safety

equipment should be

used when changing

over Chlorine

cylinders?

I N B R I E F

The Man From Boggy CreekMax Thomas 1981

I’m heading up the Tanjil, Pete,

where the country’s a delight.

I thought you’d like to come along,

And he replied alright.

Now, Pete’s a pretty cautious chap

As Bacto’s mostly are,

But he didn’t catch my crafty grin

As we loaded up the car.

The talk was mostly straight, youknow,

Cause Lyn was in the back,

But I’ll swear she caught whatDonlon thought

As we crashed down Orton’s track.

Hullo trouble, what brings you ‘ere?

As if I need to ask.

This is P’Peter, I said

He’s here to …. supervise the t’task

Well, the man from Boggy Creek, itseems,

Was one for keeping score.

I’d get the Boys to run yers up.

He’d seen the likes of us before.

Only the Boys…aint ‘ere,

And the Fergy’s runnin’ hot

Look, go on, get up on the dray,

I’d like to see this sampling spot.

I’ll walk if you don’t mind, I said,

In a half suspicious tone.

Go on, get on up, he said,

Perched high on Fergy’s throne.

Well, there we sat like tourists,

With muck and straw all round,

He let the Fergy have her head,

And she knew the roughest ground.

I don’t know if you go for pork,

Or if you like it rare,

But the question’s really who’ll eatwho,

The way pigs look at you up there.

Lyn clutched the sample bottles,

Porkers followed on the trot.

When one tried to mount the dray

She nearly lost the plot.

A nice fat goose that is, Pete said,

Are you going to pluck it?

Pipe down you! If I want a pig,

I’ll rattle on the bucket.

So now the ordeals over,

And the brew-room sceptics doubt,

But ‘til you’ve sampled on the Boggy,

You don’t know what sampling’sabout.

At last, up by the Tanjil,

In the land of sudden storms,

They’ve made the place a sanctuary,

For faecal Coliforms.

Editors Note: The poem describes awater sampling trip in the forests ofGippsland in the distant past. Namesin the poem have not been changedto protect the innocent !! The“innocent” may well recall their past!!

Answers to Disinfection Brain Teaser1. C2. E3. B4. A5. B6. 2.6 kg/day7. C8. C (the actual ratio dependson the conditions but 4:1 by

weight is a suitable startingpoint)9. A10. A11. Advantages •paying same delivery costsfor more “active ingredient”(There may be others?)Disadvantages•Gassing

•Loss of active ingredient•Dangerous Good(There may be others?)12. Safety equipment shouldinclude•Self contained breathingapparatus•Gloves•Safety boots

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