An Expert Panel on Health was appointed to oversee the planning including the consideration of submissions which it may receive from organisations or individuals. The Panel released an ‘issues paper’ back in May, at which we took a brief look at that time.
This month they have released their final report titled: “Public Health and Safety in relation to Water Purification for Drinking Water Supplies - Advice to the Chief Minister of the ACT and the ACT Government on the health and public safety of the Water2WATER proposal”.
It seems that the committee have thrown their support behind a high-pressure membrane-based treatment system. They appear to have dismissed the alternative treatment schemes (which are used in other inland cities) incorporating such technologies as ozonation and biological activated carbon filtration (BAC).
The Executive Summary is plagiarised below. You can download the full report from here. I’d be grateful to receive your thoughts via the usual means...
Executive Summary
This report has been prepared as the advice to the Chief Minister of the Australian Capital Territory (ACT) and the ACT Government on the public health and safety aspects of ACTEW’s Water2WATER proposal. This proposal is for the installation of a modern day membrane-based (micro or ultrafiltration followed by reverse osmosis) water purification plant (WPP), followed by wetlands and an enlarged Cotter Reservoir, to access water from the Lower Molonglo Water Quality Control Centre (LMWQCC) effluent for the supplementation of the drinking water supply for Canberra and area.
The Terms of Reference for the Expert Panel on Health (the Panel) focus on the capability of the proposed treatment system to produce a purified water that complies with the quality specified in the 2004 Australian Drinking Water Guidelines (ADWG). This has been extended by the Panel to include the new draft 2007 Australian Guidelines for Water Recycling - augmentation of drinking water supplies (AGWR) which set out a more rigorous and extensive set of guidelines for this purpose.
While the Panel has examined the information, provided by ACTEW on the Water2WATER proposal, it has also considered the context in which this proposal is made. The effect of the current drought and likely impact of climate change on rainfall make the enhancement of Canberra’s water resources a necessity. The provision of a secure water supply in an urban area is a first priority for public health, for sanitation and for drinking water supply. The Water2WATER proposal provides one alternative mechanism for ensuring water security, based on the reliability of supply of water from the LMWQCC.
A prerequisite for the Panel’s work is that public health and safety must not be compromised at all by the Water2WATER proposal.
The Panel has reviewed the levels of treatment expected from the proposed WPP and the likely quality of purified water produced. It has assessed the level of risk and has suggested requirements for ACTEW to monitor and manage any residual risk.
The community consultation program has been examined and evaluated, and the community response assessed.
The process and criteria by which the Panel evaluated health risk and its management in safe drinking water supply is explained. Risk is inherent in life, and drinking water guidelines are determined on the basis of acceptable or tolerable risk.
The current Canberra water supply is described, including the raw water quality obtained from the Cotter River, Queanbeyan River and Murrumbidgee River. Only the Murrumbidgee water is supplied directly into the Canberra supply after treatment at Mt. Stromlo Water Treatment Plant (WTP). This plant was constructed in 2004, following the reduction in water quality from the Cotter River after the bushfires. It has capability for handling turbid water from the Cotter or the Murrumbidgee through flocculation and dissolved air flotation, dual medium filtration, chlorine disinfection and is currently being fitted with UV disinfection to further reduce the risk of Cryptosporidium entering the drinking water supply.
The Mt. Stromlo WTP forms the last safety barrier of the Water2WATER proposal, as it treats the water from the present Cotter Reservoir, and from any future enlarged Cotter Reservoir. It provides drinking water for the whole of Canberra if needed and its operation is carried out in terms of an all-encompassing, third party certified, Hazard Analysis and Critical Control Point (HACCP) Plan that covers the drinking water supply system in Canberra.
The LMWQCC handles 90% of Canberra’s wastewater, which is processed, disinfected and discharged into the Molonglo River upstream of the junction with the Murrumbidgee. The plant is a highly effective operation, removing solid and suspended material, pathogens, degradable organic compounds, phosphorus and a large proportion of nitrogen. The discharge water easily meets all guidelines imposed by the EPA. The present monitoring of the wastewater discharged is described in detail in this report, which includes frequent measurement of major components including faecal organisms, and less frequent measurement of such possible contaminants as pesticides and organic chemicals.
Prior to detailed design of a WPP using this source water from LMWQCC, it is essential to considerably extend the monitoring program to include endocrine disrupting compounds (EDCs), pharmaceutical products and more disinfection by-products. It is also necessary to monitor for a range of possible pathogens, including helminths, protozoa, bacteria and viruses. The LMWQCC is the first barrier in the Water2WATER system, which removes the bulk of wastewater contaminants and infectious organisms, and as such it must be protected through a diligent and comprehensive trade waste or source control plan. This latter plan must address all trade waste generated in Canberra and which are discharged to sewer and hence gain access to the LMWQCC.
HACCP accreditation for both Trade Waste control and the LMWQCC are required and this must also be incorporated into the current drinking water proposal to ensure that an integrated HACCP plan is in place for the entire Water2WATER project.
The initial Water2WATER proposal presented to the Panel comprised three alternative treatment trains. One is the reverse osmosis-based (RO) train, and the other two trains rely on ozone/biological activated carbon (BAC). There are fundamental differences between these two approaches in relation to salt, nutrient and organic carbon removal.
In a RO treatment train the salt is separated into a brine stream, distinct from the purified water stream. Only the purified water proceeds into the wetlands and reservoir, therefore not affecting the salt content of the reservoir or the drinking water. However, in the ozone/BAC treatment train, while the pathogens and organic constituents of the water are removed, salts pass unaltered into the output stream. This would increase the salinity of the reservoir water and therefore the drinking water to an unacceptable level.
Further, the two ozone/BAC treatment trains do not achieve the levels of removal of nutrients and organic carbon that are achieved in the RO treatment train, and the Panel therefore recommends that these two treatment trains are not considered further in this proposal.
The proposed treatment train, incorporating reverse osmosis, employs, as first step, microfiltration/ultrafiltration for removal of fine particles, protozoa, bacteria and some viruses. This is followed by RO for removal of salts, larger organic molecules and viruses, then ultraviolet light plus hydrogen peroxide (referred to as the Advanced Oxidation Process) for oxidative destruction of residual viruses and organic chemicals.
Operation elsewhere has demonstrated that the reduction in pathogens and chemical contaminants of all types in this RO-based treatment system well exceeds the requirements for drinking water augmentation. The Panel understands that the operational characteristics of this system will be evaluated in a pilot plant in Canberra, prior to final approval of the Water2Water proposal.
The purified water produced by the WPP will be pumped up to the Cotter catchment, and discharged into shallow wetlands. The Panel consider that the main benefit from this will be temperature equalization with the environment, reducing hydraulic streaming in the Cotter Reservoir. Some reduction in any residual nutrients and pathogens may also result, depending on the overall biological and temperature environment of the wetland. The Panel also noted that pathogens may also be introduced from the fauna of the wetland, as occurs widely in nature. Following the wetland the proposal is for the purified water to flow into the Cotter Reservoir. The Panel consider that it is an essential part of the overall proposal to enlarge the Cotter Reservoir, to provide an effective barrier in the supply system. This adds a safety component that cannot be provided by the current reservoir. Without the enlargement the retention time in the small Cotter Reservoir would be short, and the operating limitations on the current reservoir would result in the purified water running over the spillway during periods of rain.
The Panel notes that the purified water entering the Cotter Reservoir will still contain residual levels of nitrate and phosphate and as a result there could be an increase in the concentration of these two nutrients in the water in the Cotter Reservoir. It recommends that this potential increase should be modelled and if there is a likelihood of the increase causing toxic cyanobacterial blooms in the reservoir, then remedial action will be necessary. This remedial action can be modification of the LMWQCC to further reduce nitrogen and phosphate in the feedwater to the WPP and/or the modification of the Mt Stromlo WTP to use powdered activated carbon in the water treatment process in instances when cyanobacterial outbreaks are experienced in the Reservoir.
Risk management of drinking water supply systems using purified water from wastewater sources is a key component of ensuring public health and safety. Such processes inherently carry higher levels of risk, due to the prevalence of pathogens and complex chemicals in untreated wastewater. Acute health effects would be readily observed as outbreaks of disease. Any chronic health effects would be more difficult to measure as they would not be immediately detectable, requiring epidemiological analysis between otherwise comparable populations or comparison over sufficiently long time spans.
Epidemiological investigations to date of populations consuming drinking water augmented with purified water have not shown any increase in gastrointestinal disease.
An on-going study of water-borne infectious disease in Canberra would be a valuable monitoring component of the consequences of drinking water augmentation with purified recycled water.
While microbial pathogens are a major concern, the monitoring of pharmaceuticals and their products and natural and synthetic endocrine disruptors in purified water is also essential. Health outcome monitoring is also required, including on-going assessment of community rates of cancer and birth defects from existing population-based data sets.
The Panel notes that with the treatment train proposed by ACTEW and with appropriate levels of operational monitoring and management, along with operator training and skills at the level recommended by the Panel, the quality of purified water that is transferred to the Cotter Reservoir will comply with all the health related guidelines of both the 2004 ADWG and the draft 2007 AGWR.
In addition, the Panel notes that the 2007 draft AGWR states that a treatment train with a configuration as proposed by ACTEW will produce a purified water that complies with the health related guideline values – for both acute and chronic parameters.
Community views on the Water2WATER proposal were assessed during the ACTEW consultation process and the consultants will provide a detailed report to ACTEW. The largest single route of community access to information was the ACTEW website, with 4429 hits. Community forums, briefings and displays recorded 2441 contacts.
The Panel received only two formal written submissions, from Engineers Australia and from Professor Peter Collignon. Engineers Australia argued for the expeditious securing of improved water resources for Canberra, with cost-benefit analysis of alternatives. They suggest that a risk management plan for Water2WATER should be made available prior to the project being agreed. The detailed submission is available on the website www.expertpanelonhealth.canberra.net.au
The submission from Professor Collignon raised concerns that ‘recycling water from sewage into drinking water is a high risk procedure’ and that it should only be undertaken as a last resort. He raised concern about adding recycled water into the small Cotter Reservoir, which would mean that the proposal is effectively a direct potable recycling scheme. His full submission is available as above.
The Panel also received e-mails expressing concerns over the Water2WATER proposal ranging from outright opposition to concerns about human error and equipment failures.
Overall only a small proportion of the Canberra community actively participated in the community consultation process despite a wide range of mechanisms to do so.
Community views that were obtained by random contact and by surveys tended to be positive or neutral to Water2WATER, compared to the negative viewpoints of those who submitted their views through e-mail, letters or submissions.
On the basis of all the available information it appears reasonable to conclude that the majority of the community are not greatly concerned with the Water2WATER proposal.
Meanwhile, the community has also clearly communicated a desire for a more detailed investigation of other options for securing Canberra’s water supply.
The Panel recommends that an on-going community engagement process take place if the Water2WATER proposal is adopted. This will allow for more detailed information to be made available to the public, and a long-term collaborative engagement and participation of the public in the development of the proposal.
Overall, at present there is qualified support within the community for the use of nonpotable and potable recycled water. However, some concerns have been raised about health and safety issues of the current ACTEW Water2WATER proposal. These require sufficient time and resources to be fully addressed. The community recognises the need for the ACT Government to act expeditiously in securing the future water supply, but urges fuller investigation of all options for securing sustainable water for the future.
The Panel considers that a reverse osmosis-based water purification plant is feasible as a method of increasing the water supply for Canberra, subject to stringent health and safety requirements being met as set out in the draft AGWR and the approval of ACT Health as the regulatory body responsible.
The Panel recommends that:
1. ACTEW only proceed to continue investigation into a dual membrane Water Purification Plant (WPP) and that the alternative treatment train using ozone and biologically activated carbon not be considered further, due to the salt, nutrient and organic carbon loads entering the drinking water supply if this method of treatment were to be used;
2. The lower Cotter Reservoir be enlarged and the Panel notes the intention to construct this simultaneously with the water purification plant and ancillaries;
3. An extensive monitoring program be undertaken at the Lower Molonglo Water Quality Control Centre (LMWQCC) on the influent (water entering the system) and effluent (water leaving the system) concentrations of microorganisms and contaminants of concern prior to detailed design of the purification plant;
4. ACTEW provide a Recycled Water Management Plan that includes the following information before the process is commissioned:
o The staffing levels proposed for the new plant;
o The level of training that the plant operators will have undergone prior to plant commissioning;
o The means by which the operation of each of the stages of treatment in the WPP is monitored and maintained at the optimum level (e.g. where relevant, details of membrane integrity testing, specialised on-line instruments etc);
o An approved Hazard Analysis and Critical Control Point (HACCP) Plan that shows the likely Critical Control Points (CCPs) for the various stages and barriers in the WPP, together with ‘action’ and ‘shutdown’ values; and
o An integrated Drinking Water HACCP plan that incorporates the Plans for the LMWQCC, the WPP and for the regulation and control of trade wastes that enter the sewer;
5. The WPP be staffed for 24 hours/day for at least the first 5 years of its life;
6. ACTEW carry out a modelling exercise to investigate the impact of the nutrient loading in the purified water on the water quality in the enlarged Cotter Reservoir;
7. An ongoing community engagement process take place if the Water2WATER proposal is adopted. This would allow for more detailed information to be made available to the community and to begin developing mechanisms for a longer term collaborative engagement approach in which the community can become partners in decision-making processes; and
8. Community consultation and engagement be incorporated into and inform all stages of future water security initiatives including the planning, design, implementation and management stages of specific projects. This would encourage a system of water stewardship that places a priority on partnerships between the community and water authorities.
9 comments:
Dear Stuart
To quote the Bard " I do smell all horsepiss" (The Tempest)
A scheme devised by loonies for loonies. Of course it is technically feasible, that was never in doubt, the only problems are associated with the COST, both capital cost and the running costs which rise exponentially with the increase in level of security required.
We already have the most highly treated and expensive sewage discharge in Australia( and possibly , the world) This is a system which will have extraordinary overheads, hail , rain or shine, I believe that the artificial wetlands as proposed will be unattainable. On viewing the area, there appears to be insufficient capacity to enable transit times of weeks necessary to effect biological filtration, a fact raised in one of the studies . It would seem that transit times are likely to be in terms of days or even hours in periods of heavy rainfall.
The whole idea is based on fallacious assumptions, scant regard for science (especially gravity and the cost of overcoming it) and an apparent total rejection of economics.
Thanks Rwindsor,
I take your point about the cost of the scheme and concur that it will not be cheap. The need to sustainably manage the membrane waste-stream in an inland region will also have a significant cost-impact. And of course, the cost required to elevate the water back up into the Cotter catchment will also be considerable.
I suppose the question that needs to be asked by the Canberra community is “are the benefits sufficiently great to justify the costs?” Its probably not a question that I can provide an answer for, but I reckon I already know yours!
Dear Stuart
At the time when the water recycling scheme was not even a twinkle in the eye of planners (2005) the preferred Tennant Dam scheme was costed at $159 million and a figure of 24 cents per Kl was bandied about (Average current consumer pays $1.88 per Kl at present inclusive of all fees and charges)
Between 2005 and 2007, the cost of the Tennant Dam has ballooned to $300 million ( still makes water cost less than 50 cents per Kl) with recurrent spending on maintenance at a low level and effectively no pumping costs).
On the other hand, the enlarged Cotter Dam to hold the 10 Gl per year of recycled water will cost at least as much, and the water recycling scheme will cost a similar amount in capital cost with enormous running costs. I am unable to get any reliable costings in Australia but comparable technology overseas is delivering water at $2.50 to $5.00 per Kl. Given that the ACT Govt is using ACTEW ( the water supply authority) as a cash cow, then it is conceivable that a consumer cost in the region of $4.00 to $ 7.00 per Kl is not out of the question.
Is a doubling or tripling of charge reasonable? Not in my books when it is ideologically driven.
As an interesting diversion, the current Cotter dam and stretch of river up to Bendora are managed with primary concern for ecological considerations. If the same restrictions are applied to the enlarged dam, then the usefulness of the extra capacity is totally negated. See the links from http://www.actew.com.au /futurewateroptions/
for more details
Regards
R
Thanks for this information, Rwindsor.
I understand that the Tennant Dam is a very popular proposal among the ACT community and also that it is generally agreed that it is indeed the next best site for a new dam. I don't think it has necessarily been scrapped from further consideration has it? Or is it considered that the enlargement of Cotter Dam (which seems practically inevitable) makes the Tennant Dam less urgent?
It is certain that water prices throughout Australia can be expected to increase significantly during the next decade. However, I expect it will be some time before Canberran's are paying $7 per KL (at least for a reasonable household consumption level).
Hi Stuart,
I understand that I'm outside the terms of reference, but why are we so focussed on putting recycled water into the drinkable water supply? Is it not possible to use the LMWQCC as a source for a secondary water supply system for the various water users that do not need drinkable water? (Any organisation with significant area of park land or ovals, many industrial uses, the various dust management activities that ultimately translate into filling trucks with water to spray on the road!) Would this not make rapid use of the recycled water without the need to treat it all that highly? Also, would it not reduce our demands on the current drinkable water supply by much larger amounts than pointless water restrictions? Are the only real costs associated with building and operating a seocndary distribution system? (I'm no expert, but is that just laying pipes and running some pumps?) Is it not the role of governments to invest in infrastructure? Once commenced, this sort of solution could be made available even to residential customers on a "When the pipes go past your house" basis. It could also be made mandatory in all new developments. Once again, I'm asking for governments to LEAD!
Hello OzGremlin,
Non-potable water recycling does indeed offer lots of good opportunities to save drinking water for most cities.
As you suggest, the major difficulty and expense is distribution of a second segregated supply. This is usually not a major obstacle if you can identify a small number of significant users. Some great existing examples include Bluescope Steel in Wollongong, BP Amaco in Brisbane and Eraring Power Station south of Newcastle. An alternative approach is where you can identify a tight cluster of smaller users such as at the Kwinana industrial estate, south of Perth.
The idea of providing a pipeline of recycled water, which customers may tap into is a good one. You may like to read some of the earlier posts here on the Liverpool-to-Ashfield pipeline.
Recycled Water can also be delivered as a separate non-potable supply to houses (such as done in numerous new suburbs in NSW, Victoria, Queensland and South Australia). However, it is generally acknowledged that it is not economically (nor probably socially) feasible to dig up existing suburbs (and houses) to retro-fit a second plumbing system.
A further important factor to consider when identifying users for recycled water is just how much potable water can be saved when it is most needed. Irrigating parks and gardens has a significant value, but these are uses which tend to be curtailed during water restrictions anyway. If the recycled water can instead be allocated for uses that would continue during water restrictions (such as most industrial applications), then the consequent water savings can be more fully achieved.
I would be interested to know of any potential major users of recycled water that you can identify in the ACT.
Well I'm no expert on this subject, merely an interested resident, but I can readily name a number of large water users in the ACT who are able to continually achieve exemptions from water restrictions:
1. Parliament House
2. Most of the Parliamentary triangle (Although they are now starting to use lake water from Lakey Burley Griffin - is that really going to be sustainable in serious droughts?)
3. The major golf courses
4. The "significant" parks - botanic gardens, arbortoreum, etc.
5. The "elite" sporting facilities - Canberra stadium, Manuka Oval, Viking park, Ainslie Football club.
6. The top tier private schools.
Now I know already that some of those in my list make use of bore water, but I also know that they revert to town water when ever bore water is not available.
Also, in response to some of your points:
1. The ACT was constructed in such a way that suburban schools are usually clustered with local ovals, local parks, and even the local shopping centre. Significantly, this cluster often includes public or semi-public (Sporting ground change rooms) toliet facilities. This would seem to be the right kind of clustering to make a non-potable water supply worth doing.
2. What industry we have in the ACT is clustered around a very small number of industrial centres (Fyshwick, Mitchell, Hume) which also significantly improves the viability of providing non-potable water supplies.
3. The nature of Canberra's geographic sprawl includes large areas of "nature park". This means that significant stretches of pipeline can be laid with zero need to dig up either roads or suburbs.
4. Almost all large scale construction activities include dust management requirmeents. This is especially tue of all road works. This equates to filling trucks with water and spraying it on any exposed dirt. These trucks are utilising the nearest fire hydrant as the water source because its commercially sensible to do so. If there were a non-potable alternative that was reasonably accessable, it would be realistic to force these activites away from the town water supply.
As I stated before, I don't understand why we are so focussed on the drinkable water supply, when we have a high quality non-drinkable water supply that we simply don't use.
Thanks OzGremlin,
There are all good ideas and I take your point regarding the ‘clustered’ nature of Canberra’s design…I’m sure it must indeed offer some unique opportunities.
Some of the suggestions that you have made are consistent with the approach already taken by ACTEW. For example, the North Canberra Water Reuse Scheme. The pipe system and major users are shown here. Typically the users are a golf course, ovals and playing fields.
Nonetheless, I agree with you that there must be further opportunities.
Dear Stuart
OzGremlins comments perfectly illustrate the farcical nature of the process of public commentary. ACTEW has already done all this preliminary work to the point of costings as I understand. The current "sewer mining " units serving Southwell park have been in operation long enough to show their reliability and economies. LMWQCC is some 20 Km from the city centre and as this area is already well served by the current recycling system utilisinmg Fishwyck sewage treatment plant and the Southwell park system, the implications are that recycled water will have, at least, a further 20 km to go to meet the southside requirements.
If ACTEW were honest and transparent, this information would have been placed in the public arena before the debate was initiated. Instead, smoke and mirrors techniques to hide the hard facts, have been employed
If one looks at http://www.actewagl.com.au/wastewater/treatment/cranos.aspx
one finds a very informative page on scaleable "sewer mining" units which, on the face of it, appear to solve most problems without the enormous cost of pipeline duplication or the even more horrendous costs of centralised recycling.
This is still side-stepping the real issue, that Canberra cannot grow with its present water security, without a significant reduction in health security or standard of living.
It also side-steps the underlying issue of population control.
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