If walking along the banks of the Waikato River can be a health risk, MONIQUE DEVEREUX discovers how it can be safe to drink the water.
The silver-haired engineer in the orange safety jacket is standing on a hill, peering through the glass of water he is holding.
It looks as clear as any tap water. He takes a sip. He does not splutter, cough or choke.
Derrick Adams is Auckland's Watercare Services general manager projects. His glass of water originated from the Waikato River.
This is the same river that starts off in Taupo looking crystal clear and refreshing, and ends up spilling into the Tasman Sea as a rush of murky brown water that scientists warn is a health risk to swimmers.
This is the water that by the middle of June will make up about 10 per cent of most Aucklanders' drinking water.
Experts - both international and domestic - say the "raw source" water quality is completely irrelevant to drinking water supplies. They say the treatment process the water goes through before ending up in any glass is so rigorous it erases any evidence of the nasty bugs that are known to live and breed in the river.
"It has to," says Adams. "I will be drinking it, my family will be drinking it. Over anything else, I wouldn't knowingly put my children at any risk."
Hamiltonians have been drinking the water for 31 years. In that time there have been no health scares or concerns with the treated water.
Twenty other communities, including Tokoroa, Ngaruawahia, Huntly and Cambridge, also use the river as their main water supply. None have had health concerns.
Environment Waikato water scientist Bill Vant spends a good part of his work looking at the quality of the river. Swimming is not recommended, "ever, really". Drinking the treated version is another story.
"I drink it. I know what is in it probably more than most people. The treated version is completely acceptable. I know there is a lot of hype, but it's unnecessary."
Hamilton City Council water, drainage and refuse manager Leroy Leach, agrees.
His water treatment system is also vigorous and gives Hamilton city dwellers a healthy product. He is reluctant to comment on why Aucklanders might have a problem with the water quality.
"I'm happy. I live here with my family, I've got three great boys. We are as healthy as buckrats. I like the taste of our water. I'm comfortable with it."
His comfort is not universally shared.
The Green Party is opposed to the idea of Waikato River water becoming Auckland drinking water. So is the outspoken Water Pressure Group and various councillors on Auckland's councils.
All feel there are better options to back-up Auckland's supply.
T HE idea of tapping the Waikato for Auckland began when the city was hit by the crippling drought of 1994. City dwellers were urged to conserve as supply levels in the Hunua Ranges - Auckland's main source of water - sank to an extreme low.
The region survived that shortage but it made evident that Auckland's dams would not be able to keep up with Auckland's swelling population. (Since the water crisis Auckland's population has already increased by the size of Dunedin.) An additional water source was needed.
Years of investigation and consultation, feasibility studies, and environmental reports sifted through some 96 different options.
"You might as well say we looked at everything - starting with the possibility of towing in icebergs," said Adams.
The final verdict: Auckland's water supply would be topped up by the Waikato River via a pipeline, at a cost of $155 million.
Construction of the treatment plant to clean up the river water and make it drinkable began a year and a half ago. It started as a grassy hill, but today "Project Waikato" is a slick-looking industrial building with pipes sprouting in all directions, big round concrete water tanks and the constant hum of large pumps.
The plant sits on the banks of the mighty Waikato near Tuakau, on one of the last big bends in the river before it heads out to sea. Sometime in the next few weeks it will be fine-tuned ready to pump water out of the river and through its four treatment "barriers".
As this gets under way, the Ministry of Health will begin a rigorous 10-day testing programme to ensure the water meets New Zealand drinking standards.
Only after every test is passed can the river water begin chugging along the 38km of pipeline that will deliver it into Auckland's main water supply.
Watercare Services acknowledges that the Waikato River is a dirty water source. Because of this, the treatment plant built to cleanse the water is more sophisticated than any other in the Southern Hemisphere.
Watercare is at pains to point out this is not just because it has to be. The plant has the benefit of new technology developed long after other treatment plants were built.
On day one of Waikato River water use, gravity will pull 50,000cu m of water 13m underground into the first pumping station. Before getting into that first pipe the water will pass through four screens that are dense enough to stop fish, whitebait, small leaves, twigs, and little stones.
Next it is routed up the hill to the clarification segment. Here a coagulant is pumped into the water that attracts anything solid that is left in the water - namely sand, grit or sediment.
It also removes the nasties like giardia and cryptosporidium, which cause stomach bugs and can even kill people with fragile immune systems.
Bonded by the coagulant, the solid material falls to the bottom of the tank. It will later be processed into a dry sludge of cake consistency, that eventually ends up in a nearby landfill.
This first stage of cleansing removes 99 per cent of any solid material or parasites lurking in the water. And it is just the beginning.
Part two is the membrane filtration - the section that is unique in New Zealand and regarded by Watercare Services as "the best thing since sliced bread".
Developed by a Canadian company, the membrane system is made up of hundreds of thousands of hollow straw-coloured cords that dangle into water tanks in "cassettes". Each membrane is the width of a piece of spaghetti and to the naked eye looks like a smooth, solid surface.
A microscope reveals the millions of tiny holes or pores, all smaller than a pin-prick, that cover the membrane. Each pore is so small the cysts that carry nasties like giardia and cryptosporidium cannot physically pass through them.
The water is sucked up the middle of the membrane, leaving the cysts and other bacteria on the outside, and whisked away to stage three of the treatment process.
Stages three and four are common in all New Zealand water treatment plants - carbon filtration and chlorine treatment. After the last stage the water can begin its journey along the Waikato Pipeline to Manukau's Redoubt Rd reservoir.
Here it will be mixed with around 270,000cu m of water that had been sourced from the Hunua dams and finally launched into the network of pipes that cover Auckland.
But that is all irrelevant, says Green Party co-leader Jeanette Fitzsimons.
"There is no reason why Aucklanders should have to drink Waikato River water. It simply isn't needed. The Greens have been saying for years now that Aucklanders should keep drinking their current high quality water from catchments with no industrial or sewage discharges, and that the Waikato water should be used for industrial purposes in those South Auckland industries closest to the Waikato," she says.
"It could also be used for emergency supply in a very dry year. Short-term exposure to the contaminants is quite different from drinking them for a lifetime."
Fitzsimons says it would be expensive to have two different reticulation systems around Auckland and it also poses the risk of "getting them mixed up".
There are a number of large industries in South Auckland which use large quantities of water for non-food related uses, she says, and a separate pipe to them could be justified much more easily.
Last month Fitzsimons went further saying "the Waikato Pipeline must be put on hold until the Ministry of Health can give quality advice to Watercare Services about gender bender hormones in drinking water".
She was referring to a British study commissioned by the British Government which found that drinking water from rivers was being contaminated with highly concentrated female hormones from the urine of women using contraceptive pills.
These hormones were changing the sex of around half of all male fish and possibly affecting male fertility.
Her concerns were taken up last week by Auckland's vocal Water Pressure Group, which was set up to protest against water privatisation in Auckland.
The group raised the issue at last week's Auckland City Council meeting and have planned a public meeting for May 8. But Watercare Services says there is no issue with oestrogen.
"At the time [Fitzsimons'] comment was made, the issues that were coming out were based around some interim press released prior to the release of the full report of the oestrogen issue in the UK," says Derrick Adams.
"Now that the report has been released, we have had it reviewed by our experts to see whether it has any implications for a water supply. The conclusions they have ... is that it doesn't have any implications for our water supply.
"It's all related to issues to do with the fish and environment rather than to do with drinking water."
Adams pointed to a thesis completed two years ago that specifically looked for oestrogenic activity, written by Auckland University Masters student Jennifer Gadd. "No oestrogenic activity was detected in either the raw drinking water or the treated drinking water at the Hamilton water treatment plant," Gadd's summary said.
Adams said Watercare Services had also peer-reviewed international reports of water treatment capabilities.
"They clearly demonstrate that if there was something there, it would be removed by the treatment processes that we have."
"Internationally the issue hasn't made its way into drinking water standards because drinking water processes deal with it. We have a vested interest in water quality and we're not interested in short-changing the public in any way at all ."I T WILL take the first drop of water almost an entire day to move from the river to the start of the Waikato Pipeline, and up to three days to get to Manukau. Allow another one to three days - depending on what part of town the tap is turned on - for the water to end up in the glass.
"Not that anyone will be able to tell the difference in taste or colour," Adams says.
"The Waikato water is treated more rigorously, partially because it has to be but also because of that new membrane system. At the end process we actually won't need to use as much chlorine as we do for the Hunua source so by itself it would taste better.
"Of course there is so little of it mixing in with the other, no one will realise how much better quality they are getting."
Exactly what the ratio of Hunua to Waikato water will end up in the average Auckland household supply is not possible to work out, says Adams.
Once the two sources merge at Redoubt Rd reservoir the water becomes "one big source. You can't separate it."
Under normal circumstances, however, some areas of Auckland should not need to draw from the Waikato source or the Hunua source.
A lot of the Waitakere region is fed by its own dams and treatment plants. Only under unusual circumstances - drought, serious blockage, treatment plant fault - would that region need to use the Hunua supply.
Onehunga, Papakura and Ardmore also have their own treatment plants.
"But we don't want to send out any kind of message saying various people won't ever get Waikato water. It's not that simple," says Adams.
"Under normal circumstances it is more than likely they will not, but you can't really say what is going to change those circumstances from day to day."
John Gaston is recognised as a world authority on drinking water and its treatment systems. Now vice president of a Californian engineering company, he has previously worked for the Californian Department for Health, and before that the US Environmental Protection Agency's national drinking water advisory council.
Four years ago he was called in by Sydney's health department to investigate the cryptosporidium scare that plagued the city's drinking water. (There was no crypto - faulty laboratory testing was to blame.)
He is now contracted to Watercare Services and has visited the Waikato River plant periodically, working with the health ministry to ensure quality controls are being set up properly.
Gaston says he understands the concerns due to the raw quality of the Waikato River but he "stands behind the plant 110 per cent, as if I built it myself".
Displaying his knowledge of Antipodean matters, he offered his condolences over New Zealand's loss of the World Cup hosting rights - the California twang makes the conversation surreal - before being persuaded to talk about the "warder".
"People are more than a little paranoid, which is okay. But they really have nothing to be concerned about. The water will be delicious."
nzherald.co.nz/environment
They're drinking our water
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