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Concerns over Columbia's water quality postpone well placement

Tuesday, November 3, 2009 | 12:01 a.m. CST; updated 8:35 a.m. CST, Tuesday, November 3, 2009

COLUMBIA — Be careful what you drink, because you might be drinking it again.

Chlorides are creeping into Columbia’s water supply wells in the Missouri River bottoms at McBaine, indicating that treated wastewater, once funneled far from the wells, is finding its way back into the city's supply.

The chlorides themselves aren't harmful, said Tom O'Connor, an environmental engineer who sits on the city's Environment and Energy Commission as well as the Water and Light Advisory Board. Columbia's drinking water currently meets all Environmental Protection Agency standards. However, the presence of chlorides does show that other potentially harmful contaminants, such as pharmaceuticals and other household chemicals, could stay circulating in the water supply.

O'Connor told the City Council on Monday that if council members vote to move forward with placing a new well in a site identified by Columbia Water and Light, they risk adding to the problem. The proposed site sits near four other wells that show significantly elevated chloride levels.

"It seemed like that (site) was questionable from a water quality standpoint," he said.

On Monday, the council voted to allow the Environment and Energy Commission and the Water and Light Advisory Board more time to study the placement of the well. The council also directed city staff to look for alternative sites.

O'Connor suggested that a site to the northwest end of the McBaine bottoms, where existing wells haven't shown elevated levels of chlorides, could be a safer alternative. But a U.S. Geological Survey report presented to the City Council suggested those wells, which sit near the Missouri River, showed higher levels of agricultural contaminants and discharge from cities upstream.

"(Those sites) would be better for some things, but it could be worse for others," said Michael Schmitz, interim director of Columbia Water and Light.

Finding a new site would also require buying new land and building new infrastructure to service the wells, which could also add to the cost of the project. By waiting, the city could also lose access to some economic incentives, including a low-interest loan.

Schmitz said the project would cost as much as $350,000 if constructed on the previously identified site.

Finding a new site would also delay the project beyond next summer, which could strain the city's water supply. Schmitz said the last two cool, wet summers and the economic slowdown could have masked an increase in demand.

"From an engineering perspective, we like to be a step ahead from what we think pumping demand is going to be," he said.

The EPA is expected to tighten its regulations and add to its list of regulated contaminants. Mayor Darwin Hindman said he expects the city will eventually need to look at new water treatment options in the future regardless of where this new well is placed.

Columbia has been in violation of EPA water standards before.

In 2007, tests showed the city's drinking water exceeded Environmental Protection Agency standards for trihalomethanes, cancer-causing compounds that form when water and organic matter mix with the chlorine used in water treatment. To reduce the levels of trihalomethanes, the city switched to ammonium sulfate, an alternative disinfectant.

An analysis of the city's water sources, produced by MU researchers, says the measures taken by the city are a temporary solution. The researchers report that Columbia's wells have high potential for formation of trihalomethanes, suggesting levels of the contaminant will remain close to — or could exceed — the EPA limits.

The report says the city should make other modifications to the water treatment process that would allow an eventual switch back to chlorine. A study commissioned by the council at a previous meeting will study the entire water treatment system and make recommendations based on what the consultant firm, Carollo Engineers, believes EPA standards will look like in the future.


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Comments

Allan Sharrock November 3, 2009 | 8:18 a.m.

When I ran for city council the city put on a meeting to introduce the candidates on how the city operates. The former water and light guy gave his speech and how they were going to drill a new well and I asked him at that time if it was smart to put all of our wells in the same location and if it was safe. He said it was OK and apparently it is not.

(Report Comment)
Mark Foecking November 4, 2009 | 3:05 p.m.

I wish reporters (or maybe Water and Light) would be more clear about how our water is being disinfected these days.

The water is being chlorinated as usual. The ammonium sulfate is then added as a source of ammonium ion, which reacts with the chlorine (strictly, hypochlorous acid, which is the product of free chlorine and water) and forms chloramines. These chloramines also disinfeect like chlorine does, but are not active enough to chlorinate organic material and form THMs.

Tap water is one of the most tested materials in the US. CWL tests for about 80 contaminants, as well as microbiological tests. Our water is quite safe, otherwise they would be required by law to order people not to drink it.

If you're worried about it (and you really shouldn't be), catch rainwater and run it through an reverse osmosis system. No residual anything, no contaminants. I have a system like this at my off-grid property, and I really like the way the water tastes. Unfortunately, water prepared this way has no beneficial minerals (like calcium), so you have to arrange to get those some other way.

DK

(Report Comment)
Joy Unruh November 4, 2009 | 11:08 p.m.

You mention reverse osmosis as a means for purifying your water, which can be good as long as you keep your filter/s and membrane changed regularly (which can end up being expensive), but RO is not very effective when it comes to bacterial or large hits of other contaminents. Why not look at distillation appliances for POU (point of use)? There are several options available from countertop to fully automatic units and by boiling the water, capturing the vapor(steam), cooling the vapor and condensing it back into as pure a consumable water as possible you can remove virtually 99.9% of organic, inorganic, biological, radiological, protozoa (such as cryptosporidium and giradia)and pharmaceuticals that may be present in the water source. This would be the safest method and in the long run the least expensive method of insuring safe consumable water in every home, office, medical facility etc.

(Report Comment)
Joy Unruh November 4, 2009 | 11:52 p.m.

In my previous comment I primarily referenced distillation appliances for homes, offices, etc. There are also units available to handle as much as 5000 gallons plus per day as well as complete packages for water stores where one can fill their own bottles. Distillation is an excellent alternative to RO that a lot of people are not aware of or do not understand the difference. RO is a barrier system of filters and a membrane that needs a certain amount of pressure in order to be effective in backwashing the contaminents from the membrane which also contributes to anywhere from 1-10 gallons(depending on the system) of wasted water for every gallon of good water.

Distillation is actually a separation process wherein the pure water rises in the vapors to be condensed into water, leaving the contaminents behind in the boiling chamber to be drained away with hardly any waste. It kind of duplicates nature's hydrologic cycle.

It is interesting that whenever there is a water contamination issue and the media issues a public "boil" the water alert in order to kill the bacteria, (which by the way are still in the water but dead) they should note that if you just boil the water you are concentrating all the other contaminents such as nitrates,nitrites, lead, copper, toxic chemicals etc.

As a side note, this is also true when you boil water for cooking purposes. The foods being cooked absorb the heavier concentrations of contaminents and are being consumed as you eat the food. No wonder there are so many health problems!

(Report Comment)
Allan Sharrock November 5, 2009 | 8:33 a.m.

I think the bottom line is that the city may need to look at other places to drill for water. There is that old saying not putting all your eggs in one basket.

(Report Comment)
Mark Foecking November 5, 2009 | 8:41 a.m.

Joy Unruh wrote:

"but RO is not very effective when it comes to bacterial or large hits of other contaminents."

Actually it is quite effective if you keep the system sanitized after long shutdown periods. A reverse osmosis membrane has an effective pore size of a few billionths of a micron, which is far smaller than any bacteria or virus. Depending on the membrane chemistry, they can reject all ionic components and most organic contaminants over a certain molecular size. Carbon filters can take care of the rest. My system has a UV post-treatment (for bacteria) to be on the safe side, but it is likely not needed. This is the system:

http://www.home-water-purifiers-and-filt...

Distillation is also a good way to treat water, but it is very energy intensive. At my off-grid place, I don't have the electrical capacity to run any kind of a still, other than a solar still (which I may set up one of these days).

My reject line flows back into my catchment, so no water is wasted.

Some organic contaminants can co-distill with water (it's called steam distillation when you do it on purpose). It is good to run distilled water over carbon to rtake out traces of co-distilled organics.

Reverse osmosis/filter systems are used to generate type I water for lab use, which is as chemically pure water as you'll find anywhere. Distillation has fallen out of favor in laboratories because of it's high energy consumption per unit of water produced.

As far as boil orders, they are typically only issued in demonstrated, or suspected, cases of microbiological contamination. Consuming a few dead bacteria is harmless. Our tap water does not contain nitrates, nitrites, or heavy metals (they test for them). In cases of toxic contamination, they would have to issue bottled water to people.

DK

(Report Comment)
Mark Foecking November 5, 2009 | 8:49 a.m.

Also, Joy, the reason we have so many health problems, generally, is we weigh too much and don't get enough exercise. Food contamination has very little to do with it.

Allan Sharrock wrote:

"I think the bottom line is that the city may need to look at other places to drill for water."

The troublee with that is the water treatment plant is close to the wellfields. Drilling somewhere distant will require a pipeline to McBaine, will all the cost of contruction and right-of-way/easements that will involve.

The question that has not been answered reliably is:

Is there a measurable health risk from the wells picking up some previously treated wastewater from the wetlands? CWL's testing has not so far found one (other than the THM's, which are not an issue anymore).

DK

(Report Comment)
Allan Sharrock November 5, 2009 | 5:21 p.m.

I agree it may require piping however at some point Columbia will need more water than can be collected at the current location. Land is cheaper now than in the past so it may be worth looking into.

(Report Comment)
john crawford November 9, 2009 | 6:11 p.m.

We own 45 acres within 1/4 mile of the plant and it has an old well used for a orchard.I'm not saying this will supply Columbia with all of its water but there are various springs that run out of the hill year round.Is it possible to drill wells in the river bluffs or does the same contamination that affects the river valley affect the springs 1/4 mile away?

(Report Comment)
Mark Foecking November 11, 2009 | 1:08 p.m.

john crawford wrote:

"does the same contamination that affects the river valley affect the springs 1/4 mile away?"

Without knowing the exact shape of the "contaminant" plume, there isn't a good way of knowing.

The "contaminant" they test for is chloride (the form of chlorine in table salt). You could take a sample of your well water and have it tested for that.

DK

(Report Comment)
Thomas McElroy December 7, 2009 | 8:45 p.m.

Just over the past month, maybe two, sitting in my indoor jetted bathtub for any signficant period of time has started leaving an very strange and disconcerting skin odor. I thought that it may be coming from the jets/piping of the tub, and have run various chemicals through the system (bleach, white vinegar, PineSol) to try to clean it out and eliminate the odors, but this has not worked. I am concerned that there is actually something in the waer supply causing this odor. I wonder if anyone else has experienced this sort of thing.

(Report Comment)

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