Irish stains are trying

Question: My wife and I have just retired and moved to our “dream” home in rural Ireland—alas, the dream is turning into something of a nightmare! We have no experience of well water, having lived all of our lives in cities or large towns, so when we noticed a sulphur-like smell and silty appearance about our tap water, we sent a sample for analysis. The experts told us: “The chemical analysis denotes a hard water. The levels of turbidity and iron exceed their limits for a drinking water of 4.0 NTUs and 200 µg/L Fe respectively. The water is satisfactory for human consumption in relation to its microbiological quality.”

Having no idea what all of this meant, we rang a company who supplies and installs water treatment equipment. Their representative ran some tests and scared us with talk of “excessive limescale” and “very” hard water, with iron limits that would clog our central heating and probably our arteries as well. Of course, he could put it all right—at a cost! Unfortunately, our budget is already stretched beyond endurance and the figure he quoted was beyond our reach. Just how bad is all of this? And what sort of equipment do we really need to keep our central heating, electric kettle, washing machine, etc., from seizing up…? Hope you can help us renew the dream…!

Brian O’Brien
County Galway, Ireland

Answer: The sulfur smell could be hydrogen sulfide (H2S), which frequently coexists with iron bacteria, and creates a “rotten egg” odor. I assume you may also have a staining problem on porcelain fixtures, etc. NTUs are nephelometric turbidity units and are used to measure color (i.e., light refracted by suspended solids) in the water among other things. Limescale is simply calcium carbonate (as CaCO3), which denotes hardness in your water. It may be measured in terms of grains per gallon (gpg), where one grain equals 17.1 milligrams per liter (mg/L) or parts per million (ppm); ug/L is micrograms per liter, which also translates to parts per billion (ppb).

More specifically, the sulfur odor is commonly the product of a soil type, sulfur-reducing bacteria. These bacteria are not harmful, but they react to form a gas—H2S, which again resembles the odor of rotten eggs. If the well is older, it may be controlled by a shock, one-time chlorination of the well. Other disinfection procedures may be necessary. A local well service company may be able to help.

The water analysis shows “high” hardness, but that isn’t qualified. There are several ways of reporting hardness, which is calcium and magnesium bicarbonates in water. The several scales can be converted and I’m not sure which one is used in your location, but high hardness would be 10-plus gpg, which translates to 170 ppm (or mg/L). Low, or acceptable hardness, would be in the range of 75-to 85 mg/L or below.  If the level is above that, a water softener can remove hardness. I have no idea of what the market value is for one in your area and suggest you consult with several (perhaps three) firms.

The turbidity of 4.0 NTU is rather high, but it’s more important to determine what in the water is contributing to that level. It can be silt, clay or other precipitates. The NTU value alone does not tell you the composition. Particulate matter can be filtered but, in this instance, it would be useful to determine the composition so the filter type and filter life can be determined.

The iron level of 200 µg/L, is the same as 0.2 mg/L. Here in the United States, and in Europe as a whole, 0.3 mg/L or below is considered acceptable. Iron, which causes rust-colored to brown stains when excessive, should not be a problem (high magnesium levels can also leave stains but these are purple to black). If however, that was misreported (which I doubt) you may need to reconsider. All in all, if the microbiology of the well is acceptable, simple sediment filtration and perhaps a water softener is all that is needed.

The initial solution is a simple water softener, which will reduce the 15-grain hard water and iron. It’s not recommended for turbidity reduction, however; a 25-micron cartridge filter before the softener is the least up-front capital expense way to go, but you may find yourself changing cartridges frequently (operating cost). The odor may be H2S although my bet is that it’s organic and will be reduced along with the turbidity by the filter. If filter cartridges are not changed frequently, bacteria and algae will grow—therefore, chlorination may be required.

PS: Yes, we do have a “staining problem” with wash basins, baths and toilets—anything white, in fact, and we have only been in the house about four weeks! Our report on water hardness says: “Total Hardness (as CaCO3) (mg/L)…253.” Regarding the dealer’s suggestions, I’m afraid the sales rep spoke so quickly and bombarded us with so much technical jargon, I could only pick-up items like “iron-sulphur unit…UV light… precipitation unit…” and a great deal of talk about stainless steel equipment, brass fittings and solid silver connections. I do remember the cost of all this, however. It was £3,000—I think about $4,500 in your currency.—Brian O’Brien

Correction: A reference in C.R. Fricker’s story (“Removal of Cryptosporidium pavum from Water by Filtration,” WC&P, February 2000, pp. 72-76) was incorrect. It should have read: Jokipii, L. and A. Jokipii, “Timing of Symptoms and Oocyst Excretion in Human Cryptosporidiosis,” New England Journal of Medicine, 315 (26): 1643-1647, 1986.


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