RO and distillation: Both have advantages, drawbacks
I read with interest in WC&P’s November 1999 issue the letter “Distillation: When RO is not a must!” (Christine Kuck, West Bend Water Systems). Ms. Kuck is correct in pointing out that reverse osmosis is not the only technology that will work and perhaps the “Ask the Expert” response she referred to should have indicated that distillation was an equally viable option.
Unfortunately, she devotes a fair amount of her letter to pointing out the disadvantages of RO without pointing out the disadvantages of distillation.
To start with, distillation does not automatically produce higher quality water than RO; because RO removes a percentage of the salts in the water, the quality of the permeate will be a function of feed water quality.
Certainly, fouling is a significant problem with membrane technologies; however, my experience with distillation is that it’s also a significant problem with this technology unless significant quantities of feed water are run to the drain—which she was quick to point out is a disadvantage of RO.
Curiously enough, she avoided mentioning the particular disadvantages of distillation, which are high-energy usage, the fact that the distillate (pure water) is hot and—in the case of distillers—use of fan for cooling purposes can be rather noisy.
There’s no doubt that distillation is a viable and valuable water treatment technology, and perhaps doesn’t get the recognition it deserves. On the other hand, I believe that it’s less fair to “bash” a competitive technology without objectively acknowledging the shortcomings of one’s favorite technology.
Peter S. Cartwright, P.E., CWS-VI
Cartwright Consulting Co.
WQA on HPC with MAC upsets reader
I have read with both professional and personal interest the ongoing debate on heterotrophic plate count (HPC) bacteria. Ironically, I’m president of AquaPrima Inc., the innowave distributor for Northern California, and I’m infected
with Mycobacterium avium complex (MAC).
On the personal side, I became infected with MAC about 10 years ago. At the time, no doctor seemed able to diagnose the small spots on my lung. In 1998, when I began to cough up blood, x-rays found a hole the size of a golf ball in my right lung. MAC was literally eating the lung tissue for the last 10 years. I was lucky. I was properly diagnosed and now am being treated for a life threatening bacterial infection. Up until this incident, I was as healthy as any 50-year-old woman. I ran marathons, exercised regularly and considered myself more health conscious than most.
As I read some of the expert opinions from WQA members or advisors (see Reasoner, D.J., and J.F. Harrison, “HPC Bacteria—Point/Counterpoint, Part 1&2,” WC&P, October/November 1999), I have one question—how do they know that HPCs are not causing disease? There’s no reporting agency that monitors illnesses like mine. I’d like to refer you to two Internet sites that might bring some light on just this one bacterium. The first is a white paper on the San Francisco Public Utilities webpage. The research from that paper states that over 400 HIV individuals die each year from MAC in San Francisco, four times more than die from cryptosporidiosis: www.ci.sf.ca.us/puc/html/mac/027.pdf
I’m not HIV positive or immune-compromised in any way that’s apparent—so about 5,000 other seemingly healthy people and I are not reported to any agency that tracks HPCs or bacterial disease. The only large-scale awareness of this disease is at the National Jewish Hospital in Colorado, which has a staff dedicated to this illness: www.njc.org/ msu/10n6MSU_m_avium.html
I’d also like to point out a USEPA funded grant in which the University of Washington and Seattle Biomedical Research Institute have been given $360,000 to study MAC, E. coli and H. pylori. If HPC has “no health effects,” why the $360,000 grant?
I don’t know how I became infected and no one knows how thousands otherwise healthy people are becoming infected. I do know I have an under-the-sink filter and, until I got into the water business in 1997, I just was unaware of how often a filter should be changed and I wasn’t aware it could breed illness-causing bacteria. This may have been the case. I drank only filtered water or bottled water for the last 10 or 15 years. Or maybe I became infected breathing shower vapors? I really don’t know nor do my doctors at Stanford. They only know more of this is turning up in healthy individuals.
I think it’s unconscionable for WQA to state “that HPC has no health effects” when so many questions are unanswered or in doubt.
Lynne Leahy, President