Water pollution

Accidents in swimming pools can be serious or fatal (drowning, broken necks) but fortunately they are rare. For pool operators one of the more likely nightmares of daily operation is when someone has "a fecal accident." In other words, someone craps in the swimming pool. CDC has guidelines for chlorinated pools (which covers most public pools; they are guidelines because regulations are on the state, not federal, level). And they just revised them. It makes interesting reading, although I suppose this is an acquired taste. Here are the details, followed by a classic dramatic re-enactment on…
Another one of those stories about what is truly, a technological marvel: shrinking a gas chromatograph/mass spectrometer down to the size of an iPod, with the target size being that of a matchbox. Designed by MIT engineers, the device which can analyze the air for hazardous gases (and could be adapted for other media like water) is touted as a possible distributed sensor for water supplies to protect us against chemical attacks or in subway systems to warn of terrorist attacks. I think this is bullshit and I'll explain why after a description of this ingenious device: Their detector uses gas…
Too much nutrient in wastewater can lead to serious water pollution. The nutrients act as food for micro-organisms and algae who use up dissolved oxygen in the water when they metabolize them. When oxygen levels go too low -- when the stream or river or pond "goes anaerobic" -- new micro-organisms predominate, ones that don't use oxygen as their final electron acceptor but use other oxidizing agents. Many use sulfur compounds, and when these become reduced by the transferred electrons they produce hydrogen sulfide, the rotten egg odor. Hydrogen sulfide not only smells bad. It is quite toxic.…