Summary-line: 24-Jan n, wilcox@cis.ohio-state. #Ozone for Water Treatment Return-Path: Date: Thu, 24 Jan 91 08:12:33 pst From: cnorman (Cynthia Norman) To: cnorman, wilcox@cis.ohio-state.edu, luna@ccwf.cc.utexas.edu, anasaz!john@asuvax.eas.asu.edu, dwyer@nosc.mil, jgautier@ads.com, b-davis@cai.utah.edu, richter@triton.unm.edu, hxkpy@slacvm.slac.stanford.edu, botteron@bu-it.bu.edu, rollo@xylogics.com, proud@ihlpy.att.com, bill@picard.att.com, jsparkes@bnr.ca, island!green@uunet.uu.net, ann@snow-white.merit-tech.com, iex!neptune.iex.com!bert@uunet.uu.net, siang@biochem.umass.edu, smalley@pilot.njin.net, king@reasoning.com, mnetor!perle!kevin@cs.toronto.edu, afc@shibaya.lonestar.org, mark.ochsankehl@p2.f175.n120.z1.fidonet.org, pjz@ceres.physics.uiowa.edu, ardyk@tc.fluke.com, cyn@mdaali.cancer.utexas.edu, ogicse!sequent!roseal@ucsd.edu, paulxxxx@portia.stanford.edu, andrea@sdd.hp.com, mvac23!thomas@udel.edu, ames!claris!netcom!shelamer@ucsd.edu, nick@icad.com, marks@ocfmail.ocf.llnl.gov, schillin@scl.cwru.edu, 880039a@acadiau.ca, lbrueck@wpi.wpi.edu Subject: Ozone for Water Treatment Reply-To: cnorman@ucsd.edu *** EOOH *** Return-Path: Date: Thu, 24 Jan 91 08:12:33 pst From: cnorman (Cynthia Norman) To: cnorman, wilcox@cis.ohio-state.edu, luna@ccwf.cc.utexas.edu, anasaz!john@asuvax.eas.asu.edu, dwyer@nosc.mil, jgautier@ads.com, b-davis@cai.utah.edu, richter@triton.unm.edu, hxkpy@slacvm.slac.stanford.edu, botteron@bu-it.bu.edu, rollo@xylogics.com, proud@ihlpy.att.com, bill@picard.att.com, jsparkes@bnr.ca, island!green@uunet.uu.net, ann@snow-white.merit-tech.com, iex!neptune.iex.com!bert@uunet.uu.net, siang@biochem.umass.edu, smalley@pilot.njin.net, king@reasoning.com, mnetor!perle!kevin@cs.toronto.edu, afc@shibaya.lonestar.org, mark.ochsankehl@p2.f175.n120.z1.fidonet.org, pjz@ceres.physics.uiowa.edu, ardyk@tc.fluke.com, cyn@mdaali.cancer.utexas.edu, ogicse!sequent!roseal@ucsd.edu, paulxxxx@portia.stanford.edu, andrea@sdd.hp.com, mvac23!thomas@udel.edu, ames!claris!netcom!shelamer@ucsd.edu, nick@icad.com, marks@ocfmail.ocf.llnl.gov, schillin@scl.cwru.edu, 880039a@acadiau.ca, lbrueck@wpi.wpi.edu Subject: Ozone for Water Treatment Reply-To: cnorman@ucsd.edu Return-Path: Date: Wed, 23 Jan 91 21:29:38 -0500 From: botteron@bu-it.bu.edu Someone asked recently: Ozone sounds good because it avoids the halogenated hydrocarbons (e.g. chloroform, present in chlorinated municipal water supplies), but what compounds does ozone create when it reacts with bacterial proteins and organics? Are they any better for you than chloroform etc??? any chemists out there? Since no one else has tackled this, I'll try. I'm a grad student in environmental engineering at Tufts University, and have a background in chemistry. But I'm not an expert. Chlorine reacts with organic substances in water, forming trihalo- methanes such as chloroform. Chloroform is a probable carcinogen. Before the mid 1970s chlorination was often the first step in the processing of surface water for drinking. Now it is typically done only once, late in the process, so less chlorine is used. Trihalomethanes can be reduced by aerating the water or by treating with activated carbon, but both methods have problems including recontamination of the water. Prevention of halomethane formation is the preferred approach. Ozone is a molecule consisting of three oxygen atoms, unlike ordinary oxygen molecules, which have only two. Ozone is very reactive; it tends to add oxygen to molecules and often breaks them into smaller molecules. It has often been used to reduce taste, odor, and color. "Ozonation does not form any known health-related byproducts when applied in water processing. ... Ozone is an effective disinfectant that forms no known products significant to human health." -- Warren Viessman, Jr., and Mark J. Hammer, "Water Supply and Pollution Control," 4th ed. New York, Harper & Row, 1985, pp 406-407 In treatment of wastewater (e.g. sewage or industrial effluent) another consideration is that chlorination of organic compounds makes them less biodegradable, but addition of oxygen typically makes them more biodegradable. An advantage of chlorination of drinking water is that chlorine forms a residual, chlorine that stays in the water and continues to disinfect it. Ozone does not form a residual. In wastewater treatment, a chlorine residual is unnecessary or undesirable (since it is desirable for natural microorganisms to be able to continue breaking down the remaining organics in the wastewater). Some European water treatment systems use ozone as the major disinfectant, with just enough chlorine to provide a residual. Only a few plants in the United States use ozone. So -- as best I can find out, ozone doesn't produce any nasty compounds, but it doesn't protect drinking water from germs that may enter or multiply after it leaves the treatment plant. Also ozone costs considerably more (sorry, no numbers). A friend's husband works at a small biotech company in Cambridge, Mass. (Cambridge has its own water system, essentially separate >from the rest of the Boston area.) Last year Cambridge told the company that its wastewater contained too much chloroform. The scientists analyzed their processes but couldn't figure out where the chloroform was coming from. Until they decided to measure the chloroform level in Cambridge tap water.... I hope this was helpful enough to be worth its length. Carol Botteron botteron@bu-it.bu.edu