Received: from THEORY.CS.CMU.EDU by K.GP.CS.CMU.EDU; 25 Feb 88 15:55:17 EST Received: from THEORY.CS.CMU.EDU by THEORY.CS.CMU.EDU; 25 Feb 88 15:53:44 EST To: bovik@k cc: reder (Lynne Reder) @ basil.psy.cmu.edu Subject: Water purifiers Date: Thu, 25 Feb 88 15:53:41 EST Message-ID: <22998.572820821@THEORY.CS.CMU.EDU> From: Timothy.Freeman@THEORY.CS.CMU.EDU Here's the responses I got about my request about water purifiers. I don't believe the one about reverse osmosis being better than distilling; according to the Sears catalog, their distiller removes a superset of the impurities that their best osmosis system removes. One chemical that their distiller deals with that their osmosis filter doesn't is natrates. I'm going to get a small distiller from Sears for $200. It has the advantage of not requiring any plumbing. Received: from CAD.CS.CMU.EDU by THEORY.CS.CMU.EDU; 20 Feb 88 10:31:05 EST Date: 20 Feb 1988 10:17-EST From: David.Lampenfield@CAD.CS.CMU.EDU To: Timothy.Freeman@THEORY.CS.CMU.EDU Subject: Re: Water purifiers Message-Id: <572368624/dcl@CAD.CS.CMU.EDU> In-Reply-To: Timothy.Freeman's bboard message of 19-Feb-88 21:37 Culligan will give you flyers which involve all of the main technologies. But C is ETREMELY expensive; $150 for a filter that can be bought at Busy Beaver for $20. Reverse osmosis units are another option. The just force the pure water though a semi-permeable membrane. They are low capacity units in general. A question of effciency arises ; how many gallons of waste water are dischaged for every gallon of pure water delivered? You probably will want a filter with anything that you buy, if nothing else just a paper cartridge for sediment et al. Another note is that the ones teeth are constantly recalcified by the minerals and flouride in drinking water. Received: from ML.RI.CMU.EDU by THEORY.CS.CMU.EDU; 20 Feb 88 12:19:04 EST Date: 20 Feb 1988 12:16-EST From: Hans.Tallis@ML.RI.CMU.EDU To: Timothy.Freeman@THEORY.CS.CMU.EDU Subject: Re: Water purifiers Message-Id: <572375802/tallis@ML.RI.CMU.EDU> Tim, chemist friends of mine own a home-use-designed deionizer, which removes lots of the odd tastes from the steel-mill runoff water we get around here. I don't know where they got it from. --Hans Date: 20 Feb 1988 13:33-EST From: Kenneth.Cline@THEORY.CS.CMU.EDU To: Timothy.Freeman@THEORY.CS.CMU.EDU Subject: Re: Water purifiers Message-Id: <572380434/cline@THEORY.CS.CMU.EDU> In-Reply-To: Timothy.Freeman's bboard message of 19-Feb-88 21:39 Tim, There are three main types of water filters on the market: Particulate filters which use an element which works like filter paper; Activated carbon filters; and reverse osmosis filters. About all the particulate filters do is remove suspended particles of dirt and such along with heavier debris that is washed through the pipes such as bits of rust and sand, they are most useful as an initial stage in a filtering system which prevents the main filter from becomming prematurely clogged. Another important use of particulate filters is to remove biological contaminants from water, but I assume that this is not your main concern. Activated carbon filters really do remove nasty chemicals from water. The activated carbon actually adsorbs molecules in solution and hangs on to them. Unfortunately, not all chemicals are removed by such a filter. The best kind of filter uses a reverse osmosis membrane. The water pressure in your plumbing forces water, but very little else, through a semi-permiable membrane and stores it in a tank for later use. And of course, as you mentioned, distillation is another alternative method for water purification. The big advantage of carbon filters is that they are cheap. For about $25 you can buy a nice carbon filter that will fit under you kitchen sink (I don't think the miniature faucet mounted filters are worthwhile). I know that Sears sells such filters, and they will probably improve the taste and odor of the water, but they will not remove all dangerous chemicals (Sears has a brochure describing which chemicals are actually removed by various types of filters). There are filters which use a block of compressed activated carbon which are supposed to be better than the regular aquarium style carbon chunks, but I don't know who sells any of these. I personally feel that a good reverse osmosis filter (preferably using preliminary particulate and activated carbon stages) is the best way to go if you are willing to pay $400 or more on your filter. Culligan rents such filters (I have used one) which is nice because they come by to replace the carbon and particulate filter cartridges and clean the RO unit periodically. However, Culligan is expensive. I think you can order reverse osmosis filters from the Sears catalog, but they are not available in the local stores. I talked to Culligan, and they claimed to be the only source for RO filters in the area. I don't remember why, but the consumer advocate who ran a radio program on KPFK radio in Los Angeles and is extremelyconcerned with water quality, was not interested in distillation the last time I heard her show. It is possible that home distillers do not remove all of the organic contaminants with boiling points similar to that of water. But even so they need electricity, and produce hot water which is not always what you want. I hope this helps Ken Received: from A.PSY.CMU.EDU by THEORY.CS.CMU.EDU; 22 Feb 88 09:31:37 EST Received: from basil.psy.cmu.edu by a.psy.cmu.edu with DECNET ; 22 Feb 88 09:28:20 EST Date: Monday, 22 Feb 88 09:24:24 EST From: reder (Lynne Reder) @ basil.psy.cmu.edu Subject: re: Water purifiers To: Timothy.Freeman @ THEORY.CS.CMU.EDU I hate it when all my responses are "I'm interested too", but I am interested as I will be remodelling my kitchen soon. Let me tell you what little I know. There are carbon systems one can install on the kitchen tap and there are other systems that I have very brief descriptions on (I can quote the book if you are interested, but the book does not give pointers). I currently have Polar Water delivered to my home which allows me to have essentially unlimited drinkable water for about $14/month or less than 50c. per day. We pulled out the water softening device that came with the house. I think water softeners are a bad idea as they chew up the pipes in your home or pass wierd chemicals onto the consumers (that is what I read years ago anyway). Well, thanks for passing along any useful info you receive. Sorry that my knowledge is so impoverished. --L. Received: from NL.CS.CMU.EDU by THEORY.CS.CMU.EDU; 23 Feb 88 08:53:25 EST Date: Tue, 23 Feb 88 08:38:45 EST From: Eric.Nyberg@NL.CS.CMU.EDU To: timothy.freeman@THEORY.CS.CMU.EDU Subject: Re: water conditioners We had a General Ionics water conditioner installed in our house. It connects very simply at the point where the city water enters your home. There are two components: a ~5' high cylinder filled with special pellets (some kind of resin coated with a bacteriostatic silver compound), and a shorter, wider plastic container filler with pure rock salt. Every 70k gallons, the main cylinder cleans itself (back flush out into the cellar drain trap) with water pumped through the salt. The unit has a timer and cleans itself in the middle of the night. The unit can be taken offline with a simple throw valve. We have had excellent results with this unit since we installed it last June. The quality of the water that the unit provides is fantastic. The home demo given by the salesman is quite convincing - he will show you just how awful the city water is by hooking up a small version of the unit to your sink and doing a comparison test. In addition to healthier, better tasting water (rice and steamed veggies take on new meaning), you save a lot of money on soap and detergents as well (one bottle of shampoo lasted us about 6 months, and we use one tablespoon of Tide in the wash to do a full load of clothes). I guess it sounds like we're pretty enthusiastic about this unit - we are! The only drawback is the price. The unit costs between $2-3000, installed. They have financing available - we have a monthly payment of about $50. We think it's worth it, if you add up the aggravation of toting bottled water around and still showering in chlorinated Allegheny water. General Ionics has the only units that are approved by the Feds, I might add. Let me know if you're interested, and I can hunt down the literature I have at home. -ehn