Recarbonation of Softened Water' B y Charles P. Hoover \V.,T,?X
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U!?*- of an air compressor and were forced into a large tank of w:iter througli diffusers in the bottom of the tank. Based
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Tliiid A i i n u d Report. Ohio Conleicricc on IVutrr Piiiificnlion.
rnal carburrates crystallize oilto surface (,f blie sand grains, covering them with an adlierent cont,iiig mid causing them to grow in size and firinlly to lose t.heir effectiveness w a filter medium. (Figure 3) The sand grains not only grow in size, but tiicy also cemciit tbemselves together, forming hard lumps iii filters, and the water to be filtered will not pass throiiglr tlieiii. Once or twice a year it is necessary to spade lip tliesc filters and crusb all hard lumps, and after seven or eight yciirs of service the filter must be rebuilt. (Figure 4) J.hnc-softeiicd wator niily be clienpiy and satisfiictoriiy st,abiliaed by recarbonating it with carbon dioside gas prodiiccd by burniiig coke, pulverized coal, oil, or gns iii it suitable frirnacc and forcing the gas, after i>cing pnssed tl,rouglr a scrubber and drier, into tlie mater. This gas is diffused into the water tbrougli small openings in a grid system and is applied nftcr it htis pa d tlirougli tile settling basins aiid beioro it r e d i e s tlie filters. The carbon dioxide gas converts tlic normal ciirbonates, which are only slight.ly soluble, to bicarbonates, which are biglily soluble, and mill therefore not be easily precipitated from the vatcr. Enoiigli carbon dioxide shoiild be added so that tile ctrrbiiiintd aatcr xill show just a Suint. t,race of C O I O ~w11~1rpliciiolplitli:ilciii is added Cities Having Kecarhonation Plants F i w r e 1-calcite coatin* m p u s i i e d from Lime-Sotcened Water on I n f r r i ~ r uf B Hot-Wafer Pipe
As far as exn be learned, the first attempt to carbonate a public water supply was made at WinnPpeg, Canada, about
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Rcceivcd March 29. 1927. Presented bciore t h e Diviilon of Water, Sevaye, and Sanitalioe Chemistry st the i3id Meeting 01 fhr dmerirnn Chemical Sorieiy, Richmond, Vh., April 11 to 16, IS??.
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