CHLORINE COMPOUNDS

Wairarapa Times-Age, 14 February 1939, Page 3

CHLORINE COMPOUNDS

USE IN DAIRY HYGIENE. SOME RECIPES FOR MIXING. Chlorine has long been in popular use for sterilising water reservoirs, wells, public baths and elsewhere, and is eciually valuable in the dairy. There are three chemical compounds commonly used as chlorine disinfectants —calcium hypochlorite (or bleaching powder), sodium hypochlorite and "chloramine T.” Calcium hypochlorite is a powder containing approximately 30 per cent chlorine. It is not highly soluble in water, and froms a thick precipitate of chalk. Since chlorine easily escapes from the powder, as well as from the solution, only fresh solutions made from fresh powder should be used. A solution of one ounce to two gallons of water is a good disinfectant, but it is not reliable. Bleaching powder is more generally used in a mixture with boracic acid or washing soda, which gives more satisfactory results. The following are given, by reliable authorities, as two suitable mixtures for use in the dairy shed:— No. I..—Quarter pound of calcium hypochlorite (bleaching powder), Jib. boracic acid, two gallons of water. The mixture should be stirred well and allowed to stand overnight in a closed jar or bottle, the clear liquid being poured off next morning. In summer the mixture should be made up once a week and in winter less often, and kept in a cool, dark place. For use, the mixture is diluted to one part in 20 parts of water. Ten gallons of such a solution should not cost more than 3d. No. 2.—One pound of bleaching powder, 41b. of washing soda, 6oz. of salt and one gallon of water. Dissolve the washing soda in one gallon of hot water, allow to cool, and then add the salt and bleaching powder. Stir the solution at frequent intervals for an hour, close, and leave to stand. When the solution is clear, pour it off into

a dark glass or earthen jar; cork firmly and keep in a cool place. For disinfecting dairy utensils, half a pint of the solution is used to four gallons of water. The mixture should be freshly made each week.