International Standards for Drinking-water

10-ml portions acetate agar aliquot ammonia ammonia nitrogen ammonia-free water ammonium hydroxide analysis Apparatus bacteriological examination bottle broth buffer solution calcium calibration carbon cell chemical chloroform coliform group coliform organisms colonies colour cool count cyanide detection determined Dissolve distilled water dithizone drinking-water EDTA examination of water extract faecal coliform fermentation tubes filter filtrate g of potassium g of sodium glass hydrochloric acid incubated indicator interference laboratory lactose limit litre medium membrane method mg/l micrometer microscope minutes ml of concentrated ml of distilled ml of sample MPN index Nessler tubes oxidizing plankton pollution potassium chromate precipitate Precision and accuracy prepared present procedure radioactivity reagent redistilled removed residue saprobity separating funnel sodium hydroxide sodium thiosulfate solution contains standard solution sterilization stock solution stopper substances sulfate sulfuric acid temperature tion titration treatment turbidity volume volumetric flask volumetric standard units wash water and dilute water quality water-supply