PERIODICAI. LITERATURE 247 



indicated quite plainly that this sugar does not come from the cellulose 

 portion of the wood, but very probably from the carbohydrates of the 

 spruce wood that are soluble in water. Waste sulphite liquor cannot 

 be directly fermented, due to the presence of sulphurous acid and such 

 organic acids as acetic acid and formic acid, and these must first be 

 neutralized. This is accomplished by first aerating the liquor with com- 

 pressed air to oxidize the sulphurous acid and other reducing sub- 

 stances, and at the same time adding the neutralizing agent, which is 

 usually freshly slaked lime. Pulverized limestone is finally added to 

 insure complete neutralization, and the liquor after settling is drawn 

 off into tanks, where it is cooled and distributed to the fermenting vats. 

 Quicklime cannot be used in neutralization, as the momentary alka- 

 linity produced around each particle of lime as it becomes wetted with 

 liquor breaks up the fermentable sugars. The neutralized liquor is 

 fermented in large vats with special resistant yeast. The yield of alco- 

 hol obtained is very much influenced by the kind and quality of the 

 yeast. Waste sulphite liquor contains an insufficient quantity of nutri- 

 ment for the yeast, and special mixtures to supply the necessary phos- 

 phates and nitrogen must be added to the liquor in building up the cul- 

 tures of yeast. The fermented mash is distilled in column stills, and 

 an alcohol with a strength of 96 per cent by volume can be directly 

 obtained. This alcohol is, however, quite impure, containing as much 

 as 3 per cent of methyl alcohol, with lesser quantities of aldehyde and 

 fusel oil. The aldehyde and fusel oil are readily removed by redistilla- 

 tion, and recent improvements in distillation methods render possible 

 the removal of the methyl alcohol through controlled distillation. The 

 effect of the dealcoholized mash, or waste liquor, upon fish in streams 

 is as yet a moot question, though it is certain that it is much less dam- 

 aging than the ordinary waste sulphite liquors. The cost of production 

 of alcohol from waste liquor, including interest and amortization, is 

 given as approximately 10 cents per United States gallon. 



B. L. G. 



Waste Sulphite Liquor and its Conversion into Alcohol. Pulp and Paper Maga- 

 zine of Canada, December 6, 1917, pp. 1125-1129; December 13, 1917, pp. 1157- 

 1 164; December 20, 1917, pp. 1185-1192. 



