NOTES ON GOULBURN WATER. 397 



clear the next morning after eighteen hours. Even using 

 larger quantities, up to '1 gram, of slaked lime, the water 

 did not become as clear as that obtained by using '0342 

 grams of alumino-ferric. 



Having decided that alumino-ferric was the best clarify- 

 ing agent, the minimum quantity required to clarify the 

 water in twenty-four hours was next determined ; this was 

 found to be *015 grams to 200 cc. This amount clarified 

 tlie water almost completely in two hours, the water being 

 perfectly clear after twenty-four hours. The ammonia and 

 hardness were determined after clarifying 1,000 cc. of 

 water in this manner allowing the water to stand eighteen 

 hours, with the following results : — 



Ammonia. Hardness. 



Organic. Free. Total Temporary. Permanent. Total. 



Before After Before After Before After Before After Before After Before After 



•066 -029 -053 -091 -119 -120 4 nil 16 20 20 20 



The organic ammonia is decreased and the free ammonia 

 correspondingly increased, the total remaining the same. 

 The permanent hardness is increased and the temporary 

 decreased to the same amount, the total remaining the same. 



Cost of Clarifying the Water.— Assuming that the popu. 

 lation to be served by the water supply is 15,000 and the 

 consumption per head at 40 gallons per day, the total 

 supply per day would be 600,000 gallons. The amount of 

 alumino-ferric required at the rate of '015 grams per 200 cc. 

 is 73 tons per annum. The price of alumino-ferric in 

 England is about £2 10s. per ton, and might be landed at 

 Goulburn for £5 per ton. The total cost for the clarifying 

 agent would therefore be about £365 per annum. The 

 price quoted in Sydney is £8 per ton, and freight and car- 

 tage to the reservoir would probably bring it up to £8 10s. 

 per ton ; the cost per annum would therefore be about £620. 



