76 



the surface it is conveyed directly to the softening plant. In its 

 natural state the water is hard, being derived from the chalk, and 

 impregnated with carbonate of lime, its hardness being reckoned as 

 fifteen degrees, an equivalent to fifteen grains of carbonate of lime 

 per gallon. The purity of chalk water is well known, and the sole 

 objection to its use is on the score of hardness. Many towns in 

 England use a water of twenty-two to twenty-four degrees of 

 hardness. In Bournemouth, the water taken from the chalk is 

 softened to between nine and ten degrees of hardness, resulting in 

 the supply of the most desirable water to be obtained for drinking 

 and all other purpose. The process of softening is effected in three 

 stages. First, there is an apparatus for the continuous production 

 of lime water ; second, a reservoir of sixty-two thousand gallons 

 capacity in which the actual softening takes place, by mixing the 

 hard water with lime water in the correct proportion ; third, a 

 battery of filters for dealing with the water, after softening, by passing 

 it through a material similar to sail cloth stretched on a framework 

 of metal. In mixing the lime water with the hard water great 

 care has to be exercised to prevent an excess of either. Should the 

 well water be in excess the product would be improperly softened, 

 but on the other hand if the lime water predominates the object in 

 view would be defeated, as there is a possibility of the softening 

 reaction taking place, and the water re-hardening to even a greater 

 degree than originally. The chemical reaction which takes place 

 during the softening process is represented as follows : — 



H^2C03} CaOHsO = 2Ca CO3 -f 2H2O 



Calcium , Lime _ Calcium w t r 



Bicarbonate Water ~ Carbonate water. 



After the process of softening and purification is completed the 

 water is rendered suitable for consumption. 



The precipitated carbonate of lime produced in softening the 

 water after having been washed off the filter-cloths, is pumped in 

 the form of sludge to special settling tanks, situate in a field 

 adjoining the pumping station. The softened water is pumped to 

 Alderney, which may be termed the town depot of the water-supply. 

 The water from the gravel-beds at Longham is also pumped to this 

 station, and is then passed through sand-filters, after which it mixes 

 with the Wimborne softened water in the reservoirs. From 

 Alderney the water falls by gravitation into the mains of the town. 

 The average pressure of water in the town is about thirty-five 

 pounds per square inch, which is equivalent to a column of water 

 nearly eighty feet in height. 



In 1908 the amount of water supplied from Wimborne was 

 five hundred and thirty-one million gallons, and from Longham two 

 hundred millions, making a total of seven hundred and thirty-one 

 million gallons. 



During a dry week in the summer the company has supplied 

 twenty-eight million gallons of water into Bournemouth. 



