CHAPTER XVIIT. 



WASTE WATER. 



Water Containing Sodium Chlorid. 



Of all the injuries caused by waste water, the most common are those 

 produced by sodium chlorid. These are found especially in regions where 

 extensive hard coal mining takes place. From the experiments published 

 by Konig^ in association with Storp-, Bohmer,"' Stood** and Haselhoff"', we 

 will quote a few figures about the composition of mine water which will 

 suffice to show what quantities of sodium chlorid and other salts are con- 

 tained in it at times. It contains per litre 



Name of Mining Sodium Calcium Magnesium Potassium Magnesium 



Company chlorid chlorid chlorid sulfate sulfate 



Levin 65.949 g 1 1.056 g 3.736 g 0.659 g — 



Matthias Stinnes.. 33.244 g 3-631? 1-735 g — 0.042 g 



Saline Konigsborn. 45.413 g 4-o6i g 0.189 g — 1-256 g 



From these examples it is easy to reckon the effect of irrigating, or 

 flooding land with such solutions. The action will be direct, as well as 

 indirect, according to the changes which the soil undergoes. In the latter 

 connection, the fact that nutrient substances in the soil (Potassium, calcium, 

 magnesium, and, under certain circumstances, also phosphoric acid) are 

 dissolved in increased amounts and washed away should receive first consid- 

 eration. This leaching process begins with the percentage of 0.5 g. sodium 

 chlorid per litre. Nevertheless, all water containing any considerable 

 amount is dangerous for irrigation. Pot experiments with meadow grass 

 show a considerable reduction in harvested substances corresponding to the 

 loss in nutrition of the soil. 



A second disadvantage of irrigation with water containing sodium 

 chlorid is the increased density of the soil. Even 0.41 per cent, sodium 



Die landwirtsch Versuchsstat. Miinster i. W. Denkschrift 1.S96, p. I!i3. 



Landwirtsch. Jahrblicher 1883, XII, p. Ttif). 



Ibid, p. 897. 



Landwirtsch, Versuchsstat. 1S99, P. 113. 



Landwirtsch. .lahrbiicher 1893, p. 845. 



