* 873*1 ^ Solution of the Sewage Problem. 61 



destruction, requires only a brief notice. By its very nature 

 it forces us to condemn it : destruction has always been a 

 favourite method of disposal of inconvenient elements, 

 from time immemorial. Considerable difference of opinion 

 exists as to what constitutes inconvenient elements, — but 

 once admit the principle, and we find men using it to 

 justify the murder of children by Lycurgus, and the mon- 

 ster fires of religious persecution. For our own part 

 nothing will satisfy us but rational utilisation. Under the 

 head of destructive processes we include the lime process of 

 Tottenham and General Scott's cement process. By General 

 Scott's process an effluent of a low standard of purity is ob- 

 tained, whilst the result is in an agricultural point of view the 

 most wasteful that could be devised. The sludge instead of 

 being returned to the land is employed in the making of a kind 

 of Portland cement. Human beings live directly and indirectly 

 upon the produce of the land. Now scientific agriculture 

 tells us that land unless properly manured becomes soon 

 exhausted ; and it is clear that the waste products of human 

 beings, being most valuable in rendering the land fertile, 

 should be returned to the land as manure, and not be destroyed. 

 Few persons have any idea of the enormous waste which is 

 committed in casting London sewage into the Thames. Mr. 

 Mechi, a great authority on all agricultural subjects, tells 

 us that the inhabitants of London consume daily the annual 

 available produce of 20,000 acres, and a similar quantity is 

 required weekly for London horses. The manurial wealth of 

 this 20,000 acres of land is absolutely wasted, and the 

 country thereby loses as much food as if three million 

 quartern loaves were daily floating down the Thames 

 towards the sea. 



We come now to the consideration of the fourth scheme 

 of defoecating sewage, by precipitating the solid constituents. 

 The object of precipitation is to remove in a solid, dry, or 

 semi-dry state the putrescible constituents of the sewage, 

 and to render the filtrate or effluent water sufficiently pure 

 to mingle with our streams, or be employed for purposes 

 of irrigation. There are several processes which profess to 

 remove more or less of the impurities from the water. 

 Amongst these may be mentioned the Phosphate Sewage 

 Company's process, the lime precipitation process, and the 

 ABC process. In the Phosphate Sewage Company's pro- 

 cess "the water is left still maintaining all its nitrogenous 

 and valuable properties, plus any excess of phosphoric acid 

 which has been added, and, therefore, highly useful for the 

 irrigation of cereals and other crops." This process, which 



