MODEEN METHODS OF STREET CLEANING 



the liquid from the solid portion. The solid part is 

 sold as nightsoil. 



The liquid portion, containing a small amount of 

 finely divided solid matter, is run into storage-tanks 

 fitted with mechanical agitators. Here sulphuric acid 

 is added to fix the ammonia. The mixture is then run 

 by gravity into a series of steam-jacketed dryers where 

 it is reduced to a solid state. The gases from these 

 dryers are conveyed underneath the grates of a cre- 

 mator which renders them innocuous. The solid manure 

 produced by the drying process is stored in large bins 

 and eventually carried by an automatic conveyor to 

 the top floor of the building where it is filled into bags 

 and packed into railway cars standing on an adjoining 

 siding. 



While in storage preparatory to being bagged, the 

 manure is fortified by the addition of a sufficient quan- 

 tity of ground bones and dried fish refuse to bring it 

 to a standard of value. When sold, the city guaran- 

 tees that the manure always contains from 3| to 4 per 

 cent of ammonia, 8 per cent bone phosphate, 0.75 per 

 cent potash solids, and 38 J per cent organic matter. 

 The price received is about $15 per ton. 



Every care is taken to insure cleanliness in the depots 

 and other places where refuse is handled and used. In 

 cleanness of the man y years, practically a lifetime, during 

 Depots which the works have been in operation, it 

 is said that not a single case of infection has occurred. 



Notwithstanding the peculiarly offensive nature of 

 the work, the depots, stables, storehouses, docks, and 

 other places visited by me were characterized by a 

 degree of cleanliness and freshness not common even 

 in industrial works about which no especially offensive 



