STERILIZATION 195 



t Trouville, in France, where about half of the 1,800 houses 

 ere connected up and worked at the company's expense at an 

 verage annual charge of i6s. per house. The method is based 

 n the separation of " excrementitious " and " non-excremen- 

 tious" matters. The latter, including rain, storm, and surface 

 ater and industrial effluents, are conveyed by separate con- 

 uits, " utilizing as much as possible the existing sewers of 

 owns." It is said that these liquids " in consideration of their 

 athogenic inoffensiveness can be safely delivered into the 

 earest watercourse, after being clarified, if necessary." It 

 ust be remarked that, as we have shown in the first chapter, 

 road and field drainage is by no means inoffensive, that indus- 

 trial effluents are frequently putrescent, and that the droppings 

 of animals are often highly pathogenic. 



The "polluted liquids, including faecal matter, sink slops, 

 soapy and dirty water," pass through iron pipes into closed 

 iron underground receptacles, thence by 4-inch pipes to " dis- 

 trict reservoirs," communicating by pipes of 10 to 30 inches 

 '' internal diameter with the central pumping station. A slight 

 vacuum is continually maintained, and at intervals the whole 

 ji system is exhausted by sections into a main reservoir. In the 

 ' original description the excreta, with as little admixture of 

 water as possible, were heated with i to 2 per cent, sulphuric 

 acid, like a Kjeldahl process on a large scale, until the whole 

 j was reduced to a brown syrup, containing nearly all the original 

 I nitrogen as ammonium sulphate. This was either distilled with 

 lime and the ammonia utilized, or dried up with ashes and sold 

 as manure, containing, however, usually an excess of acid. The 

 cost in Holland was said to amount to 4s. lod. per head per 

 annum. In this system — (i) Sewers can be laid at a uniform 

 depth, just sufficient to protect them from frost, and at 2 or 3 feet 

 in such countries as India. (2) No flushing is required, which 

 is important in places where water is scarce. (3) No gratings 

 or ventilating columns are needed, as the air pumps remove all 

 gases, and the ordinary manholes are also not required. (4) As 

 the system depends on working of a vacuum, any leak will be 

 at once detected, and percolation of the subsoil will be pre- 

 vented. (5) There is no dependence on fall, therefore it can be 

 used on land of any contour. 



FAt Trouville^ the sewage was stored in a large covered brick 

 ank for about a week (thereby undergoing septic change), then 

 ^ Report of Surveyor to Tendring Rural District Council, Essex, July, 1899. 

 .3-. 



