ON THE TREATMENT AND UTILIZATION OF SEWAGE. 177 



have been laid out, one to the north and the other to the south of the town, 

 and an outfall server made to each. 



Underdrainage has not been uniformly adopted on both farms ; but where 

 it previously existed, a peculiar arrangement has been made for the reappli- 

 cation of the drainage-water. 



The distribution of the sewage is chiefly effected by what is known as the 

 catchwater system, which is necessarily, under ordinary conditions, accom- 

 panied by an overflow, in preference to its appHcation in smallei; quantities, 

 sufficient to satisfy the demands of vegetation and to wet the land thoroughly 

 without any overfloAv ; while the absence of storage -reservoirs necessitates 

 the continuous application of the sewage to some parts of the land by night 

 as well as by day. 



The population of Tunbridge Wells is 19,410. 



The total quantity of sewage discharged is 1,000,000 gallons per 24 hours, 

 of which about 400,000 gallons are supplied to the northern farm, and about 

 600,000 gallons to the southern one. 



The northern sewage is applied to 123 acres of land, which have cost 

 ^21,000, and the southern to 167 acres, which have cost £27,000. 



To deliver the sewage from the two main outlets of the town to the land, 

 culverts or conduits, with precipitating-tanks for the separation of the 

 larger portions of the solid matter from the liquid, have been constructed in 

 a very substantial manner. The delivering-conduits on the north, extending 

 for a length of two miles with the precipitating-tanks, have costi<£258713s. Id., 

 while those on the south (of which the length is three miles) have cost 

 .£5809 17s. 8d. The tanks on the north farm have cost ,£833 3s. 9d., those 

 on the south £1188 5s. Id. 



Thus the total cost of external delivering works amounts to £10,418 19s. 7d., 

 which, added to the cost of the land, will be £58,418 lds.7d., or £201 8s. lid. 

 per acre. 



The solid matter collected in the tanks is removed from time to time, and 

 used on the farms as additional manure. The tanks are not covered ; and 

 there is consequently a strong smell in their proximity, which is not dis- 

 coverable in any other part of the farms. 



The sewage having been delivered on to the land, is conveyed from one part 

 to anotlier by open main carriers and iron pipes, the former following contour- 

 lines, and the latter partaking of the nature of inverted siphons in order to 

 cross existing valleys or hollows. 



The cost of these internal works per acre has been — 



For Carriers £18 13 



Drain 3 12 



Iron pipes 4 6 



Grubbing and trenching . . 3 16 



Eoads 6 7 6 



Wire fence 1 5 6 



Or in all £38 per acre. 



Or a total of £239 8 11 per acre. 



The soil of nearly the whole of the northern farm is of a stiff clayey cha- 

 1-acter, manifestly requiring underdrainage. It had for the most part been 

 drained by the late owners before the Commissioners of Tuiibridge Wells 

 purchased it j but owing to the work being done as ordinary farm-drainage 



1871. N 



