v.— MISCELLANEOUS. 



Art. XLVIII. — Sanitary Seiverage. 



By H. P. HiGGiNSON, M.Inst. C.E. 



[Read before the Wellington PJiUosopMcal Society, 9th Jaiuianj, 1889.} 



The question : "How shall sewage be dealt with?" is one 

 that has been found extremely difficult to answer. It has 

 occupied the minds of sanitary reformers for many years, and 

 been treated in a variety of ways, not always successfully. 

 At all periods of the world's history where civilisation attained 

 to any degi'ee of refinement sanitary measures were adopted. 

 It is usual to discuss the question intermittently until the time 

 at length arrives when action must be taken. A virulent 

 epidemic forces the matter to the front in a most unpleasant 

 manner. 



The site of the City of Wellington in its original state con- 

 sisted of hill-slopes falling on all sides towards the harbour, 

 offering ready means of drainage, requiring little experience or 

 thought in the carrying-out. Modern improvements and the 

 expansion of trade have necessitated the reclamation from the 

 harbour of the whole frontage ; and though on the one hand 

 this has covered the foreshore upon which sewage-mud festered 

 in the sun to the annoyance of the citizens and detriment of 

 the public health, on the other hand it has greatly increased the 

 difficulty of constructing a properly effective sewerage system, 

 as where the sewers traverse the reclaimed area they become 

 tide-locked twice in twenty-four hours, with the result that, 

 their contents being impounded, the loss of velocity is the cause 

 of the deposition of the solid particles. This, in the form of 

 sewage-mud, becomes mixed with road-detritus and material 

 washed from the hill-slopes during heavy rains, gradually 

 forming an ever-increasing deposit which solidifies to such an 

 extent as to withstand the action of even the rush of water 

 during heavy rainfall. When this accumulation threatens to 

 block up the outlet it must be removed by hand-labour. 



The worst feature of this stagnant deposit with which 

 sewage-mud is incorporated is that it generates foul gases, 



