Sewage Disposal and River Pollution. 73 



disregarded — the more valuable elements I have intercepted in 

 another form. Nevertheless, the sludge remains to be disposed 

 of. We will suppose that a commercial attempt is being made 

 to utilise the value of the elements retained as manure ; then 

 the same fuel employed to create the aerating draft, to pump 

 when necessary the low-level outfall and to work the filtering 

 materials by grinding, &c, will also dry and calcine the sludge. 

 The oxidised sludge is mixed with the coarse filtering materials 

 by precipitating them into a drying floor or underground flue, 

 which conveys the waste heat ; here the material may lie 

 undisturbed till dried. It may also be mixed with the ordinary 

 town refuse, and the whole thus dried together, and once dry 

 it can be treated as an ordinary raw material for manure, or 

 more correctly as a vehicle for the reception of other valuable 

 manure constituents, as in ordinary artificial manure industry. 

 At the close of the lecture Mr. Hartland explained that owing 

 to an accident to his experimental apparatus in transit from 

 Glasgow, it had been necessary to effect some repairs, and they 

 were only accomplished just before the lecture. He hoped, 

 however, that the apparatus would be in full working order 

 next morning, and anyone calling at the Museum after twelve 

 o'clock would find it at work purifying the Belfast sewage. 

 A discussion, which was chiefly of a technical nature, followed, 

 in which Rev. Robert Workman, Mr. Wm. Gray, Mr. J. J. 

 Murphy, Mr. L. L. Macassey, C.E.; Professor Everett, Mr. E. 

 N. Banks, C.E., and Mr. F. W. Lockwood took part. Mr. 

 Hartland replied, and the meeting concluded. 



