The Purification of Sewage by Bacteria. 39 



be freely discharged into any stream without fear of damage, 

 and the sample to be shown by Dr. Jefferson, M.O.H for 

 Lisburn, taken August, 1^97, showed no signs of change or 

 decomposition at that time. 



Dr. Jkffkrson (Lisburn) said — Mr. Chairman, I can add very 

 little to what Dr. St. George has said, but shall, with your 

 permission, read a few notes I took when examining the 

 differtnt schemes. In the universal system at Ilkeston there is 

 an Ives Settling Tank, the sludge is pumped out night and 

 morning with a gas engine, and during this operation gives off 

 a most offensive smell. The eflfluent is very cloudy, and gives 

 off a strong smell of sewage. The International at Hendon has 

 a Candy's Patent Sludge Removal Apparatus. There is an 

 enormous quantity of sludge, viz. — 1,300 tons for a population 

 of 14,500. The treatment and disposal of the sewage cost 

 £^19 '7S- yd. for years iJ<96-i8q7. In the above systems 

 chemicals are used. The solids are screened, raked out every 

 hour, carted away and buried. The Hendon authorities were 

 threatened with an action by the River Conservators for 

 pollution of the river Brent, on account of the reaction that 

 occurred when chemicals are used. The following are, in my 

 opinion, the advantages of the Exeter system, viz. — i, no 

 screening ; 2, no chemicals, and consequently no reaction in 

 rivers ; 3, no expensive machinery, it is automatic ; 4, working 

 expenses very light, a man about an hour two days in the week 

 would be quite sufficient ; 5, very httle sludge, which would 

 not require rem.oval for several years ; 6, effluent very good, no 

 smell whatever, and may be discharged into a river without 

 further treatment of any sort. 



Mr. Peddie (Belfast) was in favour of the system, and showed 

 that there would be a great saving in both the initial expense 

 and also in the upkeep of this system, as compared with the one 

 that had been promoted for Armagh. 



Mr. MuNCE, Assistant City Surveyor, Belfast, said he had 

 from the first formed a good opinion of the septic tank system, 

 and he believed the precipitation idea was dead, because the 



