38 The Furification of Sewage by Bacteria. 



as the area required would be about 3,000 acres ; and chemical 

 precipitation he did not favour, because it left the sludge question 

 undealt with, which was the bete noir of sanitary engineers. 

 The question of the disposal of the sludge had practically 

 sounded the death knell of chemical precipitation as a means 

 of purifying sewage. '1 here was. then, only left the bacterial 

 method, which the septic tank treatment carried out. They in 

 Belfast therefore should not be any longer lax in this matter, 

 but should benefit by the able lecture they had heard from Mr. 

 Martin, and see that the sewage of the city should not be any 

 longer discharged in a crude state into Belfast Lough. The 

 question of the purification of the sewage was, as has been said, 

 one of ^ s d ; but the septic tank treatment was merely one of 

 first cost, with practically a minimum of working expense after- 

 wards, the system being automatic. 



Dr. St. Ghorge (Lisburn), after complimenting Mr. Martin 

 on the clearness of his lecture, said that dirt was only matter in 

 a wrong place, and that sewage only was a nuisance and 

 required to be grappled with on acccount of the aggregation ot 

 people in towns, therefore the disposal of it (sewage) by nature's 

 methods was at once the simplest, the cheapest, and the best. 

 The sooner the public could be made to understand that 

 Bacteria were not all raging lions ready to prey on the human 

 race the better, but that even bacteria had their part in the 

 cycle of nature, acting and reacting, each in its proper sphere. 

 There seemed no manner of doubt that the septic tank 

 system fulfilled this, and from personal observation during 

 August, 1897, he was prepared to support all that had been 

 said by the lecturer. The other systems he had visited first 

 screened their sewage, none admitting raw sewage in the true 

 sense of the word. The chemical precipitation left enormous 

 quantities of sludge to be disposed of, which was valueless as 

 manure, being deprived of nearly all its nitrogen. Then the 

 initial cost being the only expense was a very considerable 

 factor for the system, one labourer being sufficient to look after 

 the works. The eflfluent having no chemicals, solution could 



