686 PROCEEDINGS OF SECTION I. 



Septic tanks in Europe are by no means new, and the writer saw 

 one that dealt with tiie sewage of a town of over 30,000 inhabitants 

 that measured only 50 ft. long and 50 ft. wide. This has been work- 

 ing most satisfactorily for over twelve years. The effluent after 

 passing over an aerator went through a charcoal filter, and into the 

 liver. It was quite harmless and odourless, and said to be free from 

 any objectionable organisms. 



Haying dealt with the leading features of a modern system of 

 treatment, and shown that the less water used the better, the question 

 of collection has next to be considered. There are two that may be 

 called modern methods before the world; but, for various reasons 

 that cannot be dealt with here, neither method has come largely into 

 use. Both methods have a common point that will appeal to most 

 people, and that is that, instead of large brick or concrete sewers 

 made at great cost deep down in the roads, comparatively small cast- 

 iron pipes can be laid at a greatly reduced cost under the footpaths 

 and near the building alignment, so that the cost to property owners 

 for connecting their buildings becomes very trifling, as compared with 

 making connection with the big sewers deep down in the earth. 



As these methods are not well known, a brief description of them 

 may be desirable. One is a combined gravitation and pneumatic 

 pressure system by which the sewage flows from the houses into 

 mains in the streets, and on into a metal district receiver placed at 

 the lowest convenient point. This district receiver is connected, to a 

 system of compressed air supply, and operates automatically, so that 

 when it becomes full of sewage, air, under pressure, is admitted, and 

 the sewage is ejected from the receiver, and is forced along the mains 

 to another receiver, and so on as often as is necessaiy until it reaches 

 the point of treatment or discharge. Tliis system is in satisfactory 

 ojjeration in Singapore and a few other places, but the author is not 

 aware of it being in use anywhere in conjunction with septic tank 

 treatment; and it is doubtful whether the aeration of the sewage 

 that occurs in this system would not be detrimental to the microbic 

 action in the septic tank. This system would work well in a hilly 

 place like Brisbane, and while it has many points in its favour, it is 

 open to the serious objection that the pipes are under pressure, and 

 any leakage means escape into the atmosphere. The appliances for 

 use with this method are made by several well-known firms. 



The second method is just the opposite. The sewage is drawn 

 from the houses by means of a vacuum into a district receiver, and 

 from there it is drawn into the main receiver for final treatment. In 

 this system each house is' provided with a receptacle which collects 

 the sewage, and this is emptied once or twice a day by a vacuum 

 which causes all the sewage in the section to immediately leave the 

 receptacles and fly along the small cast-iron pipes to the district 

 receiver. 



This vacuum system has many advantages, among which are^ — 

 (1) that all smells are drawn tJitu the system, (2) a minimum amount 

 or water can be used, (3) the sewage is delivered in the most suitable 

 condition for septic tank treatment, (4) and the pipes are kept clean, 

 any leakage means drawing smells into the system instead of forcing 

 them out. 



