! 



84 THE HOUSE AND ITS EQUIPMENT. 



SEWAGE DISPOSAL. 



Arrangements for Disposal Detritus Tanks Septic Tanks Treatment of Effluent Costs. 



IT is only during the last few years that this important subject has been seriously considered generally 

 by property-owners. It has usually been sufficient for them to hope that all was well so long as the 

 house itself was not apparent!} inconvenienced. Sanitary science has made tremendous strides, 

 but it is to be hoped that in ten years time some existing methods will be looked upon as out of date. 

 Better consideration should be given to the position of the sanitary arrangements within a house. 

 It would be ideal to adopt for houses the planning usual in modern hospital buildings, and place the baths, 

 w.c. s and sinks in a separate block cut off from the main part of the house by a thoroughly cross- 

 ventilated lobby. However, the ordinary arrangements of to-day, so long as they last, must be made 

 as free as possible from danger, and the shortest length of waste-pipes fixed inside the house will help to 

 achieve this. All pipes so fixed should be exposed, so that frequent and easy examination is possible. 

 All w.c. s and slop sinks should be trapped at the nearest point to the receiving receptacle, and should 

 have a flushing cistern of not less capacity than three gallons where the water companies will permit. 

 Most companies, however, will only allow two gallons, which is certainly not sufficient. It is important 

 that the &quot; waste &quot; dealt with should be conveyed and disposed of with the least possible risk of con 

 tamination. It must, therefore, be removed as quickly as possible and treated in the most efficient 

 manner compatible with reasonable capital outlay and a low maintenance cost. Details of the arrangement 

 of pipes, gulleys and traps are too technical to be dealt with usefully within the limits of this article, which 

 is concerned rather with methods of disposal. 



The selection of a site for disposal works depends to some extent on the system to be installed, 

 for some require a greater fall in the ground than others. The important fact must be borne in mind 

 that with any system there may be a slight &quot; earthy odour &quot; near the tanks, which, however, can be reduced 

 to a minimum if the system is properly designed and trees are planted close to the tanks. In deciding 

 upon the system to be employed, four principal factors should be taken into consideration i. Possible 

 position of the site, together with its levels and nature of subsoil. 2. Possible outlet and discharge for 

 resultant effluent. 3. Quantity and quality of sewage to be dealt with. 4. Cost, both of installation 

 and of maintenance. The site should be as far as possible from the house consistent with a reasonable 

 length of drain. Provided the tanks are fairly closed in by high vegetation and are not in the direct line 

 of the prevailing winds, a distance of about one hundred yards is ample. They are often placed much nearer, 

 without disagreeable results. Bacteria beds should not be in a too exposed position, as the bacterial 

 action is somewhat reduced during cold weather. A site giving the most fall or greatest difference in 

 levels is preferable, as it will allow of a good &quot; fall &quot; in the tanks without resort to pumping or other form 

 of lifting. It is important that a good outlet for the effluent should be at hand, either in the form of 

 a natural watercourse or an arrangement whereby it can be economically distributed or utilised in the 

 garden. Where this form of use is possible, it is against economy to allow the effluent to run to waste. 

 Quality and quantity of sewage per person varies greatly, the quantity being from fifteen to eighty gallons 

 per head, depending a good deal upon the source of water supply and extent of garages, stabling and 

 home-farm property, and also on whether the rain-water is discharged into the drain. For ordinary purposes, 

 however, twenty-five gallons per head per twenty-four houis can generally be safely reckoned upon. The 

 initial cost depends upon the falls obtainable, the quality and quantity of the sewage, and upon the degree 

 of purity of the effluent required, which again depends upon the nature of the ultimate disposal of the effluent. 

 Cost and maintenance depend upon the system installed, the quality of materials and workmanship 

 employed, and the care given to the installation from the first day it is in operation. It must be 

 remembered that no disposal works are absolutely automatic, and that regular and careful atte-ntion 

 is therefore required. 



The object of a disposal works is to liquefy the solids and obtain an effluent free from solid matter 

 and practically free from solids in suspension. It depends somewhat upon the nature of the outlet available 

 for the ultimate discharge of the effluent as to whether a good chemical or good bacteriological result is 

 desired. The first operation necessary in all systems is to free the sewage from &quot; foreign matter,&quot; such 

 as rags and scrubbing-brushes ; in fact, from all matter that will pass through to the various tanks and 

 beds and not liquefy in a reasonable time. This is generally achieved by discharging the sewage into 

 a sump chamber, or detritus tank, fitted with a fairly large mesh screen, so that the sewage will pass 



