DISTRIBUTION AND DISTRIBUTORS 



309 



gauged to any required size. The sewage to be tested is dis- 

 tributed on the top by a tipper working at a measured rate. 

 The filter effluent can be drawn off at any one of six levels. By 

 means of a water tank and syphon arrangement the amount 

 of air which is supplied to the filter bed can be measured. 

 Mr. Moncrieff claims that the apparatus is capable of deter- 

 mining the depth of the filter required to produce the necessary 



g^^ L 



Fig. 57. — Scott- MoNCRiEFF Sewage Testing Apparatus. 



standard of purity in the effluent, the quantity of air necessary 

 for the life processes of the organisms, the proper rate of flow 

 per unit of filter bed surface in order to obtain the best results, 

 and the best period of rest between every discharge. The 

 apparatus is likely to be of great use in competent hands pro- 

 vided that due allowances are made for the smallness of the 

 quantity of sewage it is possible to experiment with on an area 

 of only three square feet, and for this, provision has been made 

 by an ingenious device for gauging the liquid without having 

 any small orifices. It is maintained that one square foot of 

 filter bed is as good a unit as any other for estimating surface 

 distribution, and as the testing machine is six feet in depth it is 

 of full size in this particular. 



