DISTRIBUTION AND DISTRIBUTORS 



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filter No. i gradually fills a receptacle into which dome E dips. 

 The taps supplying the inlet and outlet may be set so that the 

 receptacle fills in any given time, when, as in Fig. 31, the air 

 will be transferred to the feed C, causing an air lock which will 

 divert the sewage to the next feed or bed. " With this apparatus 

 any desired area may be flooded for a given time, sewage being 

 sent to one area or bed after the other, regardless of the numbers 

 used or volumes dealt with, automatically and without move- 

 ment." 



II. Ridgway Automatic Distributor (Mather and Piatt, Man- 

 chester). Screened or sedimented sewage is received into a 

 syphon chamber built to hold a given number of gallons 

 according to the average volume to be treated. When full, the 

 syphon discharges this amount into the *' Distributing Chamber." 

 At the same time, a hollow cylindrical float, which has been 

 previously raised by the filling of the syphon chamber, descends 

 to the bottom, and by a pawl and rachet wheel causes a 

 horizontal shaft to revolve, and, by means of cams, to open or 

 close in succession a series of valves communicating with 

 different beds [patent 12287 of igoi]. 



At Hale, near Manchester, Dr. Garstang reported in 1899 

 that this distributor was passing 72,000 gallons per day on to 

 180 sq. yds. of single contact beds (2 million gals, per acre per 

 diem), during a period of 10 months. He gives the following 

 average analyses : 



It appears from the report that the effluent remains at the 

 bottom of the bed for two hours before being expelled by the 

 next succeeding charge. This involves an increase in the 

 capacity of the bed, and renders denitrification changes possible. 



III. Cameron's Automatic Alternating Gear at Exeter has 

 been already mentioned (Chap. IX.). At Barrhead six of the 

 eight filters are in use at once, one being filled at a time. As 

 soon as a filter is full, the flow of tank effluent is automatically 



