372 Report S.A.A. Advancement of Science. 



The bacteria beds are fitted with automatic timed discharge 

 syphons operated by the liquid in the beds passing through a small 

 regulating cock which can be set so as to start the syphon and 

 discharge the contents of the bed after it has been in the bed. and 

 consequently in contact with the bacteria, any desired length of time. 



When these beds are working up to their full capacity each bed 

 will be filled three times during the 12 hours of day and will stand 

 empty to aerate during the 13 hours of night. 



The filtrate from the bacteria beds passes into an effluent chan- 

 nel which discharges into an irrigation furrow, from whence it is led 

 over the land in furrows or on to beds according to the requirements 

 of the crops to be irrigated. 



Each of the Bacteria Beds is 20 feet long by 8 feet wide and 

 averages 3 feet in depth and when working to their full capacity will 

 deal with sewage at the rate of 822,800 gallons per acre per diem. 



The cost of the construction of the works was ^400. 



The information and data which we have regarding the Ijacterial 

 system of sewage purification is derived from works which have been 

 constructed in countries which have a humid climate, where on 

 account of the dense jwpulation it is desirable that the area set apart 

 for sewage disposal should be as small as is compatible with the 

 purpose and where the excessive rainfall makes it necessary that the 

 superfluous water should be got rid of as soon as possible. In this 

 country those conditions are reversed ; here we have a dry climate 

 and at present a scanty population, and under these conditions the 

 waste water from sewage works instead of being looked upon as a 

 necessar}' evil, to be got rid of as soon as possible, would be stored 

 for irrigation purposes and thus form a valuable asset. The area 

 of land which would be utilized for the final treatment of the purified 

 effluent instead of being as .small as possible would be as large as tht^ 

 volume of water would irrigate, and when we consider that the appli- 

 cation of water to land increases its value from jQi to ^20 jDer acre 

 it seems reasonable to assume that the cost of carr}'ing out Sewage 

 Disposal Works in this countPv' will be largely met bv the increased 

 value of the land utilized and by the sale of the waste water for 

 irrigation purposes. 



