CHEESE-FACTORY 



for 10,000 pounds of milk, whose treated sewage 

 passes out into heavy soil with little natural drainage. 

 The material used in tank construction can be iron, 

 cement or wood. Each part should be large enough 

 to hold the sewage of 24 hours. By this arrangement 

 the sewage is in the tank for three days. At the 

 end of this period it may be carried by piping or tile 

 to its final place of deposit. The overflow-pipes 

 should be ventilated to prevent siphoning of the con- 

 tents after it starts to overflow. The tanks are 



f 



FIG. 20 SERIES OF SEPTIC TANKS CAPABLE OF HOLDING 



THREE DAYS' SEWAGE FROM A CHEESE-FACTORY 

 HANDLING 10,000 POUNDS OF MILK A DAY 



better placed under ground so that the top just 

 reaches the surface. It should have a good top and 

 may then be covered with earth. It is advisable to 

 have a water-trap in the pipe delivering the sewage 

 from the factory to the septic tank in order to pre- 

 vent odors returning. This system is very efficient 

 and may be used in almost any locality. In some 

 places it is advisable to deposit the treated sewage 

 on a prepared, gravel filter-bed. 



