The problem of sewage disposal. Composition and character of sewage. Action of bacteria. Soils and their value for sewage treatment. Three essential conditions for effective sewage purification. Rates of operation. Preliminary and final treatment.
Function and capacity of settling tanks. Their construction. Siphon chambers. Use of concrete. Pipe connections. Roof. Baffle boards. Imhoff or Emscher tanks.
Advantages of sub-surface irrigation for sewage disposal. Details of system. Tables for use in constructing. Siphon chambers. Sub-surface tile. Alternate use of separate portions of area. Underdrainage.
Relative efficiency of various types. Sand Filters. Tables for use in constructing siphons. Dosing and distribution methods. Maintenance. Contact Beds. Methods of construction. Alternate and timed siphons for filling and discharging. Table for use in constructing. Sprinkling Filters. Their construction and operation. Complicated and undesirable for small installation.
Fertilizing elements in sewage. Value of sewage for irrigation. Area required for sewage irrigation. Methods of applying the sewage. Maintenance of irrigated areas.
Cost of material: of laying sewers and drains; of sand; of excavating and refilling; of rock excavation; of concrete work; of valves; of dosing devices; of filling material for beds; of finishing and cleaning up. Table to show items to be considered in estimate of cost.
