Sewage or Effluent Lagoons

11. Sewage or Effluent Lagoons

11.1 Design Standards

1. with a liner, consisting of porous material in which seepage is governed by Darcy's Law, that has a maximum hydraulic conductivity calculated by the following equation
   where
   • KT = maximum hydraulic conductivity of liner in the field, being at least one order of magnitude greater than the laboratory value, metres/second
   • T = required or proposed thickness of liner, metres
   • C = 5.2 X 10-9 metres/second,

   or

2. with a flexible polymeric membrane liner having a minimum thickness of .5 mm or 500 µm (20 mils) and
   1. membranes less than 1.5 mm or 1,500 µm (60 mils) thick are covered with a 300 mm layer of fine grained soil on the slopes to prevent liner damage, and
   2. PVC and other membranes that are susceptible to weathering when exposed, shall be covered with soil on both the side slopes and bottom.

1. a sewage depth of not greater than 1500 mm (5 ft.),
2. a 600mm (2 ft.) freeboard height above the design operating depth,
3. a berm slope not steeper than 1 vertical to 3 horizontal,
4. sufficient surface area to evaporate 125% of the expected annual volume of sewage discharged into it, and the design surface area shall
   1. consider the net evaporation at the system location determined by the average annual precipitation and evaporation rates recorded by the Prairie Farm Rehabilitation Administration as reproduced in the Appendix A.2.A and Appendix A.2.B, and
   2. provide adequate storage to hold expected volumes of sewage during winter or other periods of low net evaporation, and

   Note: Formulas to calculate the required size of the lagoon are included in Appendix A.2.C.

5. provide a minimum 1800 mm (6 ft.) wide berm at the top.

   Intent: Sewage lagoons for private systems built to this Standard are not meant to rely on periodic discharge and must be sized to evaporate all sewage. Annual precipitation and evaporative rates must be considered in the design.

See Pg. 213, Fig. L 1 in Appendix "B"
See Pg. 161, Sewage or Effluent Lagoons in Appendix "B"

The sewage lagoon is not intended to be pumped out into a receiving water way or other location off site as is the case with municipal lagoons in many cases. Private sewage lagoons must evaporate the sewage to remove the need to pump out the lagoon. This article requires the lagoon be designed to evaporate 125 % of the sewage volume to provide a safety factor.

Intent: Entering the pipe in this pit should provide a constant 600 mm (2 ft.) cover of water over the pipe that should provide protection from frost. The pit should be approximately 1800 mm x 1800 mm x 1800 mm (6 ft. X 6 ft. X 6 ft.) deep with the pipe entering 1200 mm (4 ft.) above the bottom of the pit.

See Pg. 213, Fig. L 1 in Appendix "B"
See Pg. 161, Sewage or Effluent Lagoons in Appendix "B"

Intent: The fence should be designed to preclude the entrance of children and to discourage trespassing. The fence should also serve to preclude the entrance of livestock. Fences should be located away from the outside toe of the berm to facilitate mowing and maintenance operations.

Where the lagoon is located near developed areas, a chain link fence may be required to prevent children from gaining entry. In addition, an access gate should be provided to allow entry of maintenance equipment, and this gate should be equipped with a lock to prevent entrance of unauthorized personnel. Signs should be posted to identify the lagoon and advise against trespassing.

See Pg. 161, Sewage or Effluent Lagoons in Appendix "B"

11.2 Installation Standards

1. A lagoon serving a single family dwelling or duplex shall not be located within
   1. 90 m (300 ft.) from a water source,
   2. 90 m (300 ft.) from a water course,
   3. 45 m (150 ft.) from a dwelling, and
   4. 30 m (100 ft.) from a property line.

2. All measurements shall be taken from the outside of the berm, where the side slope of the berm intersects with the natural ground surface.

1. A lagoon serving other than a single family dwelling or duplex shall not be located within
   1. 90 m (300 ft.) from a dwelling or building other than a farm building,
   2. 90 m (300 ft.) from a water source,
   3. 90 m (300 ft.) from a water course,
   4. 30 m (100 ft.) from a property line, and
   5. 90 m (300 ft.) from a numbered primary or secondary road.

2. (2) All measurements shall be taken from the outside of the berm, where the side slope of the berm intersects with the natural ground surface.