• Heavy clay soils (i.e., poorly percolating) that do not promote the use of conventional systems.
• Shallow soils (a liner is installed).
• Karst topography (i.e., sink holes).
• Where improved effluent quality is desired.

• Septic tank required.
• Uses highly permeable porous media to support the roots of emergent aquatic vegetation. Materials
• include clean round stone (90 per cent at 20 - 50 mm, and 10 per cent at 50 - 125 mm), and high phosphorus-adsorption material such as man-made clay aggregates. Wood chips are often used on the surface to aid in denitrification.
• Wetland may be designed with a plastic PVC liner and an overflow disposal chamber.
• Consider aerobic pre-treatment such as a sand filter.
• Generally less than 60 cm depth, but may be as deep as 90 cm depending on freezing potential. Some flow manipulation or insulation may be considered to reduce the potential for freezing.
• Must ensure enough water at all times to maintain aquatic plants.
• Appropriate emergent plant species include: cattail, arrowhead, lizard's tail, iris, marsh marigold, and soft
• rush. Common reed is effective, but can move beyond the welland and become invasive.
• Typical three-bedroom household would require a surface area of about 150 M2 and a depth of 60 cm,
• The wetland can be rectangular, take an irregular shape, or contoured along a slope, as iong as the design width/depth ratios are achieved
• Inlet and outlets consist of distribution headers located near the bottom of the wetland at the inlet and outlet ends. Water levels are maintained 20 cm below the stone surface.
• Holding water levels below the surface of the stone reduces risk of direct contact with podsible viruses, and deters breeding insects.

Comments: send me email: kwatson@kos.net
URL: www.rideau-info.com/local/septic-wetlands.html
© 1999-2008 Ken W. Watson