US EPA

6446555 

Journal Article 

Aquatic Plant/Microbial Filters for Treating Septic Tank Effluent 

Wolverton, BC 

1989 

The use of natural biological processes for treating various types of wastewater has been developed at the John C. Stennis Space Center during the past 15 yr. The design and operating experience with some of these systems at various locations in Mississippi is described. Septic tank effluent from single homes can be treated to advanced secondary levels or better using a 400-sq ft washed gravel filter. The filter should be 1.0-1.5 ft deep, with the wastewater level maintained at 6 in below the rock surface. When ornamental plants (e.g., calla lily, Zantedeschia aethiopica, canna lily, Canna flaccida, elephant ears, Colocasia esculenta, yellow iris, Iris pseudacorus, and ginger lily, Hedychium coronarium) are planted in the rock filter, their roots penetrate to the wastewater level, adding oxygen and increasing biological activity. If a point-source discharge is not desired, approximately 20 ft of 4-in perforated leach field tubing is used to disperse the effluent from the rock/plant filter beneath the soil. Large septic tanks use in small towns and communities in lieu of open sewage lagoons have many advantages over open lagoon systems. Several tanks in different locations can discharge their effluent to one or more rock/plant filters for further treatment. Size of the rock/plant filter is dictated by the volume of septic tank effluent and the level of treatment desired. When these systems are properly installed, sewage will not be exposed to the air before treatment has been accomplished. (See also W90-04392) (Rochester-PTT) 

; Wetlands; Land disposal; Mississippi; Wastewater treatment; Artificial wetlands; Septic tanks; Biological wastewater treatment; Water pollution control; Aquatic plants; Performance evaluation; Rural areas/