Long-term Objectives:

1. To determine the effectiveness of constructed wetlands in removing nutrients, organic solids and pathogens from swine lagoon effluent.

2. To determine which plant species are most effective and adapted to constructed wetland treatment systems.

3. To develop management practices for maintaining vegetation in constructed wetland treatment systems.

---

Short-term objectives:

1. To determine the effect of lagoon effluent at full strength and half strength on growth of Juncus effusus and Scirpus validus.

2. To compare nitrogen removal rates of vegetated and unvegetated wetland cells.

3. To determine the effects of oxygen transport to the rhizosphere of wetland plants on soil redox potential and nitrification.

4. To determine if root exudates from several wetland plants kill pathogens in lagoon effluent.

---

Accomplishments:

1. A previous project demonstrated the effectiveness of constructed wetland cells in reducing N, P, suspended solids and chemical oxygen demand in domestic septic tank effluent.

2. Demonstrated that Juncus effusus and Scripus valid grow vigorously in half-strength swine lagoon effluent.

3. Demonstrated the effectiveness of wetland plants in reducing total amounts of N and P in effluent and reduce the volume of effluent.

---

Significance:

The amount of nitrogen and phosphorus in wastewater generated by large swine farms often exceeds tbe capacity of available crop land to effective assimilate these nutrients. Treatment by a constructed wetland system can reduce the nutrient concentration in effluent and reduce the area needed for land application. Utilizing constructed wetlands in a waste disposal system can reduce the risk of polluting surface water and groundwater with excess N and P.

---

Future Plans:

1. Continue to evaluate the effectiveness of constructed wetlands for treatment of lagoon effluent.

2. Evaluate common wetland plants as to their value and effectiveness in constructed wetlands for wastewater treatment.

---

Published by: North Carolina Cooperative Extension Service

Publication Number:

Last Electronic Revision: JULY 1996 (MSD)

---