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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #107510
Title: CONSTRUCTED WETLANDS FOR CONFINED SWINE WASTEWATER TREATMENT

Author
item SZOGI, A - NC STATE UNIV.
item RICE, J - NC STATE UNIV.
item HUMENIK, F - NC STATE UNIV.
item Hunt, Patrick
item STEM, G - USDA-NRCS, RALEIGH, NC

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 1/27/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Currently, most animal production enterprises apply both solid and liquid waste to forage and crop land. Land application of waste becomes a problem when more manure nitrogen is produced than crop or forage land can assimilate. Consequently, public concern and changing environmental regulations are stressing the need for alternative treatment methods that require less land area for manure treatment. These alternative methods include constructed wetlands. The goals of our studies were to assess the ability of constructed wetlands to remove nitrogen and thereby prevent overloading of land application areas. Saturated-soil culture soybean and flooded rice produced modest grain yields while treating wastewater for removal of N. The wetlands with natural plants showed great promise by removing >80% of the N at an application rate of 25 kg/ha/d. At this rate and 300 application days, wetlands could remove >5,000 kg/ha/yr which is much higher than what cropland or forage land can remove on a yearly basis We assumed that most of the N was microbially converted to N gas by nitrification-denitrification processes. However, additional investigations indicated that the wetlands were highly reducing and nitrate limited. Since ammonia is the prevalent form of N in these wetlands, some direct loss of N as ammonia gas cannot be disregarded. Additional research is being carried out to increase their N mass removal efficiency by nitrifying the effluent prior to wetland treatment. This pre-wetland treatment will eliminate wastewater dilution and lower gaseous loss of ammonia.