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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 #80134
Title: SWINE WASTEWATER TREATMENT BY MEDIA FILTRATION

Author
item SZOGI, ARIEL - NC STATE UNIV
item HUMENIK, FRANK - NC STATE UNIV
item RICE, J - NC STATE UNIV
item Hunt, Patrick

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/24/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Disposal of wastewater generated by confined swine production can cause water pollution problems when farmland is limited for land treatment. Wastewater treated and stored in anaerobic lagoons is rich in nitrogen, phosphorus, and solids. Removal of suspended solids and phosphorus and transformation of nitrogen into nitrate form are necessary to renovate wastewater. This can be achieved with aeration treatment using media filtration. A media filter was constructed to treat swine wastewater after anaerobic lagoon treatment. The media filter consisted of a tank (1.5-m diameter by 0.6-m height) filled with marl gravel. Wastewater flow rate across the cross section area of the filter was 606 L/sq m/d. Wastewater was recycled through the filter up to four times. Total nitrogen and total phosphorus loads were 198 and 50 g/sq m/d, respectively. Total suspended solids (TSS) removal after one cycle was 50% of initial levels; however, additional cycling reduced TSS levels at a much lower rate of 7% per cycle. Up to 24% of total nitrogen was converted to nitrate. Removal efficiencies for total phosphorus ranged from 37% to 52% (one to four cycles), but sustainable phosphorus removal would be limited by the sorption capacity of the gravel. Effluents with high nitrate levels can be treated further to transform nitrate into innocuous nitrogen gas by constructed wetlands or anaerobic lagoon.

Technical Abstract: A media filter was constructed to treat swine wastewater after anaerobic lagoon treatment. The media filter consisted of a tank (1.5-m diameter by 0.6-m height) filled with marl gravel. The marl gravel had a carbonate content of 300 g/kg. Gravel particle size distributions were 85 and 14% in the 4.7- to 12.7-mm and 12.7- to 19-mm size classes, respectively. Porous space of the filtration unit was 57%. Wastewater flow rate was 606 L/sq m/d. Total Kjeldahl nitrogen (TKN) and total phosphorus (TP) loads were 198 and 50 g/sq m/d, respectively. The media filter removed 54% of chemical oxygen demand (COD) content after one cycle, but increased cycling did not produce additional COD reduction. Total suspended solids (TSS) removal after one cycle was 50% of initial levels, and additional cycling reduced TSS levels at a much lower rate of 7% per cycle. Removal efficiencies for TP ranged from 37% to 52% (one to four cycles), but long-term phosphorus removal would be limited by the sorption capacity of the gravel. Up to 24% of TKN was converted to nitrate-plus-nitrite-N (NO2+NO3-N). Effluents with high NO2+NO3-N levels can be treated further for denitrification with constructed wetlands or anaerobic lagoon. This is important in cases where land is limited for wastewater application.