Browsing by Author "Sarah Liehr, Committee Member"

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    Swine Wastewater Treatment in an Integrated System of Anaerobig Digestion and Duckweed Nutrient Removal: Pilot Study
    (2005-04-13) Lyerly, Courtney Neil; Sarah Liehr, Committee Member; Jiayang Cheng, Committee Chair; Francis de los Reyes, Committee Member
    Organics destruction and nutrient uptake in an integrated pilot system of anaerobic digestion and duckweed nutrient removal for swine wastewater treatment were monitored under field conditions. Raw swine wastewater of 100 gallons/day was first treated in a 1,000-gallon anaerobic digester with floating ballast rings. Organic compounds in the wastewater were digested to produce biogas. Many nutrients including nitrogen and phosphorus remain in the effluent of the anaerobic digester. Three duckweeds (Lemna gibba 8678, Lemna minor 8627, and Spirodela, punctata 7776) were grown in three 1,000- gallon tanks to recover nutrients from the anaerobic effluent. The duckweed was periodically harvested and can be used as animal, poultry, and fish feed. The Three species were compared for growth and nutrient removal characteristics. This research provides an initial understanding of the attached-growth anaerobic digester and the characteristics exhibited by duckweed in the treatment of swine wastewater under conditions similar to those found in North Carolina. Both the anaerobic digester and the duckweed tanks were run as completely mixed systems. The performance of the system was monitored by measuring chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), ammonia nitrogen, total phosphorus (TP), ortho-phosphate-phosphorus, and pH in the influent and effluent of each treatment unit.