@article{vanotti_szogi_hunt_millner_humenik_2007, title={Development of environmentally superior treatment system to replace anaerobic swine lagoons in the USA}, volume={98}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2006.07.009}, abstractNote={A full-scale treatment system for swine manure was developed to eliminate discharge to surface and ground waters and contamination of soil and groundwater by nutrients and heavy metals, along with related release of ammonia, odor, and pathogens. The system greatly increased the efficiency of liquid–solid separation by polymer injection to increase solids flocculation. Nitrogen management to reduce ammonia emissions was accomplished by passing the liquid through a module where bacteria transformed ammonia into harmless nitrogen gas. Subsequent alkaline treatment of the wastewater in a phosphorus module precipitated phosphorus and killed pathogens. Treated wastewater was recycled to clean swine houses and for crop irrigation. The system was tested during one year in a 4400-head finishing farm as part of the Agreement between the Attorney General of North Carolina and swine producers Smithfield Foods, Premium Standard Farms and Frontline Farmers to replace traditional waste treatment anaerobic lagoons with environmentally superior technology. The on-farm system removed 97.6% of the suspended solids, 99.7% of BOD, 98.5% of TKN, 98.7% of soluble ammonia (NH4+–N), 95.0% of total P, 98.7% of copper and 99.0% of zinc. It also removed 97.9% of odor compounds in the liquid and reduced pathogen indicators to non-detectable levels. Based on performance obtained, it was determined that the treatment system met the Agreement's technical performance standards that define an environmentally superior technology. These findings overall showed that cleaner alternative technologies are technically and operationally feasible and that they can have significant positive impacts on the environment and the livestock industry.}, number={17}, journal={BIORESOURCE TECHNOLOGY}, author={Vanotti, Matias B. and Szogi, Ariel A. and Hunt, Patrick G. and Millner, Patricia D. and Humenik, Frank J.}, year={2007}, month={Dec}, pages={3184–3194} } @article{vanotti_rice_ellison_hunt_humenik_baird_2005, title={Solid-liquid separation of swine manure with polymer treatment and sand filtration}, volume={48}, DOI={10.13031/2013.19190}, abstractNote={Small particles typical of liquid swine manure often clog sand filter beds and fine filters. We evaluated the effectiveness of polymer flocculants to improve drainage and filtration performance of sand filter beds by increasing the particle size of manure. A pilot separation unit was evaluated at the Swine Unit of the NCSU Lake Wheeler Road Laboratory in Raleigh, North Carolina, in 40 consecutive cycles during a 20-month period. The unit consisted of a homogenization tank that mixed the flushed swine manure, an in-line polymer mixer, and two sand filter beds (29.7 m2) designed to receive 30.5 cm (1 ft) depth of the polymer-treated effluent. Flocculation treatment using polyacrylamide (PAM) polymer improved drainage characteristics of the sand filter by preventing clogging and surface sealing. The combination of flocculation and filtration treatment removed 97% of total suspended solids (TSS) and volatile suspended solids (VSS), 85% of biochemical oxygen demand (BOD5), and 83% of chemical oxygen demand (COD) from the flushed manure. Along with the solids, treatment resulted in capture of 61% total Kjeldahl nitrogen (TKN) and 72% total phosphorus (TP). Most of the nutrients removed in the solids were organic forms. Drying time to produce removable cakes varied significantly with the loading rate of solids applied to the sand filter bed. A load of <2 kg TSS m-2 per drying cycle allowed completion of the drying cycle in about 8 days, which is desirable to reduce potential fly problems. Our results indicate that PAM flocculation enhances performance of dewatering sand filter beds for swine manure applications.}, number={4}, journal={Transactions of the ASAE}, author={Vanotti, M. B. and Rice, J. M. and Ellison, A. Q. and Hunt, P. G. and Humenik, F. J. and Baird, C. L.}, year={2005}, pages={1567–1574} } @article{humenik_rice_baird_koelsch_2004, title={Environmentally superior technologies for swine waste management}, volume={49}, ISSN={["0273-1223"]}, DOI={10.2166/wst.2004.0732}, abstractNote={The high nitrogen content of animal waste provides opportunities for processing to marketable byproducts and challenges for proper management to avoid harmful impacts. Technologies are being developed to conserve and utilize nitrogen as well as other valuable constituents in animal waste. Advanced treatment technologies are also being developed for housing/waste management systems that address public concerns and protect soil, water and air quality. Smithfield Foods, Premium Standard Farms and Frontline Farmers have entered into an agreement with North Carolina to develop environmentally superior technologies that meet these goals. The 18 candidate technologies are identified and three with the longest operating period, and thus most data to date are discussed. Methods for distributing this information for implementation of cost-effective technologies through the Curriculum Project and the National Center for Manure and Animal Waste Management will be presented. This work supports priority goals to conserve and utilize valuable animal waste constituents while also protecting against negative impacts.}, number={5-6}, journal={WATER SCIENCE AND TECHNOLOGY}, author={Humenik, FJ and Rice, JM and Baird, CL and Koelsch, R}, year={2004}, pages={15–21} } @article{szogi_vanotti_rice_humenik_hunt_2004, title={Nitrification options for pig wastewater treatment}, volume={47}, DOI={10.1080/00288233.2004.9513612}, abstractNote={Abstract Nitrification is a necessary and often limiting process in animal waste treatment for removal of nitrogen as N2 through biological nitrification/denitrification systems. We evaluated three technologies for enhancing nitrification of pig lagoon wastewater prior to denitrification: overland flow, trickling filter, and a bioreactor using nitrifying pellets. The overland flow system consisted of a 4 × 20‐m plot with 2% slope with a subsurface impermeable barrier receiving a total N loading rate of 64–99 kg N ha−1 day−1. Total N removal efficiency ranged from 36 to 42%, and 7% of the total N application was recovered in the effluent as nitrate. The trickling filter consisted of a 1‐m3 tank filled with marl gravel media which supported a nitrifying biofilm. Lagoon wastewater was applied as a fine spray on the surface at hydraulic loading rates of 684 litres m−3 day−1 and total N loading rates of 249 g m−3 day−1. The media filter treatment transformed up to 57% of the inflow total N into nitrate when wastewater was supplemented with lime. The nitrifying pellets technology used acclimated nitrifying cells immobilised in 3–5 mm polymer pellets. Pig wastewater was treated in an aerated fluidised reactor unit with a 15% (w/v) pellet concentration. Nitrification efficiencies of more than 90% were obtained in continuous flow treatment using total N loading rates of 438 g N m−3 day−1 and hydraulic residence time of 12 h. Two conclusions are suggested from this research: (1) that substantial nitrification of pig lagoon wastewater can be attained particularly using aerobic treatments with enriched nitrifying populations, and (2) that large mass removal of N from pig wastewater may be possible by sequencing nitrification and denitrification unit processes.}, number={4}, journal={New Zealand Journal of Agricultural Research}, author={Szogi, A. A. and Vanotti, M. B. and Rice, J. M. and Humenik, F. J. and Hunt, P. G.}, year={2004}, pages={439–448} } @article{stone_hunt_novak_johnson_watts_humenik_2004, title={Stream nitrogen changes in an eastern Coastal Plain watershed}, volume={59}, number={2}, journal={Journal of Soil & Water Conservation}, author={Stone, K. C. and Hunt, P. G. and Novak, J. M. and Johnson, M. H. and Watts, D. W. and Humenik, F. J.}, year={2004}, pages={66–72} } @article{miner_humenik_rice_rashash_williams_robarge_harris_sheffield_2003, title={Evaluation of a permeable, 5 cm thick, polyethylene foam lagoon cover}, volume={46}, DOI={10.13031/2013.15442}, abstractNote={Anaerobic lagoons and liquid manure storage basins are widely used for the treatment and storage of livestock and poultry manure. Although relatively inexpensive to construct, these devices have been widely criticized based upon their odor and ammonia release. A floating, permeable, composite cover manufactured from recycled polyethylene chips topped with a geotextile layer containing zeolite particles was evaluated under both laboratory and field conditions. Under laboratory conditions, the cover was found essentially to eliminate odor release and to reduce ammonia emissions by approximately 80%. When installed on a 0.4 ha swine manure lagoon in eastern North Carolina, the cover survived severe storms and allowed even intense rainfall to pass through without causing cover inundation. Under these field conditions, the cover was found to reduce ammonia emissions approximately 80%. Odor emissions measured twice during one month of the study were consistently low in concentration and near neutral relative to quality, as determined by an analysis by a trained odor panel. Microbiological examination of the cover after four months of use showed an active population of aerobic bacteria and protozoa; analysis showed that nitrifying, sulfide oxidizing, and methanotrophic bacteria were likely trophic components of the microbial populations observed. The surface of the cover became covered with an algal population within two weeks of installation. This and other vegetative growth had no discernable impact on the performance of the cover.}, number={5}, journal={Transactions of the ASAE}, author={Miner, J. R. and Humenik, F. J. and Rice, J. M. and Rashash, D. M. C. and Williams, C. and Robarge, W. and Harris, D. B. and Sheffield, R.}, year={2003}, pages={1421–1426} } @article{szogi_hunt_humenik_2003, title={Nitrogen distribution in soils of constructed wetlands treating lagoon wastewater}, volume={67}, DOI={10.2136/sssaj2003.1943}, abstractNote={Constructed wetlands have the potential to be used for treatment of N‐rich livestock wastewater. Our objectives were to evaluate both the time effect and increasing N loading rates on soil N distribution and NH+4–N concentration in surface‐pore water of constructed wetlands. A 5‐yr study in North Carolina investigated two wetland systems that treated swine lagoon wastewater. Wetland System 1 was planted to a Schoenoplectus americanus (Pers.) Volkart ex Schinz & R. Keller, S. tabernaemontani (K.C. Gmel.) Palla, Scirpus cyperinus (L.) Kunth, and Juncus effusus L. plant community, and Wetland System 2 was planted to a Typha angustifolia L., T. latifolia L., and Sparganium americanum Nutt. plant community. Nitrogen loading rates were increased annually from 0.6 to 2.7 g m−2 d−1 Soils were analyzed for total N annually. Surface‐pore water was sampled with equilibrators and analyzed for NH+4–N. Although the total N accumulation significantly increased with time in both systems, total soil N accumulation by depth did not differ significantly between systems. Distribution profiles in the surface‐pore water column showed that NH+4–N was transported upward into surface water at N loading rates from 1.2 to 2.7 g m−2 d−1 As total N loading rates increased annually in both wetland systems, soil pore water had higher levels of NH+4–N but N removal efficiency of the wetlands sharply decreased. Accumulation of high levels of NH+4–N (>200 mg L−1) in soil pore water could negatively affect long‐term ability of wetland systems to treat wastewater with high N levels.}, number={6}, journal={Soil Science Society of America Journal}, author={Szogi, A. A. and Hunt, P. G. and Humenik, F. J.}, year={2003}, pages={1943–1951} } @article{poach_hunt_sadler_matheny_johnson_stone_humenik_rice_2002, title={Ammonia volatilization from constructed wetlands that treat swine wastewater}, volume={45}, number={3}, journal={Transactions of the ASAE}, author={Poach, M. E. and Hunt, P. G. and Sadler, E. J. and Matheny, T. A. and Johnson, M. H. and Stone, K. C. and Humenik, F. J. and Rice, J. M.}, year={2002}, pages={619–627} } @article{stone_hunt_szogi_humenik_rice_2002, title={Constructed wetland design and performance for swine lagoon wastewater treatment}, volume={45}, number={3}, journal={Transactions of the ASAE}, author={Stone, K. C. and Hunt, P. G. and Szogi, A. A. and Humenik, F. J. and Rice, J. M.}, year={2002}, pages={723–730} } @article{hunt_szogi_humenik_rice_matheny_stone_2002, title={Constructed wetlands for treatment of swine wastewater from an anaerobic lagoon}, volume={45}, number={3}, journal={Transactions of the ASAE}, author={Hunt, P. G. and Szogi, A. A. and Humenik, E. J. and Rice, J. M. and Matheny, T. A. and Stone, K. C.}, year={2002}, pages={639–647} } @book{miner_humenik_overcash_2000, title={Managing livestock wastes to preserve environmental quality}, ISBN={0813826357}, publisher={Ames: Iowa State University Press}, author={Miner, J. R. and Humenik, F. J. and Overcash, M. R.}, year={2000} } @article{szogi_hunt_humenik_2000, title={Treatment of swine wastewater using a saturated-soil-culture soybean and flooded rice system}, volume={43}, DOI={10.13031/2013.2708}, abstractNote={Constructed wetlands have potential for treatment of livestock wastewater, but they generally contain wetland plants rather than agronomic crops. We evaluated two agronomic crops, saturated-soil-culture (SSC) soybean and flooded rice, in a constructed wetland system used for swine wastewater treatment. Both crop production and treatment efficiency were evaluated from 1993 to 1996 in two 4-m ×33.5-m constructed wetland cells that were connected in series. The first cell contained SSC soybean — four cultivars planted in a randomized complete block design with four replications. Flooded rice ‘Maybelle’ was planted in the second cell. From the first to fourth year, wastewater application rates were gradually increased to obtain rates of 2.0 to 8.8 and 0.5 to 2.2 kg ha –1 d –1 for total N and P, respectively. The best soybean grain and dry matter yields were 4.0 and 9.1 Mg ha –1 , respectively. These were obtained with soybean ‘Young’ at the lowest wastewater application rate. Increasing total N loading rates and the associated higher NH 4 -N concentrations depressed soybean seed yield and dry matter production. On the other hand, both rice grain and dry matter production were stable over the application range; mean values were 4.0 and 10.9 Mg ha –1 , respectively. Nutrient mass reductions were good; removal values increased linearly with loading rates (y = 0.69N load + 0.45 , R 2 = 0.99 and y = 0.45P load + 0.20, R 2 = 0.95). At the highest loading rate, the system removed 751 and 156 kg ha –1 yr –1 N and P, respectively. It appears that the SSC soybean and flooded rice system could be useful for liquid manure management in confined livestock production. The system produced comparable treatment to systems with natural wetland plants; moreover, the soybean and rice are marketable crops. However, the flooded rice seems to be the more robust component for high wastewater application rates.}, number={2}, journal={Transactions of the ASAE}, author={Szogi, A. A. and Hunt, P. G. and Humenik, F. J.}, year={2000}, pages={327–335} } @article{hunt_stone_humenik_matheny_johnson_1999, title={In-stream wetland mitigation of nitrogen contamination in a USA coastal plain stream}, volume={28}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1999.00472425002800010030x}, abstractNote={AbstractNonpoint source N from riverine origin is a major water quality problem throughout the world. Nitrogen removal from a contaminated (6.6 mg L−1, NO3‐N) stream was evaluated in this study using an instream wetland (ISW). The ISW was established at the exit of a 425‐ha USDA Water Quality Demonstration watershed in the Coastal Plain of North Carolina. It ranged in depth from about 0.2 to 2 m, and it was <1% (3.3 ha) the size of the watershed. The ISW dramatically lowered mean stream NO3‐N from 6.6 to 2.0 mg L−1. Nitrate‐N mass removal was highly correlated to inflow NO3‐N (r = 0.93) in the warmer months when biological processes were more active. Ammonia‐N mass removal was opposite that of NO3‐N. It was highly correlated to inflow NH3‐N (r = 0.81) during the cooler months. Removal of both NO3‐N and total‐N (NO3‐N + TKN) were positively correlated to temperature with r values of 0.77 and 0.62, respectively. Total annual N removal for the ISW was approximately 3 kg ha−1 d−1, which was about 37% of the inflow N. The ISWs appear to be very good landscape features for mitigating excess nonpoint source N in the southeastern Coastal Plain of the USA. As such, they are a good complement to other best management practices for improved water quality.}, number={1}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Hunt, PG and Stone, KC and Humenik, FJ and Matheny, TA and Johnson, MH}, year={1999}, pages={249–256} } @article{humenik_szogi_hunt_broome_rice_1999, title={Wastewater utilization: A place for managed wetlands - Review}, volume={12}, ISSN={["1011-2367"]}, DOI={10.5713/ajas.1999.629}, abstractNote={Con~mlctcd wc:~laI1~ arc: being \I~c: