|JOHNSON, M - Environmental Protection Agency (EPA)|
|LIBRA, J - Leibniz Institute|
|BAE, S. - Seoul Women'S University|
Submitted to: Chemosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2015
Publication Date: 5/23/2015
Citation: Ro, K.S., Novak, J.M., Johnson, M.G., Szogi, A.A., Libra, J.A., Spokas, K.A., Bae, S. 2015. Leachate water quality of soils amended with different swine manure-based amendments. Chemosphere. 142:92-99. doi:10.1016/j.chemosphere.2015.05.023.
Interpretive Summary: Hydrochar is a carbonaceous solid made from heating wet biomass slurry under pressure (wet pyrolysis). This study evaluated the potential of hydrochar made from swine manure as a soil amendment. Soil fertility and water quality characteristics of swine hydrochar amended soils were compared with other swine based soil amendments such as raw swine manure, swine compost, and thermal swine char made from dry pyrolysis. All swine manure-based amendments significantly increased soil carbon, cation exchange capacity and available nutrient contents of the soil. However, thermal swine char and swine compost amended soils leached high concentrations of phosphorus, which may cause water pollution problems for receiving water bodies. On the other hand, swine hydrochar did not leach nutrients such as nitrogen, phosphorus, and potassium. Although it is still not clear how these nutrients were retained in the soil amended with hydrochar, it suggests a great potential for hydrochar as an alternative manure management option as the hydrochar can be soil applied while minimizing potential environmental issues from the leaching of high nutrient concentrations to water bodies.
Technical Abstract: In the face of the rising level of manure production from concentrated animal feeding operations (CAFOs), management options are being sought that can provide nutrient recycling for plant growth and improved soil conditions with minimal environmental impacts. Alternatives to direct manure application are composting and thermochemical conversion which can destroy pathogens and improve handling and storage. The effect of four forms of swine manure-based soil amendments (raw, compost, hydrochar, and pyrochar) on soil fertility and leachate water quality characteristics of a sandy soil were investigated in soil incubation experiments. All four amendments significantly increased soil carbon, cation exchange capacity and available nutrient contents of the soil. However, hydrochar amended soil leached lower amounts of nitrogen (N), phosphorus (P), and potassium (K) compared to the other amendments including the control. On the other hand, pyrochar and compost amended soil released higher concentrations of P and K. Subsequent tests on the hydrochar for K and N adsorption isotherms and surface analysis suggested that these nutrients were not sorbed directly to the hydrochar surface. Although it is still not clear how these nutrients were retained in the soil amended with hydrochar, it suggests a great potential for hydrochar as an alternative manure management option; the hydrochar can be soil applied while minimizing potential environmental issues from the leaching of high nutrient concentrations to water bodies.