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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #210545
Title: Nitrogen loss during solar drying of biosolids

Author
item O`Shaughnessy, Susan
item SONG, INHONG - UNIVERSITY OF MINN.
item ARTIOLA, JANICK - UNIVERSITY OF ARIZONA
item CHOI, CHRISTOPHER - UNIVERSITY OF ARIZONA

Submitted to: Environmental Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2007
Publication Date: 1/4/2008
Citation: Oshaughnessy, S.A., Song, I., Artiola, J.F., Choi, C.Y. 2008. Nitrogen loss during solar drying of biosolids. Environmental Technology. 29:55-65.

Interpretive Summary: Biosolids are the solid byproducts of wastewater management. These solid waste products are treated to reduce heavy metals and pathogens before disposal in landfills or application on agricultural fields as high nitrogen, low cost fertilizer. Dewatering reduces pathogens and is commonly used by small wastewater treatment plants because it is low cost and simple. This study investigated how solar drying impacts the nitrogen content of biosolids. Biosolid samples were tested during summer and winter solar drying field experiments to measure their nitrate (NO3-) and ammonium (NH4+) ion concentrations. Tilling was applied to speed the drying. Nitrogen losses varied depending on the solar drying season and tillage. The main nitrogen loss occurred through ammonia volatilization.

Technical Abstract: Solar drying has been used extensively to dewater biosolids for ease of transportation and to a lesser degree to reduce pathogens prior to land application. The nitrogen in biosolids makes it a relatively inexpensive but valuable source of fertilizer. In this study, nitrogen loss from tilled and untilled biosolids was investigated during the solar drying process. Samples of aerobically and anaerobically-digested biosolids during three solar drying experiments were analyzed for their nitrate (NO3-) and ammonium (NH4+) ion concentrations. Nitrogen losses varied depending on the solar drying season and tillage. Although not directly measured, the majority of nitrogen loss occurred through ammonia volatilization- organic nitrogen content (organic N) remained relatively stable for each sample, nitrate concentrations for the majority of samples remained below detectable levels and the decline of ammonium-nitrogen (NH4+-N) generally followed the trend of moisture loss in the biosolids.