AUTHOR=Oliveira Filho Jose de Souza , Daguerre-Martini Silvana , Vanotti Matias B. , Saez-Tovar Jose , Rosal Antonio , Perez-Murcia Maria D. , Bustamante Maria A. , Moral Raul 

TITLE=Recovery of Ammonia in Raw and Co-digested Swine Manure Using Gas-Permeable Membrane Technology

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=2

YEAR=2018

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2018.00030

DOI=10.3389/fsufs.2018.00030

ISSN=2571-581X

ABSTRACT=<p>Anaerobic digestion of agro-industrial and livestock waste generates considerable digestate volumes that are important sources of nitrogen (N). However, on some occasions, the high concentrations of N present in the digestates may represent an obstacle to its use locally as fertilizer, since it can cause an environmental impact (European Community, <xref ref-type="bibr" rid="B8">2000</xref>). This study analyzes the efficiency of gas-permeable membranes (GPM) in the recovery of the ammoniacal nitrogen (<inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula>) present in the swine manure (SM, Control) and three digestates generated from the anaerobic co-digestion of mixtures of SM, fruit and vegetable sludge (FVS) from the vegetable industry (peppers and artichokes), and by-products of the tomato processing industry (TW) (skins and seeds), which were mixed at three different proportions [TW + FVS]: [SM]. Their NHx<sup>+</sup> content was 2,240 mg L<sup>−1</sup> for the SM and 4,670–5,370 for the digestate mixtures. Throughout the duration of the Necovery experiment (96 h), the percentages of <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>NH</mml:mtext></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula> removal and recovery achieved were consistent among treatments, approximatelly 78 and 96%, respectively. The recovery of NH<sub>4</sub>+ for the digestate mixtures seems to be dependent on the treatment time, since the potential of N recovery was higher when the treatment time increased. However, for the control experiment (SM), with lower N concentration, the maximum N recovery was obtained at the experimental time established, without increasing the treatment time.</p>