|FILHO-OLIVEIRA, JOSE - Universidade Federal Do Ceara (UFC)|
|DAGUERRE-MARTINI, SILVANA - Miguel Hernandez University|
|SAEZ-TOVAR, J - Miguel Hernandez University|
|ROSAL, ANTONIO - Pablo De Olavide University|
|PEREZ-MURCIA, MARIA - Miguel Hernandez University|
|BUSTAMANTE, M - Miguel Hernandez University|
|MORAL, RAUL - Miguel Hernandez University|
Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2018
Publication Date: 6/6/2018
Citation: Filho-Oliveira, J.D., Daguerre-Martini, S., Vanotti, M.B., Saez-Tovar, J., Rosal, A., Perez-Murcia, M.D., Bustamante, M., Moral, R. 2018. Recovery of ammonia in raw and co-digested swine manure using gas-permeable membrane technology. Frontiers in Sustainable Food Systems. https://doi.org/10.3389/fsufs.2018.00030.
Interpretive Summary: Anaerobic co-digestion has been used as a way to minimize the negative effects of the accumulation of swine manure and other organic residues on rural areas, generating biogas (renewable energy) and digestate, which can be used as agricultural fertilizer. The co-digestion has been used as a way to improve the efficiency of biogas production systems vs. using a single manure substrate. For example, co-digestion of swine manure with vegetable processing residues or fruits and vegetable wastes have increased methane production by 200 to 500%. However, the digestate effluents contain high concentrations of nitrogen (N) and cause negative impacts to the environment due to its application in agricultural areas. In this research, gas-permeable membrane (GPM) technology was evaluated to remove and recover N from co-digested effluents. The new process using GPM consists of submerging the membranes in the N rich liquid causing the ammonia gas to penetrate into the membrane pores and is captured by an acidic solution circulating in the membrane interior. The study evaluated three digestates generated from the anaerobic co-digestion of mixtures of swine manure with fruit and vegetable sludge from the vegetable industry (peppers and artichokes), and by-products of the tomato processing industry, which were mixed in various proportions. The ammonia content of the co-digested effluents was very high, approximately 5,000 milligrams (mg) per liter. The process removed 80% of the N and recovered 96% of the N. The study showed that the GPM technology is useful for recovery of high N content effluents such as those generated by co-digestion of manure and vegetable wastes.
Technical Abstract: 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. This study analyzes the efficiency of gas-permeable membranes in the recovery of the ammoniacal nitrogen (NH4) 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 NH4 content was 2,240 milligrams (mg) per liter for the SM and 4,670 to 5370 mg per liter for the digestate mixtures. Throughout the duration of the N recovery experiment (96 hours), the percentages of NH4 removal and recovery achieved were consistent among digested treatments, approximately 78% and 96%, respectively. However, in the case of the digestate mixtures, the NH4 recovery kinetics indicated that the potential of the N recovery process was higher with an increase in treatment time, whereas in the case of the control experiment (SM) with lower N concentration, the maximum N recovery was observed within the experimental time imposed.