Nitrogen Recovery from Landfill Leachate Using Lab- and Pilot-Scale Membrane Contactors: Research into Fouling Development and Membrane Characterization Effects

Ilaria Righetto; Raed A Al-Juboori; Juho Uzkurt Kaljunen; Ngoc Huynh; Anna Mikola

doi:10.3390/membranes12090837

Nitrogen Recovery from Landfill Leachate Using Lab- and Pilot-Scale Membrane Contactors: Research into Fouling Development and Membrane Characterization Effects

Membranes (Basel). 2022 Aug 27;12(9):837. doi: 10.3390/membranes12090837.

Authors

Ilaria Righetto^{1

2}, Raed A Al-Juboori², Juho Uzkurt Kaljunen², Ngoc Huynh³, Anna Mikola²

Affiliations

¹ Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy.
² Water and Environmental Engineering Research Group, Department of Built Environment, Aalto University, P.O. Box 15200, Aalto, FI-00076 Espoo, Finland.
³ Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, P.O. Box 11000, Aalto, FI-00076 Espoo, Finland.

Abstract

Membrane contactor technology affords great opportunities for nitrogen recovery from waste streams. This study presents a performance comparison between lab- and pilot-scale membrane contactors using landfill leachate samples. Polypropylene (PP) and polytetrafluoroethylene (PTFE) fibers in different dimensions were compared in terms of ammonia (NH₃) recovery on a lab scale using a synthetic ammonium solution. The effect of pre-treating the leachate with tannin coagulation on nitrogen recovery was also evaluated. An ammonia transfer on the lab and pilot scale was scrutinized using landfill leachate as a feed solution. It was found that PTFE fibers performed better than PP fibers. Among PTFE fibers, the most porous one (denoted as M1) had the highest NH₃ flux of 19.2 g/m².h. Tannin pre-treatment reduced fouling and increased NH₃, which in turn improved nitrogen recovery. The mass transfer coefficient of the lab-scale reactor was more than double that of the pilot reactor (1.80 × 10^-7 m/s vs. 4.45 × 10^-7 m/s). This was likely attributed to the difference in reactor design. An analysis of the membrane surface showed that the landfill leachate caused a combination of inorganic and organic fouling. Cleaning with UV and 0.01 M H₂O₂ was capable of removing the fouling completely and restoring the membrane characteristics.

Keywords: ammonia transfer rate; landfill leachate; membrane contactor; membrane fouling; nutrient recovery; tannins.

Grants and funding

This research received funding from Ministry of the Environment in Finland RAKI2 project VN/2250/2019 and from Maa- ja vesitekniikan tuki r.y. (MVTT).