Ammonium removal from synthetic wastewater promoted by current generation and water flux in an osmotic microbial fuel cell

Abstract

Recovering useful resource from wastes represents a new approach of clean production with significant environmental and economic benefits. Ammonium nitrogen, which is an important inorganic contaminant and also a resource for fertilizer, can be removed and recovered from wastewater. As the first step of recovery, ammonium removal was successfully demonstrated in this study by using an innovative treatment system-osmotic microbial fuel cells (OsMFC). This OsMFC achieved the removal efficiency of 80.1 ± 2.0 % with an anolyte flow rate of 0.4 mL min-1. Current generation was a key driving force for ammonium ion movement and increasing current generation from 0 to 1.8 ± 0.1 A m-2 could greatly enhance the removal efficiency from 40.7 ± 2.4 % to 85.3 ± 3.5 %. When current generation was similar, water flux could contribute significantly to facilitating ammonium removal, and as a result the OsMFC exhibited 55.2 ± 6.5 % higher ammonium removal with water flux of 1.3 ± 0.2 LMH than that without water flux. In addition, ion diffusion and ion exchange contributed to 17.3 ± 2.4 % and 2.8 ± 0.1 % of ammonium removal, respectively, with 35 g L-1 NaCl as a catholyte. The key challenges such as the exact mechanism of ammonium transport, disposal of ammonium residue after recovery, effects of draw solutes, and system scaling up have been identified and discussed. The results of this study will help develop an efficient approach for NEW recovery (NEW: nutrient, energy and water) from wastewater.

Forward Osmosis Application in Manufacturing Industries: A Short Review

“…Investigation of forward osmosis application ranges from lab-scale experiments (with either synthetic or real water) to full-scale implementation (with real water) and covers many fields, including: seawater desalination to produce drinking water [ 62 , 63 , 64 ], emergency water supply with so-called hydration bags [ 78 ], treatment of wastewater from oil and gas production as well as from mining [ 34 , 79 , 80 , 81 , 82 ], agricultural use for fertigation [ 83 , 84 , 85 ], biological wastewater treatment with osmotic membrane bioreactors [ 37 , 86 , 87 , 88 , 89 ], treatment of anaerobic digester centrate [ 90 , 91 ], microbial fuel cells [ 92 , 93 , 94 , 95 , 96 , 97 , 98 ], removal of trace organic compounds [ 99 , 100 , 101 , 102 , 103 , 104 ]. …”

(Bio)electrochemical ammonia recovery: progress and perspectives

“… 5.5 a Qin et al ( 2016 ) Synthetic (lifestock) wastewater MFC-O 2 c FO 2.6 0.7 a 52.5 ± 4.7 25.9 a 79.5 a n.r. Qin et al ( 2017 ) Synthetic (lifestock) wastewater MEC b Stripping/FO/MAP 0.76 a n.d. 99.7 ± 13 n.r. n.r.…”

“…This process has also been integrated with an additional struvite (MgNH 4 PO 4 ·6H 2 O, MAP) precipitation step to maximize nutrient recovery, increasing the complexity of the treatment process (Zou et al 2017 ). As an alternative, direct integration of the FO membrane in the BES, as a separator between anode and cathode compartment, showed promising results and simplified the overall system (Qin et al 2017 ).…”

Research on Forward Osmosis Membrane Technology Still Needs Improvement in Water Recovery and Wastewater Treatment

“…The integrated FO system include osmotic microbial fuel cell (OsMFC) and osmotic membrane bioreactor (OMBR). Recent literature have elucidated the integration of osmosis in MFC and MBR for simultaneous recovery of osmotic water, the concentration of wastewater, and the improvement of effluent quality through the application of the FO membrane [106,107].…”