Treatment of N-Nitrosodimethylamine (NDMA) in Groundwater Using a Fluidized Bed Bioreactor

Hatzinger, Paul B.; Webster, Todd S.

doi:10.21236/ada607489

Cited by 1 publication

(1 citation statement)

References 15 publications

(36 reference statements)

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“…While nitrate has a similar redox potential to perchlorate (+1.25 V), its chemical structure makes the nitrogen atom more available for reduction, with lower activation energy (47.18 [kJ mol −1 ]) than perchlorate [3,19]. The conventional bioreactors include fluidized-bed biofilm (FBB), using either sand or GAC as the support media [20,21], or fixed-bed biofilm reactor (FBR) with acetate, acetic acid, molasses, or ethanol as the electron donor [14,22]. These are suitable for the treatment of highly concentrated waste streams [3].…”

Section: Introductionmentioning

confidence: 99%

Oxyanion Removal from Impaired Water by Donnan Dialysis Plug Flow Contactors

Fox,

Stadnik,

Thakur

et al. 2023

Membranes

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In the last twenty-five years, extensive work has been done on ion exchange membrane bioreactors (IEMB) combining Donnan dialysis and anaerobic reduction to remove trace oxyanions (e.g., perchlorate, nitrate, chlorate, arsenate) from contaminated water sources. Most studies used Donnan dialysis contactors with high recirculation rates on the feed side, so under continuous operation, the effective concentration on the feed side of the membrane is the same as the exit concentration (CSTR mode). We have built, characterized, and modelled a plug flow Donnan dialysis contactor (PFR) that maximizes concentration on the feed side and operated it on feed solutions spiked with perchlorate and nitrate ion using ACS and PCA-100 anion exchange membranes. At identical feed inlet concentrations with the ACS membrane, membrane area loading rates are three-fold greater, and fluxes are more than double in the PFR contactor than in the CSTR contactor. A model based on the nonlinear adsorption of perchlorate in ACS membrane correctly predicted the trace ion concentration as a function of space-time in experiments with ACS. For PCA membrane, a linear flux dependence on feed concentration correctly described trace ion feed concentration as a function of space-time. Anion permeability for PCA-100 was high enough that the overall mass transfer was affected by the film boundary layer resistance. These results provide a basis for efficiently scaling up Donnan dialysis contactors and incorporating them in full-scale IEMB setups.

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