Denitrification of Spent Regenerated Brine Using Molasses

Brigita Tepuš,Marjana Simonič,Aleksandra Petrovič,Jasmina Filipič

doi:10.5562/cca2363

Brigita Tepuš, Marjana Simonič + Show 2 more

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https://doi.org/10.5562/cca2363

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Abstract

Spent BRINE from the regeneration of exhausted resins has to be properly treated before its disposal. The heterotrophic denitrification of regenerated brine was studied in present work. Molasses which served as a carbon source has until now not been applied during brine denitrification. The nitrate and nitrite consumptions were observed according to different ratios between total organic carbon and nitrate (TOC / NO3 ratios) and the influence of NaCl was studied during batch experiments. This work ascertained that molasses is a very good source of carbon, and no addition of other nutrients is necessary. The complete nitrate removal from regenerated brine could be achieved using molasses.

Highlights

In drinking water treatment systems, nitrate is usually removed using ion exchange
When molasses was used as a carbon source the total nitrate and nitrite removals were achieved within 48 hours as seen form Table 3 in reactors 1 and 2
If only glucose was used as a carbon source, the nitrate ions were removed within 3 days and the nitrite within 5 days which meant the slowest denitrification rate compared with other reactors

Summary

Introduction

In drinking water treatment systems, nitrate is usually removed using ion exchange. After the regeneration of ion exchange resin, the spent brine solution has to be properly treated before its disposal. Denitrification of spent regeneration brine relies on an external carbon source as an electron donor and microorganisms which use nitrate rather than oxygen as an electron acceptor.[1,2] If there is insufficient carbon in the wastewater, an external source is necessary. Various carbon sources in different amounts could be used for denitirfication processes, discrepancies have been reported regarding process efficiency.[3] Some authors claim that better efficiencies could be achieved using acetic acid as a carbon source when compared to glucose, methanol or ethanol.[4] Other have shown comparable results using acetic acid and methanol.[5,6] Another group of researchers gained the best results using ethanol and methanol.[7,8] Some authors have reported that ethanol has many advantages over methanol, acetic acid, and glucose.[9]

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