Sequential sulfur-based denitrification/denitritation and nanofiltration processes for drinking water treatment

Gulfem Asik; Tulay Yilmaz; Francesco Di Capua; Deniz Ucar; Giovanni Esposito; Erkan Sahinkaya

doi:10.1016/j.jenvman.2021.113083

Sequential sulfur-based denitrification/denitritation and nanofiltration processes for drinking water treatment

J Environ Manage. 2021 Oct 1:295:113083. doi: 10.1016/j.jenvman.2021.113083. Epub 2021 Jun 23.

Authors

Gulfem Asik¹, Tulay Yilmaz², Francesco Di Capua³, Deniz Ucar⁴, Giovanni Esposito⁵, Erkan Sahinkaya⁶

Affiliations

¹ Bioengineering Department, Istanbul Medeniyet University, Uskudar, Istanbul, Turkey.
² Environmental Engineering Department, Faculty of Civil Engineering, Istanbul Technical University, 34469, Maslak, Istanbul, Turkey.
³ Department of Civil, Environmental, Land, Building Engineering and Chemistry, Polytechnic University of Bari, Via E. Orabona 4, 70125, Bari, Italy; Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125, Naples, Italy.
⁴ Department of Environmental Engineering, Bursa Technical University, 16310, Bursa, Turkey.
⁵ Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125, Naples, Italy.
⁶ Bioengineering Department, Istanbul Medeniyet University, Uskudar, Istanbul, Turkey. Electronic address: erkan.sahinkaya@medeniyet.edu.tr.

PMID: 34171780
DOI: 10.1016/j.jenvman.2021.113083

Abstract

Efficient and cost-effective solutions for nitrogen removal are necessary to ensure the availability of safe drinking water. This study proposes a combined treatment for nitrogen-contaminated groundwater by sequential autotrophic nitrogen removal in a sulfur-packed bed reactor (SPBR) and excess sulfate rejection via nanofiltration (NF). Autotrophic nitrogen removal in the SPBR was investigated under both denitrification and denitritation conditions under different NO₃^- and NO₂^- loading rates (LRs) and feeding strategies (NO₃^- only, NO₂^- only, or both NO₃^- and NO₂^- in the feed). Batch activity tests were carried out during SPBR operation to evaluate the effect of different feeding conditions on nitrogen removal activity by the SPBR biofilm. Bacteria responsible for nitrogen removal in the bioreactor were identified via Illumina sequencing. Dead-end filtration tests were performed with NF membranes to investigate the elimination of excess sulfate from the SPBR effluent. This study demonstrates that the combined process results in effective groundwater treatment and evidences that an adequately high nitrogen LR should be maintained to avoid the generation of excess sulfide.

Keywords: Autotrophic denitrification; Denitritation; Drinking water; Elemental sulfur; Nanofiltration; Packed bed reactor.

MeSH terms

Autotrophic Processes
Bioreactors
Denitrification
Drinking Water*
Nitrates
Nitrogen
Sulfur
Water Purification*

Substances

Drinking Water
Nitrates
Sulfur
Nitrogen