Nitrate removal from drinking water using different reactor/membrane types: A comprehensive review

Abstract

Nitrate is considered one of the key contaminants in drinking water sources, particularly groundwater. This could be a result of excessive human activities. Numerous studies have been successfully developed and are still developing eco-friendly and cost-effective treatment techniques for highly efficient nitrate removal from drinking water. Although most of the nitrate removal techniques are physically and chemically based, for example, ion exchange and reverse osmosis, biological treatment is an equally potent approach applied in full scale through autotrophic and heterotrophic denitrification. However, many studies are trying to reduce some of the disadvantages of the biological treatment, such as the need for further treatment for microbial or organic carbon removal. This paper addresses some of the conventional nitrate removal approaches and reviews the biological denitrification processes, highlighting the advantages and disadvantages of the following methods: (i) conventional nitrate removal techniques, (ii) biological denitrification via bioreactor membrane techniques, (iii) membrane bioreactor (MBR), (iv) membrane biofilm-reactor (MBfR), (v) ion exchange membrane bioreactor (IEMBR), and (vi) biofilm-electrode reactor (BER).