Treated municipal wastewater to fulfil crop water footprints and irrigation demand – a review

Abstract

Abstract Direct application of raw municipal wastewater for irrigation purposes may create many undesirable harmful consequences. Therefore, treated effluent through different technologies is generally preferred for reuse especially in water-scarce regions. In the present study, the performances of some treatment technologies like constructed wetland (CW), waste stabilisation pond (WSP), membrane bioreactor (MBR), vermi-biofiltration (VBF) and land treatment methods for removal of chemical and biological impurities from municipal wastewater were reviewed. The study revealed that the treated water quality varied depending on the hydraulic retention time under different treatment methods. The reservoir should be considered an integral part of the wastewater treatment system and not merely an operative ponding volume for irrigation. The comparatively advanced MBR technique showed better performance for removal of BOD, COD, fecal coliforms, Escherichia coli and other biological impurities than the traditional approach. Some techniques like land treatment methods and VBF were found to be equally attractive in developed as well as developing nations. The future projections of global green and blue water scarcities indicate treated water to be a valuable alternative water resource to fulfil required crop water footprints as well as irrigation demands.