Abstract:
With declining trend in global water resources wastewater reclamation and reuse has
gained considerable importance worldwide. The present study was conducted with the
objective to reuse domestic wastewater treated by using membrane technology for crop
irrigation. Membrane based septic tank was designed (MBST) by submerging a woven
fiber microfiltration membrane module (WFMF) to treat domestic wastewater. To evaluate
the performance efficiency of MBST, effluents were characterized for microbiological and
physical parameters. Removal of organics (COD), turbidity, nutrients deduction (P and N)
and indicator bacteria (Escherichia coli) removal efficiency was about 73, 96, 48 and 88 %
respectively. Three crops Triticum aestivum (wheat), Coriandrum sativum (coriander) and
Mentha arvensis (mint) were irrigated with treated MBST effluents under controlled
conditions. All the crops were also grown using untreated wastewater (after primary
settling) and tap water for comparative study. Upon maturity, the roots, shoots and leaves
of these plants were aseptically removed for microbiological analysis. Two bacterial strains
Escherichia coli and Salmonella sp. were isolated from MBST treated effluents and crops
which were irrigated with these effluents. These bacterial strains were identified using
biochemical test, 20E API kit and 16S rRNA gene analysis. A remarkably positive effect
was observed on removal of bacterial load (p<0.001) and helminthes eggs from effluent
treated by MBST. While on the other hand increase in germination percentage, dry biomass,
root and shoot length and reduction in bacterial strains was observed in crops irrigated by
MBST discharge in comparison with untreated wastewater. The current study revealed that
wastewater treated with MBST with UV disinfection may be used to meet the irrigation
requirements and better yield.
