Abstract:
The efficiency of both Integrated Constructed Wetland (ICW) and Membrane Bioreactor (MBR)
in the treatment of wastewater was assessed using physicochemical, microbial, and molecular
studies. Temperature, pH, turbidity, dissolved oxygen (DO), chemical oxygen demand (COD),
nitrate (NO2), nitrite (NO3), phosphate (PO4), total dissolved solids (TDS), total suspended solids
(TSS), total kjeldahl nitrogen (TKN) and electrical conductivity (EC) were recorded regularly over
a period of six months. MBR system effectively reduced COD, TSS, NO3, PO4 and turbidity to a
greater extent than ICW with a consistent NEQS compliance level. In comparison, ICW treatment
achieved moderate reductions in PO4, TSS and turbidity.
Bacteriological examinations were done on Escherichia coli, Salmonella sp and Shigella sp using
isolation technique. The initial concentrations of all three species were higher for ICW than in
MBR. Overall the MBR 'system achieved higher microbial reductions which is in line with the
systems ability to maintain a controlled environment.
Real time PCR was then used to confirm microbial findings through quantification of gene copies
of its targeted marker genes of E. coli. Both microbial systems experienced a marked reduction in
gene concentrations and the MBR showed significantly reductions due to the better operational
conditions.
This study demonstrates the capability of MBR systems efficiency for treating wastewater and
highlights the requirement for appropriate optimizations in ICW system for similar results.
