Reclaimed wastewater reuse for irrigation to crop plants is evaluated in a laboratory-scale experiment to assess growth and water saving potential from natural resources. A prototype laboratory-scale treatment plant was established for this purpose with suspended and attached growth configurations. Chakwal wheat variety was selected to examine growth parameters. The removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were evaluated to check the quality of treated water. It was found that a suspended growth sequencing batch bioreactor (SGSBBR) achieved 97% ± 2 removal efficiency over a 4 h hydraulic retention time (HRT). For an attached growth sequencing batch bioreactor (AGSBBR) results showed 98% ± 2 removal efficiencies with polyurethane. TN and TP removal efficiency was 58.7 ± 3% and 64 ± 4.8% in SGSBBR, 53 ± 0.17% and 67 ± 2.7% in polyurethane. AGSBBR enhanced performance with AGSBBR may be due to enforced anoxic/aerobic conditions in the inner layers of biofilm formed on biocarriers which facilitate the required metabolic conditions for treating high strength wastewater. Plant growth was visibly greater in SGSBBR treated wastewater than AGSBBR because of less nutrient removal.
Keywords: attached and suspended configuration, biocarrier, plant growth, sequencing batch bioreactors