PRELIMINARY STUDY ON EFFECT OF DETENTION TIME ON NUTRIENT REMOVAL FROM GREYWATER USING WATER HYACINTH

Increasing water scarcity has resulted in the reuse of wastewater for non-potable purposes after treatment. In this laboratory-scale study, the effect of different hydraulic detention time (HDT) for remediation of nutrients from greywater was undertaken. Greywater was collected from the hostel building of educational institute in Surat, India. The experimental study was carried out in a circular plastic reactor all in triplicate and average removal were reported. The physicochemical properties of influent and effluent were monitored throughout the experiment duration. The average influent greywater characteristics were: water temperature (27.52 ± 0.22°C), pH (6.95 ± 0.07), turbidity (57.80 ± 11.14 NTU), COD (273.60 ± 11.53 mg/L), ammonium-nitrogen (5.32 ± 0.84 mg/L), phosphate-phosphorous (1.30 ± 0.07 mg/L), and sodium (57.80 ± 11.14 mg/L). Water hyacinth was planted in all three sets, and one was kept as control (without adding water hyacinth). Significant nutrient reduction was observed in reactor planted with water hyacinth compared to control. The result showed that reactor with HDT of 3 days performed optimum for remediation of nutrients from greywater. The average removal under optimal HDT observed for turbidity, ammonia, phosphate-phosphorous, and sodium was 97.77 ± 0.33%, 89.80 ± 2.48%, 84.64 ± 0.84%, and 40.36 ± 1.23% respectively. This study shows the optimum HDT of 3 days are required for greywater treatment in batch mode. However, further study is needed to explore the optimum HDT for continuous operation mode for greywater treatment.