Modelling Inflow and Outflow of Wastewater Treatment through a Three-Spout Rapid Sand Filter for Irrigation
A. Y. Arku *
Department of Agricultural and Environmental Resources Engineering, University of Maiduguri, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
In this study, three wastewater samples (Domestic-W1, Abattoir -W2 and Industrial-W3) were filtered through a three-spout rapid sand filter earlier designed and constructed with three depths; d1 = 0.20 m, d2 = 0.40 m and d3 = 0.60 m. Modelling the designed filter in this study was based on INPUT – OUTPUT phenomena using filter bed depth (d) and time (t) as variables for predicting discharge rate (q) and effluent quality concentration (C). Mathematical models were developed and validated using the Matlab 7.1 residual plots from generated experimented data in the filtration process. Discharge rate of domestic wastewater in the 5.50 x10-4m filter was 0.13 m3/h after the 3-hour filtration and reduced to 0.08 m3/h after the 60-hour for d1 while they were 0.12 m3/h to 0.08 m3/h and 0.08 m3/h to 0.06 m3/h for d2 and d3 respectively. For abattoir wastewater, values obtained for d1 were 0.06 m3/h to 0.04 m3/h while at d2 the discharge rate values were 0.16 m3/h to 0.13 m3/h. At d3, the discharge rate values were 0.12 m3/h to 0.08 m3/h. Discharge rates for industrial wastewater were 0.16 m3/h to 0.13 m3/h at d1, 0.13 m3/h to 0.09 m3/h at d2 and 0.12 m3/h to 0.08 m3/h at d3.
Coliform count reduction (CCr) values in domestic wastewater were 8.90, 10.71 and 15.72 %, while for turbidity reduction (TBr) values were 40.67, 40.00, and 45.50% at d1, d2 and d3 respectively
It was discovered that the filtered wastewater did not meet the Food and Agriculture Organization (FAO) recommended guidelines for irrigation. Hence, it was recommended that other additives be added to reduce the coliform and turbidity concentrations.
Keywords: Wastewater, modeling, filtration, irrigation, recommended guidelines, coliform, turbidity