Cost-Effective Utilisation of Industrial Fly Ash Waste in Treatment of Domestic Wastewater

In the present research an economically effective porous fly ash-based filter candle (FFC) was developed for the treatment of domestic wastewater using fly ash, sodium silicate, wood dust, silica fume and water. The four testing specimens of FFC having different sizes (10, 20, 30, and 40 mm) were prepared. The parameters such as turbidity, total suspended solids (TSS), dissolved oxygen (DO), total dissolved solids (TDS), and pH of domestic wastewater were studied before and after treatment. The test results showed that there is a decrease in values of turbidity from 7 to 5.9 NTU, TSS from 300 to 218 mg/L, TDS from 400 to 302 mg/L, pH from 10.6 to 7.9, and BOD from 9.5 to 7.9 while DO values decreased in the range of 8.9 to 7.7. The observed porosity, compressive strength, and flow rate of FFC fall in the range of 24.55-27.26 %, 1.5-2.3 MPa, and 180-290 ml/h, respectively. The filtration tests using FFC exhibited good performance with >92 % filtration efficiency. Overall results have shown that FFC having a 30 mm bed thickness is recommendable for effective wastewater treatment. Thus, an attempt has been made to introduce a novel technology for domestic wastewater treatment using industrial fly ash waste.