Technical evaluation of the performance of Dolochar in the removal of phosphates from hand washing wastewater.

Abstract

Dolochar, a waste generated from coal-based direct reduction of iron ore, has the potential to contribute to environmental sustainability and public health. This study focused on the utilization of dolochar as a treatment agent for wastewater. The objective was to evaluate its performance in removing phosphates from waste water and assess its suitability as a sustainable treatment method. The proximate analysis of dolochar revealed its composition, with 3.32% moisture content, 34.64% ash content, and 65.36% volatile matter. The elemental analysis showed that dolochar consisted of 53.23% silica, 21.94% aluminum oxide, 12.34% iron (III) oxide, and 10.18% calcium oxide. Batch experiments were conducted using handwashing waste water with known characteristics including total suspended solids (TSS), total dissolved solids (TDS), true color, phosphates, nitrates, pH, Escherichia coli (E. coli), and electrical conductivity (E.C). Dolochar was used as an adsorbent material, and different dosages ranging from 1 g/L to 14 g/L, with varying retention times, were used. Results demonstrated that dolochar exhibited a higher affinity for phosphates present in handwashing wastewater. The optimum dosage and retention time for achieving 99% removal efficiency of phosphates were determined as 12 g/L and 40 minutes, respectively. Additionally, significant reductions in TSS, true color, and nitrates were observed at the optimal operating parameters. However, dolochar did not show a significant effect on TDS, E.C, and E. coli, indicating the need for additional treatment methods to address these pollutants. Adsorption kinetic modeling revealed that phosphate adsorption followed a pseudo-second-order model, suggesting chemisorption as the controlling mechanism. Based on these findings, a series arrangement for complete wastewater treatment was proposed, involving initial screening, adsorption, filtration, chemical coagulation, and disinfection. The findings of this study suggested that dolochar holds promise as an effective treatment agent for wastewater, offering a sustainable solution for pollutant removal. Overall, this study contributes to the understanding of dolochar’ s potential as a valuable resource in wastewater treatment, highlighting the need for continued exploration and optimization of its application.