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.