Effect of calcium hydroxide on the characteristics of volatile organic compounds emission during sewage sludge incineration

Abstract

AbstractEmission of volatile organic compounds (VOCs) during sludge incineration was explored after the addition of calcium hydroxide (Ca [OH]2), and the effects of incineration temperature, sludge particle size, and moisture content were investigated in a lab‐scale tubular furnace. Further, the contribution of the emission of VOCs in ozone formation potential (OFP) without Ca (OH)2 was calculated. The results indicated that incineration temperature in the range of 550–950°C can inhibit the emission of VOCs, with concentrations of the emissions varying from 3076.91 to 1277.11 μg/m3. Ca (OH)2 content had pronounced effects on the emission of VOCs during sludge incineration. The emission concentration of the VOCs decreased from 2421.16 to 1226.68 μg/m3 with Ca (OH)2 content increasing from 0 to 0.8 g. Sludge particle size and moisture content had little effects on the total amount of emitted VOCs during sludge incineration. Meanwhile, the contribution of the components of VOCs from sludge incineration in OFP was analyzed, which exhibited a decreasing trend: aromatic compounds > other substances > alkanes and olefins > chlorinated organic compounds. Aromatic compounds displayed the highest contribution rate at 92.72% because of the high concentration of benzene (1033.43 μg/m3). Our study provided theoretical data and a strong evidence of reduction in the emission of VOCs, OFP, and environmental regulation during sludge incineration.