Comparative life cycle assessment of two ceramsite production technologies for reusing municipal solid waste incinerator fly ash in China.

Harmless treatment and reuse of municipal solid waste incinerator fly ash are challenging. Two reuse technologies of converting incinerator fly ash to ceramsites via rotary kiln sintering and non-sintering have been demonstrated in China. Field monitoring results reveal that the destruction efficiency of PCDD/Fs are both higher than 99% in two processes. The leaching rate of heavy metals in both ceramsite products, their pollutant emissions in production process meet the standards. Environmental impacts of two ceramsite products were compared using life cycle assessment approach. Rotary kiln sintering ceramsite has lower environmental impacts in most categories and delivers a smaller integrated impacts index than non-sintering ceramsite. For rotary kiln sintering ceramsite, transportation, electricity and curing agent in dust disposal are the most significant contributors to most of environmental impacts categories results, accounting for 33.7%, 29.0% and 24.6% to the integrated impacts index, respectively. For non-sintering ceramsite, curing agent and electricity contribute 69.6% and 15.8% to the integrated impacts index, respectively. Based on these life cycle assessment results, recommendations for current plant operation and new plants planning are proposed.