Effects-of-sulfur-on-lead-partitioning-during-sludge-combustion-based-on

heavymetalemissionscannotbeeffectivelyremovedbyexhaustgas-cleaningdevices(Degerejietal.,2013;LinandMa,2012).Furthermore,duringwasteincineration,theheavymetalsinwastecannotbedestroyed.Theythenvolatilizeduringincinerationandcondenselatertoformmetalcompoundsandsubmicronmetallicparticlesasthefluegasiscooled(MeylanandSpoerri,2014).Previousstudies(Luanetal.,2013;Jiaoetal.,2011;Zhangetal.,2008)indicatedthatthepartitioningbehaviorofheavymetalsdur-ingwasteincinerationisinfluencedbythecompositionofthegasstream,theincinerationtemperature,theconcentrationofmetalsinthewaste,andtheconcentrationofchlorine(Cl),sulfur(S),phosphorus(P),H2O,andsoon.Becausebothrawsludgeanddewateredsludgehavehighmoisturelevelsandlowheatingval-ues,addingauxiliaryfuelisnecessaryforindependentsludgeincinerationortheco-combustionofsludgewithMSWandcoal.InChina,theadditionofsulfurcontainingcoalisacommonprac-ticeintheco-combustionofsludgewithMSWbecauseofitslowcost(Chengetal.,2007).Theeffectofchloridesonthetransferofheavymetalshasbeeninvestigated(Chiangetal.,1997;Hanetal.,2008;Lietal.,2010);nevertheless,therehavebeenfewreportsofexperimentalstudiesontheeffectofsulfuronheavymetalcharacteristicsduringsludgeincineration.Infact,knowingwhichformofsulfurisintheMSWisverycomplicatedbecauseoftheusageofsulfurcompoundsinmanyindustries,suchastex-tiles,pigments,rubber,papermaking,detergents,soaps,amongothers.StatisticaldatashowthatthesulfurconcentrationintheMSWof12citiesisapproximately0.09%,whereasinsomecitiesitrangesbetween0.18%and1%,reachingashighas6%insomeMSWorothersolidwastesamenabletoincineration(Xietal.,2002;Lietal.,2003;Tanetal.,2007).Furthermore,thesulfurcon-centrationsin7typessludgefromChinahavebeenlistedinthelit-erature(Lietal.,2006;Ranetal.,2008;Wangetal.,2007;Dengetal.,2008)andarebetween0.17%and5.63%.Duringsludge–coalorsludge-MSWco-combustion,thesulfurconcentrationinthefuelcouldbemorethanthatinthesludge.Althoughtheconcentrationofsulfurinthesludgeisoftenlower,itstillplaysanimportantroleandaffectsthetransformationo