Analysis of the Odor Source in Leather-making Processes with a Delphi Survey
Odor problems in leather-making processes have received more and more attention with increasing environmental awareness among the populace.However,there is currently a lack of systematic research and a summary on the sources,causes,and control methods of odor from the leather-making processes.A three-round Delphi survey was conducted to study the odor levels and sources of the leather-making processes by consulting 51 experts from leather-making enterprises,industry associations,and universities in the leather field.Results show that the odor in the leather-making processes mainly comes from seven procedures and the odor levels of these procedures,from high to low,are storage,unhairing,liming,soaking,fleshing,deliming,and splitting.The main odorous substances are odorous gases generated by decaying hides or hide scraps in the rawhide warehouse,fleshing and splitting machines,and ground gaps;odor of industrial sulfide impurities;and ammonia and hydrogen sulfide released from ammonium salt deliming.It is recommended that tanneries prevent and control odor pollution by inhibiting rawhide decay;keeping fleshing machine,splitting machine,and tannery ground clean;adopting low-sulfide hair-save unhairing and ammonia free deliming technologies;and spraying deodorants.