摘要
Extracellular polymeric substances(EPS)are eco-friendly and economical biopolymers with a significant role in pollutant removal,bio-flocculation,settling and dewatering of activated sludge.In this study,growth profile and EPS production by an EPS-producing microbial strain(isolated from wastewater sludge or WWS)was studied using activated sludge fortified with glycerol.The study compared three crude glycerol samples as carbon sources from different biodiesel companies(BIO-LIQ,BIOCARDEL,ROTHSAY)and their effect on EPS production and characterisation was observed.The maximum slime EPS(S-EPS)concentration(12.34 g/L)was produced when sludge fortified with BIO-LIQ crude glycerol was used,higher than pure glycerol(10 g/L)at 72 h.The S-EPS was enhanced(16 g/L)when purified BIO-LIQ glycerol(by acid treatment)was used.It was also observed that S-EPS concentration increased 1.6-2.6 times by using sludge fortified with glycerol as compared to only glycerol(no sludge)as EPS production medium.In addition,the S-EPS produced from different glycerol samples yielded different characteristics in terms of protein-carbohydrate content,flocculation activity and dewaterability.The S-EPS from purified BIO-LIQ glycerol(with sludge)gave maximum flocculation activity and dewaterability i.e.93.71%and 60.2%respectively.The comparison between Ca(OH)2 and NaOH used as alkaline sludge pre-treatment methods revealed that the EPS produced from Ca(OH)_(2)-treated sludge fortified with glycerol solutions to be better in terms of protein content,flocculation activity and dewaterability.Structural composition analysis using Fourier Transform Infrared Spectroscopy(FT-IR)revealed the presence of distinct functional groups(carboxyl,hydroxyl,amine groups)in the produced S-EPS.
