Characterization of soluble microbial products in the effluent of thermophilic anerobic digestion
2010
Hao, Li-Ping | He, Pin-Jing | Lu, Fan | Shao, Li-Ming
The effluent from wastewater treatment by anaerobic digestion contains a variety of dissolved organic matter (DOM) among which the majority is soluble microbial products (SMP). The occurrence and characteristics of SMP significantly affect the effluent quality and the efficiency of follow-up advanced wastewater treatment facilities. To investigate the property of SMP as a function of molecular weight (MW), DOM in the effluent from a thermophilicanaerobic digester treating simu1ated glucose wastewater was fractionated using size exclusion chromatography (SEC), characterized using dissolved organic carbon content (DOC), UV254 absorbance and fluorescence excitation emission matrix (EEM). The results showed that, SMP accounted for 90.8% of the DOM in the effluent. The SMP from thermophilic anaerobic digestion was characterized by relatively high percentage of tyrosine-like substances and low ratio of fulvic acid-like and humic acid-like substances. DOC of the fractions with high (10-100 kDa),medium(1-10 kDa), and low MW (<1 kDa) took up 46.8%, 45.4%, and 7.8% of the total DOC in the effluent, respectively. The SMP in the fractions with high MW showed high UV absorbility than those with low and medium MW. The fractions with low MW mainly contained tyrosine-like aromatic substances, while almost all the fulvicacid-like and humic acid-like substances distributed in the fractions with medium MW. Tryptophan-like aromatic protein and soluble microbial by-product-like substance extensively distributed in all the fractions. There was no significant difference between the fluorescence profiles of the fractions with high and medium MW, except a little change in the structures of tryptophan-like aromatic protein and soluble microbial by-product-like substances.
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