Three-dimensional fluorescence excitation–emission matrix (EEM) spectroscopy with regional integration analysis for assessing waste sludge hydrolysis treated with multi-enzyme and thermophilic bacteria

• Published in: Bioresource technology 2014-11, Vol.171, p.22-28
• Main Authors: Guo, Liang, Lu, Mingmin, Li, Qianqian, Zhang, Jiawen, Zong, Yan, She, Zonglian
• Format: Article
• Language: English
• Subjects: Applied sciences; Bacteria - metabolism; Biodegradation, Environmental; Biological and medical sciences; Biological Oxygen Demand Analysis; Centrifugation; EEM; Enzymes - metabolism; Exact sciences and technology; FRI; Fundamental and applied biological sciences. Psychology; Hydrolysis; Microwaves; Multi-enzyme; Pollution; Sewage - microbiology; Sludge hydrolysis; Spectrometry, Fluorescence - methods; Thermophilic bacteria; Wastes
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2014.08.025

•Multi-enzyme and thermophilic bacteria hydrolysis was evaluated by EPS and DOM.•Composition and structure of sludge EPS and DOM were analyzed using EEM with FRI.•Accumulation of non-biodegradable material was disadvantage for further utilization.•EEM with FRI provided a new insight toward sludge hydrolysis and bio-utilization. The hydrolysis effect of waste sludge after multi-enzyme and thermophilic bacteria pretreatments is investigated using excitation–emission matrix (EEM) with fluorescence regional integration (FRI) in this study. The compositional characteristics of extracellular polymeric substances (EPS) and dissolved organic matters (DOM) were analyzed to evaluate the sludge disintegration. The EPS and cell wall in sludge were disrupted after hydrolysis which led to carbohydrate, protein and soluble chemical oxygen demand (SCOD) of DOM increasing in sludge supernatant. The bio-degradability level in the extracted fractions of EPS and DOM depending on the fluorescence zones was found after hydrolysis. The highest proportion of percent fluorescence response (Pi,n) in EPS and DOM was soluble microbial by-product and humic acid-like organics. A significant increase of humic acid-like organics in DOM after thermophilic bacteria hydrolysis was obtained. The assessment of hydrolysis using EEM coupled with FRI provided a new insight toward the bio-utilization process of waste sludge.