Early warning indicators for monitoring the process failure of anaerobic digestion system of food waste.

To determine reliable state parameters which could be used as early warning indicators of process failure due to the acidification of anaerobic digestion of food waste, three mesophilic anaerobic digesters of food waste with different operation conditions were investigated. Such parameters as gas production, methane content, pH, concentrations of volatile fatty acid (VFA), alkalinity and their combined indicators were evaluated. Results revealed that operation conditions significantly affect the responses of parameters and thus the optimal early warning indicators of each reactor differ from each other. None of the single indicators was universally valid for all the systems. The universally valid indicators should combine several parameters to supply complementary information. A combination of total VFA, the ratio of VFA to total alkalinity (VFA/TA) and the ratio of bicarbonate alkalinity to total alkalinity (BA/TA) can reflect the metabolism of the digesting system and realize rapid and effective early warning.

[1]  B. Ahring,et al.  Volatile fatty acids as indicators of process imbalance in anaerobic digestors , 1995, Applied Microbiology and Biotechnology.

[2]  D. T. Hill,et al.  Using volatile fatty acid relationships to predict anaerobic digester failure. , 1987 .

[3]  Manfred Lübken,et al.  Mono fermentation of grass silage by means of loop reactors. , 2009, Bioresource technology.

[4]  G. K. Anderson,et al.  Determination of bicarbonate and total volatile acid concentration in anaerobic digesters using a simple titration , 1992 .

[5]  T. Vicent,et al.  Alkalinity ratios to identify process imbalances in anaerobic digesters treating source-sorted organic fraction of municipal wastes , 2013 .

[6]  F. Yusoff,et al.  Maximum organic loading rate for the single-stage wet anaerobic digestion of food waste. , 2012, Bioresource technology.

[7]  V. Alcaraz-González,et al.  A robust control scheme to improve the stability of anaerobic digestion processes , 2010 .

[8]  Hisham Hafez,et al.  Biochemical methane potential (BMP) of food waste and primary sludge: influence of inoculum pre-incubation and inoculum source. , 2012, Bioresource technology.

[9]  B. Ahring,et al.  Regulation and optimization of the biogas process: Propionate as a key parameter , 2007 .

[10]  Liang Meng,et al.  Effects of volatile fatty acid concentrations on methane yield and methanogenic bacteria , 2009 .

[11]  B Mattiasson,et al.  Evaluation of new methods for the monitoring of alkalinity, dissolved hydrogen and the microbial community in anaerobic digestion. , 2001, Water research.

[12]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[13]  W. Verstraete,et al.  Early warning indicators for process failure due to organic overloading by rapeseed oil in one-stage continuously stirred tank reactor, sewage sludge and waste digesters. , 2012, Bioresource technology.