title: The effect of pH control and 'hydraulic flush' on hydrolysis and Volatile Fatty Acids (VFA) production and profile in anaerobic leach bed reactors digesting a high solids content substrate.
abstract: The effect of hydraulic flush and pH control on hydrolysis, Volatile Fatty Acids (VFA) production and profile in anaerobic leach bed reactors was investigated for the first time. Six reactors were operated under different regimes for two consecutive batches of 28days each. Buffering at pH ∼6.5 improved hydrolysis (Volatile Solid (VS) degradation) and VFA production by ∼50%. Butyric and acetic acid were dominant when reactors were buffered, while only butyric acid was produced at low pH. Hydraulic flush enhanced VS degradation and VFA production by ∼15% and ∼32%, respectively. Most Probable Number (MPN) of cellulolytic microorganisms indicated a wash out when hydraulic flush was applied, but pH control helped to counteract this. The highest VS degradation (∼89%), VFA yield (0.84kgCODkg(-1)VS(added)) and theoretical methane potential (0.37m(3)CH(4)kg(-1)VS(added)) were obtained when pH control and hydraulic flush were applied, and therefore, these conditions are recommended.
authors.affiliation: University of Southampton, School of Civil Engineering and the Environment, University Road, Southampton, SO17 1BJ, UK. denisecysneiros@hotmail.com
authors.forename: Denise
authors.initials: D
authors.lastname: Cysneiros
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Banks
authors.forename: Sonia
authors.initials: S
authors.lastname: Heaven
authors.forename: Kimon-Andreas G
authors.initials: KA
authors.lastname: Karatzas
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods*; D002021:Buffers; D002482:Cellulose / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D014835:Volatilization; D014867:Water / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D002021:Buffers; D005232:Fatty Acids, Volatile; D014867:Water; D002482:Cellulose