Use of modeling to aid design of a two-phase grass digestion system.

A sequentially fed leach bed system coupled with a leachate holding tank and an Upflow Anaerobic Sludge Blanket (UASB) was modeled based on 310d of grass silage digestion with the goal of generating specific design instruction. The model suggests the hydrolysis rate is proportional to the sprinkling rate and retention time. It suggests that raising the sprinkling rate by a third (from 600L/d to 800L/d) increases the volatile solids destruction from 70% to 80% for a retention time of 30d yielding 370L CH(4)/kg VS. The volume of the leachate holding tank has a minimal influence on methane production (reducing its volume by a factor of 2 reduces methane yield by 1%). The model suggests that for a constant sprinkling rate, shorter retention time increases daily methane production, but lowers specific methane yield (L CH(4)/kg VS). Longer retention time increases methane content in the biogas.

[1]  A. Nizami,et al.  Design, Commissioning, and Start-Up of a Sequentially Fed Leach Bed Reactor Complete with an Upflow Anaerobic Sludge Blanket Digesting Grass Silage , 2011 .

[2]  Soon Huat Tan,et al.  Cytocompatibility and Mechanical Properties of Hydroxyapatite Composite Reinforced with Multi-Walled Carbon Nanotubes and Bovine Serum Albumin , 2013 .

[3]  J. Rintala,et al.  Anaerobic digestion of grass silage in batch leach bed processes for methane production. , 2008, Bioresource technology.

[4]  H. W. Yu,et al.  Energy recovery from grass using two-phase anaerobic digestion. , 2002, Waste management.

[5]  P. V. Danckwerts.  Continuous flow systems. Distribution of residence times , 1995 .

[6]  Abdul-Sattar Nizami,et al.  How much gas can we get from grass , 2012 .

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

[8]  Abdul-Sattar Nizami,et al.  Optimizing the operation of a two-phase anaerobic digestion system digesting grass silage. , 2011, Environmental science & technology.

[9]  Norman N. Li,et al.  Chemical Reactor Design, Optimization, And Scaleup , 1987 .

[10]  T. Thamsiriroj,et al.  Difficulties Associated with Monodigestion of Grass as Exemplified by Commissioning a Pilot-Scale Digester , 2010 .

[11]  S. Heaven,et al.  The role of phase separation and feed cycle length in leach beds coupled to methanogenic reactors for digestion of a solid substrate (Part 1): Optimisation of reactors' performance. , 2012, Bioresource technology.

[12]  Nicholas E. Korres,et al.  Review of the integrated process for the production of grass biomethane. , 2009, Environmental science & technology.

[13]  D. Bagley,et al.  Modeling Microbial Kinetics in an Anaerobic Sequencing Batch Reactor ‐ Model Development and Experimental Validation , 1999 .

[14]  X Flotats,et al.  Hydrolysis kinetics in anaerobic degradation of particulate organic material: an overview. , 2008, Waste management.

[15]  B Tartakovsky,et al.  Anaerobic digestion model no. 1-based distributed parameter model of an anaerobic reactor: I. Model development. , 2008, Bioresource technology.

[16]  Sonia Heaven,et al.  The role of phase separation and feed cycle length in leach beds coupled to methanogenic reactors for digestion of a solid substrate (Part 2): Hydrolysis, acidification and methanogenesis in a two-phase system. , 2011, Bioresource technology.

[17]  A. Lehtomäki,et al.  Two-Stage Anaerobic Digestion of Energy Crops: Methane Production, Nitrogen Mineralisation and Heavy Metal Mobilisation , 2006, Environmental technology.

[18]  Irini Angelidaki,et al.  Anaerobic digestion model No. 1 (ADM1) , 2002 .

[19]  A. Nizami,et al.  Role of Leaching and Hydrolysis in a Two-Phase Grass Digestion System , 2010 .

[20]  P. V. Danckwerts.  Continuous flow systems , 1953 .

[21]  Jerry D. Murphy,et al.  What is the energy balance of grass biomethane in Ireland and other temperate northern European climates , 2009 .

[22]  T. Thamsiriroj,et al.  Modelling mono-digestion of grass silage in a 2-stage CSTR anaerobic digester using ADM1. , 2011, Bioresource technology.

[23]  Ulf Jeppsson,et al.  Aspects on ADM1 Implementation within the BSM2 Framework , 2005 .

[24]  Niamh M. Power,et al.  An argument for using biomethane generated from grass as a biofuel in Ireland , 2009 .

[25]  G. Kiely,et al.  How can we improve biomethane production per unit of feedstock in biogas plants , 2011 .

[26]  E. Nauman.  Chemical Reactor Design , 1987 .

[27]  Nicholas E. Korres,et al.  Is grass biomethane a sustainable transport biofuel? , 2010 .

[28]  Sergey V. Kalyuzhnyi,et al.  Dispersed plug flow model for upflow anaerobic sludge bed reactors with focus on granular sludge dynamics , 2005, Journal of Industrial Microbiology and Biotechnology.

[29]  J. C. Converse,et al.  Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes , 1986 .

[30]  S. Han,et al.  Performance of UASB reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. , 2001, Water research.