Elsayed Elbeshbishy - Academia.edu (original) (raw)

Papers by Elsayed Elbeshbishy

Current Developments in Biotechnology and Bioengineering

Anaerobic Digestate Management

Water Environment Research

Social Science Research Network, 2021

Water Environment Research, 2022

This study demonstrates the potential of an innovative anaerobic treatment technology for municip... more This study demonstrates the potential of an innovative anaerobic treatment technology for municipal biosolids (IntensiCarb), which relies on vacuum evaporation to decouple solids and hydraulic retention times (SRT and HRT). We present proof‐of‐concept experiments using primary sludge and thickened waste activated sludge (50–50 v/v mixture) as feed for fermentation and carbon upgrading with the IntensiCarb unit. IntensiCarb fully decoupled the HRT and SRT in continuously stirred anaerobic reactors (CSAR) to achieve two intensification factors, that is, 1.3 and 2, while keeping the SRT constant at 3 days (including in the control fermenter). The intensified CSARs were compared to a conventional control system to determine the yields of particulate hydrolysis, VFA production, and nitrogen partitioning between fermentate and condensate. The intensified CSAR operating at an intensification factor 2 achieved a 65% improvement in particulate solubilization. Almost 50% of total ammonia was extracted without pH adjustment, while carbon was retained in the fermentate. Based on these results, the IntensiCarb technology allows water resource recovery facilities to achieve a high degree of plant‐wide intensification while partitioning nutrients into different streams and thickening solids.

Waste Management, 2021

This study focused on investigating the effect of combined chemical and hydrothermal pretreatment... more This study focused on investigating the effect of combined chemical and hydrothermal pretreatment (HTP) on the anaerobic digestibility of thickened waste activated sludge (TWAS). Three different combined pretreatment conditions of HTP + free nitrous acid (FNA), HTP + Acid, and HTP + Alkaline were applied to TWAS. To control and compare the effect of combined pretreatments and a single pretreatment, Acid, Alkaline, FNA and HTP pretreatments were applied done prior to AD. The results of this study revealed that combined pretreatments have higher potential to improve methane production yield and rate but not in the solubilization of COD. The highest methane yield of 275 mL CH4/g TCOD added was achieved for the combined pretreatment with FNA and HTP. HTP + FNA pretreatment was found to produce higher methane yields compared to the combination of other typical acid and alkaline reagents with hydrothermal pretreatment. Methane yields of 594, 527, and 544 L CH4/g VSS added, were achieved for HTP + FNA, HTP + ALK, and HTP + ACID pretreatments, respectively. The preliminary economic analysis showed that out of the combined pretreatment, only combining HTP with FNA is economically feasible.

Science of The Total Environment, 2021

This research compared the impact of two primary treatment options (i.e. primary clarification an... more This research compared the impact of two primary treatment options (i.e. primary clarification and rotating belt filtration (RBF)) on biological nutrients removal (BNR) process, using sludge fermentation liquid (SFL) as a carbon source. The liquid fraction of both fermented primary and RBF sludges comparably enhanced BNR. Despite the significant contribution of the unpurified SFL to the sharp increase in nutrient levels; i.e. 47%-64% (primary effluent; PE), and 45%-53% (RBF) of the soluble nitrogen and phosphorus loads; readily biodegradable COD and volatile fatty acids (VFAs) fractions of the combined feed increased significantly (2.5-6.1 times), compared to the original feed by additional SFL. Removal efficiencies in the reactors reached 57% (total nitrogen) and 92% (total phosphorus) after addition of SFL. Effluent nitrogen and phosphorus of the two reactors were close in the range of 15 ± 6 mg N/L, and 0.5 ± 0.3 mg P/L, respectively. Kinetics studies showed denitrification rates of 1.3, and 1.13 kg NO3-N/m3.d for primary effluent and RBF effluent-fed reactors, respectively. Phosphorus release rates were 11.7 and 9.7 mg PO4-P/g VSS.h, for primary, and RBF effluents, respectively; showing 20%-22% lower rates in the RBF SFL. Incorporating experimental data into a plant-wide model for a 100 MLD facility receiving typical medium strength wastewater, showed that although primary treatment enhanced the biogas production by 96% (primary clarification) and 62% (RBF) trains; combined fermentation and anaerobic digestion was effective to enhance the biogas production by 59% on average, compared to the base scenario without primary treatment. Additionally, if primary clarification exists, then the addition of fermentation results in additional revenue of C$1890/d in the plant, considering additional revenue of C$2230/d due to VFA generation in contrast to only C$340/d loss due to the reduced methane production.

Waste Management, 2020

This research assessed the impact of volatile fatty acids (VFA) recovery and biomethane potential... more This research assessed the impact of volatile fatty acids (VFA) recovery and biomethane potential in an integrated fermentation-digestion process with a single stage digestion of primary and rotating belt filtration (RBF) sludges. Implementing semi-continuous fermentation at 1, 2, and 4 days solids retention time (SRT) showed a direct impact on the hydrolysis and VFA recovery which increased as SRT increased, while also improving the dewaterability by reducing the concentrated sludge volume index of the processed sludge. pH-controlled fermentation was effective improving the VFA yields by up to 93% and 72% at pH 9 (relative to no pH control), for RBF and primary sludges, respectively; although fermentation at pH 6 (optimum) showed promise for enhancing VFAs while lowering the required chemicals significantly. Although cellulose constituted only 21.0% and 29.5% of the TSS in primary and RBF sludges, it contributed 38-41% of the methane production for the two sludges, respectively. Experimental results of integrated fermentation-digestion and single stage digestion processes were incorporated in technoeconomic analysis. Results confirmed the economic viability of fermentation with payback periods of 2.7 ± 1.1 years (RBF), and 3.6 ± 2.7 years (PS), while also revealed that VFA recovery could save up to 7.2 ± 2.0% (RBF), and 7.6 ± 2.7% (PS) of the respective total sludge handling and disposal costs, despite an average of 12.7% and 8.4% decrease in biogas production due to VFA extraction in the integrated systems of RBF and primary sludges, respectively. Overall, the integrated fermentation-digestion system economically outperformed the single stage digestion for both sludge types under all studied scenarios.

Bioresource Technology, 2020

This research showed the interrelated impact of cellulase enzyme, temperature, and SRT on enhance... more This research showed the interrelated impact of cellulase enzyme, temperature, and SRT on enhancement of primary and rotating belt filter (PS, RBF) sludges fermentation. SRTs of 1, 2, and 4-days were tested at 25°C and 35°C. Enzymatic enhancement was examined using three different doses of enzyme (i.e. 0.5%, 1%, and 1.5% of the total solids in the feed). The results showed a positive impact of enzyme dose as well as temperature and SRT on VFA and soluble COD production. For the RBF sludge, enzyme addition enhanced the VFA yield of fermentation at room temperature (25°C) from 52-103 mgCOD/g VS to 93-188 mgCOD/g VS, as compared with increase from 78-192 to 87-202 mgCOD/gVS in PS. Intensification of the fermentation process, particularly for the cellulose-rich RBF sludge, by enzyme addition confirms process viability as an alternative to the extraneous carbon sources for biological nutrient removal in wastewater treatment plants. to simultaneously increase treatment efficiency and reduce operational costs. With increasing demand on resource recovery, the production of value-added chemicals including VFAs from fermentation of wastewater treatment biosolids for use in BNR processes is eliciting the

Proceedings of the Water Environment Federation, 2016

Water Environment Research, 2019

Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverab... more Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverable. For the first time, comprehensive mapping and tracking the fate of cellulose across various unit processes at full-scale in two water resource recovery facilities located in North America and Europe was undertaken. The influent cellulose content accounted for approximately one-third of the total suspended solids (TSS). Although about 80% of the raw wastewater cellulose was removed in primary treatment, the type of primary treatment process (rotating belt filter [RBF] vs. primary clarification [PC]) had a significant impact on cellulose capture and diversion. The high cellulose content of the RBF sludge accounting for 35% of the TSS facilitates cellulose recovery. For the North American plant, with a conventional activated sludge process (SRT of 6-7 days, preceded by PC), cellulose biodegradation efficiencies of 70%-90% of the PC effluent were observed in summer and winter. For the European plant, with a modified University of Cape Town process (SRT of 14 days, without primary treatment in train 2, or preceded by RBF in train 1), comparable cellulose biodegradation efficiencies were also observed. Results from laboratory SBRs indicated that cellulose biodegradation efficiency at room temperature was 86% of the influent cellulose.

Journal of Hydrology, 2019

This paper proposes a new conceptual modelling approach and calibration method for sewer systems,... more This paper proposes a new conceptual modelling approach and calibration method for sewer systems, driven by the interest in using the sewer as a bioreactor and long-term biochemical modelling of the integrated system consisting of the sewage collection system and the wastewater treatment plant (WWTP). The new approach consists of a method for simplifying a complex sewer network into a simpler, yet accurate, computationally efficient (conceptual) model able to capture the relevant sewer dynamics, both in terms of water quantity and water quality entering the wastewater treatment plant. Water quality predicted by the conceptual model was assessed using a detailed biochemical process model and compared against a whole-network biochemical model that covers all hydraulic segments and pipes of the sewer system. The conceptual biochemical model achieves very similar results as the whole-network model in terms of water quality, while providing much faster simulation speed (minutes rather than hours) and easy calibration. Given these advantages, the conceptual biochemical model of a collection system can be used in an integrated model with which sewer and WWTP can be simulated simultaneously for long-term evaluation of optimization scenarios. The model was applied to the prediction of the biochemical components, e.g. sulfide, organics and nutrients, which are 2 essential for the control and management of sewer corrosion and pollutant removal.

Data in Brief, 2019

The presented dataset in this data article provides quantitative data on the production of bioene... more The presented dataset in this data article provides quantitative data on the production of bioenergy (biogas and biomethane) from mesophilic batch anaerobic digestion (AD) of thermally hydrolyzed organic fraction of municipal solid waste (OFMSW). The discussion and interpretation of the data are provided in another publication entitled "Hydrothermal Pretreatment of Source Separated Organics for Enhanced Solubilization and Biomethane Recovery" (Razavi et al., 2019). The data and information presented in the current data article include (1) the ratio of soluble to particulate chemical oxygen demand (COD) under different thermal hydrolysis condition, (2) the daily measured biogas and biomethane data, (3) the cumulative methane yield data in terms of mL CH 4 produced per gram of volatile suspended solids (VSS) as well as feedstock added, (4) the ultimate methane yield data as well as the relative improvement in methane recovery compared to the control (non-hydrolyzed) digester, (5) the data of firstorder organics biodegradation rate constants, (6) the procedure of measuring biogas composition via gas chromatography, (7) the procedure of converting the biogas/methane volume data acquired under the actual experimental condition (mesophilic temperature of 38°C and atmospheric pressure) to the standard temperature (0°C) and pressure (1 atm) condition, and (8) the procedure of determining the first-order kinetic rate constants.

Proceedings of the Water Environment Federation, 2018

A fast, convenient and user-friendly modelling tool was used to model biochemical and physico-che... more A fast, convenient and user-friendly modelling tool was used to model biochemical and physico-chemical processes in the collection system. With this new tool two case studies were investigated with different scopes and purposes: one with a focus on the integrated modelling of sewer and wastewater treatment plants (WWTP) and the other aiming at a large-scale sewer network. Scenario analysis was carried out under different chemical dosing strategies. The work proves that processes in sewers can cause a significant impact on a downstream WWTP, and the wastewater treatment process can be better managed and optimized with the help of sewer-WWTP integrated modelling. The tool can also identify hotspots of key indicators like total dissolved sulfide in a large-scale collection system. It is suggested that investigating the network from a wider perspective can help target key issues and regions.

Proceedings of the Water Environment Federation, 2018

Bioresource Technology, 2018

The objective of this research was to evaluate the effect of the hydrothermal pretreatment on the... more The objective of this research was to evaluate the effect of the hydrothermal pretreatment on the solubilization of source separated organics (SSO) as well as the biomethane recovery through the mesophilic batch anaerobic digestion process. For this purpose, the SSO was subjected to fifteen different pretreatment conditions within five different severity index (SI) values (3, 3.5, 4, 4.5, and 5). The pretreatment temperature, holding time, and pressure ranged from 150 to 240°C, 5 to 30 min, and 476 to 3367 kPa, respectively. The highest solubilization improvement of ∼50% was achieved under the pretreatment condition of "220°C-10 min-2323 kPa" corresponding to the SI value of 4.5. However, the maximum biomethane production yield of 280 mL/g TCOD added and biomethane production rate of 30 mL/g TCOD added were obtained under the less intense pretreatment conditions of "190°C-20 min-1247 kPa" and "170°C-30 min-786 kPa", respectively.

Proceedings of the Water Environment Federation, 2018

Current Developments in Biotechnology and Bioengineering

Anaerobic Digestate Management

Water Environment Research

Social Science Research Network, 2021

Water Environment Research, 2022

This study demonstrates the potential of an innovative anaerobic treatment technology for municip... more This study demonstrates the potential of an innovative anaerobic treatment technology for municipal biosolids (IntensiCarb), which relies on vacuum evaporation to decouple solids and hydraulic retention times (SRT and HRT). We present proof‐of‐concept experiments using primary sludge and thickened waste activated sludge (50–50 v/v mixture) as feed for fermentation and carbon upgrading with the IntensiCarb unit. IntensiCarb fully decoupled the HRT and SRT in continuously stirred anaerobic reactors (CSAR) to achieve two intensification factors, that is, 1.3 and 2, while keeping the SRT constant at 3 days (including in the control fermenter). The intensified CSARs were compared to a conventional control system to determine the yields of particulate hydrolysis, VFA production, and nitrogen partitioning between fermentate and condensate. The intensified CSAR operating at an intensification factor 2 achieved a 65% improvement in particulate solubilization. Almost 50% of total ammonia was extracted without pH adjustment, while carbon was retained in the fermentate. Based on these results, the IntensiCarb technology allows water resource recovery facilities to achieve a high degree of plant‐wide intensification while partitioning nutrients into different streams and thickening solids.

Waste Management, 2021

This study focused on investigating the effect of combined chemical and hydrothermal pretreatment... more This study focused on investigating the effect of combined chemical and hydrothermal pretreatment (HTP) on the anaerobic digestibility of thickened waste activated sludge (TWAS). Three different combined pretreatment conditions of HTP + free nitrous acid (FNA), HTP + Acid, and HTP + Alkaline were applied to TWAS. To control and compare the effect of combined pretreatments and a single pretreatment, Acid, Alkaline, FNA and HTP pretreatments were applied done prior to AD. The results of this study revealed that combined pretreatments have higher potential to improve methane production yield and rate but not in the solubilization of COD. The highest methane yield of 275 mL CH4/g TCOD added was achieved for the combined pretreatment with FNA and HTP. HTP + FNA pretreatment was found to produce higher methane yields compared to the combination of other typical acid and alkaline reagents with hydrothermal pretreatment. Methane yields of 594, 527, and 544 L CH4/g VSS added, were achieved for HTP + FNA, HTP + ALK, and HTP + ACID pretreatments, respectively. The preliminary economic analysis showed that out of the combined pretreatment, only combining HTP with FNA is economically feasible.

Science of The Total Environment, 2021

This research compared the impact of two primary treatment options (i.e. primary clarification an... more This research compared the impact of two primary treatment options (i.e. primary clarification and rotating belt filtration (RBF)) on biological nutrients removal (BNR) process, using sludge fermentation liquid (SFL) as a carbon source. The liquid fraction of both fermented primary and RBF sludges comparably enhanced BNR. Despite the significant contribution of the unpurified SFL to the sharp increase in nutrient levels; i.e. 47%-64% (primary effluent; PE), and 45%-53% (RBF) of the soluble nitrogen and phosphorus loads; readily biodegradable COD and volatile fatty acids (VFAs) fractions of the combined feed increased significantly (2.5-6.1 times), compared to the original feed by additional SFL. Removal efficiencies in the reactors reached 57% (total nitrogen) and 92% (total phosphorus) after addition of SFL. Effluent nitrogen and phosphorus of the two reactors were close in the range of 15 ± 6 mg N/L, and 0.5 ± 0.3 mg P/L, respectively. Kinetics studies showed denitrification rates of 1.3, and 1.13 kg NO3-N/m3.d for primary effluent and RBF effluent-fed reactors, respectively. Phosphorus release rates were 11.7 and 9.7 mg PO4-P/g VSS.h, for primary, and RBF effluents, respectively; showing 20%-22% lower rates in the RBF SFL. Incorporating experimental data into a plant-wide model for a 100 MLD facility receiving typical medium strength wastewater, showed that although primary treatment enhanced the biogas production by 96% (primary clarification) and 62% (RBF) trains; combined fermentation and anaerobic digestion was effective to enhance the biogas production by 59% on average, compared to the base scenario without primary treatment. Additionally, if primary clarification exists, then the addition of fermentation results in additional revenue of C$1890/d in the plant, considering additional revenue of C$2230/d due to VFA generation in contrast to only C$340/d loss due to the reduced methane production.

Waste Management, 2020

This research assessed the impact of volatile fatty acids (VFA) recovery and biomethane potential... more This research assessed the impact of volatile fatty acids (VFA) recovery and biomethane potential in an integrated fermentation-digestion process with a single stage digestion of primary and rotating belt filtration (RBF) sludges. Implementing semi-continuous fermentation at 1, 2, and 4 days solids retention time (SRT) showed a direct impact on the hydrolysis and VFA recovery which increased as SRT increased, while also improving the dewaterability by reducing the concentrated sludge volume index of the processed sludge. pH-controlled fermentation was effective improving the VFA yields by up to 93% and 72% at pH 9 (relative to no pH control), for RBF and primary sludges, respectively; although fermentation at pH 6 (optimum) showed promise for enhancing VFAs while lowering the required chemicals significantly. Although cellulose constituted only 21.0% and 29.5% of the TSS in primary and RBF sludges, it contributed 38-41% of the methane production for the two sludges, respectively. Experimental results of integrated fermentation-digestion and single stage digestion processes were incorporated in technoeconomic analysis. Results confirmed the economic viability of fermentation with payback periods of 2.7 ± 1.1 years (RBF), and 3.6 ± 2.7 years (PS), while also revealed that VFA recovery could save up to 7.2 ± 2.0% (RBF), and 7.6 ± 2.7% (PS) of the respective total sludge handling and disposal costs, despite an average of 12.7% and 8.4% decrease in biogas production due to VFA extraction in the integrated systems of RBF and primary sludges, respectively. Overall, the integrated fermentation-digestion system economically outperformed the single stage digestion for both sludge types under all studied scenarios.

Bioresource Technology, 2020

This research showed the interrelated impact of cellulase enzyme, temperature, and SRT on enhance... more This research showed the interrelated impact of cellulase enzyme, temperature, and SRT on enhancement of primary and rotating belt filter (PS, RBF) sludges fermentation. SRTs of 1, 2, and 4-days were tested at 25°C and 35°C. Enzymatic enhancement was examined using three different doses of enzyme (i.e. 0.5%, 1%, and 1.5% of the total solids in the feed). The results showed a positive impact of enzyme dose as well as temperature and SRT on VFA and soluble COD production. For the RBF sludge, enzyme addition enhanced the VFA yield of fermentation at room temperature (25°C) from 52-103 mgCOD/g VS to 93-188 mgCOD/g VS, as compared with increase from 78-192 to 87-202 mgCOD/gVS in PS. Intensification of the fermentation process, particularly for the cellulose-rich RBF sludge, by enzyme addition confirms process viability as an alternative to the extraneous carbon sources for biological nutrient removal in wastewater treatment plants. to simultaneously increase treatment efficiency and reduce operational costs. With increasing demand on resource recovery, the production of value-added chemicals including VFAs from fermentation of wastewater treatment biosolids for use in BNR processes is eliciting the

Proceedings of the Water Environment Federation, 2016

Water Environment Research, 2019

Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverab... more Cellulose from toilet paper is a significant fraction of particulate organics, which is recoverable. For the first time, comprehensive mapping and tracking the fate of cellulose across various unit processes at full-scale in two water resource recovery facilities located in North America and Europe was undertaken. The influent cellulose content accounted for approximately one-third of the total suspended solids (TSS). Although about 80% of the raw wastewater cellulose was removed in primary treatment, the type of primary treatment process (rotating belt filter [RBF] vs. primary clarification [PC]) had a significant impact on cellulose capture and diversion. The high cellulose content of the RBF sludge accounting for 35% of the TSS facilitates cellulose recovery. For the North American plant, with a conventional activated sludge process (SRT of 6-7 days, preceded by PC), cellulose biodegradation efficiencies of 70%-90% of the PC effluent were observed in summer and winter. For the European plant, with a modified University of Cape Town process (SRT of 14 days, without primary treatment in train 2, or preceded by RBF in train 1), comparable cellulose biodegradation efficiencies were also observed. Results from laboratory SBRs indicated that cellulose biodegradation efficiency at room temperature was 86% of the influent cellulose.

Journal of Hydrology, 2019

This paper proposes a new conceptual modelling approach and calibration method for sewer systems,... more This paper proposes a new conceptual modelling approach and calibration method for sewer systems, driven by the interest in using the sewer as a bioreactor and long-term biochemical modelling of the integrated system consisting of the sewage collection system and the wastewater treatment plant (WWTP). The new approach consists of a method for simplifying a complex sewer network into a simpler, yet accurate, computationally efficient (conceptual) model able to capture the relevant sewer dynamics, both in terms of water quantity and water quality entering the wastewater treatment plant. Water quality predicted by the conceptual model was assessed using a detailed biochemical process model and compared against a whole-network biochemical model that covers all hydraulic segments and pipes of the sewer system. The conceptual biochemical model achieves very similar results as the whole-network model in terms of water quality, while providing much faster simulation speed (minutes rather than hours) and easy calibration. Given these advantages, the conceptual biochemical model of a collection system can be used in an integrated model with which sewer and WWTP can be simulated simultaneously for long-term evaluation of optimization scenarios. The model was applied to the prediction of the biochemical components, e.g. sulfide, organics and nutrients, which are 2 essential for the control and management of sewer corrosion and pollutant removal.

Data in Brief, 2019

The presented dataset in this data article provides quantitative data on the production of bioene... more The presented dataset in this data article provides quantitative data on the production of bioenergy (biogas and biomethane) from mesophilic batch anaerobic digestion (AD) of thermally hydrolyzed organic fraction of municipal solid waste (OFMSW). The discussion and interpretation of the data are provided in another publication entitled "Hydrothermal Pretreatment of Source Separated Organics for Enhanced Solubilization and Biomethane Recovery" (Razavi et al., 2019). The data and information presented in the current data article include (1) the ratio of soluble to particulate chemical oxygen demand (COD) under different thermal hydrolysis condition, (2) the daily measured biogas and biomethane data, (3) the cumulative methane yield data in terms of mL CH 4 produced per gram of volatile suspended solids (VSS) as well as feedstock added, (4) the ultimate methane yield data as well as the relative improvement in methane recovery compared to the control (non-hydrolyzed) digester, (5) the data of firstorder organics biodegradation rate constants, (6) the procedure of measuring biogas composition via gas chromatography, (7) the procedure of converting the biogas/methane volume data acquired under the actual experimental condition (mesophilic temperature of 38°C and atmospheric pressure) to the standard temperature (0°C) and pressure (1 atm) condition, and (8) the procedure of determining the first-order kinetic rate constants.

Proceedings of the Water Environment Federation, 2018

A fast, convenient and user-friendly modelling tool was used to model biochemical and physico-che... more A fast, convenient and user-friendly modelling tool was used to model biochemical and physico-chemical processes in the collection system. With this new tool two case studies were investigated with different scopes and purposes: one with a focus on the integrated modelling of sewer and wastewater treatment plants (WWTP) and the other aiming at a large-scale sewer network. Scenario analysis was carried out under different chemical dosing strategies. The work proves that processes in sewers can cause a significant impact on a downstream WWTP, and the wastewater treatment process can be better managed and optimized with the help of sewer-WWTP integrated modelling. The tool can also identify hotspots of key indicators like total dissolved sulfide in a large-scale collection system. It is suggested that investigating the network from a wider perspective can help target key issues and regions.

Proceedings of the Water Environment Federation, 2018

Bioresource Technology, 2018

The objective of this research was to evaluate the effect of the hydrothermal pretreatment on the... more The objective of this research was to evaluate the effect of the hydrothermal pretreatment on the solubilization of source separated organics (SSO) as well as the biomethane recovery through the mesophilic batch anaerobic digestion process. For this purpose, the SSO was subjected to fifteen different pretreatment conditions within five different severity index (SI) values (3, 3.5, 4, 4.5, and 5). The pretreatment temperature, holding time, and pressure ranged from 150 to 240°C, 5 to 30 min, and 476 to 3367 kPa, respectively. The highest solubilization improvement of ∼50% was achieved under the pretreatment condition of "220°C-10 min-2323 kPa" corresponding to the SI value of 4.5. However, the maximum biomethane production yield of 280 mL/g TCOD added and biomethane production rate of 30 mL/g TCOD added were obtained under the less intense pretreatment conditions of "190°C-20 min-1247 kPa" and "170°C-30 min-786 kPa", respectively.

Proceedings of the Water Environment Federation, 2018