scholarly journals EFFECT OF HYDROTHERMAL PRETREATMENT ON THE ACIDIFICATION OF THICKENED WASTE ACTIVATED SLUDGE AND SOURCE SEPARATED ORGANICS

2021 ◽  
Author(s):  
Farokh laqa Kakar
Keyword(s):  
Activated Sludge ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Pre Treatment ◽  
The Impact

The objective of this study was to investigate the impact of the hydrothermal pre-treatment (HTP) on solubilization and acidification of thickened waste activated sludge (TWAS) and source separated organics (SSO). The temperatures, retention times, and pressures used in this study ranges were 150-240°C, 5-30 min, and 69-488 psi, respectively. Mesophilic batch acidification tests were conducted for all pretreated and non-pretreated samples. For the TWAS, the highest overall COD solubilization due to HTP and acidification of 64% was observed at “200°C-10 min” compared to 30% for raw TWAS. The highest VFAs yield of 2856 mg VFAs/g VSS added was observed at “190°C-10 min” compared to 1251 for raw TWAS. For the SSO, the highest overall COD solubilization of 63% was observed at “210°C-20 min” compared to 17% for raw SSO. The highest VFAs yield of 1536 mg VFAs/g VSS added was observed at “210°C-20 min” compared to 768 for raw SSO.

scholarly journals EFFECT OF HYDROTHERMAL PRETREATMENT ON THE ACIDIFICATION OF THICKENED WASTE ACTIVATED SLUDGE AND SOURCE SEPARATED ORGANICS

2021 ◽  
Author(s):  
Farokh laqa Kakar
Keyword(s):  
Activated Sludge ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Pre Treatment ◽  
The Impact

The objective of this study was to investigate the impact of the hydrothermal pre-treatment (HTP) on solubilization and acidification of thickened waste activated sludge (TWAS) and source separated organics (SSO). The temperatures, retention times, and pressures used in this study ranges were 150-240°C, 5-30 min, and 69-488 psi, respectively. Mesophilic batch acidification tests were conducted for all pretreated and non-pretreated samples. For the TWAS, the highest overall COD solubilization due to HTP and acidification of 64% was observed at “200°C-10 min” compared to 30% for raw TWAS. The highest VFAs yield of 2856 mg VFAs/g VSS added was observed at “190°C-10 min” compared to 1251 for raw TWAS. For the SSO, the highest overall COD solubilization of 63% was observed at “210°C-20 min” compared to 17% for raw SSO. The highest VFAs yield of 1536 mg VFAs/g VSS added was observed at “210°C-20 min” compared to 768 for raw SSO.

scholarly journals THE EFFECT OF HYDROTHERMAL PRETREATMENT ON THE ANAEROBIC DIGESTION OF THICKENED WASTE ACTIVATED SLUDGE AND SOURCE SEPARATED ORGANICS

2021 ◽  
Author(s):  
Ahmad Shabir Razavi
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Pretreatment Condition ◽  
Wide Range ◽  
Biomethane Production ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Severity Indexes

The objective of this study was to evaluate the impact of hydrothermal pretreatment of source separated organics (SSO) and thickened waste activated sludge (TWAS) on the solubilization and biomethane production. The feedstocks went through 15 different conditions in a wide range of temperature (150-240°C), retention time (5-30) min and severity indexes (3-5). The result of the study revealed that the effect of hydrothermal pretreatment can vary based on the feedstock primary properties and the optimum pretreatment condition. In this study, the optimum pretreatment conditions for highest solubilization and solid reduction of the SSO were 220°C and 10 minutes retention time, however, for highest methane production, it was 190°C for 20 minutes. In case of TWAS, the result revealed that the maximum biomethane production was achieved at pretreatment conditions of 160°C and 20 min, while, the highest solubilization and solid reduction was observed in 220°C and 10 minutes retention time.

scholarly journals Biomethane production improvement by hydrothermal pretreatment of thickened waste activated sludge

2020 ◽  
Author(s):  
Ahmad Shabir Razavi ◽  
Farokhlaqa Kakar ◽  
Ehssan Hosseini Koupaie ◽  
Hisham Hafez ◽  
Elsayed Elbeshbishy
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Hydrothermal Pretreatment ◽  
Effect Of Temperature ◽  
Waste Activated Sludge ◽  
Pretreatment Condition ◽  
Production Improvement ◽  
Biomethane Production ◽  
Pretreatment Conditions ◽  
The Impact

Abstract This study evaluated the impact of hydrothermal pretreatment on thickened waste activated sludge (TWAS) for solubilization enhancement and biomethane production improvement through the mesophilic anaerobic digestion process. In order to assess the effect of temperature, retention time and severity index (SI) of the hydrothermal pretreatment, TWAS was exposed to fifteen different pretreatment condition within a combination of 10 different pretreatment temperature range (150–240 °C), five different retention time (5–30 min) and five different severity indexes (SI = 3, 3.5, 4, 4.5 and 5). The solubilization enhancement was observed in all hydrothermally pretreated samples with the highest solubilization efficiency of 49% in pretreatment condition of 200 °C and 10 min retention time within the corresponding SI = 4. Biomethane production was not improved in all fifteen pretreatment conditions, pretreatment with SI beyond 4 decreased the biodegradability of TWAS. The highest biomethane production was observed in the pretreatment condition of 170 °C and 10 min by 40% increase compared to non-pretreated TWAS.

scholarly journals THE EFFECT OF HYDROTHERMAL PRETREATMENT ON THE ANAEROBIC DIGESTION OF THICKENED WASTE ACTIVATED SLUDGE AND SOURCE SEPARATED ORGANICS

2021 ◽  
Author(s):  
Ahmad Shabir Razavi
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Hydrothermal Pretreatment ◽  
Waste Activated Sludge ◽  
Pretreatment Condition ◽  
Wide Range ◽  
Biomethane Production ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Severity Indexes

The objective of this study was to evaluate the impact of hydrothermal pretreatment of source separated organics (SSO) and thickened waste activated sludge (TWAS) on the solubilization and biomethane production. The feedstocks went through 15 different conditions in a wide range of temperature (150-240°C), retention time (5-30) min and severity indexes (3-5). The result of the study revealed that the effect of hydrothermal pretreatment can vary based on the feedstock primary properties and the optimum pretreatment condition. In this study, the optimum pretreatment conditions for highest solubilization and solid reduction of the SSO were 220°C and 10 minutes retention time, however, for highest methane production, it was 190°C for 20 minutes. In case of TWAS, the result revealed that the maximum biomethane production was achieved at pretreatment conditions of 160°C and 20 min, while, the highest solubilization and solid reduction was observed in 220°C and 10 minutes retention time.

Minimizing of foaming in digesters by pre-treatment of the surplus-sludge

2000 ◽  
Vol 42 (9) ◽  
pp. 235-241 ◽  
Author(s):  
M. Barjenbruch ◽  
H. Hoffmann ◽  
O. Kopplow ◽  
J. Tränckner
Keyword(s):  
High Pressure ◽  
Activated Sludge ◽  
Treatment Methods ◽  
Foaming Agents ◽  
Instance Reduction ◽  
Filamentous Microorganisms ◽  
Hydrophobic Substances ◽  
Pre Treatment ◽  
Heating Up ◽  
The Impact

Several reasons can lead to the emergence of foam in digesting tanks, for instance overloading or the impact of hydrophobic substances. Furthermore, the foaming is in regular periods going together with the emergence of filamentous microorganisms. Up to now, several strategies to avoid foaming have been tested out (for instance reduction of the sludge load in the activated sludge stage, lowering of the sludge level in the digestion tank, dosage of anti foaming agents), but these have been done relatively unsystematically and with more or less success. For our contribution, laboratory-scale digestion tests were run to analyse mechanical and thermal pre-treatment methods for the destruction of the surplus sludge. Whereas the disintegration by a high pressure homogeniser did only achieve a low reduction of the foam phase, the thermal pre-treatment at 121°C made for an effective subduing of the foam emergence. Both methods allowed for a cutting up of the filaments, but only the heating up effected the reduction of the hydrophobic substances; thus, the foaming is possibly caused by them.

scholarly journals Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

2018 ◽  
Vol 78 (8) ◽  
pp. 1772-1781 ◽  
Author(s):  
Hyungjun (Brian) Jo ◽  
Wayne Parker ◽  
Peiman Kianmehr
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Waste Activated Sludge ◽  
Thermal Pretreatment ◽  
Decay Products ◽  
Anaerobic Biodegradability ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Aerobic And Anaerobic

Abstract A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.

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