Thermal Hydrolysis of a Sludge Prior to Anaerobic Digestion

Barnard, James; Coleman, Pat; Weston, Phil

doi:10.2175/193864702785301952

Cited by 8 publications

(5 citation statements)

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“…Previous studies on other types of pretreatment techniques such as, thermal treatment, mechanical treatment and ultrasound, indicated that temperature ( Wang et al 1999 ; Barnard et al, 2002 ) and intensity of the pretreatment method ( Tiehm et al, 2001 ; Muller et al, 2003 ), sludge concentration, and percentage of sludge pretreated ( Barber, 2002 ) affect efficiency of the pretreatment. Therefore, in this project, the effects of these variables were investigated on:…”

Section: Experimental Designmentioning

confidence: 99%

“…Thermal disintegration methods with high temperatures (160‐170 °C) and pressures (600‐800 kPa) appear to be superior to other methods with a surplus energy gain due to higher biogas production compared to control reactors. Because of the high temperatures reached during pretreatment, pathogen removal efficiency was also higher ( Barnard et al, 2002 ; Abraham and Kepp, 2003 ).…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of Batch Waste Activated Sludge Digestion by Microwave Pretreatment

Eskicioğlu¹,

Kennedy²,

Droste³

2007

Water Environment Research

100

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Batch anaerobic digesters were used to stabilize microwave (MW)-irradiated waste activated sludge (WAS). A low temperature range (50-96 8C) MW irradiation was applied. Effects of pretreatment temperature (T) and intensity (I), concentration (C) and percentage of sludge pretreated (PT) were investigated in a multilevel factorial statistical design containing 54 mesophilic batch reactors by monitoring cumulative biogas production (CBP). Variance analysis (ANOVA) determined that the most important factors affecting WAS solubilization were temperature, intensity, and sludge concentration. Improvements in CBP from WAS were significantly affected by sludge percentage pretreated, temperature, and concentration. Pretreatment resulted in 3.6 6 0.6 and 3.2 6 0.1 fold increases in soluble to total chemical oxygen demand (SCOD/TCOD) at high and low sludge concentrations, respectively. WAS, microwaved to 96 8C, produced the greatest improvement in CBP with 15 6 0.5 and 20 6 0.3% increases over controls after 19 d of digestion at low and high WAS concentrations. Dewaterability of microwaved sludge was enhanced after anaerobic digestion. Water Environ. Res., 79, 2304Res., 79, (2007.

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Section: Experimental Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhancement of Batch Waste Activated Sludge Digestion by Microwave Pretreatment

Eskicioğlu¹,

Kennedy²,

Droste³

2007

Water Environment Research

100

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“…Pretreatment technologies have included physical (Cartmell et al, 2004), chemical (Chiu et al, 1997) and thermal (i.e. thermal hydrolysis) (Barnard et al, 2002;Park et al, 2004) processes. The thermal hydrolysis (TH) technology promises increased volatile solids destruction, reduced residence times for digestion, increased biogas generation and the generation of USEPA Class A biosolids as a final product.…”

Section: Introductionmentioning

confidence: 99%

Integrated Simulation of Wastewater Treatment, Sludge Pre- Treatment and Anaerobic Digestion

Parker¹,

Jones²,

Takács³

et al. 2009

proc water environ fed

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Combined lab testing and model application was conducted to develop an approach to model TH pretreatment of sludges prior to anaerobic digestion. Anaerobic degradability of a variety of raw and thermal hydrolysis pretreated sludges were evaluated in batch digestion tests. The batch test provides an effective approach to evaluate the stoichiometric conversion of constituents thus providing a good understanding of the extent of digestion, especially if the influent and effluent constituents are properly measured. The raw sludge characteristics were estimated by simulation of the full scale wastewater treatment plant and then employed as input parameters for simulation of the batch digestion tests. In this batch digestion simulation study, TH-treatment did not appear to enhance the ultimate digestibility of the sludges tested. The existing model was capable of simulating the observed overall COD removal and CH 4 generation responses of both the raw and TH-treated sludges. Hence, TH treatment did not appear to convert any non-biodegradable COD fractions to biodegradable fractions. However, examination of the simulated fractions suggested that the particular characteristics of the sludges tested in this study were the reason for the negligible increase in biodegradability for the TH-treated samples. This result reinforces the need to consider the characteristics of the sludge source when assessing biosolids treatment. The use of modeling is essential in this regard. Soluble COD concentrations for raw sludge digestions were adequately simulated with the existing model. Simulated residual soluble COD concentrations for TH-treated sludges were consistently less than the observed values, thus suggesting that TH-treatment of sludges formed non-biodegradable soluble COD.

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“…Hence, there is interest in options for pretreatment of solids to improve digestibility as well as improving and optimizing the digestion process. Pretreatment technologies have included physical (Cartmell et al, 2004), chemical (Chiu et al, 1997) and thermal (Barnard et al, 2002) processes. However, a serious limitation for objectively evaluating optimization and pre-treatment strategies is the lack of knowledge on the properties of primary and waste activated sludges that impact their degradability.…”

Section: Introductionmentioning

confidence: 99%

Characterization of sludges for predicting anaerobic digester performance

Jones

Parker

Khan

et al. 2008

Water Science and Technology

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Batch anaerobic digestion tests of primary sludge and waste activated sludge were conducted for a duration of 123 days to determine the ultimate degradability of the sludges. For primary sludges the inert fraction of the particulate COD that was predicted by the wastewater models could be employed to predict their biodegradability under anaerobic conditions. The degradation of waste activated sludge was adequately characterized for the first 60 days of digestion using a model that assumed equivalent biodegradability of particulate COD components under aerobic and anaerobic conditions. However after 60 days of anaerobic digestion it appeared that decay of the endogenous products was occurring. This could be described with a first order decay function with a coefficient of 0.0075 d -1. For continuous flow digesters operating at SRTs of 30-60 days, the predicted VSS destruction with the modified model was approximately 10% higher than that predicted on the basis of inert endogenous decay products.

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Thermal Hydrolysis of a Sludge Prior to Anaerobic Digestion

Cited by 8 publications

References 0 publications

Enhancement of Batch Waste Activated Sludge Digestion by Microwave Pretreatment

Enhancement of Batch Waste Activated Sludge Digestion by Microwave Pretreatment

Integrated Simulation of Wastewater Treatment, Sludge Pre- Treatment and Anaerobic Digestion

Characterization of sludges for predicting anaerobic digester performance

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