Benefits and drawbacks of thermal pre-hydrolysis for operational performance of wastewater treatment plants

Phothilangka, P.; Schoen, M. A.; Wett, Bernhard

doi:10.2166/wst.2008.500

Cited by 44 publications

(27 citation statements)

References 9 publications

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“…Producing Class A biosolids, as defined by the USEPA, provides more diverse disposal options (USEPA, 1999). Several studies have shown that the increase in biogas production could be sufficient to preheat the WAS and heat the anaerobic digesters (Bougrier et al, 2007;Phothilangka et al, 2008;Gurieff et al, 2011). The high temperatures are typically applied by heat exchangers or steam injection (Climent et al, 2007).…”

Section: Objectivesmentioning

confidence: 99%

“…Therefore a change in the measured concentration of non-biodegradable particulate COD could be due to a change in the concentration of X i or Z e or both. Phothilangka et al (2008) considered the transformation of Z e to bCOD but did not consider the transformation of X i to bCOD. Ramdani et al (2010) have shown that the COD fractionation of activated sludge is substantially simplified when the system is fed with a synthetic soluble biodegradable substrate such as acetate.…”

Section: Existing Pretreatment Modelsmentioning

confidence: 99%

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Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Burger¹,

Parker²

2013

proc water environ fed

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Waste activated sludge (WAS) pretreatment technologies are typically evaluated in terms of the associated improvement in biogas and sludge production during digestion and post-digestion dewaterability. However, WAS properties, and hence the impact of pretreatment on WAS properties, are dependent upon the raw wastewater composition and configuration of the wastewater treatment plant (WWTP). A generally accepted means of characterizing and comparing all pretreatment processes does not exist. The motivation for this project was to evaluate the impact of pretreatment on WAS properties in terms of changes in COD fractionation. The first objective of this study was to fractionate the COD of the WAS before and after pretreatment to show how pretreatment may increase the rate and extent of aerobic digestion. The second objective was to develop a COD-based stoichiometric pretreatment model that may be integrated into WWTP simulations.A bench-scale biological reactor (BR) with a solids retention time (SRT) of 5 days was started up with WAS from the Waterloo WWTP. The BR was fed daily with a completely biodegradable synthetic substrate so that the BR WAS contained only biomass and decay products after 3 SRTs of operation. In the first phase of the study, an aerobic digester (AD) with a SRT of 10 d was fed daily with BR WAS. The BR-AD system was operated at steady state for one month. A range of physical and biochemical properties were regularly measured in each process stream. Offline respirometric tests were regularly conducted to determine the aerobic degradability and fractionate the COD of the BR and AD WAS. The oxygen uptake rate (OUR) associated with the daily addition of BR WAS to the AD was determined as an additional measurement of the aerobic degradability of the BR WAS.In the second phase of the study, the BR WAS was pretreated prior to being fed daily to the AD.High pressure thermal hydrolysis (HPTH) pretreatment was selected for this project since it is one of the most popular and promising pretreatment techniques. A sealed volume of BR WAS was heated to 150 o C at 3 bars for 30 minutes. The same physical, biochemical and biological tests used to characterize the process streams in Phase 1 were employed to characterize those in Phase 2. The Phase 2 system was operated for two months at steady-state.The results of several independent tests showed that the COD of the BR WAS was comprised of storage products (X STO ) in addition to active heterotrophs (Z bh ) and decay products (Z e ). However, it was shown that the AD WAS only contained Z bh and Z e as X STO was depleted in the AD. iv HPTH pretreatment did not reduce the TCOD concentration of the WAS however it did solubilize 56 ± 7% of COD, 49% ± 11% of organic nitrogen, 56 ± 10% of VSS and did not solubilize ISS.Furthermore, pretreatment did not generate soluble non-biodegradable COD. These findings were consistent with prior research on HPTH WAS pretreatment. Pretreatment increased the rate at which the BR WAS was aerobically degraded. The offline res...

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Section: Objectivesmentioning

confidence: 99%

Section: Existing Pretreatment Modelsmentioning

confidence: 99%

Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Burger¹,

Parker²

2013

proc water environ fed

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“…Research shows that thermal hydrolysis increases biogas production by 75-80% and enzymic hydrolysis by 30% compared to AD [15]. A study into thermal hydrolysis showed an increase in biogas production by 155% [16].…”

Section: Adoption Of Advanced Anaerobic Digestionmentioning

confidence: 99%

Insights and Issues in the Uptake and Development of Advanced Anaerobic Digestion Within the Uk Water Industry

Gooding¹,

Booth²

2017

WIT Transactions on Ecology and the Environment

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This study explores the uptake and growth of Advanced Anaerobic Digestion (AAD) within the UK water industry to reveal the drivers and challenges the water companies are facing towards aiding the UK Government to reach its renewable energy targets. AAD was developed to replace anaerobic digestion (AD) and increase cleaner biogas production and to decrease sludge volume and widen the application of bio-solids as fertilisers so that they can be used on all crops, therefore hugely decreasing waste sent to landfill. A mixed-methods approach of surveys and semi-structured interviews was targeted at the energy managers of each of the UKs water companies. Results reveal that industry professionals consider that AAD plays a key role within the water industry and significantly contributes to government targets regarding renewable energy production. The findings attest that government incentives do not promote future investment in AAD plants and water companies are investing for operational benefits. The current incentives advocate combining food and sewage waste in the construction of new food digestions plants, which is not only very costly, but also the construction of these plants has a large environmental impact, when existing systems could be utilised. The work highlights the main implications of investing into AAD and how the government incentives hindered the uptake from the water industry, therefore meaning a waste of potential energy that could have been harvested, which would have contributed to meeting the government targets.

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“…The project is estimated to save US$20 million/year from the energy it produces, diversion of biosolids for use in agriculture rather than disposal, and avoidance of the use of lime (Brown andCaldwell 2010, Menco 2012). One study suggests that the thermo--pressure--hydrolysis process has the potential to reduce biosolids disposal costs by 25% (Phothilangka, Schoen and Wett, 2008).…”

Section: Cost (And/or Payback Time)mentioning

confidence: 99%

A Review of Commercially Available Technologies in Developing Low Carbon Eco-cities

Zhou¹,

He²,

Romankiewicz³

et al. 2015

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Benefits and drawbacks of thermal pre-hydrolysis for operational performance of wastewater treatment plants

Cited by 44 publications

References 9 publications

Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Investigation of the Impacts of Thermal Activated Sludge Pretreatment and Development of a Pretreatment Model

Insights and Issues in the Uptake and Development of Advanced Anaerobic Digestion Within the Uk Water Industry

A Review of Commercially Available Technologies in Developing Low Carbon Eco-cities

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