scholarly journals Thermal hydrolysis pre-treatment to enhance anaerobic digestion of waste activated sludge. optimization of operating conditions and evaluation of alternative schemes

2017 ◽  
Author(s):  
Leva Sapkaite
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Operating Conditions ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Pre Treatment

Anaerobic digestion of waste activated sludge combined with ozone post-treatment and recycling

2003 ◽  
Vol 48 (4) ◽  
pp. 61-68 ◽  
Author(s):  
A. Battimelli ◽  
C. Millet ◽  
J.P. Delgenès ◽  
R. Moletta
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cod Removal ◽  
Process Efficiency ◽  
Recycling Rate ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Combined Process

The aim of the study was to determine the performances of a combined ozone/anaerobic digestion system for waste activated sludge reduction. The objective was the estimation of the process efficiency and stability when keeping constant influent flow while increasing recycled chemically treated flow. The ozonation step consisted in a partial oxidation (0.16 g O3/g SS) of the anaerobic mesophilic digested sludge. Chemical treatment of digested sludge resulted in a threefold COD solubilization and a decrease of SS of 22%. Some of the advantages of digested sludge ozonation were: deodorization, better settlement and a reduction in viscosity. However there were drawbacks: foaming during ozonation and, at high ozone doses, poorer filterability. The anaerobic digestion was carried out over 6 months with an increasing recycling of ozonated flow. Suspended solids removal rate and COD removal rate were compared with initial operating conditions for the biological reactor and the whole combined process. The optimum recycling rate was 25% with increases of SS removal and COD removal of 54% and 66% respectively when considering the combined process; corresponding to a decrease of the hydraulic retention time from 24 days to 19 days.

Influence on anaerobic digestion by intermediate thermal hydrolysis of waste activated sludge and co-digested wheat straw

2018 ◽  
Vol 72 ◽  
pp. 186-192 ◽  
Author(s):  
Michael Bjerg-Nielsen ◽  
Alastair James Ward ◽  
Henrik Bjarne Møller ◽  
Lars Ditlev Mørck Ottosen
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Wheat Straw ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Hydrolysis Of

scholarly journals Effect Of Hydrothermal Pre-Treatment On Methane Production During Anaerobic Digestion Of Thickened Waste Activated Sludge

2021 ◽  
Author(s):  
Suleman Khan
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Anthropogenic Sources ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Optimum Conditions ◽  
Solid Retention Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Pre Treatment

The effects of hydrothermal pre-treatment on the production of methane and biogas on thickened waste activated sludge was investigated. This paper reviews the anaerobic digestion process and its complexities, provides an overview of the different stages of the anaerobic digestion process, different kinds of feedstocks and the essential and influential operating parameters such as temperature, pH, organic loading rate, solid retention time and particle size. This paper also demonstrates an overview of the natural and anthropogenic sources contributing to methane in the atmosphere. It further provides a recommendation on essential practices and methods required to enhance methane capture in the atmosphere. Furthermore, an experimental setup consisting of batch anaerobic digestion was employed for the sample analysis the purpose of this experimental research was to conduct a comprehensive assessment of the effect of the hydrothermal pre-treatment on thickened waste activated sludge and to determine the most optimum conditions to produce methane. Keywords: Anaerobic digestion, Thickened waste-activated sludge, Hydrothermal Pre-treatment

scholarly journals Effect of Thermal Pretreatment on the Solubilization of Organic Matters in a Mixture of Primary and Waste Activated Sludge

2015 ◽  
Vol 10 (2) ◽  
Keyword(s):  
Activation Energy ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Rate Constant ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Waste Activated Sludge ◽  
Pre Treatment ◽  
Reaction Activation Energy

The increased demand for advanced techniques in anaerobic digestion over the last few years has led to the employment of various pre-treatment methods prior to anaerobic digestion to increase gas production. These pre-treatment methods alter the physical and chemical properties of sludge in order to make it more readily degradable by anaerobic digestion. Although the thermal pre-treatment presents high energy consumption, the main part of this energy to heat can be recovered from the biogas produced in the anaerobic process. In this research a mixture of primary and waste activated sludge was thermally pretreated at 100, 125, 150, 175 and 200 oC in order to determine the reaction kinetics for the increase of soluble organic fraction (expressed as CODs and VFAs). Experimental results proved that the solubilization of sludge is a 1st order reaction with respect to both CODs and VFAs, KCODs (reaction rate constant of CODs solubilization) increased from 4.59*10-3 (min-1) to 7.55*10-3 (min-1) as the temperature increased from 100 to 200 oC, with a reaction activation energy of 7447.21 (J/mole) and frequency factor of 0.051 (min-1), While KVFAs (reaction rate constant of VFAs solubilization) increased from 5.33*10-3 (min-1) to 7.97*10-3 (min-1) for the same increase in temperature, with a reaction activation energy of 5947.22 (J/mole) and frequency factor of 0.0364 (min-1).

Prediction of thermal hydrolysis pretreatment on anaerobic digestion of waste activated sludge

2008 ◽  
Vol 58 (7) ◽  
pp. 1467-1473 ◽  
Author(s):  
P. Phothilangka ◽  
M. A. Schoen ◽  
M. Huber ◽  
P. Luchetta ◽  
T. Winkler ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Cell Mass ◽  
Waste Activated Sludge ◽  
Sufficient Information ◽  
Thermal Hydrolysis ◽  
Systematic Analysis ◽  
Complete Degradation ◽  
Ammonia Release ◽  
Decay Products

Thermal hydrolysis is known for an efficient sludge disintegration capability to enhance biogas potential—but to which extent? Obviously, residual VSS concentration in digested sludge gives not sufficient information to predict additional biogas potential. In this paper, different types of waste activated sludge (WAS) were pre-hydrolysed by a full-scale Thermo-Pressure-Hydrolysis Process (Thermo-Druck-Hydrolyse, TDH) and break-down mechanisms on specific organic compounds were investigated. The IWA Anaerobic Digestion Model No.1 (ADM1) has been used for a systematic analysis of monitoring data gained from experimental work. The TDH process combined with anaerobic digestion can be well described by a modified ADM1 model that includes an XP-fraction (inactivated aerobic biomass and their decay products). More rapid and more complete degradation of TDH-treated sludge is represented by calibrated disintegration rate and disintegration factors, while biokinetic parameters of acetogenesis and methanogenesis show no sensitivity. TDH process impacts mainly biomass and decay products while inerts Xi already contained in the raw wastewater are hardly converted. Final concentration of soluble inerts in digestion effluent has been increased from 2% to 9% of influent COD due to thermal hydrolysis. An increase in biogas generation (ca. +80%) and in ammonia release (ca. +75%) can be explained by complete degradation of cell mass.

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