Enhancement of biogas production from anaerobic digestion of waste activated sludge by hydrothermal pre-treatment

2015 ◽  
Vol 101 ◽  
pp. 42-46 ◽  
Author(s):  
Daegi Kim ◽  
Kwanyong Lee ◽  
Ki Young Park
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Biogas Production ◽  
Waste Activated Sludge ◽  
Pre Treatment

scholarly journals Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

2014 ◽  
Vol 40 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Jan Suschka ◽  
Klaudiusz Grübel
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Biogas Production ◽  
Sewage Treatment ◽  
Anaerobic Treatment ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Sludge Pretreatment ◽  
Negative Side Effects ◽  
Pre Treatment

Abstract Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

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).

scholarly journals Low intensity surplus activated sludge pretreatment before anaerobic digestion

2017 ◽  
Vol 43 (4) ◽  
pp. 50-57 ◽  
Author(s):  
Jan Suschka ◽  
Klaudiusz Grübel
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Additional Energy ◽  
Low Intensity ◽  
Treatment Processes ◽  
Sludge Disposal ◽  
Mass Minimization ◽  
Pre Treatment

AbstractSewage sludge (municipal, or industrial) treatment is still a problem in so far that it is not satisfactorily resolved in terms of cost and final disposal. Two common forms of sludge disposal are possible; the first being direct disposal on land (including agriculture) and the second being incineration (ash production), although neither of these methods are universally applied. Simplifying the issue, direct sludge disposal on land is seldom applied for sanitary and environmental reasons, while incineration is not popular for financial (high costs) reasons. Very often medium and large wastewater treatment plants apply anaerobic digestion for sludge hygiene principles, reducing the amount to be disposed and for biogas (energy) production. With the progress in sewage biological treatment aiming at nutrient removal, primary sludge has been omitted in the working processes and only surplus activated sludge requires handling. Anaerobic digestion of waste activated sludge (WAS) is more difficult due to the presence of microorganisms, the decomposition of which requires a relatively long time for hydrolysis. In order to upgrade the hydrolysis effects, several different pre-treatment processes have already been developed and introduced. The additional pre-treatment processes applied are aimed at residual sludge bulk mass minimization, shortening of the anaerobic digestion process or higher biogas production, and therefore require additional energy. The water-energy-waste Nexus (treads of) of the benefits and operational difficulties, including energy costs are discussed in this paper. The intensity of pre-treatment processes to upgrade the microorganism’s hydrolysis has crucial implications. Here a low intensity pre-treatment process, alkalisation and hydrodynamic disintegration - hybrid process - were presented in order to achieve sufficient effects of WAS anaerobic digestion. A sludge digestion efficiency increase expressed as 45% biogas additional production and 52% of the total or volatile solids reduction has been confirmed.

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