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 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

Mesophilic and Thermophilic Digestion of Thickened Waste Activated Sludge: A Comparative Study

2010 ◽  
Vol 113-116 ◽  
pp. 450-458 ◽  
Author(s):  
Yong Zhi Chi ◽  
Yu You Li ◽  
Min Ji ◽  
Hong Qiang ◽  
Heng Wei Deng ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Methane Content ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Significant Difference

This paper presents an experimental study over 204 days on anaerobic degradation of thickened waste activated sludge (TWAS) from a municipal wastewater treatment plant (WWTP). The experiments were conducted under thermophilic (55°C) and mesophilic (35°C) condition, respectively, by using the semi-continuous flow completely mixed reactors. The influent total solids (TS), hydraulic retention time (HRT) and chemical oxygen demand (COD) loading levels were around 4%, 30 days and 1.67 kg-CODCr•m-3•d-1 , respectively. During the opration period, the thermophilic anaerobic digestion process (TADP) and the mesophilic anaerobic digestion process (MADP) were stable and well-functioned without ammonia inhibition. Particulate organic matters reduction of TADP was superior to that of MADP. This result implies that TADP has higher sludge reduction efficiency than MADP. According to the simulated chemical formula of TWAS, C5.85H9.75O3.96N, and the stoichiometric equation, the methane content and the ammonia yield in the anaerobic process could be calculated, which were consistent with the experimental results. The methane yield of TADP was a little higher than that of MADP. The statistical mean values of methane content for TADP and MADP were 60.97% and 62.38%, respectively.According to paired t-test, there was a significant difference in methane content between TADP and MADP(α=0.01, n=62). Compared with the mesophilic digested sludge, the dewaterability of thermophilic digested sludge was lower.

scholarly journals The synergy of combined free nitrous acid and Fenton technology in enhancing anaerobic digestion of real sewage waste activated sludge

2019 ◽  
Author(s):  
Razieh Karimi ◽  
Seyed Mostafa Hallaji
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Methane Production ◽  
Nitrous Acid ◽  
Waste Activated Sludge ◽  
Free Nitrous Acid ◽  
Digestion Process ◽  
Treatment Technologies ◽  
Pre Treatment

Abstract Background Recently, free nitrous acid (FNA) pre-treatment of sewage waste activated sludge has been introduced as an economically attractive and environmentally friendly technique for enhancing methane production from the anaerobic digestion process. Fenton pre-treatment of sewage sludge, as an advanced oxidation process, has also been introduced as a powerful technique for methane improvement in a couple of studies. This study, for the first time, investigates the synergy of combined FNA and Fenton pre-treatment technologies in enhancing the methane production from the anaerobic digestion process and reducing waste sludge to be disposed of. Actual secondary waste activated sludge in laboratory-scale batch reactors was used to assess the synergistic effect of the pre-treatments. The mechanisms behind the methane enhancement were also put into perspective by measuring different microbial enzymes activity and solubilisation of organic matter. Result This study revealed that the combined pre-treatments release organic matter into the soluble phase significantly more than the bioreactors pre-treated with individual FNA and Fenton. For understanding the influence of pre-treatments on solubilisation of organic matter, soluble protein, soluble polysaccharide and soluble chemical oxygen demand (SCOD) were measured before and after the treatments and it was shown that they respectively increased by 973%, 33% and 353% after the treatments. Protease and cellulose activity, as the key constituents of the microbial community presenting in activated sludge, decreased considerably within the combined pre-treatments (42% and 32% respectively) and methane production enhanced by 43-69%. Furthermore, total solids and volatile solids destruction improved by 26% and 24% at the end of anaerobic digestion, which can reduce transport costs of sludge and improve the quality of sludge for application in farms and forests. Conclusions The results obtained from the experiments corroborate the synergic effect of the combined FNA and Fenton pre-treatment technologies in degrading the organic and microbial constituents in waste activated sludge, which improved methane production accordingly. This is of paramount importance because the total costs of wastewater treatment plants operation and greenhouse gas emission from sludge treatment and disposal processes would reduce considerably, which pave the way for the implementation of these technologies.

scholarly journals Anaerobic mesophilic digestion of sludge with extra-thermophilic and high ph pre-treatment

2019 ◽  
pp. 451-463 ◽  
Author(s):  
Anne Menert ◽  
Ergo Rikmann ◽  
Merje Michelis ◽  
Tarmo Vaalu ◽  
Viktoria Blonskaja ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Elevated Temperatures ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Cumulative Volume ◽  
Mesophilic Digestion ◽  
Naoh Treatment ◽  
Pre Treatment

In this study different methods of sludge pre-treatment with elevated temperatures andpH have been selected for investigation. Five sets of sludge samples were pretreated asfollows: heating at 70°C for 30 min, at 80°C for 20 min, at 90°C for 10 min, at 100°C forWWTP5 min and NaOH-treatment (pH 12 for 4 hours). For comparison a sample from Tallinn(3:1 mixture of primary (dry solids 5.2%) and activated sludge (dry solids 0.5%))was used. Extra-thermophilic pre-treatment increased the degree of hydrolyses of sludge,enabling the following anaerobic digestion process to proceed faster than that of rawsludge. However, extra-thermophilic pre-treatment was insufficient for removal ofnitrogen and phosphorous. Nitrogen can be easily solubilized during extra-thermophilicpre-treatment but solubilization of phosphorous occurs only through digestion. Theproduction of biogas during anaerobic digestion was also dependant on the quality of theinput of pre-treated sludge. The highest cumulative volume of biogas (124 mUg CODadded) was achieved by pre-treatment at 80°C. The percentage of mineralization of pretreated sludges on mesophilic digestion was the highest with 90°C sample - 65.9%.

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