Potentials and limits of anaerobic digestion of sewage sludge: Energy self-sufficient municipal wastewater treatment plant?

2012 ◽  
Vol 66 (6) ◽  
pp. 1277-1281 ◽  
Author(s):  
P. Jenicek ◽  
J. Bartacek ◽  
J. Kutil ◽  
J. Zabranska ◽  
M. Dohanyos
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Biogas Production ◽  
Treatment Plant ◽  
Self Sufficiency ◽  
Digestion Efficiency

Anaerobic digestion is the only energy-positive technology widely used in wastewater treatment. Full-scale data prove that the anaerobic digestion of sewage sludge can produce biogas that covers a substantial amount of the energy consumption of a wastewater treatment plant (WWTP). In this paper, we discuss possibilities for improving the digestion efficiency and biogas production from sewage sludge. Typical specific energy consumptions of municipal WWTPs per population equivalent are compared with the potential specific production of biogas to find the required/optimal digestion efficiency. Examples of technological measures to achieve such efficiency are presented. Our findings show that even a municipal WWTP with secondary biological treatment located in a moderate climate can come close to energy self-sufficiency. However, they also show that such self-sufficiency is dependent on: (i) the strict optimization of the total energy consumption of the plant, and (ii) an increase in the specific biogas production from sewage sludge to values around 600 L per kg of supplied volatile solids.

scholarly journals Modelling the bioenergy potential of municipal wastewater treatment plants

2018 ◽  
Vol 77 (11) ◽  
pp. 2613-2623 ◽  
Author(s):  
Kerstin Schopf ◽  
Johannes Judex ◽  
Bernhard Schmid ◽  
Thomas Kienberger
Keyword(s):  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Energy Recovery ◽  
Municipal Wastewater ◽  
Energy Content ◽  
Treatment Plant ◽  
High Energy ◽  
Recovery Efficiency ◽  
Municipal Wastewater Treatment ◽  
Self Sufficiency

Abstract A municipal wastewater treatment plant accounts for a large portion of the total energy consumption of a municipality. Besides their high energy demand, the plants also display a significant bioenergy potential. This is due to the utilisation of the energy content of digester gas and sewage sludge if there exist suitable units. To maximise the energy recovery efficiency of wastewater treatment systems (WWTS), it is important to analyse the amount of digester gas and sludge produced in different types of plants. Therefore, the present paper deals with designing a tool to answer the following research questions: Which bioenergy potentials occur in different plant types? Which mass and energy flows are related to the specific potentials? Which utilisation processes for the potentials can lead to a high energy recovery efficiency of WWTS? Preliminary analyses with the designed tool were focused on estimating the level of electric and thermal energy self-sufficiency of different plant configuration scenarios including or excluding digester gas and/or sludge utilisation units. First results based on the level of self-sufficiency and associated energy and disposal costs show that a digester gas and sewage sludge utilisation should be considered when designing future WWTS.

scholarly journals Data on Biogas Production Quality: Evidence from the Wastewater Treatment Plant of Durrës

2021 ◽  
Vol 6 (4) ◽  
pp. 85-87
Author(s):  
Stela Sefa ◽  
Tania Floqi ◽  
Julian Sefa
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Wastewater Treatment Plant ◽  
Biogas Production ◽  
Treatment Plant ◽  
Production Quality ◽  
Treatment Area ◽  
Biochemical Processes ◽  
Energy Grid

The wastewater treatment plant (WWTPD) located in Durrës, responsible for a treatment area of 205,000 inhabitants, employs the tertiary advanced wasterwater treatment to generate biogas from activated sludge for self use. The biogas collected from the anaerobic digestion tank feed the boiler and the co-generation unit which is then transformed to power its own energy grid. In order to evaluate the quality of biogas produced by anaerobic digestion of WWTPD’s sludge, is measured the percentage of CH4 and CO2 from the biogas production during a three years period (2016 – 2018). From the performed analyses has resulted a percentage of CH4 up to 75% and 25% CO2 in 2016. While the lowest percentage of CH4 in 2018 with respectively 70% CH4 and 30% CO2. Based on the value measurements, qualitative results of biogas parameters show that physicochemical and biochemical processes are performed under strict conditions and anaerobic digestion is performed according to standards.

scholarly journals Influence of Wastewater Treatment and The Method of Sludge Disposal on the Gasification Process

2014 ◽  
Vol 21 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Sebastian Werle ◽  
Mariusz Dudziak
Keyword(s):  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Fixed Bed ◽  
Treatment Plant ◽  
Experimental Investigations ◽  
Heating Value ◽  
Treatment Processes ◽  
Sludge Disposal

Abstract Municipal wastewater treatment results in the production of large quantities of sewage sludge, which requires proper environmentally accepted management before final disposal. Sewage sludge is a by-product of current wastewater treatment technologies. Sewage sludge disposal depends on the sludge treatment methods used in the wastewater treatment plant (anaerobic or aerobic digestion, drying, etc.). Taking into consideration presented given this information, a study concerning the effects of wastewater treatment processes and sewage sludge drying method on the sewage sludge gasification gas parameters was performed. Gasification is a prospective alternative method of sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed bed gasifier installation was designed and built. Two types of sewage sludge feedstock, SS1 and SS2, were analyzed. Sewage sludge SS1 came from a wastewater treatment plant operating in the mechanical and biological system while sewage sludge SS2 was collected in a mechanical, biological and chemical wastewater treatment plant with simultaneous phosphorus precipitation. The sludge produced at the plants was subject to fermentation and then, after being dehydrated, dried in a cylindrical drier on shelves heated up to 260ºC (sewage sludge SS1) and using hot air at a temperature of 150ºC in a belt drier (sewage SS2). The analysis shows that the sewage sludge properties strongly depend on the wastewater sources and the wastewater treatment processes. The gasification results, presented as a function of the amount of gasification agent, show that the greater oxygen content of SS1 caused a reduction in the reaction temperature. Paradoxically, this effect caused an increase in the quantity of combustible components in the gas. As expected, increasing the air flow rate caused a decrease in the heating value of the gas produced. A higher amount of oxidizer increases the amounts of noncombustible species and the volumetric fraction of nitrogen, thus reducing the heating value of the obtained gas. The higher hydrogen content in SS1 affects the gasification gas composition. As a result, combustible components are the majority of the syngas.

Energy self-sufficient sewage wastewater treatment plants: is optimized anaerobic sludge digestion the key?

2013 ◽  
Vol 68 (8) ◽  
pp. 1739-1744 ◽  
Author(s):  
P. Jenicek ◽  
J. Kutil ◽  
O. Benes ◽  
V. Todt ◽  
J. Zabranska ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Standard Energy

The anaerobic digestion of primary and waste activated sludge generates biogas that can be converted into energy to power the operation of a sewage wastewater treatment plant (WWTP). But can the biogas generated by anaerobic sludge digestion ever completely satisfy the electricity requirements of a WWTP with ‘standard’ energy consumption (i.e. industrial pollution not treated, no external organic substrate added)? With this question in mind, we optimized biogas production at Prague's Central Wastewater Treatment Plant in the following ways: enhanced primary sludge separation; thickened waste activated sludge; implemented a lysate centrifuge; increased operational temperature; improved digester mixing. With these optimizations, biogas production increased significantly to 12.5 m3 per population equivalent per year. In turn, this led to an equally significant increase in specific energy production from approximately 15 to 23.5 kWh per population equivalent per year. We compared these full-scale results with those obtained from WWTPs that are already energy self-sufficient, but have exceptionally low energy consumption. Both our results and our analysis suggest that, with the correct optimization of anaerobic digestion technology, even WWTPs with ‘standard’ energy consumption can either attain or come close to attaining energy self-sufficiency.

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