ANAEROBIC DIGESTION OF SLUDGE IN WASTEWATER TREATMENT PLANT FOR ENERGY RECOVERY – A CASE STUDY OF HANOI URBAN DISTRICT

In a wastewater treatment plant (WWTP) energy optimization is a big concern whilst sludge stabilization and energy recovery by anaerobic digestion implementation has recently gained importance. The calculation of an urban district level (selected as Long Bien) with 352,000 populations showed that with a total energy required of 39,750 kWh per day in WWTP, it could be supplied by utilization of biogas production, varying from 0% to ~ 43.44 % depending upon the non-application or application of anaerobic digestion for sludge treatment. In mesophylic anaerobic digestion, the biogas yields production of the calculated WWTP was obtained at 3,710 m3/day; equal to 8,394 kWh power and 13,919 kWh heat per day. As a conventional treatment process, centrifugal dewatering of sludge required an additional energy of 1,376 kWh per day for recycling, pumping, mixing as well as transporting sludge. The conclusion was that anaerobic digestion can reduce the green-house gases versus conventional dewatering. The results from this research can thus demonstrate the applicability of anaerobic digestion on conversion of waste to energy, looking forward to resource recovery.

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Measurement of Energy Production from Biogas: Evidence from the Wastewater Treatment Plant in Durres

European Journal of Engineering Research and Science ◽

10.24018/ejers.2020.5.10.2197 ◽

2020 ◽

Vol 5 (10) ◽

pp. 1260-1262

Author(s):

Stela Sefa ◽

Tania Floqi ◽

Julian Sefa

Keyword(s):

Energy Efficiency ◽

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Energy Production ◽

Biogas Production ◽

Treatment Plant ◽

Electricity Consumption ◽

Waste To Energy ◽

Energy Requirements ◽

Daily Consumption

The wastewater treatment plant serving the city of Durres, which is the second most populous city of Albania, employs the tertiary advanced wastewater treatment method and engages in biogas production to achieve energy efficiency. In order to empirically evaluate the plant’s energy efficiency realization, the total biogas produced and converted to electricity for daily consumption was measured during a three years period (2016 - 2018). The highest electricity produced was recorded in 2016, with a daily average of 844kWh compared to 550kWh and 370kWh in 2017 and 2018, respectively. So that the plant meets proper criteria to classify as an energy-efficient entity, 30.0 percent of its electricity consumption must be derived from biogas. Converted in kWh, the plant should generate 2,975 kWh/day. Based on the biomass and energy values measured during the study period, it is concluded that electricity supplied from biogas met 6.0 percent of the plant’s energy requirements, or one fifth of the energy-efficiency target. While the plant was successful in carrying out the full waste-to-energy production process, the electricity supplied from biogas was very low and did not fulfil the plant’s self-energy requirements.

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

Water Science & Technology ◽

10.2166/wst.2012.317 ◽

2012 ◽

Vol 66 (6) ◽

pp. 1277-1281 ◽

Cited By ~ 38

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.

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

European Journal of Engineering and Technology Research ◽

10.24018/ejers.2021.6.4.2474 ◽

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.

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Application of ultrasonic disintegration to waste activated sludge for increasing of biogas production by anaerobic digestion

Romanian Journal of Ecology & Environmental Chemistry ◽

10.21698/rjeec.2020.202 ◽

2020 ◽

Vol 2 (2) ◽

pp. 17-21

Author(s):

Ion Viorel Patroescu ◽

Razvan Laurentiu Dinu ◽

Mihai Stefanescu ◽

Valeriu Robert Badescu ◽

Nicolae Ionut Cristea ◽

...

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Municipal Wastewater ◽

Biogas Production ◽

Treatment Plant ◽

Experimental Tests ◽

Organic Load ◽

Municipal Wastewater Treatment ◽

Biological Sludge ◽

Sludge Stabilization

The municipal wastewater treatment is the source of significant amounts of primary and secondary sludge which is under the present legislation referring to quality and management aspects. It is estimated that a half of wastewater treatment plant costs are due to the sludge management. Anaerobically sludge stabilization, capitalization as energy source, in order to diminish the costs and sludge volume decreasing, are the aims of the main operational steps of sludge treatment, as a part of wastewater treatment plant. The improvement of sludge anaerobically stabilization process must be possible by acting in the rate limiting step - hydrolysis in order to rise the organic carbon solubilization. The increase of soluble carbon can be possible by adding a pretreatment step of waste biological sludge, ultrasonic disintegration being one option. This paper emphasized the experimental results regarding anaerobically stabilization of the thickened waste biological sludge by ultrasonication taking into account the results of blank test, without ultrasonication. Experimental tests show that ultrasonic disintegration of the sludge having initial dried substances content (d.w) 2.72% and soluble organic load COD of 598 mg O2/L led to soluble COD concentration of 4950-6710 mg O2/L after sonication with specific energy in the range of 3.06 - 14.24 kWh/kg d.w. Anaerobically stabilization during 25 test days at 36 0C of the mixture 40% disintegrated biological sludge and 60% digested sludge (inoculum) mixture led to 30-38.6% increase of biogas production comparing with parallel test with non-sonicated sludge.

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Energy saving in wastewater treatment plants

E3S Web of Conferences ◽

10.1051/e3sconf/202021201003 ◽

2020 ◽

Vol 212 ◽

pp. 01003

Author(s):

Natalia Ciobanu

Keyword(s):

Wastewater Treatment ◽

Anaerobic Digestion ◽

Wastewater Treatment Plant ◽

Energy Recovery ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Electricity Consumption ◽

Electricity Cost ◽

Starting Point ◽

Sludge Cake

This paper uses data from the Chisinau Wastewater Treatment Plant (WWTP) (2018 year) to analyze the potential for energy recovery from wastewater treatment plant via anaerobic digestion with biogas utilization with electricity generation. These energy recovery strategies could help offset the electricity consumption of the wastewater treatment plants and represent possible areas for sustainable energy policy implementation. We estimate that anaerobic digestion could save approximately 14, 444, 918 kWh annually in Chisinau WWTP. Anaerobic digestion is widely considered as an environmentally friendly technology for sewerage sludge. This study aims to highlight the potential as well as to provide a starting point for further studies regarding the treatment as sewerage sludge using anaerobic digestion in Republic of Moldova and recovery energy that could further reduce electricity cost and reduction of sludge cake.

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