scholarly journals Energy Balance of Turbocharged Engines Operating in a WWTP with Thermal Hydrolysis. Co-Digestion Provides the Full Plant Energy Demand

2021 ◽  
Vol 11 (23) ◽  
pp. 11103
Author(s):  
José García-Cascallana ◽  
Daniela Carrillo-Peña ◽  
Antonio Morán ◽  
Richard Smith ◽  
Xiomar Gómez
Keyword(s):  
Energy Balance ◽  
Energy Demand ◽  
Cheese Whey ◽  
Biogas Production ◽  
Treatment Plant ◽  
Plant Performance ◽  
Electricity Production ◽  
Baseline Scenario ◽  
Thermal Hydrolysis ◽  
Pre Treatment

The energy balance of lean-burn turbocharged engines using biogas as fuel is reported. Digestion data were obtained from the wastewater treatment plant (WWTP) of the city of Burgos (Spain), operating with a thermal hydrolysis unit for sludge pre-treatment. Operational performance of the plant was studied by considering the treatment of sludge as a comparative base for analyzing global plant performance if co-digestion is implemented for increasing biogas production. The calculation methodology was based on equations derived from the engine efficiency parameters provided by the manufacturer. Results from real data engine performance when evaluated in isolation as a unique control volume, reported an electrical efficiency of 38.2% and a thermal efficiency of 49.8% leading to a global efficiency of 88% at the operating point. The gross electrical power generated amounted to 1039 kW, which translates into 9102 MWh/year, with an economic value of 837,384 €/year which was completely consumed at the plant. It also represents 55.1% of self-consumption regarding the total electricity demand of the plant. The analysis of the system considering the use of the total installed capacity by adding a co-substrate, such as cheese whey or microalgae, reveals that total electrical self-consumption is attained when the co-substrate is directly fed into the digester (cheese whey case), obtaining 16,517 MWh/year equivalent to 1,519,160 €/year. The application of thermal hydrolysis as pre-treatment to the co-substrate (microalgae case study) leads to lower electricity production, but still attains a better performance than a mono-digestion baseline scenario.

scholarly journals Energy Valorisation of Wastewater Treatment Plant Sludge through Thermal Gasification: An Economic Perspective

Proceedings ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 3
Author(s):  
Luis F. Carmo-Calado ◽  
Roberta Mota-Panizio ◽  
Gonçalo Lourinho ◽  
Octávio Alves ◽  
I. Gato ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Electricity Production ◽  
Baseline Scenario ◽  
Municipal Wastewater Treatment ◽  
Plant Processing ◽  
Sludge Drying ◽  
Calorific Power

The technical-economic analysis was carried out for the production of sludge-derived fuel from a municipal wastewater treatment plant (WWTP). The baseline for the analysis consists of a sludge drying plant, processing 6 m3 of sludge per day and producing a total of about 1 m3 of combustible material with 8% of moisture and a higher calorific power of 18.702 MJ/kg. The transformation of biofuel into energy translates into an electricity production of about 108 kW per 100 kg of sludge. The project in the baseline scenario demonstrated feasibility with a payback time of about six years.

Ultrasound pre-treatment for anaerobic digestion improvement

2009 ◽  
Vol 60 (6) ◽  
pp. 1525-1532 ◽  
Author(s):  
S. Pérez-Elvira ◽  
M. Fdz-Polanco ◽  
F. I. Plaza ◽  
G. Garralón ◽  
F. Fdz-Polanco
Keyword(s):  
Anaerobic Digestion ◽  
Energy Balance ◽  
Specific Energy ◽  
Biogas Production ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Net Generation ◽  
Batch Reactors ◽  
Anaerobic Reactors ◽  
Pre Treatment

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT = 20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT = 15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR = 20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3–10 kW per kW of energy used.

scholarly journals Feasibility of Coupling Anaerobic Digestion and Hydrothermal Carbonization: Analyzing Thermal Demand

2021 ◽  
Vol 11 (24) ◽  
pp. 11660
Author(s):  
Rubén González ◽  
Marcos Ellacuriaga ◽  
Alby Aguilar-Pesantes ◽  
Daniela Carrillo-Peña ◽  
José García-Cascallana ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Energy Demand ◽  
Biological Process ◽  
Biogas Production ◽  
Hydrothermal Carbonization ◽  
Energy Performance ◽  
High Energy ◽  
Subsequent Treatment ◽  
Treatment Unit ◽  
Pre Treatment

Anaerobic digestion is a biological process with wide application for the treatment of high organic-containing streams. The production of biogas and the lack of oxygen requirements are the main energetic advantages of this process. However, the digested stream may not readily find a final disposal outlet under certain circumstances. The present manuscript analyzed the feasibility of valorizing digestate by the hydrothermal carbonization (HTC) process. A hypothetical plant treating cattle manure and cheese whey as co-substrate (25% v/w, wet weight) was studied. The global performance was evaluated using available data reported in the literature. The best configuration was digestion as a first stage with the subsequent treatment of digestate in an HTC unit. The treatment of manure as sole substrate reported a value of 752 m3/d of biogas which could be increased to 1076 m3/d (43% increase) when coupling an HTC unit for digestate post-treatment and the introduction of the co-substrate. However, the high energy demand of the combined configurations indicated, as the best alternative, the valorization of just a fraction (15%) of digestate to provide the benefits of enhancing biogas production. This configuration presented a much better energy performance than the thermal hydrolysis pre-treatment of manure. The increase in biogas production does not compensate for the high energy demand of the pre-treatment unit. However, several technical factors still need further research to make this alternative a reality, as it is the handling and pumping of high solid slurries that significantly affects the energy demand of the thermal treatment units and the possible toxicity of hydrochar when used in a biological process.

scholarly journals ‘Hot topic’ – combined energy and process modeling in thermal hydrolysis systems

2019 ◽  
Vol 79 (1) ◽  
pp. 84-92 ◽  
Author(s):  
Peter Aichinger ◽  
Christine DeBarbadillo ◽  
Ahmed Al-Omari ◽  
Bernhard Wett
Keyword(s):  
Process Model ◽  
Biogas Production ◽  
Electricity Production ◽  
Thermal Hydrolysis ◽  
Dynamic Effects ◽  
Operational Conditions ◽  
Hydrolysis Process ◽  
Production And Consumption ◽  
Large Heat ◽  
Steam Production

Abstract The thermal hydrolysis process (THP) is applied to enhance biogas production in anaerobic digestion (AD), reduce viscosity for improved mixing and dewatering and to reduce and sterilize cake solids. Large heat demands for steam production rely on dynamic effects like sludge throughput, gas availability and THP process parameters. Here, we propose a combined energy and process model suitable to describe the dynamic behaviour of THP in a full-plant context. The process model addresses interactions of THP with operational conditions covered by the AD model obeying mass continuity. Energy conservation is considered in balancing and converting various energy species dominated by thermal heat and calorific energy. The combined energy and process model was then applied on the THP at Blue Plains advanced WWTP (DC Water) to analyse the process and assess potential energy optimizations. It was found that dynamic effects like mismatched steam production and consumption, temporary gas shortages and underloaded units are responsible for energy inefficiencies with losses in electricity-production up to 29%.

Improvement of anaerobic digestion of sludge

2004 ◽  
Vol 49 (10) ◽  
pp. 89-96 ◽  
Author(s):  
M. Dohányos ◽  
J. Zábranská ◽  
J. Kutil ◽  
P. Jeníček
Keyword(s):  
Particulate Matter ◽  
Anaerobic Digestion ◽  
Energy Balance ◽  
Activated Sludge ◽  
High Resistance ◽  
Biogas Production ◽  
Treatment Plant ◽  
Process Conditions ◽  
Digested Sludge ◽  
Acceptable Method

Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of the process conditions, pretreatment of input sludge and increase of process temperature is frequently used. The thermophilic process brings a higher solids reduction and biogas production, a high resistance to foaming, no problems with odour, better pathogens destruction and an improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in a lysate centrifuge was proved to cause increase of biogas production in full-scale conditions. The rapid thermal conditioning of digested sludge is an acceptable method of particulate matter disintegration and solubilization.

Biogas from energy crops—optimal pre-treatments and storage, co-digestion and energy balance in boreal conditions

2008 ◽  
Vol 58 (9) ◽  
pp. 1857-1863 ◽  
Author(s):  
M. Seppälä ◽  
T. Paavola ◽  
A. Lehtomäki ◽  
O. Pakarinen ◽  
J. Rintala
Keyword(s):  
Energy Balance ◽  
Sugar Beet ◽  
Biogas Production ◽  
Energy Crops ◽  
Ambient Conditions ◽  
Volatile Solids ◽  
Biogas Plants ◽  
Farm Scale ◽  
Pre Treatment ◽  
And Storage

The objective of this research was to evaluate the biogas production from crops in boreal conditions, focusing on the optimal pre-treatment and storage methods, co-digestion and energy balance of farm-scale crop based biogas plants. Alkaline treatments offered some potential for improving the methane yield from grass and sugar beet tops. The results show that the CH4 yield of energy crops can be maintained by appropriate ensiling conditions for even after 11 months in ambient conditions. The CH4 yield was best preserved with wet grass mixture without additives. Co-digestion of manure and crops was shown to be feasible with feedstock volatile solids (VS) containing up to 40% of crops. The highest specific methane yields of 268, 229 and 213 l CH4 kg−1 VSadded in co-digestion of cow manure with grass, sugar beet tops and straw, respectively, were obtained during feeding with 30% of crop in the feedstock, corresponding to 85–105% of the total methane potential in the substrates as determined by batch assays. The energy output:input ratio of farm-scale grass silage based biogas plant varied significantly (3.5–8.2) with different assumptions and system boundaries being lowest when using only inorganic fertilizers and highest when half of the heat demand of the system could be covered by metabolic heat.

scholarly journals Thermal Hydrolysis of Sewage Sludge: A Case Study of a WWTP in Burgos, Spain

2021 ◽  
Vol 11 (3) ◽  
pp. 964
Author(s):  
José García-Cascallana ◽  
Xiomar Gómez Barrios ◽  
E. Judith Martinez
Keyword(s):  
Treatment Plant ◽  
Electricity Production ◽  
Thermal Hydrolysis ◽  
Mass Balances ◽  
Digested Sludge ◽  
Hydrolysis Process ◽  
Base Scenario ◽  
Mesophilic Digestion ◽  
Hydrolysis Of

An evaluation of the energy and economic performance of thermal hydrolysis technologies is carried out on a theoretical basis. The wastewater treatment plant (WWTP) of Burgos (Spain) was the base scenario of this evaluation. Energy and mass balances were established considering the registered data of primary and secondary thickened sludge in the WWTP for 2011 to 2016. These balances were analysed considering five different scenarios, taking as Scenario 1, the plant operating with conventional mesophilic digestion. The scenarios considered commercially available technologies. The best results were obtained when hydrolysis was applied to digested sludge and sludge from the Solidstream® process. These two scenarios showed the best performance regarding volatile solid removal and lower demand for live steam, achieving a higher amount of biogas available for valorisation using combined heat and power (CHP) units. The main advantage of the hydrolysis process is the decrease in the volume of digesters and the amount of dewatered sludge needing final disposal. The Solidstream® process allowed a 35% increase in biogas available for engines and a 23% increase in electricity production.

Performance and operating experiences of the first Scandinavian full-scale Discfilter installation for tertiary phosphorus polishing with preceding coagulation and flocculation

2016 ◽  
Vol 11 (2) ◽  
pp. 459-468 ◽  
Author(s):  
P. Kängsepp ◽  
J. Väänänen ◽  
K. Örning ◽  
M. Sjölin ◽  
P. Olsson ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Energy Demand ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Full Scale ◽  
First Year ◽  
Pilot Studies ◽  
Coagulation And Flocculation ◽  
Pre Treatment

Microscreening (using Discfilters) is a widely used technology for suspended solids removal in tertiary effluent streams of wastewater treatment plants. Several pilot studies have shown the feasibility of using coagulation and flocculation in combination with microscreens for advanced phosphorus removal, but the number of full-scale references is still limited. In summer 2014, the first Scandinavian full-scale Discfilter installation with 2-stage chemical pre-treatment (coagulation and flocculation) was started up at the Arvidstorp wastewater treatment plant in Trollhättan (Sweden). The results obtained during the first year of operation proved that low suspended solids and total phosphorus effluent values could be achieved (<5 and <0.2 mg/l, respectively). These results were obtained even during heavy rainfall, when biologically and primary treated water were mixed at the influent of the Discfilter installation, before the coagulation and flocculation tanks. Further analysis of the results showed that Discfilter in combination with coagulant and polymer pre-treatment is a robust and reliable technology with low energy demand (34 Wh/m3) and a high recovery (1.9 ± 0.4% of influent flow discharged as reject).

scholarly journals CO2 capture and storage in Greece: A case study from komotini ngcc power plant

2006 ◽  
Vol 10 (3) ◽  
pp. 71-80
Author(s):  
Nikolaos Koukouzas ◽  
Paraskevas Klimantos ◽  
Prokopis Stogiannis ◽  
Emmanouel Kakaras
Keyword(s):  
Power Plant ◽  
Co2 Capture ◽  
Energy Demand ◽  
Power Plants ◽  
Fossil Fuel ◽  
Substantial Reduction ◽  
Plant Performance ◽  
Electricity Production ◽  
Electricity Production Cost ◽  
And Storage

The aim of this paper is to examine the possibilities for the abatement of CO2 emissions in the Greek fossil fuel power generation sector. An overview of CO2 capture, transportation, and storage concepts, on which the R&D community is focused, is presented. The implementation of post-combustion CO2 capture options in an existing fossil fuel power plant is then examined and the consequences on the overall plant performance are determined. Finally, the possibilities of transportation and then underground storage of the pure CO2 stream are analyzed taking into account both technical and economical factors. The results of this analysis show that CO2 sequestration is technically feasible for existing fossil fuel fired power plants in Greece. However, substantial reduction in plant efficiency is observed due to increased energy demand of the technologies used as well as in electricity production cost due to capital and operation costs of capture, transport, and storage of CO2. .

Benefits and drawbacks of thermal pre-hydrolysis for operational performance of wastewater treatment plants

2008 ◽  
Vol 58 (8) ◽  
pp. 1547-1553 ◽  
Author(s):  
P. Phothilangka ◽  
M. A. Schoen ◽  
B. Wett
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Treatment Plant ◽  
Full Scale ◽  
Plant Performance ◽  
Ammonia Release ◽  
Hydrolysis Process ◽  
Solids Content

This paper presents benefits and potential drawbacks of thermal pre-hydrolysis of sewage sludge from an operator's prospective. The innovative continuous Thermo-Pressure-Hydrolysis Process (TDH) has been tested in full-scale at Zirl wastewater treatment plant (WWTP), Austria, and its influence on sludge digestion and dewatering has been evaluated. A mathematical plant-wide model with application of the IWA Activated Sludge Model No.1 (ASM1) and the Anaerobic Digestion Model No.1 (ADM1) has been used for a systematic comparison of both scenarios—operational plant performance with and without thermal pre-hydrolysis. The impacts of TDH pre-hydrolysis on biogas potential, dewatering performance and return load in terms of ammonia and inert organic compounds (Si) have been simulated by the calibrated model and are displayed by Sankey mass flow figures. Implementation of full scale TDH process provided higher anaerobic degradation efficiency with subsequent increased biogas production (+75–80%) from waste activated sludge (WAS). Both effects—enhanced degradation of organic matter and improved cake's solids content from 25.2 to 32.7% TSS—promise a reduction in sludge disposal costs of about 25%. However, increased ammonia release and generation of soluble inerts Si was observed when TDH process was introduced.

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