Continuous thermal hydrolysis and anaerobic digestion of sludge. Energy integration study

2012 ◽  
Vol 65 (10) ◽  
pp. 1839-1846 ◽  
Author(s):  
S. I. Pérez-Elvira ◽  
F. Fdz-Polanco
Keyword(s):  
Anaerobic Digestion ◽  
Residence Time ◽  
Pilot Plant ◽  
Scale Up ◽  
Green Energy ◽  
Point Of View ◽  
Thermal Hydrolysis ◽  
Economic Point ◽  
Gas Engine ◽  
Secondary Sludge

Experimental data obtained from the operation in a pilot plant are used to perform mass and energy balances to a global process combining units of thermal hydrolysis (TH) of secondary sludge, anaerobic digestion (AD) of hydrolysed secondary sludge together with fresh primary sludge, and cogeneration from biogas by using a gas engine in which the biogas produces electricity and heat from the exhaust gases. Three scenarios were compared, corresponding to the three digesters operated: C (conventional AD, 17 days residence time), B (combined TH + AD, same time), and A (TH + AD at half residence time). The biogas production of digesters B and A was 33 and 24% better, respectively when compared with C. In the case of the combined TH + AD process (scenarios A and B), the key factors in the energy balance were the recovery of heat from hot streams, and the concentration of sludge. The results of the balances showed that for 8% DS concentration of the secondary sludge tested in the pilot plant, the process can be energetically self-sufficient, but a fraction of the biogas must by-pass the gas engine to be directly burned. From an economic point of view, scenario B is more profitable in terms of green energy and higher waste removal, while scenario A reduces the digester volume required by a half. Considering a population of 100,000 inhabitants, the economic benefit is 87,600 €/yr for scenario A and 132,373 €/yr for B. This value can be increased to 223,867 €/yr by increasing the sludge concentration of the feeding to the TH unit to a minimum value that allows use of all the biogas to produce green energy. This concentration is 13% DS, which is still possible from a practical point of view. Additional benefits gained with the combined TH + AD process are the enhancement of the digesters rheology and the possibility of getting Class A biosolids. The integration study presented here set the basis for the scale-up to a demonstration plant.

Minimisation of excess sludge production in a WWTP by coupling thermal hydrolysis and rapid anaerobic digestion

2005 ◽  
Vol 52 (10-11) ◽  
pp. 255-263 ◽  
Author(s):  
J. Chauzy ◽  
S. Graja ◽  
F. Gerardin ◽  
D. Crétenot ◽  
L. Patria ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Pilot Plant ◽  
Hydraulic Retention Time ◽  
Wastewater Treatment Plants ◽  
Control Line ◽  
Thermal Hydrolysis ◽  
Excess Sludge ◽  
Anaerobic Digesters ◽  
Sludge Production

In many cases, reducing sludge production could be the solution for wastewater treatment plants (WWTP) that here difficulty evacuating the residuals of wastewater treatment. The aim of this study was to test the possibility of minimising the excess sludge production by coupling a thermal hydrolysis stage and an anaerobic digestion with a very short HRT. The tests were carried out on a 2,500 p.e. pilot plant installed on a recycling loop between the clarifier and the actived sludge basin. The line equipped with the full scale pilot plant produced 38% TSS less than the control line during a 10 week period. Moreover, the rapid anaerobic digestion removed, on average, more than 50% of the total COD load with a hydraulic retention time (HRT) of 3 days. Lastly, the dryness of the remaining excess sludge, sanitised by the thermal hydrolysis, was more than 35% with an industrial centrifuge. This combination of thermal hydrolysis and rapid anaerobic digestion equally permits a significant gain of compactness compared to traditional anaerobic digesters.

DECISION PRINCIPLES FOR ASCENT SUPPORTS IN BUILDING CONSTRUCTION

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Dieter Schlagbauer ◽  
Christian Hofstadler ◽  
Cornelia Ninaus
Keyword(s):  
Empirical Studies ◽  
Economic Value ◽  
Scale Up ◽  
Point Of View ◽  
Construction Sites ◽  
Economic Point ◽  
Current State ◽  
Frequency Of Use ◽  
A Site ◽  
Economic Comparison

Ladders are the ascent system most commonly used to scale up a building, due to the low initial costs compared to other ascent equipment. The insufficiency of this approach is shown in an economic comparison of ladders, stair towers, and scaffoldings with integrated ascent support. Based on empirical studies, cost data and the current state of scientific knowledge, the ascent support with the highest economic value can be determined by considering safety, cost, time, stress, physical stress and strain, and frequency of use. A survey evaluated vertical transport routes, the ascent systems ladders, stair towers, and scaffoldings with integrated ladders. The findings indicate that from an economic point of view, ladders should be used only on construction sites where less than 54 ascents were performed each day. This leads to the assumption that for typical construction sites, with at least 6 ascents per person per day and a site usage for a period longer than one week, the operation of ladders is uneconomical.

Continuous thermal hydrolysis and energy integration in sludge anaerobic digestion plants

2008 ◽  
Vol 57 (8) ◽  
pp. 1221-1226 ◽  
Author(s):  
F. Fdz-Polanco ◽  
R. Velazquez ◽  
S. I. Perez-Elvira ◽  
C. Casas ◽  
D. del Barrio ◽  
...  
Keyword(s):  
Residence Time ◽  
Pilot Plant ◽  
Biogas Production ◽  
Electric Energy ◽  
Steam Injection ◽  
Optimal Operation ◽  
Thermal Hydrolysis ◽  
Energy Integration ◽  
Operation Conditions ◽  
Solids Concentration

A thermal hydrolysis pilot plant with direct steam injection heating was designed and constructed. In a first period the equipment was operated in batch to verify the effect of sludge type, pressure and temperature, residence time and solids concentration. Optimal operation conditions were reached for secondary sludge at 170°C, 7 bar and 30 minutes residence time, obtaining a disintegration factor higher than 10, methane production increase by 50% and easy centrifugation In a second period the pilot plant was operated working with continuous feed, testing the efficiency by using two continuous anaerobic digester operating in the mesophilic and thermophilic range. Working at 12 days residence time, biogas production increases by 40–50%. Integrating the energy transfer it is possible to design a self-sufficient system that takes advantage of this methane increase to produce 40% more electric energy.

scholarly journals Supercritical CO2 Extraction of Extracted Oil from Pistacia lentiscus L.: Mathematical Modeling, Economic Evaluation and Scale-Up

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 199 ◽  
Author(s):  
Abdelkarim Aydi ◽  
André Wüst Zibetti ◽  
Abdulaal Z. Al-Khazaal ◽  
Aboulbaba ELADEB ◽  
Manef ADBERRABA ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Intact Cell ◽  
Scale Up ◽  
Extraction Yield ◽  
Point Of View ◽  
Significant Variable ◽  
Pistacia Lentiscus ◽  
Economic Point ◽  
Transfer Parameter ◽  
Mass Transfer Parameter

In this study, the extracted oil of Pistacia lentiscus L. the Tunis region was extracted using supercritical carbon dioxide (SC-CO2) extraction containing different major components in the oil such as α-pinene (32%) and terpinene-4-ol (13%). The investigation of the effect of different variables on the extraction yield with 5% level of confidence interval showed that the CO2 pressure was the main significant variable to influence the oil yield. In order to better understand the phenomena, three parameters were considered to adjust all parameters of broken and intact cell (BIC) model: grinding efficiency (G), the internal mass transfer parameter ( k S a 0 ), and the external mass transfer parameter ( k f a 0 ), which were estimated by experimental extraction curves to calculate the diffusion coefficient. From an economic point of view, we found out that the high cost of production of the extracted oil was due to the low mass of extracted oil obtained from this type of plant.

Anaerobic digestion enhanced by thermal hydrolysis: First reference BIOTHELYS® at Saumur, France

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Julien Chauzy ◽  
Didier Cretenot ◽  
Anne Bausseron ◽  
Stéphane Deleris
Keyword(s):  
Anaerobic Digestion ◽  
Nutrient Removal ◽  
Steam Injection ◽  
Green Energy ◽  
Biological Nutrient Removal ◽  
Thermal Hydrolysis ◽  
Industrial Sludge ◽  
Biological Sludge ◽  
Hydrolysis Process ◽  
Hydrolysis Of

Veolia Water has developed during these last years its own THP (Thermal Hydrolysis Process) named BIOTHELYS® in order to enhance MAD (mesophilic anaerobic digestion) of municipal or industrial sludge. The first reference BIOTHELYS® has been installed at Saumur in France, an extended aeration biological nutrient removal facility, and commissioned in April 2006. The thermal hydrolysis of dewatered sludge is realised by steam injection at a temperature of 160°C for duration of circa 30 minutes. The THP reactors are paired in order to recover flash steam and heat sludge economically. The MAD of hydrolysed sludge is done within a HRT of 15 days and reaches volatile reduction of more than 45% on extended aeration biological sludge. BIOTHELYS® turns the MAD of extended aeration biological sludge into a very attractive solution while producing green energy with biogas. MAD is thus no more only reserved for mixed sludge but also for pure biological sludge when using THP.

Economic assessment of producing and selling biomethane into a regional market

2018 ◽  
Vol 31 (1) ◽  
pp. 60-76 ◽  
Author(s):  
Mattia De Rosa
Keyword(s):  
Anaerobic Digestion ◽  
Fossil Fuel ◽  
Net Present Value ◽  
Energy Resource ◽  
Economic Assessment ◽  
Point Of View ◽  
Organic Substrates ◽  
Present Value ◽  
Economic Point ◽  
Fuel Prices

Biogas is a promising renewable energy resource produced by using anaerobic digestion of organic substrates and it is mainly used to generate electricity by means of biogas engines. Other potential utilisations are growing, e.g. grid injection and biofuels production but, generally, a treatment aimed to increase its quality is mandatory and greater investments are generally required to produce upgraded biogas (biomethane). Despite the increasing of interest on these applications, a lack of information is still present from an economic point of view. The present paper performs an extended economic assessment of upgrading and selling biogas starting from a typical farm-based anaerobic digestion plant in Northern Ireland assumed as reference. Several economic indexes have been considered to assess the economic performance of the upgraded anaerobic digestion plant, namely net present value, pay-back period, profitability index and internal rate of return. Moreover, different scenarios in terms of fossil fuel prices have been analysed. The results show that producing and selling biomethane can be economically feasible if an adequate market is fostered. Optimum anaerobic digestion sizes between 26.9 and 64.4 tonne/y have been found, with correspondent net present value and pay-back period values in the range of £6.7–64.4M and 2.8–7.5 years, respectively, depending on the price scenarios analysed and the economic index chosen. Generally, adopting the net present value as objective function of the optimisation leads to greater anaerobic digestion size than the other indexes for any price scenarios considered. Finally, tougher market conditions (i.e. higher fossil fuel prices) lead to better economic performances of the upgraded anaerobic digestion configuration.

Pretreatment of a primary and secondary sludge blend at different thermal hydrolysis temperatures: Impacts on anaerobic digestion, dewatering and filtrate characteristics

2017 ◽  
Vol 122 ◽  
pp. 557-569 ◽  
Author(s):  
Matthew J. Higgins ◽  
Steven Beightol ◽  
Ushma Mandahar ◽  
Ryu Suzuki ◽  
Steven Xiao ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Thermal Hydrolysis ◽  
Secondary Sludge

Aerobic composting and anaerobic digestion of pulp and paper mill sludges

1997 ◽  
Vol 36 (11) ◽  
pp. 181-188 ◽  
Author(s):  
Jari Jokela ◽  
Jukka Rintala ◽  
Aimo Oikari ◽  
Olli Reinikainen ◽  
Kari Mutka ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Scale Up ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Pulp And Paper Mill ◽  
Aerobic Composting ◽  
Secondary Sludge ◽  
Volatile Solids

The feasibility of aerobic vessel composting and anaerobic digestion for the treatment of pulp and paper mill sludges were studied. The composting studies made use of primary and secondary sludge from a de-inking and paper mill. In six parallely aerated 500 1 vessels with various carbon : nitrogen (C:N) -ratios, the most optimal performance was obtained with C:N -ratios of c. 22–35, while higher and lower ratios delayed the temperature increase. With the optimal ratios, the thermophilic stage was reached within 36 h, and the stage lasted for about seven days. In the scale-up study (18 m3 compost vessel), the thermophilic stage was reached within 24 h. An effective dehydratation of the mass was obtained as the total solids (TS) content of the compost increased from 31.3– to 63.8– within 21 days. The anaerobic digestion of pulp and paper mill sludges was studied using two mesophilic 5 1 digesters, their feed sludges consisting of a mixture of municipal sewage sludge and primary and secondary sludge from a pulp and paper mill. With this feed mixture and with a loading rate of about 1.0 kg volatile solids (VS)/m3d a removal of about 27 to 40– VS and methane production of about 180 1/kgVSadded feed sludge were achieved during the 80 d study period. The study showed that pulp and paper mill sludges are amenable to both aerobic composting and anaerobic digestion.

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