scholarly journals Techno-economic assessment of common reed and sewage sludge co-fermentation improved by vapothermal pre-treatment

2021 ◽  
Vol 23 (9) ◽  
pp. 2741-2755
Author(s):  
Marvin Scherzinger ◽  
Marvin Kaltschmitt

AbstractThis study examines whether vapothermal pre-treatment is technically feasible and brings economic advantages for a subsequent anaerobic co-fermentation of reeds together with sewage sludge. This is illustrated by the example of remote sites located close to constructed wetlands in the Persian Gulf states. Thus, eight different biogas plant configurations with an installed electric power between 75 and 450 kW, each with and without vapothermal pre-treatment, are investigated in detail related to technical and economic figures. Within the technical assessment, suitable plant components are chosen and overall plant layouts are designed and dimensioned. Furthermore, the requirements on the substrate by means of quantity, pre-treatment and storage capacities are investigated. Based on this, an economic evaluation following the annuity method is performed in order to calculate the respective electricity production costs. The results show that the thermal energy required for vapothermal pre-treatment can be obtained completely from the residual heat of the combined heat and power unit used in each case. Additionally, the specific electricity production costs can be reduced by a vapothermal pre-treatment up to 7 % related to the systems without pre-treatment. Furthermore, a comparison shows that vapothermal pre-treatment can compete with other pre-treatment methods such as steam explosion and hydrothermal pre-treatment for plants with higher installed electric capacity. In addition, it is shown that the considered cases can compete with the production of electricity using diesel as a fuel at a fuel equivalent price of 1.00 € Graphic abstract

ICR Journal ◽  
2013 ◽  
Vol 4 (3) ◽  
pp. 446-451
Author(s):  
Anis H. Bajrektarevic

The MENA theatre is situated in one of the most fascinating locations of the world, the Middle East and North Africa. It represents, along with the Balkans-Caucasus, the only existing land corridor that connects three continents. It also holds over a half of the world’s proven oil-gas reserves (56 percent - oil, 48 percent - gas). Furthermore, the Gulf OPEC states and Libya have by far the lowest costs of oil extraction, thanks to the high crude purity (measured by overall properties such as the state of aggregation, excavation gravity, viscosity, weight, sulfuric content and other contaminants) which simplifies and reduces the cost of the refinement process. These petrol-exporters also enjoy the close proximity to open warm seas for low-cost, fast and convenient overseas shipments. Hence, the costs per barrel of crude for Libya and the Persian Gulf states are under US$ 5; for other OPEC members, below US$ 10. This is in a sharp contrast to countries such as the US, Russia, Norway, Canada and many others that bear production costs of several tens of US$ per barrel, according to the International Energy Agency (IEA). Therefore, it is an absolute imperative for the external/peripheral powers to dominate such a pivotal geo-economic and geopolitical theatre by simply keeping its centre “soft,” and pre-empting, preventing or hindering any emancipation that might come through any indigenous socio-political modernisation. This is the very same imperative that has remained a dominant rationale of inner European and Asian machtpolitik for centuries.


Author(s):  
Zahra R. Babar

The six oil monarchies of the Persian Gulf together form one of the most concentrated global sites of international labor migration, with some of the highest densities of non-citizens to citizens seen anywhere in the world. A somewhat unique feature of the region is that while it hosts millions of migrants, it allows almost no access to permanent settlement. Gulf States have hosted large cohorts of migrants for more than half a century but have done so without efforts toward formal integration through citizenship. Although labor migration as a phenomenon is both permanent and prominent, the Gulf States’ mechanism for governing migration systematically reinforces the temporariness and transience of their migrant populations.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Anita Ejiro Nwaefuna ◽  
Karl Rumbold ◽  
Teun Boekhout ◽  
Nerve Zhou

AbstractBioethanol from abundant and inexpensive agricultural and industrial wastes possesses the potential to reduce greenhouse gas emissions. Bioethanol as renewable fuel addresses elevated production costs, as well as food security concerns. Although technical advancements in simultaneous saccharification and fermentation have reduced the cost of production, one major drawback of this technology is that the pre-treatment process creates environmental stressors inhibitory to fermentative yeasts subsequently reducing bioethanol productivity. Robust fermentative yeasts with extreme stress tolerance remain limited. This review presents the potential of dung beetles from pristine and unexplored environments as an attractive source of extremophilic bioethanolic yeasts. Dung beetles survive on a recalcitrant lignocellulose-rich diet suggesting the presence of symbiotic yeasts with a cellulolytic potential. Dung beetles inhabiting extreme stress environments have the potential to harbour yeasts with the ability to withstand inhibitory environmental stresses typically associated with bioethanol production. The review further discusses established methods used to isolate bioethanolic yeasts, from dung beetles.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Leilah Krounbi ◽  
Akio Enders ◽  
John Gaunt ◽  
Margaret Ball ◽  
Johannes Lehmann

AbstractThe conversion of dairy waste with high moisture contents to dry fertilizers may reduce environmental degradation while lowering crop production costs. We converted the solid portion of screw-pressed dairy manure into a sorbent for volatile ammonia (NH3) in the liquid fraction using pyrolysis and pre-treatment with carbon dioxide (CO2). The extractable N in manure biochar exposed to NH3 following CO2 pre-treatment reached 3.36 g N kg−1, 1260-fold greater extractable N than in untreated manure biochar. Ammonia exposure was 142-times more effective in increasing extractable N than immersing manure biochar in the liquid fraction containing dissolved ammonium. Radish and tomato grown in horticultural media with manure biochar treated with CO2 + NH3 promoted up to 35% greater plant growth (dry weight) and 36–83% greater N uptake compared to manure biochar alone. Uptake of N was similar between plants grown with wood biochar exposed to CO2 + NH3, compared to N-equivalent treatments. The available N in dairy waste in New York (NY) state, if pyrolyzed and treated with NH3 + CO2, is equivalent to 11,732–42,232 Mg N year−1, valued at 6–21.5 million USD year−1. Separated dairy manure treated with CO2 + NH3 can offset 23–82% of N fertilizer needs of NY State, while stabilizing both the solid and liquid fraction of manure for reduced environmental pollution.


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3088
Author(s):  
Henry Wasajja ◽  
Saqr A. A. Al-Muraisy ◽  
Antonella L. Piaggio ◽  
Pamela Ceron-Chafla ◽  
Purushothaman Vellayani Aravind ◽  
...  

Small-scale electrical power generation (<100 kW) from biogas plants to provide off-grid electricity is of growing interest. Currently, gas engines are used to meet this demand. Alternatively, more efficient small-scale solid oxide fuel cells (SOFCs) can be used to enhance electricity generation from small-scale biogas plants. Most electricity generators require a constant gas supply and high gas quality in terms of absence of impurities like H2S. Therefore, to efficiently use the biogas from existing decentralized anaerobic digesters for electricity production, higher quality and stable biogas flow must be guaranteed. The installation of a biogas upgrading and buffer system could be considered; however, the cost implication could be high at a small scale as compared to locally available alternatives such as co-digestion and improved digester operation. Therefore, this study initially describes relevant literature related to feedstock pre-treatment, co-digestion and user operational practices of small-scale digesters, which theoretically could lead to major improvements of anaerobic digestion process efficiency. The theoretical preamble is then coupled to the results of a field study, which demonstrated that many locally available resources and user practices constitute frugal innovations with potential to improve biogas quality and digester performance in off-grid settings.


2002 ◽  
Vol 46 (10) ◽  
pp. 199-208 ◽  
Author(s):  
D. Bolzonella ◽  
L. Innocenti ◽  
F. Cecchi

The paper deals with the performances of the mesophilic anaerobic digestion treatment of sewage sludge from a full scale BNR process without primary settling (nominally 300,000 PE). A relation between the activated sludge observed yields, Yobs, and the anaerobic digester performance was preliminarily found: for values of Yobs of 0.25 kgVSS/kgCOD the anaerobic digester specific gas production showed the best performances (0.22 m3/kgVSfed). This has to be confirmed with wider future studies. It was also shown the level of sludge pre-thickening to be reached for the self-sustaining warming of the digester also in wintertime. According to the energetic balance and to a comparison with an aerobic stabilisation process, it was pointed out as when a co-generation unit for heat and energy production was introduced about 3.4 kWh/PE y of energy were produced in the anaerobic digestion process. On the other hand, 4.3 kWh/PE y were spent if an aerobic stabilisation process was applied. The economic assessment, carried out on the basis of the energy balances, showed that the anaerobic digestion is always economically advantageous if compared to aerobic stabilisation processes, also for small WWTPs. According to the energetic evaluations an environmental balance was assessed, in terms of CO2 emissions. The difference between anaerobic and aerobic processes was about 5.3 kgCO2/PE y in favour of anaerobic processes application.


1991 ◽  
Vol 113 (1) ◽  
pp. 151-157 ◽  
Author(s):  
J. A. Paffenbarger

This paper describes the design and performance of a coal gasification combined-cycle power plant with an integrated facility for producing and storing methanol (GCC/methanol power plant). The methanol is produced at a steady rate and is burned in the combined cycle to generate additional power during periods of peak electrical demand. The GCC/methanol plant provides electricity generation and energy storage in one coal-based facility. It is of potential interest to electric utilities seeking to meet intermediate-load electrical demand on their systems. The plant configuration is determined by means of an innovative economic screening methodology considering capital and fuel costs over a range of cycling duties (capacity factors). Estimated levelized electricity production costs indicate that a GCC/methanol plant could be of economic interest as premium fuel prices increase relative to coal. The plant could potentially be of interest for meeting daily peak demands for periods of eight hours or less. The conceptual plant configuration employs a Texaco gasifier and a Lurgi methanol synthesis plant. Plant performance is estimated at peak and baseload output levels. No unusual design or operational problems were identified.


2015 ◽  
Vol 768 ◽  
pp. 496-505 ◽  
Author(s):  
Yu Yi Zheng ◽  
Hong Lin ◽  
Zhi Long Lin ◽  
Yi Fang Zeng ◽  
Yu Fang Yu ◽  
...  

This study aims to find out the optimum extraction time varied from 5 min to 60 min for extracellular polymeric substances (EPS) from sewage sludge pretreated at 80 °C. The change of the contents of EPS and its components under different time limit were recorded and compared. The results showed: the contents of soluble protein, TOC, soluble sugar and DNA was increased by 579.17 mg/l, 514.25 mg/l, 132.79 mg/l, and 34.69 mg/l, respectively, with the increase of thermal pre-treatment time during the process, and the DNA content increased the least, which indicating that the effect of thermal pre-treatment at 80 °C on cell lysis of sewage sludge was small. The EPS content, as a whole, was increased with the increase of thermal pre-treatment time. By analyzing the experimental data with the Analytic Hierarchy Process Model, which was used to identify the optimum thermal pre-treatment time of extracting EPS, the results showed that the effectiveness of EPS extraction from sludges was 30 min>60 min>50 min>20 min>40 min>10 min>5 min. Therefore, the 30 min was choosed as the optimum thermal pre-treatment time.


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