Enhancement of anaerobic digestibility of lipids and optimization of biogas production by implementing emulsification as pre-treatment method

2020 ◽  
Author(s):  
Αλέξανδρος Ευταξίας
Keyword(s):  
Biogas Production ◽  
Contact Process ◽  
Treatment Method ◽  
Pre Treatment ◽  
Anaerobic Digestibility

Στόχος της παρούσας διδακτορικής διατριβής υπήρξε η ανάπτυξη ολοκληρωμένης διεργασίας αναερόβιας χώνευσης με υψηλή περιεκτικότητα σε λίπη μέσω της διερεύνησης και βελτιστοποίησης (α) κατάλληλης διεργασίας προ-επεξεργασίας λιπών/ελαίων για περιορισμό των λειτουργικό προβλημάτων και (β) κατάλληλου τύπου αντιδραστήρα για την διαχείριση αποβλήτων υψηλής περιεκτικότητας σε λίπη. Τα λιπίδια χαρακτηρίζονται από χαμηλή διαλυτότητα και πυκνότητα, με αποτέλεσμα να παρουσιάζουν χαμηλή διαθεσιμότητα καθώς επιπλέουν στην επιφάνεια του αντιδραστήρα. Η αναερόβια χώνευση λιπιδίων μπορεί να οδηγήσει σε λειτουργικές αστάθειες όπως διάλυση των κόκκων/ φλόκων της αναερόβιας βιομάζας, αφρισμό και επίπλευση της ιλύος, παρεμπόδιση και τοξικότητα έως και πλήρη κατάρρευση των διεργασιών παραγωγής βιοαερίου. Με στόχο τον περιορισμό των παραπάνω προβλημάτων έχουν εφαρμοστεί διάφορες μέθοδοι προ-επεξεργασίας των λιπιδίων οι οποίες στοχεύουν σε αύξηση της βιοδιαθεσιμότητας αυτών και σε άρση των περιορισμών στη μεταφορά μάζας. Τέτοιες μέθοδοι είναι η σαπωνοποίηση, η ενζυματική υδρόλυση και η γαλακτωματοποίηση. Η τελευταία μέθοδος προ-επεξεργασίας, οδηγεί στην μείωση του μεγέθους των λιπιδίων σε επίπεδα του μικρομέτρου αυξάνοντας έτσι σημαντικά τη διεπιφάνεια νερού-ελαίου και περιορίζοντας την επίπλευση ελεύθερων λιπών εντός του χωνευτή. Ως μειονεκτήματα της μεθόδου είναι ότι απαιτούνται σημαντικά ποσά ενέργειας καθώς και η προσθήκη γαλακτωματοποιητών. Σύμφωνα με τα παραπάνω η αναερόβια χώνευση λιπιδίων υπόκειται τόσο σε θερμοδυναμικούς περιορισμούς των βιολογικών διεργασιών όσο και τεχνικά και λειτουργικά προβλήματα της εγκατάστασης. Για τους παραπάνω λόγους η προσθήκη λιπιδίων σε μονάδες βιοαερίου πλήρους κλίμακας δεν πραγματοποιείται είτε είναι περιορισμένη. Μελετήθηκε η γαλακτωματοποίηση ως μέθοδος προ-επεξεργασίας για την αναερόβια χώνευση διαφορετικών LCFAs σε μεσόφιλες συνθήκες σε αντιδραστήρες ημι-συνεχούς λειτουργίας. Έγινε εφαρμογή του μοντέλου (ADM1) στα πειραματικά δεδομένα το οποίο συνέβαλε στην ποσοτικοποίηση των κινητικών παραμέτρων αποικοδόμησης του ελαϊκού οξέως ως συνάρτηση της εφαρμοζόμενης προ-επεξεργασίας. Εξετάστηκε ο περιοριστικός ρόλος των ιχνοστοιχείων στην αναερόβια αποικοδομησιμότητα γαλακτωματοποιημένου ζωικού λίπους. Τα πειράματα έλαβαν χώρα σε αντιδραστήρα πλήρους ανάμιξης (CSTR) με ανακυκλοφορία της βιομάζας (contact process). Δόθηκε έμφαση στην διερεύνηση και βελτιστοποίηση ενός κατάλληλου τύπου αντιδραστήρα (CSTR και PFR) για την συν-χώνευση αγροτοβιομηχανικών αποβλήτων με λίπη και έλαια. Τέλος πραγματοποιήθηκε τεχνοοικονομική ανάλυση ως προς την δυνατότητα αναβάθμισης μιας υφιστάμενης μονάδας αναερόβιας χώνευσης από τα 500 στα 1000 kW, μέσω της προσθήκης λιπιδίων σε ποσοστό 1% v/v. Η παρούσα διδακτορική διατριβή κατέληξε στα ακόλουθα συμπεράσματα: •Η γαλακτωματοποίηση ως μέθοδος προ-επεξεργασίας διαδραματίζει σημαντικό ρόλο στην αναερόβια χώνευση λιπιδίων. •Τα ιχνοστοιχεία διαδραματίζουν σημαντικό ρόλο στην αναερόβια χώνευση αποβλήτων με υψηλή περιεκτικότητα σε λίπη. •Το μοντέλο ADM1 είναι κατάλληλο για την προσομοίωση των διεργασιών αναερόβιας χώνευση σε όλες τις περιπτώσεις. •Το περιοριστικό βήμα ως προς την αναερόβια χώνευση των διαφορετικών LCFAs που μελετήθηκαν ήταν η αποικοδόμηση του στεαρικού οξέως.

scholarly journals Bioreactor Cells as Waste Pre-Treatment Method

2017 ◽  
Author(s):  
Ruta Bendere ◽  
Ruslans Smigins ◽  
Dace Arina ◽  
Inara Teibe
Keyword(s):  
Biogas Production ◽  
Treatment Method ◽  
Baltic States ◽  
Treatment Technology ◽  
Sanitary Landfills ◽  
Pre Treatment ◽  
Waste Degradation

Bioreactor landfilling, with the acceptance of landfill Directive in EC in 1999, loosed its actuality in EC, but this method can still be used for acceleration of bio-waste degradation and biogas production as pre-treatment technology of waste. As large gas collection facilities are built and millions of EUR are invested for biogas treatment and production of electricity and heat in the new constructed sanitary landfills in Baltic States, the idea of usage of biogas production cells as bio-waste pre-treatment method is revised.

scholarly journals Mild Thermal Pre-Treatment of Waste Activated Sludge to Increase Loading Capacity, Biogas Production, and Solids’ Degradation: A Pilot-Scale Study

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6059
Author(s):  
Adrian Gonzalez ◽  
Hongxiao Guo ◽  
Oscar Ortega-Ibáñez ◽  
Coert Petri ◽  
Jules B. van Lier ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Biogas Production ◽  
Treatment Method ◽  
Pilot Scale ◽  
Organic Loading Rate ◽  
Wastewater Purification ◽  
Refractory Compounds ◽  
Volatile Solids ◽  
Methane Production Rate ◽  
Pre Treatment

Sludge pre-treatments are emerging as part of the disposal process of solid by-products of wastewater purification. One of their benefits is the increase in methane production rate and/or yield, along with higher loading capacities of existing digesters. In this study, we report the performance of a pilot-scale compartmentalized digester (volume of 18.6 m3) that utilized a mild thermal pre-treatment at 70 °C coupled with hydrogen peroxide dosing. Compared with a reference conventional anaerobic digester, this technique allowed an increased organic loading rate from 1.4 to 4.2 kg volatile solids (VS)/(m3d) and an increment in the solids degradation from 40 to 44%. To some extent, these improvements were promoted by the solubilization of the tightly-bound fraction of the extracellular polymeric substances to looser and more accessible fractions without the formation of refractory compounds. In sum, our results suggest that this pre-treatment method could increase the treatment capacity of existing digesters without significant retrofitting.

scholarly journals Effective Pre-Treatments for Enhancement of Biodegradation of Agricultural Lignocellulosic Wastes in Anaerobic Digestion – A Review

2020 ◽  
Vol 23 (3) ◽  
pp. 105-110
Author(s):  
Fatemeh Rahimi-Ajdadi ◽  
Masoomeh Esmaili
Keyword(s):  
Anaerobic Digestion ◽  
Crop Residues ◽  
Biogas Production ◽  
Biofuel Production ◽  
Agricultural Crop ◽  
Advantages And Disadvantages ◽  
Lignocellulosic Wastes ◽  
Pre Treatment ◽  
Anaerobic Digestibility ◽  
Emission Of Greenhouse Gases

AbstractAgricultural crop residues like stems, straws and leaves are valuable resources for biofuel production, especially methane, due to anaerobic digestion. Biogas from agricultural lignocellulosic wastes is capable of attaining sustainable energy yields without environmental pollution. Farmers in many developing countries burn these wastes throughout their fields, imposing environmental hazard due to emission of greenhouse gases. The main problem in this field is the recalcitrance of the agricultural lignocellulose waste that limits its enzymatic degradation and hydrolysis efficiency and consequently decreases biogas production. Therefore, efficient pre-treatments prior to anaerobic digestion are essential. Various pre-treatment methods are used for increasing the anaerobic digestibility of lignocellulose biomass, such as physical (mechanical, thermal, etc.), chemical, biological and combined pre-treatments. This paper reviews different pre-treatments used in anaerobic digestion for the agricultural lignocellulosic wastes and explains the advantages and disadvantages of each. The most frequently used pre-treatments for main agricultural wastes in process of biogas production are also introduced.

scholarly journals Folytonos anyagtovábbítású mikrohullámú kezelőegység fejlesztése

2013 ◽  
Vol 8 (1-2) ◽  
pp. 59-63
Author(s):  
Róbertné V. P. Kovács ◽  
Sándor Beszédes ◽  
Lajos Ludányi ◽  
Cecilia Hodúr ◽  
Gábor Szabó
Keyword(s):  
Food Industry ◽  
Biogas Production ◽  
Complex Structure ◽  
Cavity Resonator ◽  
Microwave Treatment ◽  
Environmental Concerns ◽  
Pre Treatment ◽  
The University ◽  
Anaerobic Digestibility ◽  
Toroidal Cavity

Most branches in the food industry have a considerable wastewater output. The problem is not only the total amount of wastewater production, but also the high content of organic matter. Anaerobic digestion is an effective way of treating wastewater for yielding profitable biogas and alleviating environmental concerns. Pre-treatment of sludge to break down its complex structure can be used for enhancing anaerobic digestibility. Research group of the Department of Process Engineering at the University of Szeged has investigated the applicability and the efficiency of microwave pre-treatment for food industry sludge. The results showed that the microwave treatment of sludge solution resulted in higher biodegradability and enhanced biogas production as well. According to these results a continuous-flow microwave toroidal cavity resonator treating-system was developed.

scholarly journals Enhanced biodegradability of dairy sludge by microwave assisted alkaline and acidic pre-treatments

2019 ◽  
Vol 7 (1-2) ◽  
pp. 92-97
Author(s):  
Sándor Beszédes ◽  
Zoltán Jákói ◽  
Balázs Lemmer ◽  
Cecilia Hodúr
Keyword(s):  
Anaerobic Digestion ◽  
Microwave Irradiation ◽  
Biogas Production ◽  
Treatment Method ◽  
Acidic Condition ◽  
Alkaline Condition ◽  
Thermal Methods ◽  
Microwave Assisted ◽  
Pre Treatment ◽  
Aerobic Biodegradability

Considering the rapid, volumetric and selective heating effects of microwaves the microwave assisted chemical methods could provide appropriate alternatives for conventional thermal methods in sludge processing. Microwave irradiation alone is suitable to accelerate the hydrolysis stage of anaerobic decomposition of sludge resulted in accelerated biogas production rate and in higher biogas yield. Alkaline pre-treatments increase the organic matter solubility and suitable for disintegration of sludge particles. In some study are concluded that acidic conditions help the disintegration of waste activated sludge and assist in the solubilisation of carbohydrates and proteins which led to increased higher biogas production, as well. Beside the promising results related to effects of microwave pre-treatments on anaerobic digestion of sludge there are very few reports on the investigation of combined acidic/alkali-microwave pre-treatment method for food industry originated sludge. Hence, our study focused on the examination of the effects of combined microwave-alkali and microwave-acidic pre-treatment on aerobic and anaerobic biodegradability of sludge produced in dairy industry Our experimental results verified, that microwave irradiation with alkaline dosage improve the solubility of organic matters in the pH range of 8-12. But enhancement of disintegration was not correlated linearly with biodegradability. During pre-treatment stage, applying pH over 10, the aerobic biodegradability show decreasing tendency. Applying of acidic condition during microwave irradiation resulted in lower disintegration degree than obtained for microwave-alkaline sludge pre-treatment method. But with microwave assisted acidic pre-treatments a higher aerobic biodegradability could be achieved than with alkaline dosage. In microwave pre-treatments acidic condition was preferable to increase the shorter aerobic biodegradability; the alkaline condition was favourable to intensify the anaerobic digestion process.

scholarly journals Effect Of Alkaline Pre-Treatment On Cassava Pulp For Optimum Biogas Production

2019 ◽  
Vol 8 (2) ◽  
pp. 5919-5923
Keyword(s):  
Chemical Oxygen Demand ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Treatment Method ◽  
Batch Mode ◽  
Biogas Yield ◽  
Cassava Pulp ◽  
Soluble Chemical Oxygen Demand ◽  
Pre Treatment

(Being produced in vast quantity as one of by-product from cassava starch processing chains, cassava pulp has great potential for energy recovery by harnessing biogas through anaerobic digestion (AD). This study aims to enhance biogas production by comparative investigation in batch mode digestion. 5%TS w/v of cassava pulp mixed with mill effluent were pre-treated with 10 molar potassium hydroxide (KOH), sodium hydroxide (NaOH), and calcium hydroxide (Ca(OH)2) solution for 6 hours contact time. Effects of different alkaline pre-treatment on cassava substrate were assessed in total dissolved solid (TDS), soluble chemical oxygen demand (SCOD), Volatile Fatty Acids to Alkalinity ratio (VFA/TA), and reducing sugars. Daily accumulated biogas yield was taken as final indicator of the effect of different pre-treatment. KOH pre-treatment in pH 11 resulted highest dissolved solid 13.07 mg/L, and improved soluble chemical oxygen demand (SCOD) formation up to 75.61% (480,000 mg/L) than control substrate. The experiment revealed peak biogas production by KOH pre-treated substrate was found at day 6 after digestion executed, and achieved 546 ml. The finding proves out of different pre-treatment method applicable to cassava pulp, KOH pre-treatment could realistically increase biogas yield for cassava mills. Biogas production increased up to 101%, 92%, and 70% using KOH, Ca(OH)2 and NaOH respectively. However, when future provision to the technology for AD system and design is concerned, the choice of highly reactive alkali could lead to complication in the system.

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

Swine manure biogas production improvement using pre-treatment strategies: lab-scale studies and full-scale application

2021 ◽  
pp. 100716
Author(s):  
Deisi Cristina Tápparo ◽  
Daniela Cândido ◽  
Ricardo Luis Radis Steinmetz ◽  
Christian Etzkorn ◽  
André Cestonaro do Amaral ◽  
...  
Keyword(s):  
Biogas Production ◽  
Swine Manure ◽  
Treatment Strategies ◽  
Full Scale ◽  
Production Improvement ◽  
Pre Treatment
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