DOCSLIB.ORG

Experimental Coupling and Modelling of Wet Air Oxidation and Packed-Bed Biofilm Reactor As an Enhanced Phenol Removal Technology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Experimental Coupling and Modelling of Wet Air Oxidation and Packed-Bed Biofilm Reactor As an Enhanced Phenol Removal Technology Experimental coupling and modelling of wet air oxidation and packed-bed biofilm reactor as an enhanced phenol removal technology 1 1 1 Marine Minière & Olivier Boutin & Audrey Soric Abstract Experimental coupling of wet air oxidation process Keywords Coupled process . Advanced oxidation process . and aerobic packed-bed biofilm reactor is presented. It has Wetair oxidation . Biological treatment . Biofilm packed bed . been tested on phenol as a model refractory compound. At Process modelling . Phenol 30 MPa and 250 °C, wet air oxidation batch experiments led to a phenol degradation of 97% and a total organic carbon removal of 84%. This total organic carbon was mainly due Nomenclature 2 to acetic acid. To study the interest of coupling processes, wet AF m air oxidation effluent was treated in a biological treatment Total biofilm surface area −1 process. This step was made up of two packed-bed biofilm BOD gBOD L reactors in series: the first one acclimated to phenol and the Biological oxygen demand second one to acetic acid. After biological treatment, phenol CO2(d) mol L−1 and total organic carbon removal was 99 and 97% respec- Dissolved oxygen concentration in WAO Hdq −1 tively. Thanks to parameters from literature, previous CWAO mol L studies (kinetic and thermodynamic) and experimental Hydroquinone concentration in WAO AcAc −1 data from this work (hydrodynamic parameters and CWAO mol L biomass characteristics), both treatment steps were Acetic acid concentration in WAO PhOH −1 modelled. This modelling allows the simulation of the CWAO mol L coupling process. Experimental results were finally well Phenol concentration in WAO PhOH −3 reproduced by the continuous coupled process model: relative C0 gm error on phenol removal efficiency was 1 and 5.5% for wet Phenol concentration at the packing/biofilm air oxidation process and packed-bed biofilm reactor interface PhOH −3 respectively. CB gm Phenol concentration in bulk liquid PhOH −3 CF gm Phenol concentration at the biofilm/boundary * Olivier Boutin layer interface [email protected] PhOH −3 Cin gm 1 Aix Marseille Univ, CNRS, Centrale Marseille, M2P2, Phenol concentration in the influent Marseille, France −1 COD gCOD L Chemical oxygen demand PhOH 2 −1 DF m s Phenol diffusion coefficient in biofilm PhOH 2 −1 DL m s Phenol diffusion coefficient in water dP m Packing characteristic size pharmaceuticals, are still refractory to conventional treat- PhOH −2 −1 jF gphenol m s ments. Moreover, environmental protection involves more Phenol flux and more stringent regulations on pollutant discharge in aquat- kLmol−1 s−1 ic environment. Phenol oxidation rate constant One way to improve pollutant removal with limiting extra −1 kPhOH ms costs is to combine different processes in order to benefit from Phenol mass transfer coefficient their advantages and to overcome their drawbacks. This could −3 Ki gm create complementary and synergistic effects. An interesting Phenol inhibition constant coupled process is the combination of chemical and biological −3 KPhOH gm processes. During the last 40 years, more than 200 studies Phenol affinity constant have been published about chemical–biological-coupled pro- LL m cesses. Four literature reviews (Guieysse and Norvill 2014; Boundary layer length Scott and Ollis 1995; Mantzavinos and Psillaki 2004;Oller Qm3 s−1 et al. 2011) relate the evolution of this field from 1976 to 2013. Phenol flow rate Moreover, integrated processes have also gained more and R Ratio of phenol diffusion coefficient in biofilm more attention (Di laconi 2012). According to the effluent, on phenol diffusion coefficient in water one of the two following sequences is more relevant: −3 −1 rgCOD-X m s Bacteria growth rate & Biological–chemical treatments aim at degrading biode- PhOH −3 −1 r gphenol m s gradable compounds and mineralizing remaining com- Phenol consumption rate pounds which are refractory to biodegradation. These Re Reynolds number coupled processes are suitable for effluents with high con- Sc Schmidt number centration of biodegradable compounds and low concen- Sh Sherwood number tration of hardly biodegradable compounds, such as pulp −3 XH gCOD-X m and paper mill effluents (Assalin et al. 2009)orlandfill Biofilm density leachates (Lei et al. 2007). They are also suitable if the −3 XV kgVS m biological treatment of an effluent leads to specific metab- Biofilm density used in R calculation olites inhibiting bacterial activity: a chemical post- −1 YX/H gCOD-X gphenol treatment allows their oxidation. Heterotrophic biomass yield & Chemical–biological treatments are the oxidation of hard- zm ly biodegradable or inhibitory compounds into more bio- Distance from packing degradable ones and then a degradation of those com- −1 μmax s pounds through a biological treatment. These coupled pro- Specific growth rate cesses allow saving energy or chemicals due to partial 2 −1 νwater m s oxidation in comparison with total chemical Water kinematic viscosity mineralisation. They are suitable for effluents containing a high fraction of hardly biodegradable compounds, such as petrochemical effluents (Ishak and Malakahmad 2013), Introduction as well as effluents containing toxic or inhibitory elements to micro-organism compounds, such as textile effluents Industrial wastewater treatment is a strong issue, as effluents with toxic dyes or pesticide effluents (Libra and Sosath could combine high organic waste concentration, refractory 2003;Parienteetal.2013). compounds at different concentrations and relatively low and intermittent flow rates. Chemical processes are known Chemical–biological processes are the most studied, as to be very efficient for the removal (oxidation) of many pol- they can treat effluents with high toxicity. Among chemical lutants. They often involve chemical and/or energy consump- and advanced oxidation processes, wet air oxidation tion (Guieysse and Norvill 2014). On the contrary, biological (WAO)—an oxidation process in subcritical water at high processes are low-energy and maintenance consumers, but temperature and pressure—is an efficient process with no they are only efficient for biodegradable organic compounds. chemical consumption (except oxygen or air). It can be They cannot easily remove highly toxic pollutants or refrac- optimised in terms of energy consumption (Lefevre et al. tory compounds in normal operating conditions (Guieysse and 2011). Verenich and Kallas (2002) showed that WAO as a Norvill 2014). Though a large range of processes are avail- pre-treatment could enhance biodegradability of pulp and pa- able, many pollutants, as for instance dyes, surfactants or per mill effluents from 24 to 89%. Moreover, this process can be economically viable for concentration of some relatively the whole process simulated in order to help the evaluation of high wastes, due to its high efficiency and short residence this coupling approach. time. However, an energy optimisation is needed in this case (Lefevre et al. 2011; Lefevre et al. 2012). Among biological processes, packed-bed biofilm reactors (PBBRs) are based on Materials and methods the biodegradation of pollutants by biomass attached on car- riers (Warnoc et al. 2005; Ranade et al. 2011). They are very Materials interesting since they need less space than suspended biomass reactors; they are easier to handle than fluidised bed High-purity phenol (>99%) and acetic acid of analytical grade bioreactors and also involve high sludge retention time were bought from Sigma-Aldrich and Carlo Erba Reagents leading to good efficiency. Zapata et al. (2010)successfully respectively. Pink dye Rhodamine WT (20 wt% rhodamine used a PBBR with a photo/Fenton pre-treatment for the de- in water) for residence time distribution (RTD) experiments contamination of pesticide-containing wastewater, achieving was bought from Acros Organics. Bioreactors were inoculated 84% of mineralisation. with samples of activated sludge from an urban wastewater In many research studies, authors target model compounds. treatment plant. For instance, several studies on chemical–biological coupling use phenol, which is found in many industrial effluents (win- Experimental setup ery, olive mill, petrochemistry, coking, refinery, etc.) and which is dangerous for human health (Busca et al. 2008). The experimental coupling of wet air oxidation with packed- Advanced oxidation process, coupled with biological process, bed biofilm reactors was carried out on a phenolic solution. is an interesting treatment for olive mill effluents containing First, oxidation of a phenolic solution was carried out in a high concentration of phenol (Mantzavinos and Kalogerakis batch WAO reactor. Then, the resulting effluent was 2005). For olive mill effluents, phenol concentrations can vary biodegraded by the means of two PBBRs in series. from 5.8 g L−1 (Rivas et al. 2001)to29gL−1 (Minh et al. 2008). Benitez et al. (1999) reached 84% of chemical oxygen Wet air oxidation step demand (COD) removal from an olive mill wastewater by coupling ozonation with an aerobic biological treatment. Figure 1 shows the wet air oxidation batch reactor (Top Although some studies give elements on the feasibility of Industrie, France). It was composed of a 152.8-mL stainless coupling chemical–biological processes for the treatment of steel reactor equipped with a stirrer (Rushton propeller, max- industrial effluents, they usually do not consider the whole imum speed 2000 rpm). It was connected to a volumetric and effective coupled process (Zapata et al. 2010;Wang pump allowing injection
Load more

Recommended publications
  • New Trends in Environmental Catalytic Technologies for Water Remediation
    water Editorial New Trends in Environmental Catalytic Technologies for Water Remediation Zacharias Frontistis Department of Chemical Engineering, University of Western Macedonia, GR-50100 Kozani, Greece; [email protected] Due to climate change, industrialization, and overpopulation, water resources man- agement is becoming a crucial sector. Consequently, as the limits of legislation for effluents’ reuse and recycling and use in crops or aquifers enrichment are becoming increasingly stringent, advanced wastewater treatment is becoming very demanding. Simultaneously, in recent years, a new generation of pollutants has emerged. The xenobiotic compounds present a disproportionately high degree of toxicity even though they are detected in mini- mal quantities, which is why they are called micro pollutants. This category contains many compounds belonging to different families, such as endocrine disruptors, pharmaceutical compounds, and personal care products. One of the main problems of this new generation of pollutants is their extremely low biodegradation or their tendency to accumulate in the sludge of conventional biological wastewater treatment systems. On the other hand, in the scientific community and the environmental restoration industry, the search for the optimal solution for removing recalcitrant organic pollutants such as humic acid and inorganics such as heavy metals from environmental matrices continues at an intensive pace. In this light, the scientific interest has turned to a new generation of physicochemical methods called advanced oxidation processes (AOPs). These processes are based on the in situ generation of reactive oxygen Citation: Frontistis, Z. New Trends species. AOPs include technologies such as photocatalysis, photo Fenton and Fenton-like in Environmental Catalytic reactions, activated persulfate, ozonation, wet air oxidation, UV/H2O2, hydrodynamic or Technologies for Water Remediation.
    [Show full text]
  • Application of Catalytic Wet Peroxide Oxidation for Industrial and Urban Wastewater Treatment: a Review
    catalysts Review Application of Catalytic Wet Peroxide Oxidation for Industrial and Urban Wastewater Treatment: A Review Juan José Rueda Márquez 1,*, Irina Levchuk 2 and Mika Sillanpää 1 1 Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12 (Innovation Centre for Safety and Material Technology, TUMA), 50130 Mikkeli, Finland; mika.sillanpaa@lut.fi 2 Water and Wastewater Engineering Research Group, School of Engineering, Aalto University, PO Box 15200, FI-00076 Aalto, Finland; irina.levchuk@aalto.fi * Correspondence: juan.rueda.marquez@lut.fi Received: 12 November 2018; Accepted: 14 December 2018; Published: 19 December 2018 Abstract: Catalytic wet peroxide oxidation (CWPO) is emerging as an advanced oxidation process (AOP) of significant promise, which is mainly due to its efficiency for the decomposition of recalcitrant organic compounds in industrial and urban wastewaters and relatively low operating costs. In current study, we have systemised and critically discussed the feasibility of CWPO for industrial and urban wastewater treatment. More specifically, types of catalysts the effect of pH, temperature, and hydrogen peroxide concentrations on the efficiency of CWPO were taken into consideration. The operating and maintenance costs of CWPO applied to wastewater treatment and toxicity assessment were also discussed. Knowledge gaps were identified and summarised. The main conclusions of this work are: (i) catalyst leaching and deactivation is one of the main problematic issues; (ii) majority of studies were performed in semi-batch and batch reactors, while continuous fixed bed reactors were not extensively studied for treatment of real wastewaters; (iii) toxicity of wastewaters treated by CWPO is of key importance for possible application, however it was not studied thoroughly; and, (iv) CWPO can be regarded as economically viable for wastewater treatment, especially when conducted at ambient temperature and natural pH of wastewater.
    [Show full text]
  • Chemical Oxidation Applications for Industrial Wastewaters
    ©2019 The Author(s) This is an Open Access book distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying and redistribution for non- commercial purposes, provided the original work is properly cited and that any new works are made available on the same conditions (http://creativecommons.org/licenses/by/4.0/). This does not affect the rights licensed or assigned from any third party in this book. This title was made available Open Access through a partnership with Knowledge Unlatched. IWA Publishing would like to thank all of the libraries for pledging to support the transition of this title to Open Access through the KU Select 2018 program. Downloaded from http://iwaponline.com/ebooks/book-pdf/521267/wio9781780401416.pdf by guest on 24 September 2021 Chemical Oxidation Applications for Industrial Wastewaters Chemical Oxidation Applications for Industrial This book covers the most recent scientific and technological developments (state-of-the-art) in the field of chemical oxidation processes applicable for the Chemical Oxidation efficient treatment of biologically-difficult-to-degrade, toxic and/or recalcitrant effluents originating from different manufacturing processes. It is a comprehensive Applications for review of process and pollution profiles as well as conventional, advanced and emerging treatment processes & technologies developed for the most relevant and pollution (wet processing)-intensive industrial sectors. Industrial Wastewaters It addresses chemical/photochemical oxidative treatment processes, case- Olcay Tünay, Işık Kabdaşlı, Idil Arslan-Alaton and Tuğba Ölmez-Hancı specific treatability problems of major industrial sectors, emerging (novel) as well as pilot/full-scale applications, process integration, treatment system design & sizing criteria (figure-of merits), cost evaluation and success stories in the application of chemical oxidative treatment processes.
    [Show full text]
  • Devdopment of the Monolith Froth Reactor for Catalytic Wet Oxidation Of
    05-19-99 15:2_ TU RESEARCH ID=9182246298 P03/09 Devdopment of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Mo_ Final Report on Jt_t_z-_l_ --_ J Martin Abraham" Department of Chemical Engineering The University of Toledo Toledo, OH 43606 John W. Fisher MS 239-1 l NASA - Ames Research Center Moffett Field, CA 94035 The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/AI.,O_ catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of ex'temally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data ,,,,,as 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The "kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate.
    [Show full text]
  • CATALYTIC WET AIR OXIDATION of INDUSTRIAL WASTEWATERS Oxidation of Bisphenol a Over Cerium Supported Metal Catalysts
    A 651 OULU 2015 A 651 UNIVERSITY OF OULU P.O. Box 8000 FI-90014 UNIVERSITY OF OULU FINLAND ACTA UNIVERSITATISUNIVERSITATIS OULUENSISOULUENSIS ACTA UNIVERSITATIS OULUENSIS ACTAACTA SCIENTIAESCIENTIAEA A RERUMRERUM Anne Heponiemi NATURALIUMNATURALIUM Anne Heponiemi Professor Esa Hohtola CATALYTIC WET AIR University Lecturer Santeri Palviainen OXIDATION OF INDUSTRIAL Postdoctoral research fellow Sanna Taskila WASTEWATERS OXIDATION OF BISPHENOL A OVER CERIUM Professor Olli Vuolteenaho SUPPORTED METAL CATALYSTS University Lecturer Veli-Matti Ulvinen Director Sinikka Eskelinen Professor Jari Juga University Lecturer Anu Soikkeli Professor Olli Vuolteenaho UNIVERSITY OF OULU GRADUATE SCHOOL; UNIVERSITY OF OULU FACULTY OF SCIENCE Publications Editor Kirsti Nurkkala ISBN 978-952-62-0898-5 (Paperback) ISBN 978-952-62-0899-2 (PDF) ISSN 0355-3191 (Print) ISSN 1796-220X (Online) ACTA UNIVERSITATIS OULUENSIS A Scientiae Rerum Naturalium 651 ANNE HEPONIEMI CATALYTIC WET AIR OXIDATION OF INDUSTRIAL WASTEWATERS Oxidation of bisphenol A over cerium supported metal catalysts Academic dissertation to be presented with the assent of the Doctoral Training Committee of Technology and Natural Sciences of the University of Oulu for public defence in Kuusamonsali (YB210), Linnanmaa, on 25 September 2015, at 12 noon UNIVERSITY OF OULU, OULU 2015 Copyright © 2015 Acta Univ. Oul. A 651, 2015 Supervised by Professor Ulla Lassi Docent Toivo Kuokkanen Reviewed by Professor Albin Pintar Doctor Sylvain Keav Opponent Professor Claude Descorme ISBN 978-952-62-0898-5 (Paperback) ISBN 978-952-62-0899-2 (PDF) ISSN 0355-3191 (Printed) ISSN 1796-220X (Online) Cover Design Raimo Ahonen JUVENES PRINT TAMPERE 2015 Heponiemi, Anne, Catalytic wet air oxidation of industrial wastewaters. Oxidation of bisphenol A over cerium supported metal catalysts University of Oulu Graduate School; University of Oulu, Faculty of Science Acta Univ.
    [Show full text]
  • Condensation By-Products in Wet Peroxide Oxidation: Fouling Or Catalytic Promotion? Part I
    catalysts Article Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process Asunción Quintanilla 1, Jose L. Diaz de Tuesta 2,3 , Cristina Figueruelo 1, Macarena Munoz 1,* and Jose A. Casas 1 1 Chemical Engineering Department, Universidad Autónoma de Madrid, Ctra. Colmenar km 15, 28049 Madrid, Spain; [email protected] (A.Q.); cgfi[email protected] (C.F.); [email protected] (J.A.C.) 2 Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal; [email protected] 3 Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, 4200-465 Porto, Portugal * Correspondence: [email protected]; Tel.: 34-91-497-3991; Fax: +34-91497-3516 Received: 22 May 2019; Accepted: 6 June 2019; Published: 11 June 2019 Abstract: The present work is aimed at the understanding of the condensation by-products role in wet peroxide oxidation processes. This study has been carried out in absence of catalyst to isolate the (positive or negative) effect of the condensation by-products on the kinetics of the process, and in presence of oxygen, to enhance the oxidation performance. This process was denoted as oxygen-assisted wet peroxide oxidation (WPO-O2) and was applied to the treatment of phenol. First, the influence of the reaction operating conditions (i.e., temperature, pH0, initial phenol concentration, H2O2 dose and O2 pressure) was evaluated. The initial phenol concentration and, overall, the H2O2 dose, were identified as the most critical variables for the formation of condensation by-products and thus, for the oxidation performance.
    [Show full text]
  • PLEASE DO NOT REMOVE THIS PAGE Accepted Manuscript
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RMIT Research Repository Thank you for downloading this document from the RMIT Research Repository 7KH50,75HVHDUFK5HSRVLWRU\LVDQRSHHQDFFHVVGDWDEDVHVKRZFDVLQJWWKHUHVHDUFK RXWSXWVRI50,78QLYHUVLW\UHVHDUFKHUV 50,755HVHDUFK5HHSRVLWRU\KWWSUHVHDUFKEDQNUPLWHGXDX Citation: Hii, K, Baroutian, S, Parthasarathy, R, Gapes, D and Eshtiaghi, N 2014, 'A review of wet air oxidation and thermal hydrolysistechnologies in sludge treatment', Bioresource Technology, vol. 155, pp. 289-299. See this record in the RMIT Research Repository at: https://researchbank.rmit.edu.au/view/rmit:30221 Version: Accepted Manuscript Copyright Statement: © 2013 Elsevier Ltd Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Australia License Link to Published Version: http://dx.doi.org/10.1016/j.biortech.2013.12.066 PLEASE DO NOT REMOVE THIS PAGE Accepted Manuscript A Review of Wet Air Oxidation and Thermal Hydrolysis Technologies in Sludge Treatment Kevin Hii, Saeid Baroutian, Raj Parthasarathy, Daniel J. Gapes, Nicky Eshtiaghi PII: S0960-8524(13)01906-8 DOI: http://dx.doi.org/10.1016/j.biortech.2013.12.066 Reference: BITE 12789 To appear in: Bioresource Technology Please cite this article as: Hii, K., Baroutian, S., Parthasarathy, R., Gapes, D.J., Eshtiaghi, N., A Review of Wet Air Oxidation and Thermal Hydrolysis Technologies in Sludge Treatment, Bioresource Technology (2013), doi: http:// dx.doi.org/10.1016/j.biortech.2013.12.066 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.
    [Show full text]
  • II EURAF Conference
    capa EURAF EUROPEAN AGROFORESTRY FEDERATION nd 2 European Agroforestry Conference Integrating Science and Policy to Promote Agroforestry in Practice Book of Abstracts June 2014 Cottbus, Germany Editor-In-Chief: Organizing Committee: João HN Palma Dirk Freese Editors: Anja Chalmin Anja Chalmin Christian Dupraz Paul Burgess Rosa Mosquera-Losada Jo Smith Anastasia Panthera Mike Strachan Norbert Lammersdorf Jabier Ruiz Mirazo João HN Palma Adolfo Rosati Joana A Paulo Scientific Committee: Adolfo Rosati Anastasia Panthera Ansgar Quinkenstein Gerardo Moreno Jo Smith Joana A Paulo João HN Palma Rosa Mosquera-Losada Sami Kryeziu ISBN: 978-972-97874-4-7 cover design: Luís Fonseca (The 50 words more frequent in this document, sized proportional to their frequency) Contents Preface .............................................................................................................................................. v New insights into carbon, water and nutrient cycling in agroforestry ........................................ 2 Biophysical Interactions in the Alley Cropping System in Saskatchewan ................................................................... 3 Soil carbon sequestration in a Mediterranean agroforestry system............................................................................. 7 Pasture management under hardwood plantations: legume implantation vs. mineral fertilization ............................ 10 Carbon Sequestration in a Poplar Agroforestry System in India with Wheat and other Crops at Different Spacing and
    [Show full text]
  • Sludge Treatment by Supercritical Water Oxidation and the Optimization of Operational Conditions
    Sludge Treatment by Supercritical Water Oxidation and the Optimization of Operational Conditions by Ze Yan A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Master of Applied Science in Environmental Engineering Carleton University Ottawa, Ontario ©2017, Ze Yan Executive summary The overall objective of this study was to investigate the performance of the supercritical water oxidation (SCWO) technology for the treatment of wastewater sludge, and investigate the degradation of p-tert-butylcatechol (TBC) which is a recalcitrant organic compound. The first phase of the study focused on the optimization of the thickening process that precedes SCWO, and investigated the impact of sludge temperature (10 oC -100 oC) on the optimum polymer dose and conditioning of wastewater sludge. The best results were observed at 35 oC -50 oC, where the highest filtrate volume, cake solids and settling velocity were obtained. The results showed that sludge conditioning at 35 oC -50 oC using the excess heat from the SCWO process can significantly improve treatment performance and result in savings for treatment plants. In the second phase, SCWO treatment of sludge was investigated under a range of operational conditions including sludge solids content (2-12 %), TBC concentration (0.1-1 %), reactor temperature (400-550 oC), reactor pressure (18-28 MPa), oxygen excess (n=1-8) and residence time (1-30 minutes). The results showed that the optimum initial sludge solids content was in the range of 8-10 %, and the optimum SCWO operational parameters were 550 oC, 25 MPa and an oxygen excess of 5.
    [Show full text]
  • Supercritical Water Partial Oxidation
    Proceedings of the 2002 U.S. DOE Hydrogen Program Review NREL/CP-610-32405 SUPERCRITICAL WATER PARTIAL OXIDATION G.T. Hong and M.H. Spritzer General Atomics 3550 General Atomics Court San Diego, CA 92121-1122 Abstract General Atomics is developing Supercritical Water Partial Oxidation (SWPO), a gasification process involving oxidative reactions in a supercritical water environment – akin to high- pressure steam – in the presence of substoichiometric quantities of oxidant. The key potential advantage of the SWPO process is the use of partial oxidation in-situ to rapidly heat the gasification medium, resulting in less char formation and improved hydrogen yield. Another major advantage is that the high-pressure, high-density aqueous environment is ideal for reacting and gasifying organics. The high water content of the medium should encourage formation of hydrogen and hydrogen-rich products and is highly compatible with high water content feeds such as biomass materials. By the same token, the high water content of the medium is effective for gasification of hydrogen-poor materials such as coal. A versatile pilot plant for exploring gasification in supercritical water has been established at the General Atomics’ facility in San Diego. Preliminary testing of the SWPO process has found hydrogen yields of about 10 grams per 100 grams of feed, comparable to those found in prior laboratory- scale work carried out at the University of Hawaii. As in that prior work, a significant amount of the hydrogen found in the gas phase products is derived from the water/steam matrix. Introduction General Atomics is developing Supercritical Water Partial Oxidation (SWPO) for the efficient and environmentally advantageous gasification and hydrogen production from low-grade fuels such as biomass, municipal/solid waste (MSW) and high-sulfur coal.
    [Show full text]
  • Design, Fabrication, and Operational Parameters of a Supercritical Water Oxidation Reactor
    Design, Fabrication, and Operational Parameters of a Supercritical Water Oxidation Reactor Stuart J. Moore A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science University of Washington 2020 Committee: Igor Novosselov, Chair John Kramlich Per Reinhall Program Authorized to Offer Degree: Mechanical Engineering © Copyright 2020 Stuart J. Moore University of Washington Abstract Design, Fabrication, and Operational Parameters of a Supercritical Water Oxidation Reactor Stuart J. Moore Chair of the Supervisory Committee: Igor V. Novosselov Department of Mechanical Engineering Supercritical Water Oxidation (SCWO) has been shown to efficiently destroy wet organic wastes. The process, iterations, and lessons learned during the design and fabrication process of a continuous, inverted SCWO reactor are described. Ethanol is oxidized in a continuous inverted supercritical water oxidation reactor at 25 MPa, with oxidant and fuel preheat temperatures of 380 to 450 °C. Optimal conditions for future operation are found by operating at various premixed fuel concentrations of 0-7 mol% ethanol in water, varying the air to fuel equivalence ratio from 1.1 to 1.8, and utilizing air and hydrogen peroxide as the oxidant. Experimental conditions are chosen for analysis of reactor temperatures during complete oxidation of pilot fuel, where ethanol will rapidly oxidize. Higher premixed concentrations of ethanol produce a more localized, higher temperature reaction occurring closer to the nozzle with longer residence times. Preliminary results find the use of air results in lower reaction temperatures than hydrogen peroxide at similar operational conditions due to nitrogen loading; the experiments with air are still on-going. The results are used to determine the capability of the reactor for the destruction of toxic organic compounds.
    [Show full text]
  • Integration of Hydrothermal Processes on a Forest-Based Biorefinery Site
    INTEGRATION OF HYDROTHERMAL PROCESSES ON A FOREST-BASED BIOREFINERY SITE Linnea Häreskog EN1811 Master thesis, 30 Credits Master of Science in Energy Engineering, 300 Credits Spring term 2018 SAMMANFATTNING Massa- och pappersindustrin är en verksamhet som årligen producerar stora mängder avfall. Förutom bark som är en restprodukt produceras även stora mängder slam från de olika delarna av industrin. Bioslam kallas det slam som kommer från den biologiska avloppsvattenreningsprocessen och är känt som ett särskilt problematiskt avfall. Det är av intresse att sänka mängden slam från pappersmasseindustrin, alternativt hitta nya sätt att hantera slammet. Det vanligaste sättet att behandla slam från massa- och pappersindustrin är genom intern förbränning i industrins barkpanna. Slam är emellertid svårt att avvattna och gör ofta mer skada än nytta när det förbränns i pannorna. Olika tekniker för att försöka avvattna slammet har undersökts tidigare, en som det nyligen börjat rapporteras om är hydrotermisk behandling. Tekniken som beskrivs i denna uppsats kallas på svenska för hydrotermisk karbonisering (HTC) som använder vatten som reaktionsmedium för att förvandla slam till ett kol-liknande material som kallas hydrokol. Hydrokolet har ett högre värmevärde än det ursprungliga slammet och är mer hydrofobt vilket gör det lättare att avvattna. Detta examensarbete beskriver tekniken bakom HTC-processen och presenterar några av de senaste artiklarna inom området. Olika typer av restslam från massa- och pappersindustrin presenteras innan integreringen av en HTC-process på bioraffinaderiområdet i Domsjö, Sverige, diskuteras utifrån tidigare publicerade artiklar. En undersökning angående slam från industrier längs med Norrlandskusten genomfördes för att undersöka om avfallsmaterial liknande det från Domsjö- området finns tillgängligt inom 500 km.
    [Show full text]