Development of Photolysis Enhanced Oxidation Technologies for the Removal of Polycyclic Aromatic Hydrocarbons from Offshore Produced Water PDF Download

Author: Jing Ping
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Offshore Produced Water (OPW) represents the largest volume waste stream from offshore oil and gas (OOG) production activities. It poses major environmental and operational challenges to offshore petroleum industries for requiring more efficient and environmental friendly on-site management. This is true particularly under growing regulatory and economic pressure to reduce the impact of waste discharges. Conventional on-site OPW monitoring and treatment is mainly focused on the oil and grease portion for meeting the regulatory standards, while limited efforts have been given to dissolved compounds especially including Polycyclic Aromatic Hydrocarbons (PAHs). PAHs are proved as one of the most significant contributors to the ecological hazard posed by OPW discharges because of their toxicity, persistency, and potential for bioaccumulation even at a trace level. As a result, effective measurement of PAHs in OPW is imperative, and advanced on-site treatment of the effluent is desired to improve the conventional systems. This dissertation research focused on the development of new analytical testing methods and photolysis and its enhanced oxidation technologies for treating PAHs in OPW. They are composed of the key tasks including: a) refining of solid-phase extraction (SPE) and liquid-phase microextraction (LPME) pretreatment systems to extract PAHs from OPW; b) enhancement of gas chromotography-mass spectrometry (GC-MS) analytical methods for background and residual PAHs analysis; c) design and fabrication of photochemical oxidation reactors for batch- and bench-scale experiments; d) systematic one-factor-at-a-time (OFAT) analysis of key parameters and factors in the course of direct photolysis and photocatalysis; e) investigation of efficacy, parameters/factors interactions, kinetics and mechanisms of the enhanced hybrid oxidation systems by integrating photolysis and ozonation (O3) and/or hydrogen peroxide (H2O2); and f) development of central composite design (CCD) based response surface modeling (RSM) models for process simulation and optimization. The major contribution of this research is the development of compact, efficient, and eco-friendly technologies for on-site OPW testing and treatment. The developed technologies are proved technically sound by lab experiments with high efficiency in detection and removal of PAHs. The research outcomes bring significant environmental, economic and social benefits to industry, government and academia by providing not only effective but also environmentally benign methods for treating OPW generated from OOG production.

Author: Jisi Zheng
Publisher:
ISBN:
Category :
Languages : en
Pages :

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As the largest waste stream from offshore oil and gas industry, offshore produced water contains dissolved toxic organic pollutants that are hard to be removed by conventional wastewater treatment technologies. Among those pollutants, polycyclic aromatic hydrocarbons (PAHs) are of growing concern due to their high toxicity and persistence in the marine and coastal environments. Removal of PAHs from produced water before disposal is thus essential for offshore oil and gas production. However, the offshore operation and facilities (e.g., platforms and ships) usually have many special technical and economic constraints that limit the applications of many treatment technologies. Since advanced oxidation processes (AOPs) are featured with high cost-efficiency, small footprints, and eco-friendliness which well match with the requirements of offshore operation and present a promising treatment option for offshore wastewater (e.g., produced water). However, limited research efforts have been reported in investigating AOPs' mechanisms, performance and applicability in treating offshore produced water. In order to help fill the knowledge and technical gaps, this research aimed at development of advanced oxidation technologies for removal of PAHs from offshore produced water treatment and examination of the oxidation processes and kinetics, and effluent toxicity and biodegradability. To ensure efficient, reliable, and acurate analysis results, a refined analytical method, Vortex and Shaker Assisted Liquid-liquid Microextraction (VSA-LLME), was first developed, tested and adopted in the analysis of 16 priority PAHs recommended by U.S. Environmental Protection Agency. Under the optimized condition, the enrichment factors ranged from 68 to 78. The recoveries of the method were 74 to 85%, and the limits of detection were as low as 2 to 5 ng/L. The linearity results (R2 values) for 16 PAHs were all above 0.99 with the relative standard deviations (RSD%) of 6 to 11%. This method also creatively utilized the organic constitutes in produced water as dispersive solvents to reduce the solvent consumption. Its straightforward procedure and excellent performance showed a strong potential for application in research and regulatory and industrial practice. The photolysis of 16 PAHs in offshore produced water was then thoroughly investigated in this research. The results indicated much more complex kinetics in the removal of PAHs from produced water than those in stilled water, mianly due to the complex chemical constitutions of the substrate. The experiment disclosed the unique mechanisms including direct photolysis, dynamic light screening, and radical induced organic synthesis. A novel kinetic model involving dynamic light screening was developed and approved to support the mechanism analysis, and a semi-empirical model was also established to simulate the photolysis process. The proposed mechanisms and kinetics not only helped answered some scientific questions but also showed strong practical significance for further AOP development and applications. The performance of ozonation in removing polycyclic aromatic hydrocarbons (PAHs) from offshore produced water (OPW) was studied. The experimental results showed that ozone dose had positive effect due to enhancement in ozone decomposition, and radical yield. On the other hand, the removal was suppressed at increased bubble size and pH, which may be attributed to the reduction of interfacial area as well as stronger radical scavenging effect, respectively. Microtox tests showed that the acute toxicity of OPW was reduced after ozonation, which was highly correlated with the removal of PAHs. Such reduction was inhibited at high ozone doses, possibly due to the formation of disinfection by-products via reactions with halogens. As compared to control, ozonated OPW had higher oxygen uptake and less organic residual after biodegradation, indicating more bioavailable organics were formed after ozonation. Results from this study can be used as good references for designing new or upgrading existing OPW treatment systems using ozonation. Based on the experimental results, the three major mechanisms affecting the PAHs removal through AOP treatment were proposed in the first time. Novel kinetic models based on the dynamic oxidant competitiveness was developed and validated. The model was able to simulate the oxidation processes, quantify the effects of different operational parameters. The testing result also indicated that insufficient treatment could lead to carcinogenetic by-products. On the other hand, proper advanced oxidation technologies could significantly increase biodegradability, showing strong potential of combining with conventional biological treatment in practice.

Author: Bo Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The growing amount and environmental impact of offshore oily wastewater especially offshore produced water (OPW) have drawn significant attention in recent years. The petroleum hydrocarbons in wastewater can have severe negative effects in a long term on coastal and marine ecosystems if without sufficient treatment before discharge. Polycyclic aromatic hydrocarbons (PAHs) as a representative of dissolved chemical compounds or environmental pollutants in oily wastewater have been a major issue of marine environments due to their carcinogenic or mutagenic, toxic, persistent and bio-accumulative properties. To reduce the negative impact of produced water to the marine ecosystem, it is required to remove all toxicants especially PAHs before discharge. Various challenges have been identified in implementing conventional technologies (e.g., physical separation, chemical oxidation and biological remediation) for treating the dissolved organic pollutants (e.g., PAHs). Therefore, the research and development of more effective technologies to address these concerns are much desired. Photocatalysis generates powerful oxidative radicals which can rapidly mineralize organics especially aromatic compounds, offering a great potential use in removing PAHs from oily wastewater. However, the photocatalytic degradation of organics can be dramatically inhibited by the complex matrix of OPW. Limited in-depth studies were reported on the behaviors and interactions of different components in produced water during photocatalysis. The mechanisms of the interferences are of utmost importance to the development of highly efficiency treatment technologies. The generation of intermediates caused by the complex matrix and inhibited treatment process could further lead to the increase in the toxicity of treated effluent to the marine ecosystem, and consequently reduce its potential in natural attenuation. In addressing these challenges and fulfill the knowledge gaps, this research is focused on the evaluation of the key factors and the mechanisms of OPW matrix in photocatalysis, and the development of enhanced photocatalytic oxidation processes to aid the OPW treatment, thus can achieve both high efficiency in removal of PAHs, and low toxicity and high biodegradability of the effluent. The matrix effect was first investigated in a suspensive photocatalytic oxidation system, in which the synthesized TiO2 nanoparticles were used. It is indicated that the degradation of PAHs was inhibited by the impurities in OPW matrix in many ways: the alkaline-earth cations caused the flocculation of the particle; the insoluble particulate matters competed with PAHs in the adsorption on TiO2; the competition and the fouling effect of other dissolved organic matters were deteriorating the process. To enhance the treatment process, immobilized TiO2 was used instead and it was compared with the TiO2 nano-particles. Improvements were found in both naphthalene adsorption and degradation in the immobilized photocatalytic oxidation system, indicating immobilized TiO2 was more efficient and durable than TiO2 nanoparticles in oily wastewater treatment. The competition of hydrocarbons especially phenols played a key role in the degradation of PAHs. The fouling on the catalyst surface was verified by the scaling of alkaline-earth metals and the deposition of organic matters. Further improvement was aimed at developing a novel UV-light-emitted diode (UV-LED)/TiO2 nanotube array (TNA)/ozonation process for treating OPW. The involvement of ozone was to reduce the competition of other organics and enhance the degradation efficiency. The TNA with hollow 1-D tubular nano-structures was applied because of the combined advantage of nano-particle and immobilization, as well as high quantum yield. UV-LED has the advantage of high energy efficiency and long-life time. In the integrated system, the removal of PAHs can be achieved within 30-min treatment with the half-lives reduced to less than 10 mins. Factorial analysis demonstrates that the best dose of TNA is 0.2 g/L. Light intensity affects the generation of iodine radicals, which is a strong scavenger of ozone thus reduces the efficiency of PAHs removal. Ozone dose is a dominated factor that promotes the degradation. Further results indicate that the degradation of phenols and PAHs with higher solubility favors to undergo to ozone-inducted oxidation, while PAHs with lower solubility are more likely oxidized on the catalyst surface. The toxicity and biodegradability of OPW treated by photocatalytic oxidation were investigated during and after the treatment. Studies on the intermediates formed during the photocatalytic ozonation treatment in the presence of halogen ions reveal the mechanism and various reaction pathways of aromatic compounds. Iodization and bromination were the dominant interfering reactions in sequential stages. Two multivariable regression models were developed to quantify the contributions of key toxicants (e.g., total PAHs, total phenols, dibromo-pentane and bromoform) to the acute toxicity of OPW during the treatment processes. It was observed that by removing the total PAHs and total phenols, the acute toxicity was increased from 3% to 57%, and the biodegradability (BOD28/COD ratio) was doubled more than 80% by the integrated UV-LED/TNA/ozonation process. Further, the biodegradation rate of bromoform was much faster than those of phenols, indicating that the proposed technology features high efficiency and has low impact on marine environment. In this research, I have investigated the matrix effect of OPW on photocatalysis and the impacts to the suspended and immobilized TiO2. A novel integrated UV-LED/TNA/ozonation process was developed to treat OPW. The efficiency of the process, the effects of operational parameters, the intermediates and degradation pathways, and their contribution to the acute toxicity and biodegradability of treated effluent were investigated. The scientific contributions of the research are: 1) revealing and summarizing the key mechanisms of OPW matrix and their key effects on photocatalysis, 2) understanding the interactions of OPW composition with catalyst surface, 3) fulfilling the knowledge gaps on the removal of PAHs from OPW by the UV-A (365 nm) photocatalytic ozonation process, including the interactive mechanisms of the adsorption and photocatalytic oxidation, the behaviors of halogenic ions, and the effects of the operational factors, 4) proposing the altered photodegradation pathways of aromatic organic matter in the presence of halogen ions, and 5) proposing toxicity contribution models targeted on the most toxic compounds in OPW with/without photocatalytic ozonation. The findings of this thesis work also help 1) develop a better strategy to countermeasure the difficulties in the application of photocatalytic oxidation for treating OPW, 2) develop an advanced alternative option for the OPW management, and 3) monitor the composition and toxicity changes during the process and hence the production of by-products in the OPW treatment practice.

Author: Marta I. Litter
Publisher: CRC Press
ISBN: 1138001279
Category : Science
Languages : en
Pages : 390

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Book Description
Advanced Oxidation Technologies (AOTs) or Processes (AOPs) are relatively new and innovative technologies to remove harmful and toxic pollutants. The most important processes among them are those using light, such as UVC/H2O2, photo-Fenton and heterogeneous photocatalysis with TiO2. These technologies are also relatively low-cost and therefore useful for countries under development, where the economical resources are scarcer than in developed countries. This book provides a state-of-the-art overview on environmental applications of Advanced Oxidation Technologies (AOTs) as sustainable, low-cost and low-energy consuming treatments for water, air, and soil. It includes information on innovative research and development on TiO2 photocatalytic redox processes, Fenton, Photo-Fenton processes, zerovalent iron technology, and others, highlighting possible applications of AOTs in both developing and industrialized countries around the world in the framework of “A crosscutting and comprehensive look at environmental problems”. The book is aimed at professionals and academics worldwide, working in the areas of water resources, water supply, environmental protection, and will be a useful information source for decision and policy makers and other stakeholders working on solutions for environmental problems.

Author: Sasan Fazeli
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Development of UVC advanced oxidation photolysis combined with membrane electro- bioreactor for simultaneous removal for emerging contaminants and reduction of by-products The continuous discharge of emerging contaminants (ECs) to the aquatic ecosystem generate concerns due to their unpredictable risks to human and environment. The presence of ECs in source water attributed to the conventional wastewater treatment facilities which are not fundamentally designed to completely eliminate these micropollutants at low concentrations. The aim of this research was to enhance the wastewater treatment to the level of its potential reuse as a source of water. The investigations were conducted at lab and pilot scale in 8 phases and several stages. Initially, the removal of selected ECs was optimized. Subsequently, the by-product formation and their identification were conducted. Then, the study focused on the by-product removal. In subsequent phases, the optimal technological parameters were verified in natural conditions, at the pilot scale in AOP (advance oxidation process) and AO-MEBR (membrane electro-bioreactor) facilities. Such approach permitted to study the removal of sulfamethoxazole (SMX), 17- alpha ethynyl estradiol (EE2), caffeine (CAF) and paracetamol (PCM) from various aqueous solutions (DI water, river water, effluent after wastewater treatment, and wastewater). A developed model investigated the effect of technological parameters on pharmaceuticals' removal efficiency and on by-product abatement. The results showed superior removal efficiency (99%) by both UV/H2O2 AOP and UV/O3 AOP of SMX, PCM, CAF and EE2 in comparison to sole UVC photolysis (30-40%). UV/O3 AOP demonstrated an elevated rate and removal by 10-15% higher than ozonation alone. The target ECs such as SMX, PCM were removed by more than 80% in effluent and more than 90% in river water during 60 minutes. The differences in the ECs and their byproducts removal from various aqueous matrices were discussed from the matrix properties perspectives, particularly non-target constituents (EfOM, NOM and sacavengers) present at different amounts in target matrices. The influence of operational parametrs (oxidant and UV doses, exposure time, pH) was defined, where particular usefulness of Surface Response Methodology was underlined. Overall, the SMX and by-products' abatement (99.99%) in different matrices by AO-MEBR hybrid system was evident. Four major SMX by-products (BP-99, BP-270, BP-288, BP-172) identified by LC-MS-MS, revealed longer lifetime and stability even after parent SMX ion removal. By applying optimal technological parameters, i.e. pH, oxidant dose and aeration rate, the by-products amounts were successfully controlled. Degradation mechanisms, reaction pathway and evolution of by-products during treatment in various aqueous solutions were conducted. Particular attention was paid on the effect of OH scavenging, the role of non-target constituencies, operation parameters, as well as aeration and superoxide radicals. Furthermore, the toxicity was decreased and energy consumption for target pollutant removal was minimized (20-25%). The AO-MEBR system not merely improved the quality of effluent with respect to refractory organic pollutants, but also likely promoted by-products and toxicity mitigation as well as saving energy leading to improved potential of water recovery from sewage.

Author: Mihaela I. Stefan
Publisher: IWA Publishing
ISBN: 1780407181
Category : Science
Languages : en
Pages : 712

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Book Description
Advanced Oxidation Processes (AOPs) rely on the efficient generation of reactive radical species and are increasingly attractive options for water remediation from a wide variety of organic micropollutants of human health and/or environmental concern. Advanced Oxidation Processes for Water Treatment covers the key advanced oxidation processes developed for chemical contaminant destruction in polluted water sources, some of which have been implemented successfully at water treatment plants around the world. The book is structured in two sections; the first part is dedicated to the most relevant AOPs, whereas the topics covered in the second section include the photochemistry of chemical contaminants in the aquatic environment, advanced water treatment for water reuse, implementation of advanced treatment processes for drinking water production at a state-of-the art water treatment plant in Europe, advanced treatment of municipal and industrial wastewater, and green technologies for water remediation. The advanced oxidation processes discussed in the book cover the following aspects: - Process principles including the most recent scientific findings and interpretation. - Classes of compounds suitable to AOP treatment and examples of reaction mechanisms. - Chemical and photochemical degradation kinetics and modelling. - Water quality impact on process performance and practical considerations on process parameter selection criteria. - Process limitations and byproduct formation and strategies to mitigate any potential adverse effects on the treated water quality. - AOP equipment design and economics considerations. - Research studies and outcomes. - Case studies relevant to process implementation to water treatment. - Commercial applications. - Future research needs. Advanced Oxidation Processes for Water Treatment presents the most recent scientific and technological achievements in process understanding and implementation, and addresses to anyone interested in water remediation, including water industry professionals, consulting engineers, regulators, academics, students. Editor: Mihaela I. Stefan - Trojan Technologies - Canada

Author: John A. Roth
Publisher: CRC Press
ISBN: 1000448495
Category : Technology & Engineering
Languages : en
Pages : 256

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This book focuses on present state of the art chemical oxidation technologies with regard to various wastewater applications. It is a valuable aid to engineers and scientists engaged in developing cost-effective solutions to complex water quality problems in today's regulatory environment.

Author: Simon Parsons
Publisher: IWA Publishing
ISBN: 1843390175
Category : Science
Languages : en
Pages : 370

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Book Description
The suitability of Advanced Oxidation Processes (AOPs) for pollutant degradation was recognised in the early 1970s and much research and development work has been undertaken to commercialise some of these processes. AOPs have shown great potential in treating pollutants at both low and high concentrations and have found applications as diverse as ground water treatment, municipal wastewater sludge destruction and VOCs control. Advanced Oxidation Processes for Water and Wastewater Treatment is an overview of the advanced oxidation processes currently used or proposed for the remediation of water, wastewater, odours and sludge. The book contains two opening chapters which present introductions to advanced oxidation processes and a background to UV photolysis, seven chapters focusing on individual advanced oxidation processes and, finally, three chapters concentrating on selected applications of advanced oxidation processes. Advanced Oxidation Processes for Water and Wastewater Treatment will be invaluable to readers interested in water and wastewater treatment processes, including professionals and suppliers, as well as students and academics studying in this area. Dr Simon Parsons is a Senior Lecturer in Water Sciences at Cranfield University with ten years' experience of industrial and academic research and development.

Author: Alfons Vogelpohl
Publisher: IWA Publishing
ISBN: 9781843394020
Category : Science
Languages : en
Pages : 348

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Book Description
Advanced oxidation processes (AOPs), based on radical reactions, are among the most prominent of a group of new treatment technologies that will enable a more effective use of water resources, particularly in the recycling of wastewater for agricultural or industrial applications. They hold out the potential of complete conversion of pollutants to carbon dioxide, water and mineral salts. To date the major barrier to their application has been high investment and operating costs, but better understanding of radical production methods and reaction pathways is identifying new processes and defining applications where AOPs are most competitive. The papers selected for these proceedings were selected from a very high-quality conference that was designed to present advances in fundamental research as well as in the development and application of AOPs. Topics covered include: fundamentals and measurement; process integration and combination; pressurized oxidation; photocatalysis; and new processes and applications. These proceedings provide an authoritative summary of current knowledge in these areas and offer pointers to future research and development of a key technology for the 21st century.

Author: Alfons Vogelpohl
Publisher:
ISBN:
Category : Oxidation
Languages : en
Pages : 396

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