Papers by Konstantinos Kostarelos
Immobilized-cell-augmented activated sludge process for treating wastewater containing hazardous compounds
Water environment research, 2007
A novel bioaugmentation scheme called immobilized-cell-augmented activated sludge (ICAAS) was dev... more A novel bioaugmentation scheme called immobilized-cell-augmented activated sludge (ICAAS) was developed. Offline enricher reactors were used to maintain immobilized acclimated cells applied to augment completely mixed activated sludge (CMAS) treating a pentachlorophenol (PCP) pulse loading. Cellulose triacetate (CA) and powder activated carbon (PAC) combined with CA (PAC + CA) were the two media types used for entrapping the PCP-degrading culture. With ICAAS at 5% by volume augmentation, PCP removal of 73.1 and 75.1% via biodegradation, volatilization, and adsorption onto suspended cells, entrapped cells, and media was achieved for the systems with CA and PAC + CA media, respectively, while PCP removal in a control CMAS, which had a comparable level of combined PCP adsorption onto suspended cells and volatilization as the ICAAS, was 48.7%. Results further showed that the immobilized cells retained their PCP-degrading ability when they were fed with the inducer (PCP) once every 20 days.
Immobilized cell augmented activated sludge process for enhanced nitrogen removal from wastewater
Water environment research, 2007
The immobilized cell augmented activated sludge (ICAAS) system combines a cell immobilization tec... more The immobilized cell augmented activated sludge (ICAAS) system combines a cell immobilization technique and an offline enricher-reactor for the bioaugmentation of the activated sludge system to improve treatment performances. In this study, enhanced nitrogen removal using ICAAS was investigated. Laboratory-scale, offline, batch enricher-reactors were used to maintain nitrification and denitrification activities of coimmobilized nitrifiers and denitrifiers used to augment a laboratory-scale completely mixed activated sludge system (CMAS) treating synthetic wastewater. Cellulose triacetate was the media used to entrap nitrifiers and denitrifiers at a 2:1 mass ratio. The ICAAS augmented with the coimmobilized cells between 5 and 20% by volume gained 24 +/- 5% higher nitrogen removal than a control CMAS, which provided nitrogen removal of 28 +/- 7%. The ICAAS scheme is a viable alternative for upgrading existing activated sludge systems to gain better nitrogen removal. .
Environmental impacts of abandoned sulphide mines - the example of Mathiatis Mine in Cyprus
The environmental impacts of the abandoned, open-cast sulphide mine of North Mathiatis (Cyprus) w... more The environmental impacts of the abandoned, open-cast sulphide mine of North Mathiatis (Cyprus) were investigated. In order to assess the pollution in the area, both soil and water samples were collected. More specifically, three water samples were taken from the crater lake and one from the mine pit above the level of the crater lake. The water in the crater lake was characterized as a calcium-magnesium-sulfur brine solution in the presence of high metal concentrations, and were also described as highly acidic (pH 2.93-3.04) with very high electrical conductivity (56905730 μS/cm). The water sample taken from the mine pit above the level of the crater lake was characterized as alkaline (pH=7.63) and, apart from lead (Pb), the concentration of all the other metals examined (Cu, Fe, Cr, Mg, Ca) are not considered elevated. Seven solid samples from the waste dumps were taken, and the sample analysis showed elevated concentrations of heavy metals and high level of acid mine drainage (AM...
Recovery of non–aqueous phase liquids (NAPLs) from the subsurface is problematic, and a serious c... more Recovery of non–aqueous phase liquids (NAPLs) from the subsurface is problematic, and a serious concern for the environmental community. Many treatment approaches are focused on in–situ approaches, either in–situ treatment or recovery of NAPLs, that rely on injecting remedial fluids into the subsurface. Consequently, an understanding of flow behavior within fractured media, and the ability to numerically model flow in fractured rock, is of special interest to environmental practitioners and the focus of this poster.
Remote and In Situ Monitoring of Subsurface Liquid Hydrocarbons
The work presented in this chapter is designed to forward the development of an optical probe for... more The work presented in this chapter is designed to forward the development of an optical probe for the remote monitoring of liquid hydrocarbons. A series of experiments were carried out to differentiate between classes of hydrocarbons and to discriminate between compounds within a class of similar molecular structures. It was observed that unique absorption spectra can be obtained for each hydrocarbon, and this uniqueness can be used to discriminate between hydrocarbons from different families. Results summarize measurements of the Near-Infrared optical absorption of alkanes, aromatics, and chlorinated hydrocarbons. This approach was selected to assess the feasibility of remote in situ measurements using optical waveguides.
Stormwater Management Practices (Closed Drainage) Study: Laboratory Simulation and Field Studies
A Catch Basin Insert (CBI) is a device for reducing stormwater pollution from runoff without requ... more A Catch Basin Insert (CBI) is a device for reducing stormwater pollution from runoff without requiring any land. The New York State Department of Transportation (NYSDOT) has funded this project to evaluate the performance and effectiveness of six commercially-available CBIs: 1) Atlantic Construction Fabric’s Siltsack®, 2) Hydro Compliance Management’s Hydro-Kleen™, 3) KriStar’s FloGard® +PLUS, 4) AbTech’s Ultra-Urban® Filter, 5) Stream Guard™ Catch Basin Insert for Oil & Grease, and 6) Stream Guard™ Passive Skimmer. This document reports the results of both the laboratory and the field studies.
Contributions to science, 2014
The Nireas International Water Research Center (Nireas-IWRC) was established in 2011 with the vis... more The Nireas International Water Research Center (Nireas-IWRC) was established in 2011 with the vision of reaching out to the wider scientific community to exchange knowledge and best practices, to advance the state-of-the-art in water-related scientific research and technologies, and to strengthen public awareness on waterrelated issues. The Centers mission is twofold: to conduct research of high international caliber, while at the same time serving the research needs of Cypriot society, economy, and industry. Among the Centers many research, social, and dissemination activities, of particular note are its efforts in the thematic research areas of: (i) Water Quality, Monitoring and Treatment; (ii) Water Supply and Urban Water Management; and (iii) Socioeconomic Analysis of Water-Related Issues. Nireas-IWRC researchers have already secured significant national, EU, and international funding, and their research results have widely been disseminated in peer-reviewed journals, internat...
RSC Advances
The conceptual application of a single-phase microemulsion in the closed-cycle oil recovery appro... more The conceptual application of a single-phase microemulsion in the closed-cycle oil recovery approach for bitumen and extra-heavy oil reserves.
Application of Miscible Ethane Foam for Gas EOR Conformance in Low-Permeability Heterogeneous Harsh Environments
SPE Journal
Summary Unconventional plays pose a challenging set of operational conditions, including high tem... more Summary Unconventional plays pose a challenging set of operational conditions, including high temperature, high salinity, low permeability, and fracture networks. Aggressive development of these plays and the low primary recovery factors present an opportunity for using enhanced oil recovery (EOR) methods. This work presents a laboratory investigation of miscible ethane (C2H6) foam for gas EOR conformance in low-permeability, heterogeneous, harsh environments [<15 md, 136,000 ppm total dissolved solids (TDS) with divalent ions, 165°F]. The use of C2H6 as an alternative to carbon dioxide (CO2) offers several operational and availability strengths, which might expand gas EOR applications to depleted or shallower wells. Coupling gas conformance also helps improve displacement efficiencies and maximize overall recovery. Minimum miscibility pressure (MMP) displacement tests were performed for dead crude oil from the Wolfcamp Spraberry Trend area using C2H6 and CO2. Aqueous stability, ...
Environmental Geotechnics
The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. ... more The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. The findings of severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) traces in waste water and the practice of disinfecting outdoor spaces in several cities in the world, which can result into the entry of disinfectants and their by-products into storm drainage systems and their subsequent discharge into rivers and coastal waters, raise the issue of environmental, ecological and public health effects. The aims of the current paper are to investigate the potential of water and waste water to operate as transmission routes for Sars-CoV-2 and the risks of this to public health and the geoenvironment. Additionally, several developing countries are characterised by low water-related disaster resilience and low household water security, with measures for protection of water resources and technologies for clean water and sanitation being substandard or not in place. To mitigate the impa...
Environmental Geotechnics, 2020
The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. ... more The coronavirus disease 2019 pandemic has posed severe threats to humans and the geoenvironment. The findings of severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) traces in waste water and the practice of disinfecting outdoor spaces in several cities in the world, which can result into the entry of disinfectants and their by-products into storm drainage systems and their subsequent discharge into rivers and coastal waters, raise the issue of environmental, ecological and public health effects. The aims of the current paper are to investigate the potential of water and waste water to operate as transmission routes for Sars-CoV-2 and the risks of this to public health and the geoenvironment. Additionally, several developing countries are characterised by low water-related disaster resilience and low household water security, with measures for protection of water resources and technologies for clean water and sanitation being substandard or not in place. To mitigate the impa...
The charge alteration of asphaltenes during electro-deposition
Colloids and Surfaces A: Physicochemical and Engineering Aspects
Abstract Electro-deposition (E-D) has been proposed as a promising method for dealing with the as... more Abstract Electro-deposition (E-D) has been proposed as a promising method for dealing with the asphaltenes deposition issue. An observed alteration of the native, positive asphaltene charge during the process has attracted wide attention since it influences the feasibility and efficiency of this method. To investigate this phenomenon, E-D of various asphaltenes with resins was studied. The results demonstrate that the charge alteration of asphaltenes is the result of net adsorption of negative charges within the fluid onto the asphaltenes under high electric field strength. The minimum electric field strength required to trigger the charge alteration of asphaltenes from coal tar and bitumen were 12000 V/cm and 4500 V/cm, respectively, exhibiting a strong influence of chemical composition of asphaltenes on the charge alteration. Moreover, the adsorption of resins on asphaltenes resulted in the repression of charge alteration behavior that varied with different resins. The resins from bitumen had the highest repression on asphaltenes from bitumen, as 2 g/L-resin can increase the minimum electric field strength required for charge alteration to 12000 V/cm. The results of the work provide an essential guide for the further development of an E-D procedure that could be used for efficient asphaltenes removal.
Surfactant flooding makes a comeback: Results of a full-scale, field implementation to recover mobilized NAPL
Journal of Contaminant Hydrology
Non-aqueous phase liquid (NAPL) remediation techniques using surfactants, such as enhanced pump a... more Non-aqueous phase liquid (NAPL) remediation techniques using surfactants, such as enhanced pump and treat (also known as Surfactant-Enhanced Aquifer Remediation, "SEAR") and micellar flooding provide a faster and more efficient way to recover NAPL from the subsurface. Micellar flooding is a recovery technique that relies on the ability of surfactants to mobilize the NAPL phase by reducing the interfacial tension between the aqueous phase and the NAPL. The application of micellar flooding for NAPL recovery has been limited to laboratory studies and some pilot-scale field applications primarily due to concerns that the technology might lead to uncontrolled movement of NAPL. This paper presents results from a full-scale field application of the micellar flood process designed to mobilize and recover an LNAPL (Jet fuel) from a surficial sandy aquifer located at a tank facility in western Jutland, Denmark. Phase behavior and flow experiments were conducted with field samples to identify suitable surfactant formulations. A field-scale simulation model was developed that indicated that a line-drive pattern with hydraulic control wells would be optimal for NAPL recovery. In addition to monitoring during the field implementation, monitoring was conducted immediately after and for a period of >1 year. The field implementation resulted in >90% recovery (approximately 36,000 Kg of LNAPL) based on the mass balance using laser-induced fluorescence (LIF) and chemical soil analysis (total petroleum hydrocarbon or TPH and BTEX) data. Post-surfactant flood site monitoring consisted of sampling water from multi-levels and from recovery wells. Groundwater samples were analyzed for total petroleum hydrocarbon (TPH) and benzene, toluene, ethylbenzene and xylene (BTEX). The pre-treatment and post-treatment mass discharges were also monitored, which led to a relationship between mass discharge with the mass reduction in the source zone. Also, the mass discharge Γ-model commonly used for DNAPL modeling was successfully implemented for LNAPL remediation. Studies of field applications of surfactant remediation processes are not readily available; it is especially rare to present a study of micellar flooding implementation for full-scale remediation processes.
Water
Despite the widespread presence of groundwater recharge check dams, there are few studies that qu... more Despite the widespread presence of groundwater recharge check dams, there are few studies that quantify their functionality. The objectives of this study are (i) to assess groundwater recharge in an ephemeral river with and without a check dam and (ii) to assess sediment build-up in the check-dam reservoir. Field campaigns were carried out to measure water flow, water depth, and check-dam topography to establish water volume, evaporation, outflow, and recharge relations, as well as sediment build-up. To quantify the groundwater recharge, a water-balance approach was applied at two locations: at the check dam reservoir area and at an 11 km long natural stretch of the river upstream. Prediction intervals were computed to assess the uncertainties of the results. During the four years of operation, the check dam (storage capacity of 25,000 m 3) recharged the aquifer with an average of 3.1 million m 3 of the 10.4 million m 3 year −1 of streamflow (30%). The lower and upper uncertainty limits of the check dam recharge were 0.1 and 9.6 million m 3 year −1 , respectively. Recharge from the upstream stretch was 1.5 million m 3 year −1. These results indicate that check dams are valuable structures for increasing groundwater resources in semi-arid regions.
An Expression for Irregularly–Distributed Hydrocarbon Volume Using Exponential Decay Method
Environmental Geotechnics
In both the oil and gas and the environmental remediation industries, the ability to locate and q... more In both the oil and gas and the environmental remediation industries, the ability to locate and quantify hydrocarbons in the subsurface is of value. Partitioning interwell tracer testing has been shown effective at detecting and measuring uniformly distributed hydrocarbon mass. Difficulty arises when the hydrocarbon is irregularly distributed – that is, when the overall hydrocarbon saturation within the swept pore volume is low but is high locally. The method of moments underestimates the saturation when most of the tracer bypasses the hydrocarbon. The small zone containing the hydrocarbon that is contacted by the tracers produces a long ‘tail’. An alternative method was developed to compute the irregularly distributed hydrocarbon saturation, and the complete mathematical derivation is presented that utilises the exponential decay of each tracer. The method was verified using experimental data from a two-dimensional physical model where the hydrocarbon saturation was high on a local...
Single Phase Microemulsions Applied to Oil Sands
SPE Western Regional Meeting
RSC Advances
Blending crude oil with short-chain paraffins is a common method to improve the oil quality durin... more Blending crude oil with short-chain paraffins is a common method to improve the oil quality during heavy oil upgrading.
The Effect of Molecular Composition on the Electro-Deposition of Asphaltene
SPE International Conference on Oilfield Chemistry
Asphaltene deposition and plugging of pipelines during oil production and transportation is consi... more Asphaltene deposition and plugging of pipelines during oil production and transportation is considered a challenging flow assurance issue. Instead of adding dispersants, the concept proposes to remove asphaltenes from the flow stream by means of electro–deposition prior to transportation to prevent later deposition. This study mainly examined the effect of molecular composition on the efficiency of electro-deposition. Two sources of asphaltene, namely asphaltenes from coal tar ("AS-C") and asphaltenes from bitumen ("AS-B") with different molecular composition were collected in this study. Elemental analysis revealed that both AS-B and AS-C possessed transition metals (V and Ni) and heteroatoms (O, N and S). The effect of oil components on the stability of two asphaltenes was studied. After conducting the electro–deposition of both asphaltenes with various oil components and electric field strength, the deposition charge and recover rate was recorded and compared. During stability test, the amount of precipitated AS-B decreased with increasing aromaticity of solvent, while that of AS-C was constant. For electro–deposition, the electro–kinetic behavior of AS-C reveals strong sensitivity to the oil components. Interestingly, both asphaltenes exhibited a change in the net charge, which occurred under 6000 V/cm and 12000 V/cm for AS-B and AS-C respectively, as evidenced by a change in the electrode upon which deposition ocurred. Based on the results, the efficiency of electro–deposition is confirmed to depend upon the metal and heteroatoms of asphaltenes; in addition, and by interaction with these elements, the oil composition and electric field affected the stability, net charge, and electro–kinetic behavior of apshaltene. However, our study is the first to show that the current density plays a role in the net charge of the asphaltene molecule and offers an explanation to the controversy over the polarity or the charge sign of asphaltenes, which gives a clue to understanding the microstructure of asphaltenes. In addition, this is the first study to include the effect of oil components and electric field strength on the performance of deposition, which makes further optimization of the proposed process possible.
A novel electro-deposition based asphaltene removal strategy
Fuel
Abstract The deposition of asphaltene on interior pipe surfaces is considered a challenging flow ... more Abstract The deposition of asphaltene on interior pipe surfaces is considered a challenging flow assurance issue. By exploiting the net charge of the asphaltene molecule, it can be effectively removed from the flow stream by means of electro-deposition before transportation to prevent later deposition. To evaluate this concept, electro-deposition of asphaltene from a synthetic oil using varying electric field strength and solvent type were studied. The results demonstrate that the asphaltene molecule possesses a native positive charge, however an induced negative charge can be observed under high current density; depending on the current density, deposition onto the cathode, anode, or both were observed. Both solvent polarity and viscosity affected the removal performance by way of effect on the asphaltene stability and electrophoretic mobility. The interaction of asphaltene and resin resulted in a slight neutralization of charge and strong repression of charge alternation behavior. A series of experiments were conducted to mimic a continuous process by means of repeated electro-deposition cycles. With 8000 V/cm electric field applied, 119 g/m2 asphaltene can be deposited onto electrodes within 10 min using ∼1 kJ energy input. Finally, electro-deposition of actual crude oil was conducted; the electric field strength required to deposit the asphaltene decreased with higher dilution ratio. The speed and high energy efficiency make electro-deposition a promising strategy for asphaltene removal.
Hydrocarbon Recovery From Oil Sands by Cyclic Surfactant Solubilization in Single-Phase Microemulsions
Journal of Energy Resources Technology
Extra heavy crude oil (bitumen) reserves represent a significant part of the energy resources fou... more Extra heavy crude oil (bitumen) reserves represent a significant part of the energy resources found all over the world. In Canada, the “oil sands” deposits are typically unconsolidated, water-wet media where current methods of recovery, such as open pit mining, steam-assisted gravity drainage (SAGD), vapor extraction, cold heavy oil production with sand, etc., are controversial due to adverse effect on environment. Chemical enhanced oil recovery (cEOR) techniques have been applied as alternatives but have limited success and contradictory results. An alternative method is described in this paper, which relies on the application of single-phase microemulsion to achieve extremely high solubilization. The produced microemulsion will be less viscous than oil, eliminating the need for solvent addition. Produced microemulsion can be separated to recover surfactant for re-injection. The work in this paper discusses phase behavior experiments and a flow experiment to prove the concept that ...
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Papers by Konstantinos Kostarelos