Plant Inlet Research Articles

Modelling the potential for multi-location in-sewer heat recovery at a city scale under different seasonal scenarios

A computational network heat transfer model was utilised to model the potential of heat energy recovery at multiple locations from a city scale combined sewer network. The uniqueness of this network model lies in its whole system validation and implementation for seasonal scenarios in a large sewer network. The network model was developed, on the basis of a previous single pipe heat transfer model, to make it suitable for application in large sewer networks and its performance was validated in this study by predicting the wastewater temperature variation across the network. Since heat energy recovery in sewers may impact negatively on wastewater treatment processes, the viability of large scale heat recovery was assessed by examining the distribution of the wastewater temperatures throughout a 3000 pipe network, serving a population equivalent of 79500, and at the wastewater treatment plant inlet. Three scenarios; winter, spring and summer were modelled to reflect seasonal variations. The model was run on an hourly basis during dry weather. The modelling results indicated that potential heat energy recovery of around 116, 160 & 207 MWh/day may be obtained in January, March and May respectively, without causing wastewater temperature either in the network or at the inlet of the wastewater treatment plant to reach a level that was unacceptable to the water utility.

Parametric, cyclic aging and characterization studies for CO2 capture from flue gas and catalytic conversion to synthetic natural gas using a dual functional material (DFM)

Abstract Solid sorbents have attracted extensive research attention for enhanced adsorption of effluent CO2. A Dual Functional Material (DFM), composed of a CO2 adsorbent (“Na2O” derived from hydrogenated Na2CO3) in combination with Ru both supported on the same Al2O3, overcome limitations of traditional sorbent technology. It captures CO2 from a simulated flue gas and catalytically converts it to synthetic natural gas (CH4) in the same reactor and temperature utilizing H2 generated from renewable sources. The methane produced is recycled to the plant inlet for repeated combustion maintaining a closed carbon loop. The process is envisioned to operate with parallel reactors, containing DFM, where one captures CO2 and the other methanates and vis versa for continuous operation. We report parametric, cyclic aging and characterization studies in a simulated natural gas power plant flue gas using 10 g of 5 mm × 5 mm tablet DFM. This material shows stable CO2 capture and conversion to CH4 performance for over 50 adsorption and conversion aging cycles (equivalent to 80 h of operation) with no loss in BET surface area, CO2 capture capacity nor Ru dispersion.

Batch leachate treatment using stirred electrocoagulation reactor with variation of residence time and stirring rate

This study aims to reduce pollutant levels of the leachate by electrocoagulation method using a stirred electrocoagulation reactor as the electrochemical water treatment. The release of active coagulants as metallic ions took place in the anode, while in the cathode, the electrolysis reaction in the form of hydrogen gas dischargeoccurred. The source of wastewater is Waste Water Treatment Plant inlet III of Bantar Gebang, Bekasi. Some parameters were analyzed in this research, i.e., Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), NH3, NO3-, NO2-, N-total, and organic substances as well as the microorganism growth before and after electrocoagulation, with variations of detention time (seconds) of 10, 20, 120, 600 and rapid mixing conditions (rpm) of 60, 100 and 200. The results show that the greater the rapid mixing speed and the detention time of electrolysis, the higher the removal of contaminants in liquid waste. The optimum condition of electrocoagulation was encountered at 200 rpm rapid mixing with 600 seconds of processing time. The removal efficiencies of electrocoagulation method for each parameter are TSS of 46.80%, BOD5 of 71.33%, COD of 73.77%, Pb of 62.5%,and NH3-N of 57.92%,whereas the pH value has been increased from 8.03 to 8.95. The electrocoagulation method can reduce levels of pollutants, complying with the environmental standards.

The effective use of data analytics in an advanced compressor performance and degradation monitoring system

Origin is the upstream operator and joint venture partner in Australia Pacific LNG. Origin’s integrated gas operations require reliable, sustainable delivery of gas to the downstream LNG facility on Curtis Island. This scale of operation requires establishing a ‘single source of truth’ regarding compressor condition and performance while achieving maximum and reliable compression capacities. Therefore, capability of monitoring performance of centrifugal compressors across the fleet is considered an essential component of production surveillance. Xodus leveraged Origin’s OSIsoft PI AF (PI Historian Asset Framework) tool. This system was used to build a compressor performance and degradation monitoring tool to accurately identify early indications of degradation in a multi-stage centrifugal compression train. The tool utilises live data from the PI historian to calculate key performance indicators which define compressor and driver operation. Dimensionless parameter analysis allows Origin to accurately quantify performance degradation regardless of variations in plant inlet conditions at each gas processing facility. Deviation from baseline performance in dimensionless parameters such as polytropic efficiency, work input number and polytropic head coefficient is used to quantify capacity losses, additional power consumption and increase in suction pressure. The tool provided the ability to use performance indicators to confidently determine the mode and extent of compressor degradation and prevent accelerated fouling which can lead to premature bundle changes. Also, this information helps streamline and has led to a major step change for the decision-making process concerning maximum production from rotating equipment. Additionally, this allowed operations to be confident on the condition of the compressor bundle, continue operation with higher capacities during high demand periods and ensure compressor bundle changeout is optimised for availability and economic aspects.

Impact of large beam-induced heat loads on the transient operation of the beam screens and the cryogenic plants of the Future Circular Collider (FCC)

The Future Circular Collider (FCC) under study at CERN will produce 50-TeV high-energy proton beams. The high-energy particle beams are bent by 16-T superconducting dipole magnets operating at 1.9 K and distributed over a circumference of 80 km. The circulating beams induce 5 MW of dynamic heat loads by several processes such as synchrotron radiation, resistive dissipation of beam image currents and electron clouds. These beam-induced heat loads will be intercepted by beam screens operating between 40 and 60 K and induce transients during beam injection. Energy ramp-up and beam dumping on the distributed beam-screen cooling loops, the sector cryogenic plants and the dedicated circulators. Based on the current baseline parameters, numerical simulations of the fluid flow in the cryogenic distribution system during a beam operation cycle were performed. The effects of the thermal inertia of the headers on the helium flow temperature at the cryogenic plant inlet as well as the temperature gradient experienced by the beam screen has been assessed. Additionally, this work enabled a thorough exergetic analysis of different cryogenic plant configurations and laid the building-block for establishing design specification of cold and warm circulators.

Geoenvironmental Impact of Effluents Generated from Al Subiya Power Plant on the Northern Kuwait Bay, State of Kuwait

The present study proposed to assess the geo-environmental impacts of Al Subiya desalination plant discharges in the Arabian Gulf, Kuwait. Most of the power and freshwater needs in the Middle East are met by the desalination of seawater. With approximately 11 million m³ of freshwater being produced each day, the salinity of the seawater along the Gulf coast is increasing. Due to brine discharge into outlet, salinity combined with higher sea surface temperatures was increased is a big environmental challenge. Therefore, in the current study the evaluation of Salinity and conductivity was higher in outlet samples than the inlet. Understanding chemical quality of sediment is important since many pollutants bind strongly to sediment particles and are persistent in the aquatic environment. The chemical and physical make-up of sediment is largely a reflection of upstream and local geology, land use, surface run off and many other complex phenomena. Many persistent compounds have high molecular weight and therefore settle out quickly and are incorporated with other settled organic materials. Since the sediment-water layer is the most reactive layer of the sea bed, changes in the sediment distribution and its physio-chemical characteristics will certainly occur in relation to time and space. In view of this, a distribution map of the sediment is important to understand the changes in composition and nature of contamination in the aquatic environment. This study set out to survey Al Subiya desalination plant inlet and outlet of marine area in Kuwait's Arabian Gulf water and to generate an updated map of the sediments of Kuwait's marine environment, in terms of pollutant factors and the corresponding map of water quality parameters during the survey of one year. The specific objectives were: 1) total organic carbon (TOC), and total petroleum hydrocarbons(TPH) in the sediment collected from selected station, 2) analyze the water quality parameters (pH, Dissolved Oxygen, temperature, salinity, turbidity, conductivity potential) in Al Subiya desalination plant inlet and outlet region, and 3) examine the level of contamination in sediments in terms of size, composition and concentration of different metals and correlate this data with the available physical water quality parameters.

Exergetic efficiency of NF, RO and EDR desalination plants

Exergetic analysis of a 2250gpm brackish water desalination plant in California was performed using its operational data. The plant contains nanofiltration, reverse osmosis and electrodialysis reversal units subject to the same source water. The correct definition of exergetic efficiency for such systems was discussed. The effect of feed salinity was also used for further illustrating the difference in the second-law efficiency definitions. The preferred definition can be used to determine the specific energy consumption and makes thermodynamic sense. The nanofiltration, reverse osmosis and electrodialysis reversal units had efficiencies of 0.087%, 0.066% and 0.078%, respectively, which are very low. Various energy recovery devices including a pressure retarded osmosis unit (having infinite area) were applied to the system to see relative increase in second-law efficiency. For the preferred definition, it was seen that the nanofiltration unit had the best efficiency. In terms of alternative designs using energy recovery devices, the pressure retarded osmosis option had efficiencies approximately equal to the hydro-turbine while the highest efficiency occurred through the use of a pressure exchanger at the plant inlet salinity. Therefore, it does not seem to be a practical energy recovery method for the investigated desalination systems.

Risk-based optimization for representative natural gas liquid (NGL) recovery processes by considering uncertainty from the plant inlet

The need to reduce energy requirement and improve operational flexibility of the NGL recovery process is a challenging problem. Different design options have been developed over the past four decades. This paper presents optimization of six selected process schemes subject to various upstream feed conditions. The process schemes were chosen for their numerous advantages such as future forefront, wide application and commercial availability. HYSYS process models were constructed for each process schemes under common sets of criteria. The information was then transferred to GAMS for optimization. One year real feed plant data was used to examine the performance of the process schemes. The results from single chance constrained optimization showed that the enhanced NGL recovery process (IPSI-1) provides a very competitive profit value with only a 6% risk of violating constraint compared to gas sub-cooled process (GSP) scheme (28%). On the other hand, profit value obtained from the joint chance constrained optimization for GSP was higher than IPSI-1 with a competitive risk of violating constraint 33% and 26%, respectively. Flexible decision to produce more sales gas or NGL product could be made before the plant operation by looking the profit value and its corresponding risk of violation of a constraint.

Novel transport delay problem solutions for gas plant inlet pressure control

The process of transferring the natural gas from the gas well to the gas separation plant encountered some delay time depending on the distance between this well and the factory, the cross section of the transport line, the geometry of this transport line, the well pressure and others. To control the factory inlet pressure by controlling the choke valve existing at the well head, the delay time makes the traditional control systems to fail. In this framework we aim to solve this problem by presenting a novel controller design and delay modeling technique. The presented technique is compared to the previous control system design and delay approximation techniques.

Editorial Commentary: What Happens in Hospitals Should Stay in Hospitals

In this edition of Clinical Infectious Diseases, Brechet et al have demonstrated that hospital wastewater is an important environmental source of extendedspectrum β-lactamase–producing Escherichia coli (ESBLEC). They analyzed wastewater samples from Besancon, France, including ones “downstream” from 2 hospitals, from unrelated wastewater sites independent of the hospitals and from the municipal wastewater treatment plant inlet and outflow. Hospital effluent was clearly identified as the major contributor to the waste stream ESBLEC burden. They also examined samples of river water upstream and downstream of the wastewater plant and of digested sludge (used to fertilize farm land), which allowed them to quantify how much ESBLEC is dispersed into the environment. They identify an important opportunity to dampen the spread of antibiotic resistance. In their study, hospital wastewater had 30-fold more ESBLEC per unit volume than did the nonhospital wastewater stream. This is consistent with the fecal excretion of ESBLEC from infected patients and selection for ESBLEC due to antibiotics in the wastewater stream. Wastewater treatment removed approximately 95% of the ESBLEC, yet the estimated amount of ESBLEC released into the river (6 × 10/day) and to farmland via sludge (2.6 × 10 ESBL/kg) remained high. Unlike drinking water, wastewater treatment is designed to decrease but not eliminate pathogens. Because downriver exposure to water-borne pathogens is mitigated by the natural die-off of bacteria in the river, and (at least in principle) eliminated by downriver drinking water treatment, this arrangement has been accepted as reasonable. However, this view may be overly optimistic. The practice of spreading raw cattle manure on agricultural land has come into question given the well-documented outbreaks of E. coli O157:H7 and Salmonella in food. Many studies have documented that E. coli O157:H7 persists in soil and water. The survival of the organisms is related to their physical environment (eg, temperature, oxygen, pH, energy sources, soil texture) and by biotic factors such as predation by protozoa and the diversity of the rest of the microbial community [1, 2]. If cow manure used as fertilizer can spread pathogens, why should one doubt that human sewage sludge can do the same? Indeed, in France, Hartmann et al have found that CTX-M ESBLEC genes were found in 20% of soil samples from farms in Burgundy, and that live ESBLEC could be cultured from soil last fertilized with manure a year before [3]. It is not hard to see how ESBLEC that has been spread on farm soil—either from animal manure or wastewater sludge—can be recycled into the human food chain, either on plants or via food animals. There should be little doubt that ESBLEC released into a river can easily enter the human population though water-borne spread. Recreational swimmers downstream of a sewage outlet will be exposed and can become unwitting reservoirs of ESBLEC and other resistant pathogens. In fact, the number of ESBLEC calculated by Brechet et al is likely to be a substantial underestimate of the amount released during periods of heavier rainfall. Their data were collected during a dry season. As in many cities, the wastewater system in Besancon collects both sewage and urban surface water (such as rain) in a combined sewer system. These systems are designed to overflow into rivers or streams when heavy rainfall threatens to overwhelm sewage treatment plants. On these occasions, a nasty mix of raw sewage and rainwater is discharged into the receiving water, putting people downstream at risk. In a landmark article by Curriero et al, it was shown that 68% of water-borne disease outbreaks in the United States were preceded by heavy rainfall in the same watershed [4]. Similar data exist for sites as diverse as Taiwan [5], Canada [6, 7], and India [8]. Once these organisms are Received 6 March 2014; accepted 9 March 2014. Correspondence: Michael Barza, MD, Department of Medicine, Steward Carney Hospital, 2100 Dorchester Ave, Boston, MA 02124 (michael.barza@steward.org). Clinical Infectious Diseases © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals. permissions@oup.com. DOI: 10.1093/cid/ciu194

Water Quality-based Real Time Control of Integrated Urban Drainage Systems: A Preliminary Study from Copenhagen, Denmark

Global Real Time Control (RTC) of urban drainage systems is increasingly seen as cost-effective solution for responding to increasing performance demands. This study investigated the potential for including water-quality based RTC into the global control strategy which is under implementation in the Lynetten catchment (Copenhagen, Denmark). Two different strategies were simulated, considering: (i) water quality at the wastewater treatment plant (WWTP) inlet and (ii) pollution discharge to the bathing areas. These strategies were included in the Dynamic Overflow Risk Assessment (DORA) RTC strategy, which allows for prioritization of the discharge points in the systems according to their sensitivity. A conceptual hydrological model was used to assess the performance of the integrated control strategy over an entire year. The simulation results showed the benefits of the proposed approaches in reducing Combined Sewer Overflow (CSO) loads at the WWTP inlet and in an upstream location discharging to sensitive bathing waters for medium CSO events (i.e. those with greater potential for control). Furthermore, when looking at the overall performance across the entire catchment during the simulation period, no significant changes were observed. These preliminary results require further analysis by including detailed water quality measurements and simulations. Nevertheless, the potential for including water-quality RTC in global RTC schemes was unveiled, providing a further option to urban water managers to improve the performance of their systems.

Susceptibility of Some Selected Nitte Municipal Wastewater Sources to Trace Metals Pollution

The negative impacts of pollution due to trace metals in wastewater on aquatic ecosystem and related organisms in water bodies are on the increase. This paper deals with the investigation on the pollution indices of trace metals in selected wastewater samples of Nitte Town, Udupi District, Karnataka State, India. Twelve wastewater samples were obtained from Students Hostels, Auto-Service Workshop Station, Foundry, Laundry, Landfill Leachate and Wastewater Treatment Plant Inlet. The measured heavy metals in the samples include: Copper (Cu), Lead (Pb), Magnesium (Mg), Chromium (Cr), Nickel (Ni), Zinc (Zn), Manganese (Mn) and Cadmium (Cd), using the air-acetylene-operated Flame Atomic Absorption Spectrometer (FAAS), Avanta GM model. The results were all compared with the EPA Effluent Standards. Findings revealed that all samples recorded dwindling levels of trace metals pollution when compared with the Standards. The heaviest concentration occurred in Cd with as high as 1856.4 ppm as found in the Stale Landfill Leachate sample, while the least contaminating metal in the samples is Manganese which was detected in only Aerated Wastewater Treatment Plant sample (2.3 ppm). This study is therefore recommending Electro-coagulation treatment method for trace metals with high concentration levels like Cd, Pb, Mg and Cu, while those with lesser concentration such as Mn, Cr, Ni and Zn in the samples are suggested to be treated with chemical precipitation method.

Oestrogen, testosterone, cytotoxin and cholinesterase inhibitor removal during reclamation of sewage to drinking water

Namibia is the driest sub-Saharan country in Africa. Namibia’s capital, Windhoek, reclaims sewage water for domestic use at the Goreangab Water Reclamation Plant (GWRP). Risks associated with sewage effluent and reclaimed sewage should be closely monitored; therefore water at the Gammams Sewage Treatment Plant (GSTP) inlet and outlet, as well as reclaimed water from the GWRP, were assayed using selected bioassays. Samples collected were analysed using enzyme-linked immunosorbent-assays and chromogenic tests for steroid hormones, neurotoxicity, cytotoxicity and inflammatory activity. Estradiol level at the sewage treatment inlet was 78 pg/mℓ and the treated sewage level showed an 83% to 95% reduction in this, while after reclamation the level was below detection limit. Estrone concentrations at the sewage treatment inlet ranged from 10 to 161 pg/mℓ. Sewage treatment reduced estrone by between 85% and 92%. After reclamation the level of estrone was below detection limit. Testosterone ranged between 162 and 405 pg/mℓ at the sewage plant inlet. Sewage treatment removed 96% of the initial testosterone. The residual testosterone was effectively removed by processes in GWRP and after reclamation no testosterone was detected in water. Acetylcholinesterase (AChE) inhibition at the sewage treatment inlet was 50% while it was only 27% after sewage treatment. After reclamation AChE inhibition was not detected. Only water at the sewage inlet in March and February showed cytotoxicity. High inflammatory activity was detected at the sewage plant inlet. Sewage treatment reduced inflammatory activity by 64%. After reclamation low inflammatory activity was induced. Treated sewage used for reclamation tested positive for most of the biomarkers and can pose a risk to human health. However, reclamation successfully removed these contaminants. Due to the presence of contaminants in the intake water at the reclamation plant, it is essential to routinely monitor the water produced by the reclamation plant for potential residues that can adversely affect human health.Keywords: Endocrine disrupting potential, cytotoxicity, neurotoxicity, inflammatory response, steroid hormones, water quality

Profit optimization for chemical process plant based on a probabilistic approach by incorporating material flow uncertainties

This paper reports how the economic performance of a chemical process plant is affected by material flow uncertainties from the plant inlet and outlet. Two chance-constrained optimization models were proposed. The models were tested using case studies of an existing gas processing plant. Profit optimization for the case studies was made with respect to the reliability of holding the process constraints at a certain confidence level [0.5, 1]. The optimal profit change for uncertainty from the plant inlet within the confidence interval [0.96, 1] was 86%. On the other hand, the optimal profit change for uncertainty from the plant outlet was only 2% for the same confidence level interval considered. This suggests that the uncertainty from the plant inlet has a major impact on the overall economic performance of the plant. Sensitivity analysis showed how uncertain parameters from both plant sides can affect the overall profit significantly.

Green crop fractionation by twin-screw extrusion: Influence of the screw profile on alfalfa (Medicago sativa) dehydration and protein extraction

Alfalfa was studied to define a new approach for green plant fractionation using twin-screw extrusion, leading to the production of a green filtrate, rich in proteins and a solid fibrous residue, rich in cellulose. The influence of the screw profile on protein recovery in the liquid extract and on plant dehydration was characterised. Three screw profiles were tested, at different liquid/solid ratios and plant inlet flow rates. A significant difference was determined, at a confidence level of 95%, between the influence of the three profiles on alfalfa dehydration and protein extraction in the raw filtrate. When mechanical action on the plant is stronger, both protein recovery and solid dehydration are better with more than half of the initial proteins (50.8%) recovered in the liquid extract in the best screw configuration (profile 3). However, extrusion is not efficient for the plant dehydration but the interest of adding a second filtration zone was demonstrated; after the first pressing and liquid expression in a first stage, water is added to the residual matter, which leads to a better protein extraction in the second filtration stage.

Distribution of volatile organohalogen compounds in petrochemical plant water streams

The study assesses halogenated volatile organic compound concentrations in the water and wastewater streams of a petrochemical plant. Water samples were collected at 11 sampling points during 5 sampling campaigns. The samples were collected from the oil dewaxing unit and in the wastewater treatment plant. Dichloromethane and 1,2-dichloroethane were the most frequently determined compounds. Tetrachloroethene was also detected at the wastewater treatment plant inlets. The concentrations of halogenated volatile organic compounds dropped significantly at wastewater discharge points compared to wastewater treatment plant inlets. The application of 1,2-dichloroethane/dichloromethane ratio as a tool to assess evaporation processes is discussed.

Toxicity identification evaluation of cosmetics industry wastewater

The cosmetics industry has shown steady growth in many developing countries over the past several years, yet little research exists on toxicity of wastewaters it generates. This study describes a toxicity identification evaluation conducted on wastewater from a small Brazilian hair care products manufacturing plant. Physicochemical and ecotoxicological analyses of three wastewater treatment plant inlet and outlet samples collected over a six month period revealed inefficient operation of the treatment system and thus treated wastewater organic matter, suspended solids and surfactants contents consistently exceeded discharge limits. Treated wastewater also presented high acute toxicity to Daphnia similis and chronic toxicity to Ceriodaphnia dubia and Pseudokirchneriella subcapitata. This toxicity was associated with suspended solids, volatile or sublatable and non-polar to moderately polar organic compounds that could be recovered in filtration and aeration residues. Seven surfactants used in the largest quantities in the production process were highly toxic to P. subcapitata and D. similis. These results indicated that surfactants, important production raw materials, are a probable source of toxicity, although other possible sources, such as fragrances, should not be discarded. Improved treatment plant operational control may reduce toxicity and lower impact of wastewater discharge to receiving waters.

Molecular detection of multiple viral targets in untreated urban sewage from Greece

BackgroundUrban sewage virological analysis may produce important information about the strains that cause clinical and subclinical infections in the population, thus supporting epidemiological studies.MethodsIn the present study, a twenty one-month survey (November 2007 to July 2009) was conducted in order to evaluate the presence of human adenoviruses (hAdV), hepatitis A viruses (HAV), hepatitis E viruses (HEV), Noroviruses (NoV), and human Polyomaviruses (hPyV) in untreated sewage samples collected from the inlet of Patras' municipal biological wastewater treatment plant, located in southwestern Greece. Nucleic acid amplification techniques were applied for viral nucleic acid detection. Positive samples were confirmed by sequencing and comparative phylogenetic analysis was performed on the isolated viral strains.ResultsIn total, viruses were detected in 87.5% (42/48) of sewage samples. AdVs, PyVs, HAV, and NoVs were detected in 45.8% (22/48), 68.8% (33/48), 8.3% (4/48), and 6.3% (3/48) of the samples collected from the plant's inlet, while HEV was not detected at all. Adenovirus types 8 (Ad8), 40 (Ad40) and 41 (Ad41) were recognized, while JC and BK polyomaviruses were recorded. Noroviruses were identified as GII.4. HAV was typed as genotype IA.ConclusionsOur study demonstrates the advantages of environmental surveillance as a tool to elucidate the molecular epidemiology of community circulating viruses. We underline the need of environmental surveillance programs in countries such as Greece with inadequate and problematic epidemiological surveillance system and no environmental surveillance system currently in action.

Demonstration and verification of post combustion capture using solvent scrubbing

This paper will present Doosan Power Systems’ Post Combustion Capture (PCC) development, testing and verification activities. Preliminary results from the Boundary Dam TKOTM process, RSTM solvent trial and the results from the ERTF test facility will be discussed. Doosan Power Systems is developing competitive PCC technologies to capture carbon dioxide (CO2) from coal and natural gas fired power plants for commercialization by 2020. Doosan Power Systems has licensed solvent scrubbing technology from HTC Purenergy Inc., which is based in Regina, Saskatchewan, Canada. HTC have developed an optimised Post Combustion Capture (PCC) process known as the Thermal Kinetics OptimizationTM (TKO) process which is designed to substantially reduce the energy requirements of the PCC process for the capture of CO2 from coal and natural gas fired power plants. Doosan Power Systems is currently undertaking FEED studies and preparing commercial bids for full-scale solvent scrubbing plants, comprising all equipment from flue gas desulphurisation (FGD) plant outlet to CO2 compression plant inlet. Among these are the CCPILOT100+ and Basin Electric PCC demonstration projects. The TKO process is currently under a formal technology verification programme at the upgraded Boundary Dam demonstration pilot plant capturing approximately 4 tonnes/day of CO2. Long term performance of HTC’s proprietary RSTM solvent is currently being assessed for CO2 removal effectiveness and the long term performance of the solvent. Solvents are also tested for degradation, heat stable salt formation and propensity for corrosion within the various system components. Doosan Power Systems has installed a PCC solvent scrubbing pilot plant on the 160 kWt Emissions Reduction Test Facility (ERTF), located at its R&D centre in Renfrew, Scotland, to capture approximately 1 tonne/day of CO2 and to permit further development and optimization of the process. The ERTF is capable of firing a wide range of world traded coals and produces flue gases representative of full scale plant. The ERTF solvent scrubbing plant will be used to carry out performance testing on a range of solvents, packings and suitability of a range of materials. The testing and verification programmes at both Boundary Dam and the ERTF will be used to substantiate the scalability of HTC’s technology under real-world operating conditions. Of paramount importance during the verification programmes are the actual rate of solvent degradation under industrial conditions, solvent make-up requirements, steam consumption and other auxiliary power requirements which add to power plant parasitic losses, such as that for fans to overcome the pressure drop created by column internals and associated pipework.

Fate Modelling of DEHP in Roskilde Fjord, Denmark

The fate of di(2-ethylhexyl)phthalate (DEHP) is modeled in Roskilde fjord, Denmark. The fjord is situated near Roskilde, which comprises 80,000 PE, various industries, a central wastewater treatment plant, and adjacent agricultural fields. Roskilde fjord is thus a suitable recipient for studying the transport and fate of DEHP, which is used in a variety of different industries and consumer products. Wastewater from households and industries is led to the local wastewater treatment plant, which leads the effluent to the fjord. The sludge is partly stored and partly amended on an adjacent field. The model applied in the present study is a simple box model coupling water and sediment compartments of the fjord with wastewater treatment plant effluent, streams leading to the fjord, and atmospheric deposition. The fjord model comprises first-order degradation, adsorption, sedimentation, vertical diffusion in the sediment, dispersive mixing in the water, and water exchange with the surrounding sea. Experimental measurements of DEHP were made in the fjord water and sediment, in the wastewater treatment plant inlet and effluent, and in streams and atmospheric deposition. The experimental data are used to calibrate the model. The model results show that freshwater from streams is the predominant DEHP source to the fjord, followed by atmospheric deposition and effluents from wastewater treatment plants. Sedimentation is the predominant removal mechanism followed by water exchange with the sea and degradation.