Use of Impaired Waters in Power Plant Cooling Tower System:Review of Regulations and Feasibility Analysis

In 2000, the freshwater withdrawn for industrial use in the U.S., including mining, industrial process usage, power generation, etc., has reached 45% of the total daily freshwater withdrawal of 346 billion gallons. Among these industries, thermoelectric generation is the largest freshwater user with a withdrawal of 136 BGD. Fierce competition for this valuable resource will force difficult decisions to be made about allocation priorities and water availability for electric power production. Studies have shown that impaired waters can be used as alternative water sources for certain applications, including makeup water in electric power plant cooling systems. Among all possible impaired waters that could potentially be used in power production, secondary treated municipal wastewater is the most common and widespread source. Review of regulations that govern water reuse revealed that there are no federal regulations specifically addressing water reuse and that a number of states have implemented their own regulations. Several states were investigated for specific regulations and/or guidelines related to water reuse in power plant cooling water systems.The geospatial analysis performed in this study was designed to evaluate the feasibility of using treated municipal wastewater for cooling in power industry. By utilizing the geoprocessing tools of a geographic information system (GIS), this study evaluated if the water demand of a particular facility can be satisfied by nearby Publicly Owned Treatment Works (POTWs). Datasets of 110 power plants proposed for development and 11785 POTWs were evaluated as part of this feasibility analysis. Estimated cooling water needs for the proposed power plants were compared with the total wastewater flowrates discharged by nearby POTWs. Data analysis revealed that 81% of the proposed power plants would have sufficient cooling water supply from POTWs within a 10 mile radius, while 97% of the proposed power plants would be able to meet their cooling water needs from POTWs located within 25 miles from these plants. On average, 1.15 POTWs were needed to completely satisfy the cooling water demand for each of these power plants. In other words, one fairly large POTW within a reasonable distance from each power plant could meet most of its cooling water needs.Dataset of 407 existing coal fired power plants was also evaluated using the same process. All of the existing power plants were assumed to be renovated to wet recirculating cooling systems regardless of their original design. Results indicate 49.4% of the existing power plants would have sufficient cooling water supply from POTWs within a 10 miles radius; 75.9% of the existing power plants would have sufficient cooling water supply from POTWs within a 25 miles radius. For those power plants which have sufficient water supply, an average number of 1.46 POTWs are required to satisfy the cooling water demand.The tools developed in this study can be used to evaluate a number of scenarios for alternative cooling water supply needed for energy generation in the future. It is clear that the reclaimed municipal wastewater can and will likely play a more prominent role in this critical industrial sector

USE OF CHLORINE, CHLORAMINE, OR CHLORINE DIOXIDE TO CONTROL BIOLOGICAL GROWTH IN POWER PLANT RECIRCULATING COOLING SYSTEMS USING TREATED MUNICIPAL WASTEWATER

Cooling water deficiency due to limited freshwater sources posed an obstacle of expending current thermoelectric power generation in the U.S. and has led the power industry to seek an alternative water resource to meet its cooling water requirement. Of all the potential alternatives, secondary treated municipal wastewater is prominent because of its vast allocation and abundant quantity. However, the impaired water quality and unique environment make the cooling tower management more challenging. Therefore, prudent water quality management with chemicals is required to prevent corrosion, scaling, and biological growth in the cooling systems. This study focused on the understanding of the kinetic, effectiveness, and dosage requirement of chlorine-based biocides (chlorine, chloramine and chlorine dioxide) in the recirculating cooling systems using treated municipal wastewater as makeup. Laboratory-scale studies and pilot-scale cooling systems were used to evaluate the biological growth under realistic conditions associated with full-scale cooling systems. Results of 30-day field tests indicated that the pilot-scale cooling towers developed in this study are reliable for evaluating different chemical regimes by maintaining steady cooling performance under various operating conditions. Direct use of secondary treated effluent for cooling water is a feasible option when using monochloramine as major biocide. The low oxidizing ability of monochloramine resulted in a high residence time and high penetrating ability, and thus provided better biocidal effectiveness against planktonic and sessile heterotrophic bacteria and Legionella in recirculating cooling systems. A minimum monochloramine residual above 3 mg/L in the recirculating cooling water is needed for proper biological growth control with this impaired water. Biological growth potential is comparable in secondary treated effluent subjected to different tertiary treatment (i.e., nitrification, sand filtration, activated carbon adsorption) regardless of total organic carbon concentration in the wastewater. The performance of monochloramine was optimized when the secondary treated effluent was subjected to nitrification and sand filtration. The key findings of this study indicate that biological growth can be controlled in cooling systems using treated municipal effluents as makeup. The biocide regime demonstrated in this study offers a useful guideline to meet biological growth control criteria in recirculating cooling systems

RISK OF SLEEP DISORDERS IN PATIENTS WITH DECOMPRESSION SICKNESS: A NATIONWIDE, POPULATION-BASED STUDY IN TAIWAN

Background: Decompression sickness (DCS) primarily manifests musculoskeletal pain, cutaneous manifestations, lymphatic symptoms, and neurological symptoms. DCS might affect the central nervous system and induce the stress in the patients, but few studies about the psychiatric morbidity after DCS have been conducted. This study aimed to investigate the association between DCS and the risk of developing psychiatric disorders. Subjects and methods: This study was a population-based, matched cohort design. A total of 738 enrolled patients, with 123 study subjects who had suffered from DCS, and 615 controls matched for sex and age, from the Longitudinal Health Insurance Databank from 2000-2010 in Taiwan, and selected from the National Health Insurance Research Database. After adjusting for the confounding factors, Cox proportional hazards analysis was used to compare the risk of developing psychiatric disorders during the 10 years of follow-up period. Results: Of the study subjects, 10 (8.13%) developed psychiatric disorders when compared to 35 (5.69%) in the control group. The study subjects were more likely to develop psychiatric disorders (crude hazard ratio [HR]: 2.79 (95% CI=1.37-5.69, P<0.01). After adjusting for sex, age, monthly income, urbanization level, geographic region, and comorbidities, the adjusted HR was 3.83 (95% CI=1.60-9.16, P<0.01). Sleep disorders was associated with DCS with the adjusted HR as 5.74 (95% CI=1.04-31.56, P<0.01). Hyperbaric oxygenation therapy was not associated with a lower risk of psychiatric disorders. Conclusions: Patients who suffered from DCS have a 3.8-fold risk of developing psychiatric disorders, and a 5.7-fold risk of sleep disorders. This finding is a reminder for the clinicians that a regular psychiatric follow-up might well be needed for these patients

Conserved charged amino acid residues in the extracellular region of sodium/iodide symporter are critical for iodide transport activity

<p>Abstract</p> <p>Background</p> <p>Sodium/iodide symporter (NIS) mediates the active transport and accumulation of iodide from the blood into the thyroid gland. His-226 located in the extracellular region of NIS has been demonstrated to be critical for iodide transport in our previous study. The conserved charged amino acid residues in the extracellular region of NIS were therefore characterized in this study.</p> <p>Methods</p> <p>Fourteen charged residues (Arg-9, Glu-79, Arg-82, Lys-86, Asp-163, His-226, Arg-228, Asp-233, Asp-237, Arg-239, Arg-241, Asp-311, Asp-322, and Asp-331) were replaced by alanine. Iodide uptake abilities of mutants were evaluated by steady-state and kinetic analysis. The three-dimensional comparative protein structure of NIS was further modeled using sodium/glucose transporter as the reference protein.</p> <p>Results</p> <p>All the NIS mutants were expressed normally in the cells and targeted correctly to the plasma membrane. However, these mutants, except R9A, displayed severe defects on the iodide uptake. Further kinetic analysis revealed that mutations at conserved positively charged amino acid residues in the extracellular region of NIS led to decrease NIS-mediated iodide uptake activity by reducing the maximal rate of iodide transport, while mutations at conserved negatively charged residues led to decrease iodide transport by increasing dissociation between NIS mutants and iodide.</p> <p>Conclusions</p> <p>This is the first report characterizing thoroughly the functional significance of conserved charged amino acid residues in the extracellular region of NIS. Our data suggested that conserved charged amino acid residues, except Arg-9, in the extracellular region of NIS were critical for iodide transport.</p

Efficacy and toxicities of doxorubicin plus ifosfamide in the second-line treatment of uterine leiomyosarcoma

PurposeUterine leiomyosarcoma is a rare and aggressive tumor known for its drug resistance and metastatic potential. The standard first-line treatment typically involves anthracycline-based chemotherapy or a combination of gemcitabine and docetaxel; however, there is currently no established second-line treatment. Therefore, the aim of this study was to evaluate the efficacy and toxicity of doxorubicin plus ifosfamide as a potential second-line treatment for uterine leiomyosarcoma.Materials and methodsThis is a retrospective, single-center, single-arm study. We reviewed the tumor registry data from January 2010 to December 2022 and identified patients with uterine leiomyosarcoma who had previously received first-line salvage or adjuvant treatment involving gemcitabine and taxotere, and later experienced tumor recurrence. Patients who met these criteria were included in the study. The primary endpoint was the efficacy of doxorubicin and ifosfamide as a second-line treatment for uterine leiomyosarcoma, as measured by progression-free survival, 1-year overall survival, and response rate. The secondary endpoint was the adverse events associated with this regimen.ResultsFifty-two patients were diagnosed with uterine leiomyosarcoma during the study period, nine of whom were included in the data analysis. All patients had previously received gemcitabine-docetaxel as first-line adjuvant therapy, with a median progression-free survival period of 8.4 months. Doxorubicin-ifosfamide was administered as second-line treatment, with a median progression-free survival of 6.0 months (range: 2.7-79.9 months). The clinical benefit rate of the second-line treatment was 66.7%, with a median overall survival of 33.0 months, and a 1-year overall survival rate of 83.3%. Previous reports have shown that the median progression-free survival for second-line treatments using other regimens ranged from 1.4-5.6 months. The most common adverse event was myelosuppression, with five patients requiring granulocyte colony-stimulating factor and one patient requiring a blood transfusion. No patient discontinued treatment due to unmanageable adverse events.ConclusionUse of doxorubicin with ifosfamide may be a promising and reasonable second-line treatment with manageable adverse events for patients with uterine leiomyosarcoma

Assessing the Decision-Making Process in Human-Robot Collaboration Using a Lego-like EEG Headset

Human-robot collaboration (HRC) has become an emerging field, where the use of a robotic agent has been shifted from a supportive machine to a decision-making collaborator. A variety of factors can influence the effectiveness of decision-making processes during HRC, including the system-related (e.g., robot capability) and human-related (e.g., individual knowledgeability) factors. As a variety of contextual factors can significantly impact the human-robot decision-making process in collaborative contexts, the present study adopts a Lego-like EEG headset to collect and examine human brain activities and utilizes multiple questionnaires to evaluate participants’ cognitive perceptions toward the robot. A user study was conducted where two levels of robot capabilities (high vs. low) were manipulated to provide system recommendations. The participants were also identified into two groups based on their computational thinking (CT) ability. The EEG results revealed that different levels of CT abilities trigger different brainwaves, and the participants’ trust calibration of the robot also varies the resultant brain activities

Reuse of Treated Internal or External Wastewaters in the Cooling Systems of Coal-Based Thermoelectric Power Plants

This study evaluated the feasibility of using three impaired waters - secondary treated municipal wastewater, passively treated abandoned mine drainage (AMD), and effluent from ash sedimentation ponds at power plants - for use as makeup water in recirculating cooling water systems at thermoelectric power plants. The evaluation included assessment of water availability based on proximity and relevant regulations as well as feasibility of managing cooling water quality with traditional chemical management schemes. Options for chemical treatment to prevent corrosion, scaling, and biofouling were identified through review of current practices, and were tested at bench and pilot-scale. Secondary treated wastewater is the most widely available impaired water that can serve as a reliable source of cooling water makeup. There are no federal regulations specifically related to impaired water reuse but a number of states have introduced regulations with primary focus on water aerosol 'drift' emitted from cooling towers, which has the potential to contain elevated concentrations of chemicals and microorganisms and may pose health risk to the public. It was determined that corrosion, scaling, and biofouling can be controlled adequately in cooling systems using secondary treated municipal wastewater at 4-6 cycles of concentration. The high concentration of dissolved solids in treated AMD rendered difficulties in scaling inhibition and requires more comprehensive pretreatment and scaling controls. Addition of appropriate chemicals can adequately control corrosion, scaling and biological growth in ash transport water, which typically has the best water quality among the three waters evaluated in this study. The high TDS in the blowdown from pilot-scale testing units with both passively treated mine drainage and secondary treated municipal wastewater and the high sulfate concentration in the mine drainage blowdown water were identified as the main challenges for blowdown disposal. Membrane treatment (nanofiltration or reverse osmosis) can be employed to reduce TDS and sulfate concentrations to acceptable levels for reuse of the blowdown in the cooling systems as makeup water

Role of pirenoxine in the effects of catalin on in vitro ultraviolet-induced lens protein turbidity and selenite-induced cataractogenesis in vivo

Purpose: In this study, we investigated the biochemical pharmacology of pirenoxine (PRX) and catalin under in vitro selenite/calcium- and ultraviolet (UV)-induced lens protein turbidity challenges. The systemic effects of catalin were determined using a selenite-induced cataractogenesis rat model. Methods: In vitro cataractogenesis assay systems (including UVB/C photo-oxidation of lens crystallins, calpain-induced proteolysis, and selenite/calcium-induced turbidity of lens crystallin solutions) were used to screen the activity of PRX and catalin eye drop solutions. Turbidity was identified as the optical density measured using spectroscopy at 405 nm. We also determined the in vivo effects of catalin on cataract severity in a selenite-induced cataract rat model. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS–PAGE) was applied to analyze the integrity of crystallin samples. Results: PRX at 1,000 μM significantly delayed UVC-induced turbidity formation compared to controls after 4 h of UVC exposure (p<0.05), but not in groups incubated with PRX concentrations of <1,000 μM. Results were further confirmed by SDS–PAGE. The absolute γ-crystallin turbidity induced by 4 h of UVC exposure was ameliorated in the presence of catalin equivalent to 1~100 μM PRX in a concentration-dependent manner. Samples with catalin-formulated vehicle only (CataV) and those containing PRX equivalent to 100 μM had a similar protective effect after 4 h of UVC exposure compared to the controls (p<0.05). PRX at 0.03, 0.1, and 0.3 μM significantly delayed 10 mM selenite- and calcium-induced turbidity formation compared to controls on days 0~4 (p<0.05). Catalin (equivalent to 32, 80, and 100 μM PRX) had an initial protective effect against selenite-induced lens protein turbidity on day 1 (p<0.05). Subcutaneous pretreatment with catalin (5 mg/kg) also statistically decreased the mean cataract scores in selenite-induced cataract rats on post-induction day 3 compared to the controls (1.3±0.2 versus 2.4±0.4; p<0.05). However, catalin (equivalent to up to 100 μM PRX) did not inhibit calpain-induced proteolysis activated by calcium, and neither did 100 μM PRX. Conclusions: PRX at micromolar levels ameliorated selenite- and calcium-induced lens protein turbidity but required millimolar levels to protect against UVC irradiation. The observed inhibition of UVC-induced turbidity of lens crystallins by catalin at micromolar concentrations may have been a result of the catalin-formulated vehicle. Transient protection by catalin against selenite-induced turbidity of crystallin solutions in vitro was supported by the ameliorated cataract scores in the early stage of cataractogenesis in vivo by subcutaneously administered catalin. PRX could not inhibit calpain-induced proteolysis activated by calcium or catalin itself, and may be detrimental to crystallins under UVB exposure. Further studies on formulation modifications of catalin and recommended doses of PRX to optimize clinical efficacy by cataract type are warranted