Outlet Points Research Articles

Thermal performance of pipe-type energy piles with open-ended heat exchange tubes

This paper examines the thermal performance of pipe-type energy piles with open-ended heat exchange tubes (abbreviation as: open-tube energy pile). This study compares the thermal performance of U-tube energy piles with open-tube energy piles through model testing. The analysis focused on heat exchange efficiency, temperature changes at inlet and outlet points, and the piles’ and surrounding soil’s temperature response characteristics. An analytical model using Laplace transform was developed for the open-tube energy pile, with simulations conducted to analyze it at full scale. Results indicate that, under the same cases, the open-tube energy pile exhibits higher heat exchange efficiency than the U-tube energy pile. Additionally, the pile and surrounding soil show more pronounced temperature responses during testing with the open-tube configuration. Compared to existing models, the heat transfer model proposed in this paper is more suitable for analyzing the heat transfer of open-tube energy pile. Moreover, changes in the thermophysical properties of the pipe pile and soil will have different effects on the heat transfer between the pile and the soil.

Innovative 3D Navigation Module for Precise Unilateral Pedicle Screw Combined with Contralateral Translaminar Facet Screw Placement in Lumbar Spine Surgery.

The incidence of degenerative diseases of the lumbar spine has increased in recent years. Unilateral pedicle screw combined with contralateral translaminar facet screw fixation offers the advantages of less trauma, better stability, and fewer complications. However, the surgical difficulty and suboptimal pinning accuracy of translaminar facet screw placement in clinical practice limit its use. Therefore, in this study, we designed a novel suspended 3D-printed navigation module to facilitate fast and accurate intraoperative screw placement. The aim of this study is to investigate the digital design, precise implementation, and evaluation methods for placing unilateral pedicle screws in the lumbar spine combined with translaminar facet screw placement using a new suspended 3D navigation module. This retrospective study included 46 patients with single-level lumbar lesions who underwent spine surgery at the Affiliated Hospital of Putian University between June 2022 and December 2023. The suspended navigation module was designed digitally. Preoperative screw placement was simulated using 3D printed models, followed by an intraoperative accurate screw placement facilitated by the navigation module and a postoperative evaluation of the accuracy of screw placement. The absolute difference in three-dimensional coordinates of the inlet and outlet points of the preoperative design and the postoperative screw-nail channel served as the precision index. In a study involving 46 patients, surgery was successful with 92 pedicle screws and 46 translaminar facet screws placed without any penetration of the cortex. The difference in coordinates before and after screw insertion was minimal, with entry points varying between 1.21 to 1.36 mm and exit points between 1.97 to 2.46 mm. When screw accuracy met certain thresholds, there was no significant difference between preoperative design and postoperative coordinates, indicating precise replication of the surgical plan. The new suspended 3D navigation module enables the precise placement of unilateral pedicle screws in the lumbar spine combined with translaminar pedicle screws for precise surgery.

Evaluation of urban drainage capacity using different satellite image sources and SWMM

ABSTRACT This research aims to cost-effectively identify inundation due to combined rainfall with tidal surges by evaluating the existing urban drainage system. The Storm Water Management Model (SWMM) applied two scenarios based on different Digital Elevation Model (DEM) sources. These are scenario A, i.e. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and scenario B, i.e. Shuttle Radar Topography Mission (SRTM). Then, catchment delineation and SWMM parameterization in the low-lying urban region of Chattogram City were executed. In contrast to scenario A, i.e. ASTER DEM, identified inundated nodes in the northwest part of the city, scenario B, i.e. SRTM DEM, showed more inundated nodes. In both scenarios, drainage capacity was observed in the field at two outlet points of Ispahani Khal (R2 = 0.91 and 0.85) and Chaktai Khal (R2 = 0.90 and 0.92), which reasonably mimics the model outcome. With an intensive field dataset, this model could provide relevant information for betterment.

Performance of Dairy Factory Wastewater Treatment Plant (Case Study of Pasuruan Dairy Factory East Java)

The 'ILP' company produces bottled milk with chocolate, melon, strawberry, and vanilla flavors in colorless HDPE (High-Density Polyethylene) plastic bottles and aluminum foil covers. The 'ILP' dairy industry wastewater treatment process stages include bar screen, grease trap, equalization tank, flocculation-coagulation, primary clarifier, aeration tank/activated sludge, and secondary clarifier. The research aims to determine the performance of the dairy factory's WWTP (Wastewater Treatment Plant) in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) parameters. This field-scale research was carried out for approximately 5 weeks (35 days) at the wastewater treatment plant of the ILP company. Wastewater sampling is carried out at the inlet point, equalization tank, primary sedimentation, aeration tank, and outlet point of WWTP. Wastewater examination conducted in the company's internal laboratory, including temperature, pH, total suspended solids (TSS), and chemical oxygen demand (COD). The dairy factory WWTP (wastewater treatment plant) can generate TSS (total suspended solids) effluent of 22 mg/L and COD (chemical oxygen demand) of 26.8 mg/L to meet the applicable wastewater quality standards. The treatment efficiency of the dairy industry WWTP for TSS is 94.7% and COD is 98.1%.

Integrated error modeling for abrasive waterjet cutting at various nozzle tilt angle

The research investigates the specific impact of high-pressure abrasive waterjet (AWJ) on the cutting accuracy of circular trajectories. The coupling relationship between the kerf taper and the jet lag of the cutting front profiles is analyzed. Thus, an integrated error model for abrasive waterjet cutting of circular trajectories is innovatively established, which can predict the deformation of the circular arc trajectory not only at right angles but also at tilt angles. Cutting experiments at vertical angles were conducted, with a maximum prediction accuracy of 2.41%. Besides, arc trajectories with different diameters were conducted with a prediction accuracy of 2.26%. In order to reduce the deformation error of arc trajectories, compensation experiments for nozzle tilt ranging from 76° to 94° were carried out. The experimental results showed that when the nozzle was tilted in the direction opposite to the traverse speed up to half of the maximum deviation angle at the jet outlet point, the maximum deformation of arc trajectories was 1.218 mm, which was reduced by 0.532 mm compared to the case of vertical incidence, and the cylindricity increased by 31.74%. This adjustment can meet the precision requirements for cutting thick materials with abrasive waterjet.

Numerical Investigation on the Influence of Substrate Board Thermal Conductivity on Electronic Component Temperature Regulation

This study presents a detailed numerical analysis of substrate boards made from various materials (FR-4, Si cladding, and Cu cladding) with nine electronic components mounted on them. Each component is subjected to different heat fluxes, and the analysis covers both natural convection (NC) and forced convection (FC) modes of heat transfer at air velocities of 4m/s and 6m/s. The findings reveal that at an air velocity of 6m/s, using a copper cladding board significantly lowers the temperatures of the electronic components by 340C to 540C compared to FR-4 and Si cladding boards. Additionally, the copper cladding reduces the required air-cooling velocity by 2m/s and achieves a temperature reduction for the IC chips ranging from 3.500C to 13.120C. It is recommended to use an air velocity of 4m/s with copper cladding to minimize fan power consumption while maintaining component temperatures below 1250C. These results provide crucial insights for thermal design engineers, aiding in the selection of appropriate substrate boards for effective thermal management of electronic components. The study emphasizes the benefits of copper cladding in distributing heat more uniformly, reducing energy consumption, and maintaining optimal operating temperatures. Furthermore, it suggests that placing high heat-dissipating components at inlet or outlet points can minimize thermal interactions and overall configuration temperatures. The research offers valuable guidance to the heat transfer community, particularly electronic thermal designers, by highlighting the importance of substrate material choice and component placement in enhancing the reliability and lifespan of integrated circuits (ICs). The comprehensive analysis and recommendations serve as a vital resource for optimizing thermal control strategies in electronic devices, ultimately contributing to improved performance and durability.

Effectiveness Evaluation of Alternative Technologies Applied in Centralized Domestic Wastewater Treatment Systems

The paper aims to determine the effectiveness of several alternative technologies that have been applied in centralized domestic wastewater management systems, especially in West Java and Banten provinces, in the removal of domestic wastewater pollutant parameters. The study was conducted in SPALD-Ts, including the Anaerobic Baffle Reactor (ABR) system, the Anobic Filter (AF) system, the combined ABR + AF system, and the Extended Aeration. The analysis was performed by sampling at the inlet and outlet points of the system for three consecutive years with sampling times from 2021 - 2023. The results of the research show that the efficiency of pollutant parameter separation based on the best technology in the separation of domestic wastewater pollutant parameters is the SPALDT extended aeration technology, where this technology can separate pollutant parameters up to an average of 88.25%, but in this technology requires more cost and periodic maintenance.

Deteksi Konsentrasi Fe, Cu, Zn dan Pb Air Sungai dan Ikan yang Tercemar Air Lindi di Bandar Lampung Dengan Menggunakan SSA

Leachate is a pollutant produced by landfills which can pollute the aquatic environment. This will have an impact on fish that live in waters contaminated with leachate and if consumed by the public it will harm health. The toxic effects of leachate are caused by the content of toxic chemicals, one of which is heavy metals. The aim of this research was to determine the concentrations of Fe, Cu, Zn and Pb in Bakung landfill leachate, Sukamaju river water and fish meat. Bakung landfill leachate samples were taken from two outlet points. The fish sampling location was carried out in the Sukamaju River. The physical factors of water measured are temperature, pH, salinity, turbidity, DO, COD and BOD. Fe, Cu, Zn and Pb concentrations were measured using the Atomic Absorption Spectrophotometry (AAS) method. The results show that the physicochemical parameters in leachate and river water exceed the threshold. The contents of Zn, Cu, Fe and Pb in the leachate at both outlet points exceeded the threshold value with values of 2.48 mg/L and 2.80 mg/L; 16.55 mg/L and 17 mg/L; 0.078 mg/L and 0.113 mg/L; 3.26 mg/L and 3.01 mg/L. The concentration of heavy metals Pb and Fe in river water is 0.083-0.162 mg/L and 2.68-2.97 mg/L which are above the quality standard value, while the heavy metal Fe content in fish meat exceeds the specified threshold value, namely 0.557 mg/100 g and 0.564 mg/100 g.

Rainfall-Runoff Simulation for Ungauged Watershed: A Case of Bessre Watershed, Duhok Province, Iraq

The scarcity of measured hydrological data poses a challenge in many developing countries, stemming from insufficiently established gauging stations. Due to the mentioned issue, it is crucial to develop models capable of conducting reliable simulations of runoff behavior, particularly for ungauged catchments. Understanding the intricate relationships in rainfall-runoff modeling is essential for estimating peak flows, a critical aspect in formulating water resources management strategies, which can aid in water resource management and planning. In areas prone to floods performing, an extensive hydrological study becomes necessary. This study determined the outflow discharge at the outlet point of the Bessre Valley Ungauged Catchment (41.4 km2) using the Watershed Modeling System, used by reliable hydrological standards as a graphical interface integrating with the Hydrologic Modeling System (HEC-HMS). Bessre Valley watershed is one of the flood-prone watersheds in the Duhok governorate, mainly due to the terrain’s steep slopes at the upper north and east of the catchment. The catchment was delineated by a Geographic Information System (GIS). Its properties were extracted from a 12.5 m × 12.5 m Digital Elevation Model (DEM), which evaluates the hydrological response of a watershed to two significant storm events: a real rainfall event in March 2020 and a hypothetical 100-year return period event by dividing the watershed into ten sub-basins. Achieving a Nash-Sutcliffe efficiency of 0.895 indicates a high accuracy between observed and simulated peak flows of the real rainfall event of March 2020, underscoring the model's reliability for hydrological predictions. Also, comparing the HEC-HMS model and the Rational Method of (100 YRP event) for calculating peak discharges revealed a mere 2.2% error. Furthermore, the study explores the potential for building additional dams based on discharge volumes from specific sub-basins to enhance flood control and water storage capabilities.

Automated assessment of hydrostatic pressure resistance in woven fabrics using the enhanced YOLOv8 network

Hydrostatic pressure resistance serves as a crucial metric in the assessment of water resistance in woven fabrics. The expeditious, precise, and efficient conduct of hydrostatic pressure tests holds paramount importance in advancing the progress and production of high-performance textiles. Addressing the challenges posed by intricate printed patterns on woven fabrics, and the presence of small, widely scattered water droplets, the study leverages the enhanced YOLOv8 model to develop a machine vision-based automated detection technique for assessing water resistance in woven fabric. The proposed method incorporates convolutional block attention module attention mechanisms into the backbone and neck network, replaces the path aggregation network structure of YOLOv8 with the bidirectional feature pyramid network structure, and introduces a dedicated detection head for small targets. These enhancements facilitate accurate identification of water outlet points on the woven fabric and precise recording of frame positions, enabling the precise measurement of hydrostatic pressure. Validation of the proposed model is conducted through a series of comparative experiments utilizing a self-collected dataset. The experimental results underscore the exemplary performance of the proposed model, evidenced by an AP0.5 score of 92.18%, showcasing superior overall efficacy in comparison with alternative models. Notably, the target localization time error is found to be less than 2 s when contrasted with manual detection. This method substantially enhances the accuracy of water droplet detection and localization in hydrostatic pressure resistance testing of woven fabric, characterized by complex surface patterns, thereby contributing to refinement of hydrostatic pressure testing methodologies in woven fabric analysis.

Analysis of Air and Water Quality at Coal Harbor in Muaro Jambi Regency

Secondary data obtained from the Safety, Health and Environment Department of PT. Winner Prima Sekata (PT. WPS) in Kemingking Dalam Village, Taman Rajo District, Muaro Jambi Regency, in 2022 it was discovered that there were cases of Acute respiratory infections (ARI). Therefore, a study was carried out regarding the analysis of air quality and water quality at the coal port location in Muaro Jambi Regency to determine the extent of the environmental impacts resulting from coal loading and unloading and stockpile activities at the Talang Duku port, Jambi Province. The research was conducted using quantitative survey and descriptive methods. Data analysis is quantitative in nature with the aim of testing predetermined hypotheses. Dust measurement results obtained between 7.98 - 10.00 mg/m3, The allowable dust threshold value is in accordance with the Minister of Manpower Circular Number. SE.01/MEN/1997 concerning the NAB of Chemicals in Workplace Air is 0.9 mg/m. So the dust level in the Muaro Jambi coal port working area exceeds the quality standards set by the Minister of Manpower. Results of calculating the output water pollution index pH and TSS at the PT Outlet point. The WPS of port locations in the period March – June 2023 in each month has a Pij value of 1.08, which means the average pH and TSS value of output water from PT. WPS is at status 1.0 < 1.09 < 5.0 with the description Lightly Polluted. Based on processing with SPSS version 27 using the One way Anova test, it was found that Fcount then H0 was rejected.

Real-time monitoring of CO2 transport pipelines using deep learning

Real-time pipeline monitoring is important for the safe transportation of captured CO2. A dynamic modeling method, which is one of pipeline monitoring methods, can provide reliable diagnostic results for various anomalies. In the dynamic modeling method, anomalies are detected by comparing the predictions and observations of pipeline monitoring variables. However, the licensing costs associated with the use of pipeline flow simulators that provides the predictions are high. In this study, we developed a real-time deep-learning-based pipeline monitoring method that can save the licensing cost of the pipeline flow simulators. The predictions are obtained using deep-learning models where the pipeline flow simulator is required only in the training step. Two improvements were made to enhance both the prediction and anomaly detection accuracies. First, the prediction accuracy for the monitoring variables can be improved by considering a delay time interval between inlet and outlet points in pairing training input and output data. Second, the anomaly detection accuracy can be also improved by conditionally choosing observations based on the normal operation ranges of the observations. As part of a field demonstration, the proposed deep-learning-based pipeline monitoring method was applied to the monitoring of a CO2 transport pipeline located in the East Sea gas field. The results showed the anomaly detection accuracy of the proposed method was improved by more than 25 %.

Does the performance enhancement through multi-model averaging at the catchment outlet gets translated to the interior ungauged points?

Accurate prediction of streamflow is essential at both the outlet and interior points for effective water resource management. This study aimed to investigate whether improved simulation results at the catchment outlet through Multi-Model Averaging (MMA) can be translated to interior ungauged points in a catchment. To achieve this, the study considered ensemble combinations of 81 conceptual hydrologic models and calibrated each model using four objective functions for two study areas (Jagdalpur and Wardha subbasins of Godavari basin). Six MMA methods were applied to evaluate their performance at interior points in the catchment. The findings revealed that, when compared to the best performing hydrologic model, the best MMA method showed an improvement in terms of Nash-Sutcliffe efficiency, ranging from 2.2% to 3.8% at the interior point of Jagdalpur and 2% to 12% at the interior points of Wardha. MMA methods with KGE-calibrated models as input exhibited better performance in terms of NSE, while those using LogarithmicNSE-calibrated and parent models as input ensembles showed better performance in terms of Percentage bias and Skill Score. Bayesian model averaging and Genetic Algorithm based averaging methods were identified as the most appropriate MMA methods, and the study findings suggest that the performance of these techniques varies at different interior points based on their spatial and temporal variation of flow characteristics. Overall, this study would be beneficial for better flow prediction at internal ungauged points, which is crucial for effective water resource management in areas where there is limited data or where new developments have occurred.

Analysis of Inlet and Outlet Wastewater Quality in WWTP Djoelham Regional General Hospital Binjai City

Hospitals produce quality liquid waste that is not by the standard value of quality standards that can pollute the environment. Indonesia is estimated to produce 48,985.70 tons of hospital liquid waste/per day. This study aims to determine the quality of inlet and outlet wastewater as well as the methods used by the Wastewater Treatment Plant (WWTP) of Djoelham Hospital, Binjai City. This study used qualitative types with observational methods. The research sample was taken from two points, namely the inlet point and the WWTP outlet point with BOD, COD, TSS, and pH parameters. Sampling technique using Composite Sampling. Data processing and analysis is carried out by statistical means. As well as data presented in the form of tables and line graphs. This research was conducted at Djoelham Hospital in Binjai City from March to May 2023. The results showed that the quality of wastewater in the parameters of BOD, COD, TSS, and pH in the inlet basin was by the quality standards of the Minister of Environment Regulation Number 5 of 2014, except for the value of TSS parameters in April 31 mg / l and May 35 mg / l. The quality of wastewater in the outlet basin based on the STORET method with a total score of 0 is classified as Class A (very good) or has met the quality standard value of the Minister of Environment Regulation Number 5 of 2014. Based on calculations, the average value of effectiveness of BOD (13.53%), COD (11.22%), and TSS (49.79%) was obtained. The WWTP method uses 2 methods, the aerobic and anerob methods. It is expected that the hospital will check the quality of inlet and outlet wastewater at least once every 1 month by PERMENLH Number 5 of 2014.

Machine Learning for Detecting Virus Infection Hotspots Via Wastewater-Based Epidemiology: The Case of SARS-CoV-2 RNA.

Wastewater-based epidemiology (WBE) has been proven to be a useful tool in monitoring public health-related issues such as drug use, and disease. By sampling wastewater and applying WBE methods, wastewater-detectable pathogens such as viruses can be cheaply and effectively monitored, tracking people who might be missed or under-represented in traditional disease surveillance. There is a gap in current knowledge in combining hydraulic modeling with WBE. Recent literature has also identified a gap in combining machine learning with WBE for the detection of viral outbreaks. In this study, we loosely coupled a physically-based hydraulic model of pathogen introduction and transport with a machine learning model to track and trace the source of a pathogen within a sewer network and to evaluate its usefulness under various conditions. The methodology developed was applied to a hypothetical sewer network for the rapid detection of disease hotspots of the disease caused by the SARS-CoV-2 virus. Results showed that the machine learning model's ability to recognize hotspots is promising, but requires a high time-resolution of monitoring data and is highly sensitive to the sewer system's physical layout and properties such as flow velocity, the pathogen sampling procedure, and the model's boundary conditions. The methodology proposed and developed in this paper opens new possibilities for WBE, suggesting a rapid back-tracing of human-excreted biomarkers based on only sampling at the outlet or other key points, but would require high-frequency, contaminant-specific sensor systems that are not available currently.

Understanding the Interactions of Climate and Land Use Changes with Runoff Components in Spatial-Temporal Dimensions in the Upper Chi Basin, Thailand

Climate and land use changes are major factors affecting runoff in regional basins. Understanding this variation through considering the interactions among hydrological components is an important process for water resource management. This study aimed to assess the variation of future runoff in the Upper Chi Basin, Northeastern Thailand. The QSWAT hydrological model was integrated into three CMIP6 GCMs—ACCESS-CM2, MIROC6, and MPI-ESM1-2-LR—under SSP245 and SSP585 scenarios for the period 2023–2100. The Land Change Modeler (LCM) was also used for future land use simulation. The results revealed that the future average long-term precipitation and temperature tended to increase while forest land tended to decrease and be replaced by sugarcane plantations. The accuracy assessment of the baseline year runoff calculation using QSWAT for the period 1997–2022 showed an acceptable result, as can be seen from the R2, NSE, RSR, and PBIAS indices. This result could lead to the temporal and spatial simulation of future runoff. Likewise, the runoff of the two SSP scenarios tended to increase consecutively, especially in the SSP585 scenario. In addition, in cases of long-term spatial changes in the subbasins scale, over 90% of the area—from upstream to the outlet point—tended to be higher due to two major factors; namely, future increased precipitation and changes in cultivation, which would be influential to groundwater and interflow components, respectively. The methodology and result of this study can be useful to stakeholders in understanding changes in hydrological systems so that they can apply it to developing a strategy for water resource management and to handling factors affecting different dimensions properly and sustainably.

Assessment of an Oxidation Ditch's Performance via COD and Nitrogen Fractionation Analysis

The rapid population growth in the southern part of Quito, driven by the pursuit of material prosperity, has increased the production of wastewater, leading to discharges into water bodies and impacting water quality. In this context, characterizing wastewater is crucial for reliable operational decisions. This research evaluates the Quitumbe Wastewater Treatment Plant's bioreactor in relation to the fractionation of COD and nitrogen, considering the sludge age as a controlled variable. Wastewater samples were collected in March at the inlet and outlet points of the bioreactor, and a physicochemical method was used for COD fractionation. The results indicate a predominance of slowly biodegradable COD (XS) and removal rates of 95% for biodegradable COD and 93% for ammonia nitrogen, demonstrating biodegradation capacity. Incomplete nitrification was confirmed, along with a cellular retention time of 20 days. This study provides a solid foundation for improving the operational management of the Quitumbe Wastewater Treatment Plant.

Performance evaluation of downhole oil–water separators in wells that use DWL technique using computational fluid dynamics: influence of velocities and flow rates

A major issue in many oil fields is the production of undesirable water from oil wells. One of the most important causes of unwanted water is water coning. This phenomenon may be leading to a decreasing oil production rate, an increasing water cut, and consequently high production costs. Downhole water loop (DWL) is a relatively new and effective technique to control water coning. Even though many studies have shown how effective the DWL approach is in reducing the problem of water cones, the issue of oil droplets escaping the drainage zone might damage the injection area and perhaps cause blockage. It is suggested to use the downhole oil–water separator (DOWS) approach to separate oil droplets from the water stream based on the difference in densities. This article gives a numerical analysis of DOWS in two stages. In order to confirm that the simulator could faithfully simulate this sort of separator, the findings of the employed simulator were first compared with the preceding analytical solutions. Then the impact of inlet velocities and flow rates was discussed numerically for seven scenarios in the second stage. The results showed that a high inlet velocity encourages the formation of oil droplets as a result of the mixture stream colliding with the separator walls, whereas a low inlet velocity produced undesirable results because the oil droplets remained dispersed in the water stream (the separation efficiency was 30.6% less than the high-velocity condition). In the following case, a novel design based on expanding the mixture input area and changing the mixture inlet and outlet points was presented to lessen the impact of mixture inlet velocity. The separation efficiency was improved by 38.65% as a result of this approach. Finally, the discussion's findings about the effect of mixture flow rates at the separator's inlet and upper outlet showed that the inlet rate has a bigger impact on separator performance than the upper outlet rate. The outcomes of this research and the numerical models can be utilized to enhance the system-level design, better understand this kind of separator, and increase its efficacy.

Radiological study of a wastewater treatment plant associated with radioiodine therapy at a hospital in West Java, Indonesia

Nuclear medicine (NM) services in Indonesia have rapidly developed due to the increasing number of patients, and this growth has been supported by standardized regulations in the field, including the management of solid waste generated. However, multiple reports indicate that licensing control does not regulate liquid waste disposal from patient excretions to protect personnel and the community from radiopharmaceutical exposure. One of the radiopharmaceuticals commonly used in NM and having the longest half-life among the radiopharmaceuticals used in NM is iodine 131(I-131). Thus, this study used a high-purity germanium detector to measure iodine-131 (I-131) activity in liquid waste from decay tanks, temporary collection channels, the hospital’s wastewater treatment plant (WWTP) outlet, and six points around the NM service and liquid waste treatment unit. Concentration measurements in three decay tanks were carried out sequentially every 12 h for 3 d, corresponding to the therapy period. The results showed that the I-131 activity levels in the decay tanks and temporary collection channels, before being mixed with liquid waste from other units, were 95.9 × 106 ± 4.4 × 106 Bq m−3. At the point where the liquid waste from other units was mixed, the activity level decreased significantly to 472 680 ± 22 160 Bq m−3, which was below the clearance level of 107 Bq m−3. However, the recorded concentration exceeded the standard for environmental radioactivity at the hospital’s WWTP outlet, namely 37 670 ± 2040 Bq m−3. The measurement results for I-131 in the air in the open space for two nuclear buildings was above the standard at 1.3 ± 0.27 Bq m−3. According to the RESRAD simulation, based on the initial dose taken from the liquid waste treatment outlet point, the accumulation of doses and the risk of cancer among workers and the community decreased within 3 months after the maximum exposure.

Water-saving optimization design of aggregate processing plant and recycled water utilization for producing concrete

Water resources utilization in large hydropower projects is primarily allocated to aggregate washing. Current washing devices are inefficient and lead to serious waste of water. Thus, a novel washing device is designed by optimizing outlet point layout and hydraulic form. The device's various nozzles, particularly the spiral ones, offer greater rinsing coverage and improved washing efficiency with multiple interfacial sprays. Compared to conventional methods, the new washing process has reduced water usage by half, and its effectiveness has been verified in Yebatan hydropower station's aggregate processing system. Subsequently, the feasibility of using recycled water for concrete mixing is verified. Recycled water may impair concrete performance due to Cl− accumulation after flocculation and high suspended solids concentration. Experiments confirm that Cl− and under 1800 mg L−1 suspended solids concentration do not significantly impair concrete performance. This work optimizes the utilization of water resources in aggregate processing from source and terminal.