Journal articles on the topic 'KF. Planning, Design, Removal'
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1
Saeed, Anwar Ameen Hezam, Noorfidza Yub Harun, Suriati Sufian, Muhammad Roil Bilad, Baiq Asma Nufida, Noor Maizura Ismail, Zaki Yamani Zakaria, Ahmad Hussaini Jagaba, Aiban Abdulhakim Saeed Ghaleb, and Baker Nasser Saleh Al-Dhawi. "Modeling and Optimization of Biochar Based Adsorbent Derived from Kenaf Using Response Surface Methodology on Adsorption of Cd2+." Water 13, no. 7 (April 5, 2021): 999. http://dx.doi.org/10.3390/w13070999.
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Cadmium is one of the most hazardous metals in the environment, even when present at very low concentrations. This study reports the systematic development of Kenaf fiber biochar as an adsorbent for the removal of cadmium (Cd) (II) ions from water. The adsorbent development was aided by an optimization tool. Activated biochar was prepared using the physicochemical activation method, consisting of pre-impregnation with NaOH and nitrogen (N2) pyrolysis. The influence of the preparation parameters—namely, chemical impregnation (NaOH: KF), pyrolysis temperature, and pyrolysis time on biochar yield, removal rate, and the adsorption capacity of Cd (II) ions—was investigated. From the experimental data, some quadratic correlation models were developed according to the central composite design. All models demonstrated a good fit with the experimental data. The experimental results revealed that the pyrolysis temperature and heating time were the main factors that affected the yield of biochar and had a positive effect on the Cd (II) ions’ removal rate and adsorption capacity. The impregnation ratio also showed a positive effect on the specific surface area of the biochar, removal rate, and adsorption capacity of cadmium, with a negligible effect on the biochar yield. The optimal biochar-based adsorbent was obtained under the following conditions: 550 °C of pyrolysis temperature, 180 min of heating time, and a 1:1 NaOH impregnation ratio. The optimum adsorbent showed 28.60% biochar yield, 69.82% Cd (II) ions removal, 23.48 mg/g of adsorption capacity, and 160.44 m2/g of biochar-specific area.
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Murali, G., M. Murugan, K. Arunkumar, P. V. Elumalai, D. Mohanraj, and S. Prabhakar. "Investigation and Process Parameter Optimization on Wire Electric Discharge Machining of Aluminium 6082 Alloy." Advances in Materials Science and Engineering 2022 (September 24, 2022): 1–16. http://dx.doi.org/10.1155/2022/5119056.
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Wire electrical discharge machining (WEDM) is an unconventional machining process that is being extensively used in the aerospace,medical devices, die, tooling, and automotive industries for machining high-hardness materials with conductivity. In the present work, WEDM of aluminium 6082 alloys was carried out since it influences diversified applications in manufacturing industries. The WEDM process includes an extensive number of variables that influence its execution. However, based on the literature survey, three process parameters such as pulse-on time (PTON), pulse-off time (PTOFF), and wire feed (WF) were taken into consideration. The factorial design was used for the selection of parameter levels and arrived at the 27 trails for the machining. The output responses of the WEDM, namely, surface roughness (SR), kerf width (KF), and metal removal rate (MRR) were measured, and its parameter optimization was also carried out to minimize the significant effect on productivity and the quality of components. The measured output response was compared with the predicted response surface methodology (RSM) results; it was found that the SR and KF values decreased with the increase of PTON. The MRR was increased with the increase of PTON.
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Yang, Yuqin, Jan van Aalst, and Carol Chan. "Examining Online Discourse Using the Knowledge Connection Analyzer Framework and Collaborative Tools in Knowledge Building." Sustainability 13, no. 14 (July 19, 2021): 8045. http://dx.doi.org/10.3390/su13148045.
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This study examines the problem of the fragmentation of asynchronous online discourse by using the Knowledge Connection Analyzer (KCA) framework and tools and explores how students could use the KCA data in classroom reflections to deepen their knowledge building (KB) inquiry. We applied the KCA to nine Knowledge Forum® (KF) databases to examine the framework, identify issues with online discourse that may inform further development, and provide data on how the tools work. Our comparisons of the KCA data showed that the databases with more sophisticated teacher–researcher co-design had higher KCA indices than those with regular KF use, validating the framework. Analysis of KF discourse using the KCA helped identify several issues including limited collaboration among peers, underdeveloped practices of synthesizing and rising above of collective ideas, less analysis of conceptual development of discussion threads, and limited collaborative reflection on individual contribution and promising inquiry direction. These issues that open opportunities for further development cannot be identified by other present analytics tools. The exploratory use of the KCA in real classroom revealed that the KCA can support students’ productive reflective assessment and KB. This study discusses the implications for examining and scaffolding online discussions using the KCA assessment framework, with a focus on collective perspectives regarding community knowledge, synthesis, idea improvement, and contribution to community understanding.
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Antonieti, Caio César, and Yovanka Pérez Ginoris. "Removal of Cylindrospermopsin by Adsorption on Granular Activated Carbon, Selection of Carbons and Estimated Fixed-Bed Breakthrough." Water 14, no. 10 (May 19, 2022): 1630. http://dx.doi.org/10.3390/w14101630.
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Climate change and the increase in the availability of nutrients in aquatic environments have increased the occurrence of cyanobacterial blooms which can produce cyanotoxins such as cylindrospermopsin (CYN). Activated carbon adsorption have been proved to be efficient for CYN removal. In the present study, a carbon with high CYN adsorption capacity was identified between two granular activated carbons. For this carbon was estimated the operating time of a full-scale granular activated carbon column under different empty bed contact times (EBCT). The fixed-bed breakthrough was estimated using the Homogeneous Surface Diffusion Model (HSDM). Wood carbon showed greater capacity to remove CYN. The experimental equilibrium data best fitted Langmuir isotherm model, in which wood carbon had a maximum adsorption capacity of 3.67 μg/mg and Langmuir adsorption constant of 0.2791 L/μg. The methodology produced satisfactory results where the HSDM simulated the fixed-bed breakthrough with a coefficient of determination of 0.89, to the film diffusion coefficient (Kf) of 9 × 10−6 m/s and surface diffusion coefficient (Ds) of 3 × 10−16 m2/s. It was observed that the increase in EBCT promotes a reduction in the carbon use rate. The best carbon use rate found was 0.43 kg/m3 for a EBCT of 10 min and breakthrough time of 183.6 h.
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Lalwani, Vishal, Priyaranjan Sharma, Catalin Iulian Pruncu, and Deepak Rajendra Unune. "Response Surface Methodology and Artificial Neural Network-Based Models for Predicting Performance of Wire Electrical Discharge Machining of Inconel 718 Alloy." Journal of Manufacturing and Materials Processing 4, no. 2 (May 6, 2020): 44. http://dx.doi.org/10.3390/jmmp4020044.
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This paper deals with the development and comparison of prediction models established using response surface methodology (RSM) and artificial neural network (ANN) for a wire electrical discharge machining (WEDM) process. The WEDM experiments were designed using central composite design (CCD) for machining of Inconel 718 superalloy. During experimentation, the pulse-on-time (TON), pulse-off-time (TOFF), servo-voltage (SV), peak current (IP), and wire tension (WT) were chosen as control factors, whereas, the kerf width (Kf), surface roughness (Ra), and materials removal rate (MRR) were selected as performance attributes. The analysis of variance tests was performed to identify the control factors that significantly affect the performance attributes. The double hidden layer ANN model was developed using a back-propagation ANN algorithm, trained by the experimental results. The prediction accuracy of the established ANN model was found to be superior to the RSM model. Finally, the Non-Dominated Sorting Genetic Algorithm-II (NSGA- II) was implemented to determine the optimum WEDM conditions from multiple objectives.
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Urgun-Demirtas, M., K. R. Pagilla, T. E. Kunetz, J. P. Sobanski, and K. P. Law. "Nutrient removal process selection for planning and design of large wastewater treatment plant upgrade needs." Water Science and Technology 57, no. 9 (May 1, 2008): 1345–48. http://dx.doi.org/10.2166/wst.2008.223.
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A protocol to select nutrient removal technologies that can achieve low nutrient effluents (total nitrogen (TN) < 5 mg/L and total phosphorus (TP) < 0.5 mg/L) was developed for different wastewater treatment plant (WWTP) sizes based on the research conducted during a Water Environment Research Foundation funded project. The adaptable protocol includes technology and cost assessment of feasible (pre-screened) nutrient removal technologies that are being successfully implemented at full scale. The information collected from the full scale nutrient removal plants to develop this protocol includes design, operational, performance, and cost data through a direct survey of plants, and published data. The protocol includes a “technology threshold” approach consisting of Tier I (TN < 5.0 mg/L; TP < 0.5 mg/L) and Tier II (TN < 3.0 mg/L; TP < 0.1 mg/L) effluent nutrient levels for different plant sizes. A very large WWTP (1,250,000 m3/day flow) in Chicago, Illinois, USA adapted this protocol for master planning and design of future nutrient removal facilities based on plant and site specific criteria.
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MacCollum, David. "Design-Based Safety." Journal of System Safety 53, no. 2 (July 1, 2017): 5. http://dx.doi.org/10.56094/jss.v53i2.86.
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The role of system safety engineers is to ensure the inclusion of design-based safety so that projects are completed ahead of schedule and under budget. Removal of hazards during planning and project design includes examining each piece of equipment to be used on the construction project. Most serious construction injuries and deaths caused by workplace accidents can be traced to inherent hazardous design defects. Construction workers are often unaware of these defects and, even if they are aware, they have no authority to improve on the design.
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Šolić, Marko, Snežana Maletić, Marijana Kragulj Isakovski, Jasmina Nikić, Malcolm Watson, Zoltan Kónya, and Jelena Tričković. "Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions." Water 12, no. 3 (March 6, 2020): 723. http://dx.doi.org/10.3390/w12030723.
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Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L−1) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the Ph of the solutions from Ph 2 to Ph 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient KF) ranging from 1.24 to 13.2 (mg g−1)/(mg l−1)n, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions.
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Singh, Rajendra, Fei Zhao, Qian Ji, Jothivel Saravanan, and Dafang Fu. "Design and Performance Characterization of Roadside Bioretention Systems." Sustainability 11, no. 7 (April 5, 2019): 2040. http://dx.doi.org/10.3390/su11072040.
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In the current study, three roadside bioretention systems with different configurations were constructed to investigate their pollutant removal efficiency in different rainfall recurrence intervals. The bioretention systems (referred as units) (unit A: 700 mm height material without submerged zone; unit B: 400 mm height material with 300 mm submerged zone; unit C: 400 mm height material without submerged zone) were used to conduct the rainfall events with uniform 120 min rainfall duration for 2-, 5-, 10-, 15-, and 30-year recurrence intervals. Results reveal that the gradual increase of rainfall return period would have negative effects on TN and NH4+-N removal. The higher filler layer may increase pollutant removal efficiency. Setting a submerged zone could improve the CODMn and TN removal compared to TP and NH4+-N removal. The values for comprehensive reduction rate of pollutant load in the three bioretention systems were recorded as follows: 64% in SS, 50%~80% in TP, 69% in NH4+-N, and 28%~53% in NO3-N separately. These results provide greater understanding of the design and treatment performance of bioretention systems.
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Iqbal, Nida, Sami A. Al-Hussain, Fozia Batool, Amina Mumtaz, Ali Irfan, Sobia Noreen, Muhammad Mustaqeem, and Magdi E. A. Zaki. "Alginate-Based Sustainable Green Composites of Polymer and Reusable Birm for Mitigation of Malachite Green Dye: Characterization and Application for Water Decontamination." Sustainability 15, no. 4 (February 9, 2023): 3194. http://dx.doi.org/10.3390/su15043194.
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Environmental sustainability appraisal of adsorption for exclusion of the malachite green toxic dye was the center of attention in this work. The influenced goals were to analyze the consequences of novel composites fabricated by sodium alginate with guar gum and birm (SA@GG@B composites) by ion gelation. This work not only explains the feasibility of the sorbent and its application for the removal of dye stuff but also proclaimed various effects of different parameters affecting the removal efficiency. Adsorption processes were carried out in the batch process. The composite was characterized by SEM, which revealed that the irregular surface of composites has pores present for high adsorption, FTIR (for functional groups detection) reveals the presence of –OH group which provides attachment sites for dye, and BET (surface analysis) with a surface area of 5.01 m2/g shows that it has a wide surface area for greater adsorption process. Adsorption was performed on synthetic composites by varying different parameters like contact time, the concentration of sorbent and sorbate, and pH. Maximum adsorption was achieved (92.7%) at 100 ppm initial concentration, 120 min interaction time, and pH 9. Adsorption isotherms (Freundlich, Langmuir, Dubnin, and Elvoich isotherm) were applied in this work and evaluated the adsorption phenomenon and nature of adsorption. Freundlich adsorption capacity KF (9.45) reveals effective adsorption of dye by the proposed adsorbent. The kinetics models show that it was better with the pseudo-second-order reaction. Effective removal of malachite green by synthesized composites reveals their importance for the industrial water purification from hazardous dyes.
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Austin, Gary. "DESIGN AND PERFORMANCE OF BIORETENTION BEDS FOR REMOVAL OF STORMWATER CONTAMINANTS." Journal of Green Building 7, no. 1 (January 2012): 17–27. http://dx.doi.org/10.3992/jgb.7.1.17.
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Ilyas, Huma, and Eric van Hullebusch. "Role of Design and Operational Factors in the Removal of Pharmaceuticals by Constructed Wetlands." Water 11, no. 11 (November 10, 2019): 2356. http://dx.doi.org/10.3390/w11112356.
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This study evaluates the role of design, operational, and physicochemical parameters of constructed wetlands (CWs) in the removal of pharmaceuticals (PhCs). The correlation analysis demonstrates that the performance of CWs is governed by several design and operational factors (area, depth, hydraulic loading rate, organic loading rate, and hydraulic retention time), and physicochemical parameters (dissolved oxygen, temperature, and pH); the removal efficiency of about 50% of the examined PhCs showed a significant correlation with two or more factors. Plants contributed significantly in the removal of some of the PhCs by direct uptake and by enhancing the process of aerobic biodegradation. The use of substrate material of high adsorption capacity, rich in organic matter, and with high surface area enhanced the removal of PhCs by adsorption/sorption processes, which are the major removal mechanisms of some PhCs (codeine, clarithromycin, erythromycin, ofloxacin, oxytetracycline, carbamazepine, and atenolol) in CWs. Although the removal of almost all of the studied PhCs showed seasonal differences, statistical significance was established in the removal of naproxen, salicylic acid, caffeine, and sulfadiazine. The effective PhCs removal requires the integrated design of CWs ensuring the occurrence of biodegradation along with other processes, as well as enabling optimal values of design and operational factors, and physicochemical parameters.
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Clancy, K. G., and D. J. Carroll. "Key Issues in Planning Submarine Outfalls for Sydney, Australia." Water Science and Technology 18, no. 11 (November 1, 1986): 159–70. http://dx.doi.org/10.2166/wst.1986.0151.
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This paper describes three large tunnelled submarine ocean outfalls, planned to safely discharge primary effluent from about two-thirds of the regional population of Sydney, Australia into deep ocean water. Environmental and investigation aspects are dealt with briefly. Interesting aspects of design and construction planning are described. The design includes the handling of special hydraulic problems such as dilution and salt water removal. The construction planning foreshadows the extensive use of tunnelling machines including roadheaders and a full face tunnel boring machine. The offshore engineering describes the design and testing of innovative G R P risers and diffusers, and their intended installation by a semi–submersible drill ship using standard oil field techniques. The cost estimate and program is included.
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LIAN, FENG-LI, and PING-CHIH LIN. "MODULE DESIGN WITH COMMUNICATION AND RECONFIGURATION FOR SNAKE-TYPE MODULAR ROBOTIC SYSTEMS." International Journal of Information Acquisition 07, no. 03 (September 2010): 205–23. http://dx.doi.org/10.1142/s0219878910002166.
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In this paper, the module hardware design is addressed and a wireless communication algorithm is proposed for the motion coordination and reconfiguration planning of snake-type robots. The objective of the modular design and the planning algorithm is on self-intelligence and distributed feature for the adding of new modules and the removal of broken parts during motion reconfiguration. Particularly, the automatic connector and wireless communication are implemented on each module, and a planning algorithm for motion reconfiguration is proposed for determining the physical position and acting role of the sequential connected modules in a snake-like robot. Finally, two types of case studies are conducted for testing the communication feasibility and motion reconfigurability of the proposed robotic modules.
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Ilyas, Huma, and Eric D. van Hullebusch. "The Influence of Design and Operational Factors on the Removal of Personal Care Products by Constructed Wetlands." Water 12, no. 5 (May 12, 2020): 1367. http://dx.doi.org/10.3390/w12051367.
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This research presents the correlation analysis of selected design and operational factors (depth, area, hydraulic and organic loading rate, and hydraulic retention time), and physicochemical parameters (pH, temperature, and dissolved oxygen) of constructed wetlands (CWs) with the removal efficiency of personal care products (PCPs). The results demonstrated that the removal efficiencies of the studied PCPs exhibit a significant correlation with two or more of these factors. The role of plants in the removal of PCPs is demonstrated by the higher performance of planted compared with unplanted CWs due to direct uptake of PCPs and their aerobic biodegradation. The enhanced removal of PCPs was achieved with the use of substrate material of high adsorption capacity and with high surface area in CWs. The removal efficiency of almost all of the studied PCPs revealed seasonal differences, but significant difference was established in the case of galaxolide and methyl dihydrojasmonate. Most of the examined PCPs demonstrated adsorption and/or sorption as their most dominant removal mechanism followed by biodegradation and plant uptake. Therefore, the efficient removal of PCPs demands the integrated design ensuring suitable environment for the occurrence of these processes along with the optimal values of design and operational factors, and physicochemical parameters.
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Maeda, T., S. Kinoshita, S. Sato, and A. Ujiie. "Design of a Snow Melting Tank Using Treated Wastewater." Water Science and Technology 29, no. 1-2 (January 1, 1994): 319–26. http://dx.doi.org/10.2166/wst.1994.0679.
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Iwamizawa City, which is located at lat. 43 deg N. and long. 141 deg E., on Hokkaido Island, in the northern part of Japan, experiences heavy snowfall during winter. Every year, the City disposes 610,000 tons of snow collected from its roads and spends 573 million yen for snow removal and 48 million yen for maintenance of the snow dumping sites. However, these dumping sites have, at present, almost reached the limit of their capacities. It is for this reason that snow melting and disposal with treated wastewater was planned. In planning the equalization tank at Nankoen Wastewater Treatment Plant (NWTP), the City intended to use the tank for snow melting during winter. As there were no available data for designing such a tank, experiments were conducted to generate data necessary for designing the snow melting tank. The full-scale tank was constructed based on findings and results of the series of experiments. Results of operation show stable snow disposal and cost reduction for snow removal.
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Abduljauwad, Sahel N., and Ali M. Dakkak. "Selection of Liner Materials and Design of Hazardous Water Facilities in Saudi Arabia." Sultan Qaboos University Journal for Science [SQUJS] 6, no. 2 (December 1, 2001): 21. http://dx.doi.org/10.24200/squjs.vol6iss2pp21-34.
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Rapid development in Saudi Arabia has produced a broad spectrum of wastes. In the last two decades, several refineries and petrochemical industries have been established. These industries have produced sludges and other toxic wastes which need proper planning for their handling and disposal. This paper covers design and selection of liner materials for two hazardous waste disposal sites. One of them is located in the Eastern Province of Saudi Arabia, while the second one is located in the Western part. The paper will present complete design details of the natural compacted and geosynthetic soil liners and the leachate collection and removal system for primary liners and leak detection/leachate collection and removal system for secondary liners.
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Wang, Mian, Julia Zhu, and Xinwei Mao. "Removal of Pathogens in Onsite Wastewater Treatment Systems: A Review of Design Considerations and Influencing Factors." Water 13, no. 9 (April 25, 2021): 1190. http://dx.doi.org/10.3390/w13091190.
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Conventional onsite wastewater treatment systems (OWTSs) could potentially contribute to the transmission of infectious diseases caused by waterborne pathogenic microorganisms and become an important human health concern, especially in the areas where OWTSs are used as the major wastewater treatment units. Although previous studies suggested the OWTSs could reduce chemical pollutants as well as effectively reducing microbial contaminants from onsite wastewater, the microbiological quality of effluents and the factors potentially affecting the removal are still understudied. Therefore, the design and optimization of pathogen removal performance necessitate a better mechanistic understanding of the hydrological, geochemical, and biological processes controlling the water quality in OWTSs. To fill the knowledge gaps, the sources of pathogens and common pathogenic indicators, along with their major removal mechanisms in OWTSs were discussed. This review evaluated the effectiveness of pathogen removal in state-of-art OWTSs and investigated the contributing factors for efficient pathogen removal (e.g., system configurations, filter materials, environmental and operational conditions), with the aim to guide the future design for optimized treatment performance.
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Bradford, Andrea, and Bahram Gharabaghi. "Evolution of Ontario's Stormwater Management Planning and Design Guidance." Water Quality Research Journal 39, no. 4 (November 1, 2004): 343–55. http://dx.doi.org/10.2166/wqrj.2004.047.
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Abstract Ontario's Stormwater Management, Planning and Design Manual released in March 2003 integrates some of the advancements made in stormwater management since the 1994 version of the Manual was published. Perhaps the most significant update is the recognition of in-stream erosion control and water balance objectives in addition to flood and water quality objectives for stormwater management. Specific design criteria which would allow these objectives to be achieved are not set out, but procedures that can assist in the development of criteria based on local watershed and receiving water conditions are described. While refinements will undoubtedly be needed, approaches to designing end-of-pipe facilities to prevent undesirable geomorphic changes are included. Approaches to protect groundwater and baseflow characteristics are also included although guidance on addressing potential trade-offs between groundwater quantity and quality is an additional challenge for the future. Little design guidance is available in Ontario on techniques to mitigate impacts on wetlands, however, developments from other jurisdictions may be transferable. The 2003 Manual promotes an integrated, treatment train approach to stormwater management that emphasizes prevention first, followed by lot-level and conveyance controls and finally, endof- pipe controls. Some information on better site design techniques is incorporated but in comparison to other jurisdictions, less emphasis has been placed on low-impact development strategies. Ontario's approach to design for water quality (suspended solids) control has evolved little. To complement the prevention and treatment train philosophy, the removal efficiency approach to sizing end-of-pipe facilities needs to be used in conjunction with effluent criteria and/or minimum requirements for source protection. Significant advancements in stormwater modelling over the last decade are not well reflected in the Manual; the limited discussion of modelling focusses on an event-based approach. Whether event or continuous modelling is utilized, Ontario practitioners will need guidance on adapting input data to account for the anticipated effects of climate change. Development of sound guidance on monitoring increasingly complex, multi-objective stormwater management systems and the ecosystems they are designed to protect will be critical to ensure that the knowledge gained from performance evaluations may continue to be utilized to refine the design and management of stormwater systems.
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Khalfaoui, Amel, Mohamed Nadir Khelifi, Anouar Khelfaoui, Abderrezzaq Benalia, Kerroum Derbal, Corrado Gisonni, Gaetano Crispino, and Antonio Panico. "The Adsorptive Removal of Bengal Rose by Artichoke Leaves: Optimization by Full Factorials Design." Water 14, no. 14 (July 18, 2022): 2251. http://dx.doi.org/10.3390/w14142251.
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Currently, the dye industry is increasing its production as a consequence of the growing need for their products in different manufacturing sectors, such as textiles, plastics, food, paper, etc... Thereafter, these industries generate very large volumes of effluents contaminated by these dyes, which require proper removal treatment before final discharge of the effluents into the environment. In this study, artichoke leaves were used as an economical and eco-friendly bio-adsorbent for Bengal Rose (BR) dye removal. Bio-adsorbent obtained from artichoke leaves was ground to powder size. The resulting powder was characterized by different methods, such as Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy(SEM), X-ray Diffraction (XRD), Fourier transfer infrared (FTIR), pH at point of zero charge (pHpzc), equilibrium pH, iodine number, methylene blue number, phenol number, density, Energy dispersive X-ray spectroscopy (EDX) and Thermo-gravimetric analysis (TGA). Thereafter, the bio-adsorbent was used to study its capability for removing BR dye by testing contact time, initial concentration of dye and temperature. The results show that the saturation of bio-sorbent was reached after 40 min and the removal rate of BR dye by artichoke leaves powder (ALP) was 4.07 mg/g, which corresponds to a removal efficiency of 80.1%. A design of experiences (DOE) based on a two-level full factorial design (23) was used to study the effects of different parameters, such as pH, temperature and bio-adsorbent dosage on BR dye removal efficiency. The obtained results show that the highest removal efficiency was 86.5% for the optimized values of pH (4), temperature (80 °C) and bio-adsorbent dosage (8 g/L). Furthermore, a satisfying accordance between experimental and predicted data was observed. The kinetic and isotherm studies show that the pseudo-second order model simulated adequately the obtained data and it was found that Langmuir and Temkin isotherm models are liable and suitable for evaluating the adsorption process performance. Free energy change of adsorption (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were furthermore calculated to predict the nature of the adsorption process.
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Liu, Suning, and Ting Fong May Chui. "Optimal In-Stream Structure Design through Considering Nitrogen Removal in Hyporheic Zone." Water 12, no. 5 (May 14, 2020): 1399. http://dx.doi.org/10.3390/w12051399.
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The hyporheic zone (HZ), the region beneath or alongside a streambed, can play a vital role in a stream ecosystem. Previous studies have examined the impacts of in-stream structures on the HZ and river restoration; however, studies on optimizing the design of in-stream structures are still lacking. Therefore, this study aims to propose a method for optimizing the design of in-stream structures (e.g., weirs) through comprehensively considering both nitrogen removal amount (NRA) and nitrogen removal ratio (NRR) in the HZ based on numerical modelling. The Hydrologic Engineering Center’s River Analysis System (HEC-RAS) and COMSOL Multiphysics are employed for surface water and hyporheic flow simulations, respectively, and these two models are coupled by the hydraulic head along the surface of the streambed. The NRA and NRR are both closely related with residence time (RT), while the NRA is also influenced by hyporheic flux. Using the model outputs under different scenarios, regression equations for estimating the relevant variables (e.g., the maximum upstream distance in the subsurface flow influenced by the weir, the RT, and the hyporheic flux) are proposed. Then, the cumulative NRA (CNRA) and NRR can be calculated, and an objective function is formulated as the product of the normalized CNRA and NRR. The results show that the optimal height of the weir can be obtained based on the proposed method, and the validation shows the good general performance of this method. Sensitivity analysis indicates that the optimal height generally can be sensitive to the river discharge, i.e., the optimal height increases when the river discharge increases and vice versa. In addition, it is observed that, in the case of the optimal height, hyporheic flux increases when the slope increases while the influence of depth to bedrock on hyporheic flux is not significant. This study enhances our understanding of the optimal in-stream structure design, and potentially benefits river restoration in the face of continual degradation caused by human activities.
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Liu, Bodi, and Neil Armitage. "The Link between Permeable Interlocking Concrete Pavement (PICP) Design and Nutrient Removal." Water 12, no. 6 (June 16, 2020): 1714. http://dx.doi.org/10.3390/w12061714.
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The construction of ‘hard’ impermeable surfaces in urban areas results in the increased flow of stormwater runoff and its associated pollutants into downstream receiving waters. Permeable Pavement Systems (PPS) can help mitigate this. The most common type of PPS in South Africa is permeable interlocking concrete pavement (PICP), but there is currently insufficient information available on the relative treatment performance of different PICP designs. This paper describes an investigation into the performance of ten different PICP systems constructed in the Civil Engineering Laboratory at the University of Cape Town for the treatment of various nutrients commonly found in stormwater runoff. It was found that removal efficiencies ranged from 27.5% to 78.7% for ammonia-nitrogen and from −37% to 11% for orthophosphate-phosphorus; whilst 4% to 20.2% more nitrite-nitrogen and 160% to 2580% more nitrate-nitrogen were simultaneously added. The presence of a geotextile resulted in higher ammonia-nitrogen removal efficiencies but also higher nitrate-nitrogen addition than those cells without—with small differences between various types. The cell with a permanently wet ‘sump’ had the highest nitrate-nitrogen addition of all. Lower pH results in higher nitrate-nitrogen concentrations, whilst the electrical conductivity strongly depends on the length of the periods between rainfall ‘seasons’, decreasing rapidly during wet periods but increasing during dry periods. Paver type also had a minor impact on nutrient removal.
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Li, Shi Long, and Xian Feng Zhao. "Processing of Grinder Plate with Bone Chips Removal Facilities Based on CAD/CAM." Applied Mechanics and Materials 217-219 (November 2012): 1831–34. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1831.
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Rotary meat grinders with bone chip removal facilities are advanced meat mincing machinery, characterized by undesirable hard-particle separation from ground meat during grinding operations. The grinder plate with an involute spiral groove to facilitate removal of hard particles is developed. The perforated plate with bone chips removal facilities has a unique design including catcher groove, bone-collection chamber and bone-removal passage. Its 3D modeling in Pro/E software, machining process planning, milling path optimization, simulation based on MasterCAM and compiling post program were introduced and verified. The results indicated that adoption of CAD/CAM offers firms the potential to pursue new innovative strategies.
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Chen, Xinhan, Zhen Hu, Yijin Zhang, Linlan Zhuang, Jian Zhang, Jing Li, and Hongying Hu. "Removal Processes of Carbamazepine in Constructed Wetlands Treating Secondary Effluent: A Review." Water 10, no. 10 (September 28, 2018): 1351. http://dx.doi.org/10.3390/w10101351.
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It is widely believed that constructed wetlands (CWs) own great potentiality as polishing wastewater treatment methods for removing carbamazepine (CBZ). Although the typical CBZ removal efficiencies in CWs are quite low, the CBZ removal performance could be improved to some extend by optimizing the CW design parameters. A comparison of current relevant studies indicates that horizontal sub-surface flow CWs (HSSF-CWs) and hybrid wetlands are attracting more interest for the treatment of CBZ wastewater. According to CBZ’s physicochemical properties, substrate adsorption (25.70–57.30%) and macrophyte uptake (22.30–51.00%) are the two main CBZ removal pathways in CWs. The CBZ removal efficiency of CWs employing light expanded clay aggregate (LECA) as a substrate could reach values higher than 90%, and the most favorable macrophyte species is Iris sibirica, which has shown the highest total CBZ assimilation capacity. Several methods for enhancement have been proposed to optimize CBZ removal in CWs, including development of hydraulic models for optimization of CW operation, introduction of extra new CBZ removal ways into CW through substrate modification, design of combined/integrated CW, etc.
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Phillips, James A., and Samuel J. Smidt. "Modeling Improved Performance of Reduced-Height Biosand Water Filter Designs." Water 12, no. 5 (May 8, 2020): 1337. http://dx.doi.org/10.3390/w12051337.
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Point-of-use biosand water filters are widely distributed in undeveloped or developing regions due to their water treatment success and low-cost design, but two gaps remain in the basic technology: (1) the filter body is oversized relative to its contaminant removal performance, and (2) the heavy design largely excludes difficult to reach locations in need of clean water solutions. Here, we model design modifications to the v.10 Centre for Affordable Water and Sanitation Technology biosand filter using a reduced filter height, increased biolayer area, and conserved reservoir volume. We compare the hydraulic characteristics (dynamic velocity and head pressure) and percent contaminant removal of bacteria Escherichia coli and virus MS2 of the modified designs to the traditional control design using a finite element approximation of Darcy’s law with discrete time steps and a slow-sand filtration model. We demonstrate that a reduced-height design has a greater impact on contaminant removal compared to the traditional design (largely due to the increased residence time from the decreased flow rate inside the filter). For example, our 70% reduced-height filter design removed 99.5% and 73.93% of E. coli and MS2, respectively, where the traditional filter design removed 62.81% and 27.6%, respectively. Reduced-height designs should be pursued as a viable solution to improve filter performance while allowing for alternative construction techniques with greater end-user accessibility compared to the traditional design.
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Yılmaz, Özgün, Nabil Aouf, Elena Checa, Laurent Majewski, and Manuel Sanchez-Gestido. "Thermal analysis of space debris for infrared-based active debris removal." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 3 (November 17, 2017): 811–22. http://dx.doi.org/10.1177/0954410017740917.
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In space, visual-based relative navigation systems suffer from dynamic illumination conditions of the target (eclipse conditions, solar glare, etc.) where most of these issues are addressed by advanced mission planning techniques. However, such planning would not be always feasible or even if it is, it would not be straightforward for active debris removal missions. On the other hand, using an infrared-based system would overcome this problem, if a guideline to predict infrared signature of space debris based on the target thermal profile could be provided for algorithm design and testing. Spacecraft thermal design is unique to every platform. This means every active debris removal target will have a different infrared signature, which changes over time not just only due to orbital dynamics but also due to its thermal surface coatings. In order to provide a space debris infrared signature guideline for most of the possible active debris removal targets, we introduce an innovative grouping system for thermal surface coatings based on their behaviour in space environment. Through the use of this grouping system, we propose a space debris infrared signature estimation method, which was extensively verified by our simulations and experiments. During our verifications, we have also discovered very important problem so-called ‘signature ambiguity’ that is unique to infrared-based active debris removal systems, which we have also discussed in our work.
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Gharabaghi, B., A. Fata, T. Van Seters, R. P. Rudra, G. MacMillan, D. Smith, J. Y. Li, A. Bradford, and G. Tesa. "Evaluation of sediment control pond performance at construction sites in the Greater Toronto Area." Canadian Journal of Civil Engineering 33, no. 11 (November 1, 2006): 1335–44. http://dx.doi.org/10.1139/l06-074.
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Receiving water quality concerns associated with increased construction activities in recent years in the Greater Toronto Area has prompted the Toronto and Region Conservation Authority (TRCA) to evaluate design criteria for sediment control ponds employed during the construction period. Stormwater management ponds located in the towns of Richmond Hill and Markham were monitored to obtain stormwater runoff quantity and influent-effluent quality data during site development. The ponds were designed and constructed in accordance with the Ontario Ministry of the Environment Stormwater management planning and design manual 2003 for an enhanced level of protection (i.e., 80% total suspended solids removal). A hydrodynamic and sediment-transport model was used to examine the effect of pond geometry on sediment removal efficiency under varying storm events. The monitoring data and the modelling results clearly demonstrate the importance of proper pond size and geometry design. This paper focuses on the effect of the ratio of pond length to pond width in minimizing the short-circuiting effect and improvement of the sediment removal efficiency of stormwater management ponds. The results of this study will be useful in updating the design criteria for stormwater management ponds.Key words: stormwater, management, pond, design, sediment.
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HONMA, Toshiyuki, Ayumi HAMADA, and Minoru KANNO. "THE STUDY ON REMOVAL OF THE BARRIER IN EXPRESSWAY REST FACILITY IN TOHOKU REGION(Architectural Planning and Design)." AIJ Journal of Technology and Design 10, no. 20 (2004): 233–38. http://dx.doi.org/10.3130/aijt.10.233.
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Lee, Huaming, Jon Scott, Jon Sims Williams, and David Cox. "Symbolic calculus for volumetric reasoning about process plans." Artificial Intelligence for Engineering Design, Analysis and Manufacturing 10, no. 3 (June 1996): 183–98. http://dx.doi.org/10.1017/s0890060400001542.
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AbstractA symbolic calculus for reasoning about process plans is proposed in this paper. The main focus of attention is the selection and sequencing of material removal operations for components in accordance with the design geometry. This is a central issue in automated process planning. The proposed symbolic calculus defines a computational formalism for symbolic manipulation of feature volumes, so that reasoning about volumetric removals can be treated in a logical manner by using well-defined procedures of algorithmic synthesis. This potentially encourages a more generic approach to the automation of outline and detailed process planning. The underlying philosophy is that a properly interpreted object topology upon the feature model allows the logical synthesis of volumetric removal sequences. The number of sequences is constrained by algorithms within the planning system that consider part geometry as expressed by features. This reduces the problem space associated with plan synthesis. Some of the geometrically viable sequences have the potential for further development to form viable machining removal sequences, or outline process plans.
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Shahawy, Abeer El, Inas A. Ahmed, Mahmoud Nasr, Ahmed H. Ragab, Saedah R. Al-Mhyawi, and Khalda M. A. Elamin. "Organic Pollutants Removal from Olive Mill Wastewater Using Electrocoagulation Process via Central Composite Design (CCD)." Water 13, no. 24 (December 9, 2021): 3522. http://dx.doi.org/10.3390/w13243522.
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Electrocoagulation (EC) was studied in this study as a potential alternative approach for treating Olive Mill Wastewater (OMW). Aluminum plates were utilized as anode and cathode to evaluate the removal of Chemical Oxygen Demand (COD) from OMW and the aluminum electrode’s weight loss. Central Composite Experimental Design (CCD) and Response Surface Methodology were used to optimize its performance. Anodes were weighed before and after each electrocoagulation experiment, to compare the experimental and the theoretical dissolved aluminum weights calculated using Faraday’s law. We discovered the following EC conditions for CCD: current density = 15 mA/cm2, pH = 4, and electrolysis time of 30 min. Under these conditions, the maximum COD removal ratio was 41%, equating to an Al weight loss of 288.89 g/m3 at an estimated operating cost of 1.60 USD/m3. According to the response optimizer, the most economical operating settings for COD removal efficiency of 58.888% are pH 4, a current density of 18.41 mA/cm2, electrolysis time of 36.82 min, and Al weight loss of 337.33 g/m3, with a projected running cost of 2.00 USD/m3.
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Zhu, Jiang, Keisuke Nomura, Tomohisa Tanaka, and Yoshio Saito. "Tool Path Planning Assist System for Freeform Surface Machining." Key Engineering Materials 447-448 (September 2010): 321–25. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.321.
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With the rapid development of CG technology and 3D scanning technology, it is easy to design the freeform surface more complexly, but it also makes it difficult to machine such complex freeform surface rapidly and accurately. In this paper, a tool path planning assist system for freeform surface machining is presented. Differing from general CAM systems, in this developed tool path planning assist system, the tool path is generated based on the features of the CAD model, and focus on the applicability of material removal process. New machining strategies for both rough cutting process and finish cutting process are presented. With the assisting of this developed system, freeform surface could be machined efficiently and accurately.
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Isnaini, Mohammad Mi’radj, and Keiichi Shirase. "Review of Computer-Aided Process Planning Systems for Machining Operation – Future Development of a Computer-Aided Process Planning System –." International Journal of Automation Technology 8, no. 3 (May 5, 2014): 317–32. http://dx.doi.org/10.20965/ijat.2014.p0317.
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The need to integrate the design and machining stages has become an important issue since the introduction of the Computer-Integrated Manufacturing (CIM) concept. The development of the Computer-Aided Process Planning (CAPP) system has been recognized to have made a significant contribution toward fulfilling the requirement for an integrated planning system. This paper reviews the development of the CAPP system, particularly for the metal removal process. Previous reviews on CAPP are gathered and discussed to show the evolution stage of CAPP in general. Main research topics that contribute to the CAPP system development are shown. Six elements of the CAPP system are identified as the most important tasks in generating a process plan. These elements consist of: (1) model convention, (2) manufacturing operation selection, (3) manufacturing resource selection, (4) cutting condition selection, (5) tool path selection, and (6) setup selection. Six elements for the development of CAPP that contribute to process planning for metal removal process are discussed. The evolution stages of each element easily show the involvement of several tools in order to support the corresponding element. For further guidance, the methods of comprehending the involvement of manufacturing information in CAPP are discussed. Knowledge structuring and logic reasoning are the main organizational steps that can be used to describe the CAPP data architecture of manufacturing information. Further, the examples of full-scale CAPP in actualizing machining process planning are presented. Finally, key technologies for future development of CAPP are discussed.
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Castelino, Kenneth, V. Sundararajan, Roshan D’Souza, Balaji Kannan, and Paul K. Wright. "AMPS-An Automated Modular Process Planning System." Journal of Computing and Information Science in Engineering 4, no. 3 (September 1, 2004): 235–41. http://dx.doi.org/10.1115/1.1710866.
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AMPS is a fully automated process planning system for milling of 2.5D parts. It consists of different modules, each of which performs specific tasks like identification of removal volumes, setup and fixture planning, tool selection and tool path planning. This article focuses on the architecture of the planning system, the integration of the different modules and the interfaces needed for smooth flow of information between these modules. Current computer aided process planning (CAPP) practices were considered while defining interfaces so that these modules can be easily integrated into a commercial CAPP system.
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Gittings, Gary L., Darren J. Torbic, and Leonard A. Zangwill. "Evaluation of Planning and Design Issues for Multiuse Trail and Highway Crossings." Transportation Research Record: Journal of the Transportation Research Board 1538, no. 1 (January 1996): 102–10. http://dx.doi.org/10.1177/0361198196153800114.
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Across the country a network of multiuse trails is evolving from abandoned rail corridors. This phenomenon creates a new set of demands on public highway and transportation agencies. These demands are most evident at public highway crossings of rail-trail projects. These demands raise new policy, planning, and engineering issues. The most difficult and controversial of the engineering issues is whether to retain or remove grade-separating rail structures. The issue often pits trail advocates against public highway and transportation engineers in a debate over whether safety is enhanced or degraded by the removal of the structure. Decisions on structures rely on a variety of factors, including the physical condition of the structure; the alignment, clearance, and sightlines at the crossing; the quality of trail plans; and the magnitude and division of responsibility for current and future costs. To effectively resolve trail and highway crossing issues, it is important to recognize that, in matters related to the crossings, the highway or transportation agency's customer base includes trail users as well as motor vehicle drivers and passengers. Decisions on crossing issues should evolve from a balanced appraisal of the sometimes differing safety and operating needs of trail as well as highway users. The process of reaching balanced, multimodal design decisions begins with better public planning before rail line abandonment. The state highway or transportation agency can enhance its decision making through better communication, coordination, and encouragement of trail planning with sister state agencies, local government(s), regional planning agencies, and trail development organizations.
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Carvalho Porto de Freitas, Rodrigo Falcão, Ana Larisse Carneiro Pereira, and Adriana da Fonte Porto Carreiro. "CAD/CAM technology for fabrication of reduction guide for RPD parallel guiding planes preparation: A dental technique." Primary Dental Journal 11, no. 4 (December 2022): 66–70. http://dx.doi.org/10.1177/20501684221132976.
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Introduction: The preparation of parallel axial wall guide planes in abutment teeth is essential for providing a correct path of insertion and removal axis for removable partial dentures (RPDs). With the introduction of digital resources, new alternatives to the conventional method can be used to manufacture guide preparation for guide planes. Aims: To describe the use of computer-aided design/computer-aided manufacturing (CAD/CAM) technology for the manufacture of guide planes to guide the reduction of the axial walls of abutment teeth according to the insertion and removal axis of the RPD. Methods: This technique used the “bite splint” module of the Dental Wings software for the virtual planning of guide planes, to promote the construction of axial walls parallel to the abutment teeth. This was performed from the virtual design on a standard tessellation language (STL) file obtained by intraoral scanning, which determined the best trajectory for insertion and removal of the metallic structure. Conclusion: Digital technology allows the design and production of guide planes for the preparation of abutment teeth, simplifying the conventionally used technique, with precision and speed.
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Yang, Wulin, Hongya Fu, Zhongxi Shao, Hongquan Zu, Qiang Wu, and Chuan Chen. "Energy Analysis of a Space-Energy Driven Laser-Ablation Debris Removal System." Sustainability 14, no. 3 (February 4, 2022): 1794. http://dx.doi.org/10.3390/su14031794.
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Space-energy driven laser-ablation debris removal is a feasible way to address the worsening space debris environment. Energy analysis is crucial for the design and run of a space-energy driven laser-ablation debris removal system. This study details the energy analysis of a space-energy driven laser-ablation debris removal system as affected by laser energy, frequency and range. The results show that the laser irradiation time and energy efficiency are decreased with increases in the laser energy and frequency, and the energy efficiency in the case of different planes is significantly lower than that in the case of coplanar. However, laser range has no effect on the perigee changing and energy efficiency. The results can effectively guide the removal scheme design and evaluation.
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Kumar, Ajay, Himanshu Joshi, and Anil Kumar. "Arsenate Removal from the Groundwater Employing Maghemite Nanoparticles." Water 14, no. 22 (November 10, 2022): 3617. http://dx.doi.org/10.3390/w14223617.
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An investigation of the potential of γ-Fe2O3 (maghemite) nanoparticles (MNPs) to remove AsV from groundwater is reported. The MNPs were synthesized using a modified co-precipitation method via refluxing. The morphological and surface characteristics of MNPs were analyzed using XRD, FTIR, SEM, TEM, and Zetasizer techniques. Their AsV removal potential was explored in synthetic water representing the elemental composition equivalent to arsenic-contaminated groundwater of the Ballia district, Uttar Pradesh, India. The arsenic concentration in the samples collected from the study area was observed to be much more than the provisional WHO guideline value for drinking water (10 µg L−1). An orthogonal array L27 (313) of the Taguchi design of experimental methodology was employed to design the experiments and optimization of AsV removal. The ANN tool was trained to evaluate Taguchi’s outcomes using MATLAB. The percentage of ionic species distribution and surface complexation modeling was performed using Visual MINTEQ. The study explored the effects of pH, temperature, contact time, adsorbent dose, total dissolved solids, and shaking speed on the removal process. The adsorption was found to occur through electrostatic interactions. The inter-parametric analysis demonstrated the involvement of secondary sites affecting the adsorption. The charge distribution multi-sites complexation (CD-MUSIC) model and 2pk-Three-Plane-Model (TPM) indicated the involvement of the reactivity of singlet (FeOH−0.5) and triplet (Fe3O−0.5) species in the examined pH range. The developed nanoparticles are observed to be efficient in AsV removal. This information could benefit field-scale arsenic removal units.
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Luo, Yuan, Jiakai Lu, Yi Zhang, Kai Zheng, Qiong Qin, Lin He, and Yanyu Liu. "Near-Ground Delivery Drones Path Planning Design Based on BOA-TSAR Algorithm." Drones 6, no. 12 (December 2, 2022): 393. http://dx.doi.org/10.3390/drones6120393.
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With the advancement of technology and the rise of the unmanned aerial vehicle industry, the use of drones has grown tremendously. For drones performing near-ground delivery missions, the problem of 3D space-based path planning is particularly important in the autonomous navigation of drones in complex spaces. Therefore, an improved butterfly optimization (BOA-TSAR) algorithm is proposed in this paper to achieve the autonomous pathfinding of drones in 3D space. First, this paper improves the randomness strategy of the initial population generation in the butterfly optimization algorithm (BOA) via the Tent chaotic mapping method, by means of the removal of the short-period property, which balances the equilibrium of the initial solutions generated by the BOA algorithm in the solution space. Secondly, this paper improves the shortcomings of the BOA algorithm in terms of slower convergence, lower accuracy, and the existence of local optimal stagnation when dealing with high-dimensional complex functions via adaptive nonlinear inertia weights, a simulated annealing strategy, and stochasticity mutation with global adaptive features. Finally, this paper proposes an initial population generation strategy, based on the 3D line of sight (LOS) detection method, to further reduce the generation of path interruption points while ensuring the diversity of feasible solutions generated by the BOA algorithm for paths. In this paper, we verify the superior performance of BOA-TSAR by means of simulation experiments. The simulation results show that BOA-TSAR is very competitive among swarm intelligence (SI) algorithms of the same type. At the same time, the BOA-TSAR algorithm achieves the optimal path length measure and smoothness measure in the path-planning experiment.
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Sonavane, P. G., and G. R. Munavalli. "Modeling nitrogen removal in a constructed wetland treatment system." Water Science and Technology 60, no. 2 (July 1, 2009): 301–9. http://dx.doi.org/10.2166/wst.2009.319.
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A constructed wetland treatment system (CWTS) has been adopted for removal of nitrogen from wastewater. The design methodologies developed for CWTS in previous studies were based on thumb rules, and first order/Monod type kinetics models. The use of kinetic models is system/environment specific. There is scope to assess the potential of other reaction kinetic models for their usefulness and applicability. In the present study, lumped and distributed parameter models incorporated with various reactions kinetic were developed. The various processes were incorporated in distributed parameter model for nitrogen transformations. Laboratory/pilot-scale field experiments were carried out and used for verification and application of models developed. The reaction rate parameters were estimated using non-linear least square analysis. The results showed that the conditions within CWTS can be simulated by plug flow. The plant uptake rate was found to be higher than denitrification for nitrate removal. Nitrification and plant uptake are equally dominant for the removal of ammonia nitrogen. The relative contributions by various processes for nitrogen removal can be established using the distributed parameter model. The developed simulation model can be used as a CWTS planning and design tool for the effective control and treatment of nitrogen induced pollution.
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Dahlan, Irvan, Emillia Eizleen Md Azhar, Siti Roshayu Hassan, Hamidi Abdul Aziz, and Yung-Tse Hung. "Statistical Modeling and Optimization of Process Parameters for 2,4-Dichlorophenoxyacetic Acid Removal by Using AC/PDMAEMA Hydrogel Adsorbent: Comparison of Different RSM Designs and ANN Training Methods." Water 14, no. 19 (September 28, 2022): 3061. http://dx.doi.org/10.3390/w14193061.
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In this study, the response surface methodology (RSM) and artificial neural network (ANN) were employed to study the adsorption process of 2,4-dichlorophenoxyacetic acid (2,4-D) by using modified hydrogel, i.e., activated carbon poly(dimethylaminoethyl methacrylate) (AC/PDMAEMA hydrogel). The effect of pH, the initial concentration of 2,4-D and the activated carbon content on the removal of 2,4-D and adsorption capacity were investigated through the face-centered composite design (FCCD), optimal design and two-level factorial design. The response surface plot suggested that higher removal of 2,4-D and adsorption capacity could be achieved at the higher initial concentration of 2,4-D and lower pH and activated carbon content. The modeling and optimization for the adsorption process of 2,4-D were also carried out by different design methods of RSM and different training methods of ANN. It was found that among the three design methods of RSM, the optimal design has the highest accuracy for the prediction of 2,4-D removal and adsorption capacity (R2 = 0.9958 and R2 = 0.9998, respectively). The numerical optimization of the optimal design found that the maximum removal of 2,4-D and adsorption capacity of 65.01% and 65.29 mg/g, respectively, were obtained at a pH of 3, initial concentration of 2,4-D of 94.52 mg/L and 2.5 wt% of activated carbon. Apart from the optimization of process parameters, the neural network architecture was also optimized by trial and error with different numbers of hidden neurons in the layers to obtain the best performance of the response. The optimization of the neural network was performed with different training methods. It was found that among the three training methods of the ANN model, the Bayesian Regularization method had the highest R2 and lowest mean square error (MSE) with the optimum network architecture of 3:9:2. The optimum condition obtained from RSM was also simulated with the optimized neural network architecture to validate the responses and adequacy of the RSM model.
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Song, Xiaojun, Per Magnus Ehde, and Stefan E. B. Weisner. "Effects of Water Depth and Phosphorus Availability on Nitrogen Removal in Agricultural Wetlands." Water 11, no. 12 (December 13, 2019): 2626. http://dx.doi.org/10.3390/w11122626.
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Excess nitrogen (N) from agricultural runoff is a cause of pollution in aquatic ecosystems. Created free water surface (FWS) wetlands can be used as buffering systems to lower the impacts of nutrients from agricultural runoff. The purpose of this paper was to evaluate critical factors for N removal in FWS wetlands receiving high nitrate (NO3−) loads from agriculture. The study was performed in 12 experimental FWS wetlands in southern Sweden, receiving drainage water from an agricultural field area. The effects of water depth (mean depth of 0.4 m and 0.6 m, respectively) and phosphorus (P) availability (with or without additional P load) were investigated from July to October. The experiment was performed in a two-way design, with three wetlands of each combination of depth and P availability. The effects of P availability on the removal of NO3− and total N were strongly significant, with higher absolute N removal rates per wetland area (g m−2 day−1) as well as temperature-adjusted first-order area-based removal rate coefficients (Kat) in wetlands with external P addition compared to wetlands with no addition. Further, higher N removal in deep compared to shallow wetlands was indicated by statistically significant differences in Kat. The results show that low P availability may limit N removal in wetlands receiving agricultural drainage water. Furthermore, the results support that not only wetland area but also wetland volume may be important for N removal. The results have implications for the planning, location, and design of created wetlands in agricultural areas.
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Shojaeizadeh, Ali, Mengistu Geza, Colin Bell, John McCray, and Terri Hogue. "A Site-Scale Tool for Performance-Based Design of Stormwater Best Management Practices." Water 13, no. 6 (March 19, 2021): 844. http://dx.doi.org/10.3390/w13060844.
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The objective of this research is to develop a module for the design of best management practices based on percent pollutant removal. The module is a part of the site-scale integrated decision support tool (i-DSTss) that was developed for stormwater management. The current i-DSTss tool allows for the design of best management practices based on flow reduction. The new water quality module extends the capability of the i-DSTss tool by adding new procedures for the design of best management practices based on treatment performance. The water quality module can be used to assess the treatment of colloid/total suspended solid and dissolved pollutants. We classify best management practices into storage-based (e.g., pond) and infiltration-based (e.g., bioretention and permeable pavement) practices for design purposes. Several of the more complex stormwater tools require expertise to build and operate. The i-DSTss and its component modules including the newly added water quality module are built on an accessible platform (Microsoft Excel VBA) and can be operated with a minimum skillset. Predictions from the water quality module were compared with observed data, and the goodness-of-fit was evaluated. For percent total suspended solid removal, both R2 and Nash–Sutcliffe efficiency values were greater than 0.7 and 0.6 for infiltration-based and storage-based best management practices, respectively, demonstrating a good fit for both types of best management practices. For percent total phosphorous and Escherichia. coli removal, R2 and Nash–Sutcliffe efficiency values demonstrated an acceptable fit. To enhance usability of the tool by a broad range of users, the tool is designed to be flexible allowing user interaction through a graphical user interface.
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Hamouda, Mohamed A., Haliemeh Sweidan, Munjed A. Maraqa, and Hilal El-Hassan. "Mechanistic Study of Pb2+ Removal from Aqueous Solutions Using Eggshells." Water 12, no. 9 (September 9, 2020): 2517. http://dx.doi.org/10.3390/w12092517.
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This study investigates the impact of eggshell particle size and solid-to-water (s/w) ratio on lead (Pb2+) removal from aqueous solution. Collected raw eggshells were washed, crushed, and sieved into two particle sizes (<150 and 150–500 µm). Batch Pb2+ removal experiments were conducted at different s/w ratios with initial Pb2+ concentrations of up to 70 mg/L. The contribution of precipitation to Pb2+ removal was simulated by quantifying removal using eggshell water, whereas sorbed Pb2+ was quantified by acid digestion. Results indicated that eggshell particle sizes did not affect Pb2+ removal. High removal (up to 99%) of Pb2+ was achieved for low initial Pb2+ concentrations (<30 mg/L) across all s/w ratios studied. However, higher removal capacity was observed at lower s/w ratios. In addition, results confirmed that precipitation played a major role in the removal of Pb2+ by eggshells. Yet, this role decreased as the s/w ratio and initial concentration of Pb2+ increased. A predictive relationship that relates the normalized removal capacity of eggshells to the s/w ratio was developed to potentially facilitate the design of the reactor.
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Rubio-Palau, Josep, Alejandra Prieto-Gundin, Leydi Mar de Abreu Graterol, and Herman Vercruysse. "Maxillomandibular Syngnathia: 3D Planning and Review of the Literature." Craniomaxillofacial Trauma & Reconstruction 11, no. 2 (June 2018): 124–30. http://dx.doi.org/10.1055/s-0037-1606248.
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Congenital maxillomandibular fusion or syngnathia is a rare craniofacial disorder with only 26 cases reported in the literature. We present a case of a congenital complex zygomatico-mandibular syngnathia associated with a palatal cleft, posterior maxilla and turbinate agenesia, mild hemifacial microsomia, and a disordered dental eruption. The patient has the highest age (15 years) at diagnosis described in the literature. 3D planning of the surgery was performed to study the patient's anatomy and design the necessary osteotomies to separate the jaws. En bloc removal of the fused fragment with bilateral coronoidectomy and aggressive long-term physiotherapy for 3 months led to a stable increase in mouth opening from 0 to 21 mm inter-incisor distance. The patient reported an improvement in speech, was able to eat without restriction regarding food consistency, and could maintain a good oral hygiene.
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Michalek, Alexander, Admin Husic, Joshua Roundy, and Amy T. Hansen. "Assessment of Climatic and Anthropogenic Controls on Bridge Deck Drainage and Sediment Removal." Water 13, no. 24 (December 12, 2021): 3556. http://dx.doi.org/10.3390/w13243556.
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Bridge deck drainage is essential to prevent hydroplaning and maintain safety along major roadways. With projected changes in climate, current designs may not be sufficient and a better understanding of the primary controls (climate, bridge deck, and inlet design) on the hydraulic efficiency and sediment removal of drainage systems is needed to maintain public safety. To evaluate the controls on hydraulic drainage efficiency, 576 controlled laboratory experiments were conducted testing grate type (rectangular bar vs. curved vane) and downspout configuration (square vs. circular and 20 cm vs. 25 cm) across a range of flow rates, cross slopes, and longitudinal slopes. An additional 144 sediment erosion experiments were performed to identify controls on the removal of sediment. Hydraulic testing indicated that inflow driven by climate is a primary control on drainage efficiency and spread of water on a roadway. For anthropogenic controls, downspout opening size was found to be the primary control followed by longitudinal slope. Sediment removal results indicated that inflow regime and grate type were the primary controls on the sediment removal rate. Given that inflow, driven by climate, is a control on both hydraulic and sediment removal performance, hydraulic engineers should consider forecasted changes in rainfall intensity in their present-day drainage designs. We provide design guidance and discussion for developing a proactive approach to hydraulic infrastructure in the face of future climate uncertainty.
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Osman, Manal, Khamaruzaman Wan Yusof, Husna Takaijudin, Hui Weng Goh, Marlinda Abdul Malek, Nor Ariza Azizan, Aminuddin Ab. Ghani, and Abdurrasheed Sa’id Abdurrasheed. "A Review of Nitrogen Removal for Urban Stormwater Runoff in Bioretention System." Sustainability 11, no. 19 (September 30, 2019): 5415. http://dx.doi.org/10.3390/su11195415.
Full textAbstract:
One of the best management practices (BMPs) for stormwater quality and quantity control is a bioretention system. The removal efficiency of different pollutants under this system is generally satisfactory, except for nitrogen which is deficient in certain bioretention systems. Nitrogen has a complex biogeochemical cycle, and thus the removal processes of nitrogen are typically slower than other pollutants. This study summarizes recent studies that have focused on nitrogen removal for urban stormwater runoff and discusses the latest advances in bioretention systems. The performance, influencing factors, and design enhancements are comprehensively reviewed in this paper. The review of current literature reveals that a bioretention system shows great promise due to its ability to remove nitrogen from stormwater runoff. Combining nitrification and denitrification zones with the addition of a carbon source and selecting different plant species promote nitrogen removal. Nevertheless, more studies on nitrogen transformations in a bioretention system and the relationships between different design factors need to be undertaken.
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Rosero Parra, Laura, Lizeth Guerrero Pantoja, Natali Lorena Mena, Fiderman Machuca-Martínez, and Julian Urresta. "Evaluation of TiO2 and SnO Supported on Graphene Oxide (TiO2-GO and SnO-GO) Photocatalysts for Treatment of Hospital Wastewater." Water 12, no. 5 (May 19, 2020): 1438. http://dx.doi.org/10.3390/w12051438.
Full textAbstract:
The effectiveness of two photocatalysts, TiO2 and SnO, supported on graphene oxide (TiO2-GO and SnO-GO) on the removal of organic matter from hospital wastewater effluent was evaluated at laboratory scale. The results of the experimental design allow us to conclude that variables such as catalyst type and catalyst concentration have a significant effect on the organic matter removal efficiency of the photocatalytic process. The highest levels of removal efficiencies—for chemical oxygen demand, 85%, for phenols, 80%, and for dissolved organic carbon, 94%—were achieved using a TiO2-GO catalyst with a concentration in the wastewater of 1.5 g/L.
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Tang, Zepei, Jonaé Wood, Dominae Smith, Arjun Thapa, and Niroj Aryal. "A Review on Constructed Treatment Wetlands for Removal of Pollutants in the Agricultural Runoff." Sustainability 13, no. 24 (December 8, 2021): 13578. http://dx.doi.org/10.3390/su132413578.
Full textAbstract:
Constructed wetland (CW) is a popular sustainable best management practice for treating different wastewaters. While there are many articles on the removal of pollutants from different wastewaters, a comprehensive and critical review on the removal of pollutants other than nutrients that occur in agricultural field runoff and wastewater from animal facilities, including pesticides, insecticides, veterinary medicine, and antimicrobial-resistant genes are currently unavailable. Consequently, this paper summarized recent findings on the occurrence of such pollutants in the agricultural runoff water, their removal by different wetlands (surface flow, subsurface horizontal flow, subsurface vertical flow, and hybrid), and removal mechanisms, and analyzed the factors that affect the removal. The information is then used to highlight the current research gaps and needs for resilient and sustainable treatment systems. Factors, including contaminant property, aeration, type, and design of CWs, hydraulic parameters, substrate medium, and vegetation, impact the removal performance of the CWs. Hydraulic loading of 10–30 cm/d and hydraulic retention of 6–8 days were found to be optimal for the removal of agricultural pollutants from wetlands. The pollutants in agricultural wastewater, excluding nutrients and sediment, and their treatment utilizing different nature-based solutions, such as wetlands, are understudied, implying the need for more of such studies. This study reinforced the notion that wetlands are effective for treating agricultural wastewater (removal > 90%) but several research questions remain unanswered. More long-term research in the actual field utilizing environmentally relevant concentrations to seek actual impacts of weather, plants, substrates, hydrology, and other design parameters, such as aeration and layout of wetland cells on the removal of pollutants, are needed.
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Xu, Zhiying, Caterina Valeo, Angus Chu, and Yao Zhao. "The Efficacy of Whole Oyster Shells for Removing Copper, Zinc, Chromium, and Cadmium Heavy Metal Ions from Stormwater." Sustainability 13, no. 8 (April 9, 2021): 4184. http://dx.doi.org/10.3390/su13084184.
Full textAbstract:
This research investigates the use of a common food waste product for removing four different types of metals typically found in stormwater. Whole, unprocessed oyster shells are explored for use in stormwater management infrastructure that addresses water quality concerns. The role of the shells’ surface area, exposure time, and the solution’s initial concentration on the removal efficiency were examined. Beaker scale experimental results demonstrated very good efficiency by the oyster shells for removing copper ions (80–95%), cadmium ions (50–90%), and zinc ions (30–80%) but the shells were not as effective in removing hexavalent chromium (20–60%). There was a positive relationship between initial concentration and removal efficiency for copper and zinc ions, a negative relationship for hexavalent chromium, and no relationship was found for cadmium ions. There was also a positive relationship between surface area and removal efficiency, and exposure time and removal efficiency. However, after a certain exposure time, the increase in removal efficiency was negligible and desorption was occasionally observed. A mid-scale experiment to mimic real-world conditions was conducted in which continuous inflow based on a 6-h design storm was applied to 2.7 kg of whole, unprocessed oyster shells. The shells provided an 86% and an 84% removal efficiency of cadmium and copper ions, respectively, in one day of hydraulic retention time. No removal was observed for hexavalent chromium, and zinc ion removal was only observed after initial leaching. This work has significant implications for sustainable stormwater infrastructure design using a material commonly found in municipal food waste.
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Adin, Avner. "Climbing the Effluent Filtration Tree: Modelling, Mechanisms & Applications—A Monograph." Energies 15, no. 17 (September 1, 2022): 6401. http://dx.doi.org/10.3390/en15176401.
Full textAbstract:
Particle filtration is a major building block in effluent treatment facilities for water reuse in agriculture, industry, and the community. Yet, its incorporation in modern hybrid treatment systems still lacks basic know-how for process optimization. This paper aims to provide a profound understanding of particle filtration vis-à-vis its various reuse applications. The methodology used follows a road map depicted as a growing tree, representing the author’s research from roots to top: roots—basic modeling, mechanisms; tree trunk—filter design approach for reuse; branches—enhanced particle removal; and tree crown—pretreatment, bioparticle, and nanoparticle removal. Contact deep-bed filtration process optimization, algorithms for economically optimal filter design, tertiary filtration and membrane pretreatment, and related energy issues are being discussed. Some of the conclusions are that pilot plant planning should be primarily derived from particle surface interactions with filter media, based on measurements of mineral particle or bioparticle size, shape, and physicochemical characteristics, and applying attachment-detachment models. Filter design optimization would comprise of selecting efficient water quality processes first, followed by economic optimization for final design parameters. A holistic approach in the design of filtration facilities, standing alone or incorporated in hybrid systems, is also considered.