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1
Liu, Chunye, Rui Wang, Wene Wang, Xiaotao Hu, Wanying Wu e Fulai Liu. "Different Irrigation Pressure and Filter on Emitter Clogging in Drip Phosphate Fertigation Systems". Water 14, n. 6 (9 marzo 2022): 853. http://dx.doi.org/10.3390/w14060853.
Abstract (sommario):
Irrigation pressures and filters have a significant influence on emitter clogging in drip fertigation systems. Exploring the anti-clogging performance of emitters at different irrigation pressures (80, 90, 100 kPa; 40, 50, 60 kPa) and filters (the disc filter with an aperture of 125 μm, the screen filter with an aperture of 125μm, and the screen filter with an aperture of 200 μm) can provide suitable guidance for the design and operation of drip fertigation systems. The average relative discharge (Dra), the Christiansen uniformity coefficient (CU), and the differential pressure (DP) were analyzed to study the anti-clogging performance of flat emitters (FE) and labyrinth emitters (LE). Meanwhile, the scanning electron microscope and energy dispersive spectrometer were used to observe the surface morphology and chemical composition of clogging substances in filters and emitters. Results showed that the irrigation pressure of 90 and 50 kPa did not cause a significant decrease in Dra, and the Dra of two types of emitters were all great than 95.22%. When the irrigation pressure was 80 and 40 kPa, the Dra decreased significantly (73.48–78.71%, 81.3–83.6% for FE and LE). The CU values of emitters were all greater than 90% except for the irrigation pressures of 80 and 40 kPa. The relative Dra and CU of LE were greater than those of FE, indicating that the LE had a better anti-clogging performance compared with the FE. The decrease in DP reflected an increase in the emitter clogging degree. Meanwhile, irrigation pressures and the interaction between irrigation pressures and filters imposed a significant effect on the CU at a significance level of p < 0.05, p < 0.01, respectively. The clogging process was mainly affected by physical and chemical factors, and the generated clogging substances included phosphate fertilizer, silicate, carbonate, and phosphate precipitations. In conclusion, the best operation mode of phosphate fertilizer in drip fertigation systems was to use the disc filter with an aperture of 125 μm and the LE at the irrigation pressure of 50 kPa. An appropriate irrigation pressure combined with effective filters can reduce emitter clogging while saving water and fertilizer.
2
Bang, Ki Woong, Jin Chul Joo, Jin Ho Kim, Eunbi Kang, Jongsoo Choi, Jung Min Lee e Yonghyok Kim. "Application of Bottom Ash as Filter Media for Construction Site Runoff Control". Water 12, n. 4 (1 aprile 2020): 990. http://dx.doi.org/10.3390/w12040990.
Abstract (sommario):
The potential application of bottom ash (BA) for construction site runoff control as an alternative filter media with high removal efficiency of total suspended solids (TSS) and longer operation period were evaluated. Both lab-scale single-layer and pilot-scale multi-layer filtration experiments were performed using BA filter media with different particle sizes and various volumetric flow rates. Due to the mesoporous, irregular, and spherical shape of gravel-size BA filter media used in this study, relatively low surface area, negligible pore volume, and greater pore size were observed. Both TSS removal efficiencies and clogging of BA filter media were a complex function of particle size of BA filter media and loading rate of TSS. Incoming TSS particles did not significantly penetrate beyond 46-cm BA filter media depth, accumulating on the upper layers and gradually forming a clogging layer to critical thickness, and finally the clogging filtration mechanism dominated the overall removal efficiency of TSS. Accumulation of TSS on BA filter media can be explained by the lumped sigmoidal empirical model, and an exponential decline in accumulation of TSS with depth results in minimal accumulation beneath the clogging layer. As practical implications, BA filter media depth of less than 46 cm is recommended with dual- or multi-media filters using mixtures of gravel-size BA and silt-size fine media, and a combination of detention basins can reduce frequent periodic de-clogging operation and management.
3
Wu, Zhengguang, Yanjuan Qi, Aihong Kang, Bo Li e Xueling Xu. "Evaluation of Particulate Matter Capture and Long-Term Clogging Characteristics of Different Filter Media for Pavement Runoff Treatment". Advances in Materials Science and Engineering 2020 (27 agosto 2020): 1–15. http://dx.doi.org/10.1155/2020/5012903.
Abstract (sommario):
The removal of particulate matter (PM) by filter media during filtration process can mitigate the pavement runoff pollution effectively. However, this process also makes the filter media prone to clogging. To better understand the size ranges of PM captured by filter media and the subsequent impact on the clogging process, filtration test and clogging test were conducted on five types of filter media. The effect of layer thickness and grain size of different filter media on particle removal efficiency was evaluated, based on the results of PM removal rate and the particle size distribution. The subsequent long-term clogging characteristics of different filter media were also investigated. The results showed that filter media presented different capabilities to capture PM, which could be enhanced by less layer thickness or finer grain size. Normally, PM with the size range of over 49 μm could be captured effectively if proper layer thickness and grain size of filter media were selected. Besides, PM removal rate was not related to the clogging resistance of filter media. Though it can capture a larger amount of PM, Vesuvianite still maintained remarkable clogging resistance. The results will be beneficial to filter media selection and system design optimization for pavement runoff treatment.
4
Reddi, Lakshmi N., Ming Xiao, Malay G. Hajra e In Mo Lee. "Physical clogging of soil filters under constant flow rate versus constant head". Canadian Geotechnical Journal 42, n. 3 (1 giugno 2005): 804–11. http://dx.doi.org/10.1139/t05-018.
Abstract (sommario):
In this study, the differences in soil filter clogging are evaluated under two operating conditions: constant head and constant flow rate. Whereas filters placed around well screens and leachate collection systems are subjected to a constant flow rate, filters in earth dams and pavement drainage systems operate under constant or slightly varying heads. In this study, the experiments revealed similar permeability reductions with respect to time in both cases; however, the permeability reduction under the condition of constant head occurred in much fewer pore volumes than under the condition of constant flow rate. Self-filtration appeared to be greater under the condition of constant head. The physical clogging model developed for the conditions of constant flow rate and constant head showed good qualitative agreement with experimental observations.Key words: particle, clogging, filter, constant, head, flow.
5
Lee, Byungsik. "Convolutional Neural Network Model for Estimating Clogging of Ash-Mixed Sand Filters". Journal of the Korean Society of Hazard Mitigation 21, n. 4 (31 agosto 2021): 159–68. http://dx.doi.org/10.9798/kosham.2021.21.4.159.
Abstract (sommario):
A deep learning model was developed to estimate the clogging of voids in bottom-ash-mixed sand filters. Filter clogging is characterized by a decrease in the infiltration ratio with an increase in the outflow. The estimation of clogging for time-series forecasting is a regression problem. Various algorithms for regression problems have been applied through machine learning and deep learning. Despite the various algorithm applications, an application for clogging appears to be emerging. Studies are required to develop dependable models for precisely predicting clogging. A convolutional neural network (CNN) clogging model was developed in this study to estimate the relationship between the infiltration ratio and outflow quantity using features defined by the mixing ratio between sand and ash. Significant clogging data required for the effective maintenance and stable operation of stormwater infiltration filters were obtained using the proposed model. The CNN clogging model is recommended as a supplement to conventional theoretical models and expensive experimental models.
6
Alimohammadi, Hossein, Kristina Vassiljeva, Eduard Petlenkov, Martin Thalfeldt, Alo Mikola, Tuule Mall Kull e Ahmet Köse. "Gray Box Time Variant Clogging behaviour and Pressure Drop Prediction of the Air Filter in the HVAC System". E3S Web of Conferences 246 (2021): 10002. http://dx.doi.org/10.1051/e3sconf/202124610002.
Abstract (sommario):
Identification and prediction of clogging behavior in heating, ventilation, and air conditioning (HVAC) filters is crucial to avoid issues such as system overheating, energy waste, lower indoor air quality, etc. Researchers are focusing more on the particle loading characteristics of a filter medium in a laboratory environment under steady-state conditions, fixed particle concentrations, area of porosity, dust feed and volumetric flow rate. However, recent research still shows uncertainties in modeling as well as the implementation problems of constructing the HVAC laboratory test bench and equipment. In addition, subjects such as non-uniform particle deposition depreciation of the condition and various type of mechanical filters such as fibrous, fabric, granular, and membrane filter or electrostatic filters which typically used in HVAC systems perform under some assumptions and still need more research. The studies become even more difficult acquiring a large number of time-varying and noisy signals. Another approach among studies is data-driven knowing that Building Automation System (BAS) is not equipped with appropriate sensor measuring the clogging, it is needed to drive the clogging mathematical model from the pressure drop signal. This paper bridges the gap between particle-size study and black box modeling of HVAC filter which has not received much attention from authors. The proposed method assumes that the pressure drop is the result of two time-varying functions; f(t), which represents the dynamics of clogging and, g(t), which refers to dynamics of remained terms. The exponential and polynomial of second order functions are proposed to express the clogging behavior. The software package based on Particle Swarm Optimization Artificial Bee Colony (PSOABC) algorithm, is developed and implemented to estimate the coefficients of the clogging functions based on smallest RMSE, high coefficient of correlation and acceptable tracking. Five Air Handling Unit (AHUs) are selected for practical verification of the model and the results show that the applied method can successfully predict clogging and pressure drop behaviour of HVAC filters.
7
Alavi Moghaddam, M. R., Y. Guan, H. Satoh e T. Mino. "Filter clogging in coarse pore filtration activated sludge process under high MLSS concentration". Water Science and Technology 54, n. 10 (1 novembre 2006): 55–66. http://dx.doi.org/10.2166/wst.2006.728.
Abstract (sommario):
Coarse pore filtration activated sludge process is a type of hybrid process in which the secondary settling tank of the conventional activated sludge process is replaced by non- woven and coarse pore filter modules. The filter has pores, which are irregular in shape, and much bigger than micro-filtration membrane pores in size. The objective of the study is to find out the effect of the microbial community structure on filter clogging in the coarse pore filtration activated sludge process under high MLSS concentration in aerobic and anoxic/aerobic (A/A) conditions. Filter clogging started from day 65 and 70 in the A/A and aerobic process, respectively, but it was more severe in the A/A process compared to that in the aerobic process. EPS contents of sludge did not change significantly during the operation in both processes, and did not have a crucial effect on the observed filter clogging. There was no strong evidence for direct effect of the type and number of metazoa on filter clogging. The main difference between aerobic sludge and A/A sludge during the filter clogging period was the relative abundance of filamentous bacteria. According to the obtained results, it can be concluded that a higher presence of filamentous bacteria could reduce the severity of filter clogging in a coarse pore filtration activated sludge process.
8
Dalri, Alexandre B., Gilmar O. Santos, Geffson de F. Dantas, Rogério T. de Faria, José R. Zanini e Luiz F. Palaretti. "Performance of drippers in two filtering systems using sewage treatment effluent". Revista Brasileira de Engenharia Agrícola e Ambiental 21, n. 6 (giugno 2017): 363–68. http://dx.doi.org/10.1590/1807-1929/agriambi.v21n6p363-368.
Abstract (sommario):
ABSTRACT The objective of this study was to evaluate the performance of three models of drippers using treated sewage effluent, pure and diluted, and two types of filters, screen and disc. The treated sewage effluent used in the experiment was collected from the city’s treatment plant. The experiment included 12 lateral lines with three types of emitters to apply pure (100%) and diluted (50%) effluent filtered by screen and disc filters. The combination of those factors set the treatments: T1 (50% effluent diluted in fresh water filtered by a screen filter); T2 (50% effluent diluted in fresh water filtered by a disc filter); T3 (pure effluent filtered by a screen filter); T4 (pure effluent filtered by a disc filter). The results showed that the flat type emitter is less sensitive to clogging, the disc filter is the most suitable to prevent clogging and the use of pure or diluted sewage effluent increases the drippers’ flow rate coefficient of variation.
9
Shuraits, A. L., A. V. Birykov e A. P. Usachev. "DEVELOPMENT OF A CALCULATION METHODFOR TWO-STAGE NATURAL GAS PURIFICATION PLANTS FROM MECHANICAL IMPURITIES". Russian Journal of Building Construction and Architecture, n. 1(49) (24 febbraio 2021): 54–65. http://dx.doi.org/10.36622/vstu.2021.49.1.005.
Abstract (sommario):
Statement of the problem. Currently, there is no methodology for calculating the degree of clogging of a multilayer filter cartridge taking into account the prevention of deposition of mechanical impurities in the gap between the coarse and fine filter cylindrical filter cartridges. In this regard, the development of such a technique is an urgent task. Results. In this paper, we propose a calculation method for determining the average integral degree of clogging of multilayer cylindrical filter cartridges with mechanical impurities and pressure loss on them which take into account the prevention of sedimentation of mechanical impurities in the gap between the coarse and fine filter cartridges.Conclusions. The results obtained make it possible to determine the pressure loss and the average integral degree of clogging of the multilayer filter cartridge depending on the decrease in the living cross-section of all filter meshes in the process of clogging and to prevent the deposition of solids in the gap between the coarse and fine filter cartridges.
10
Valmari, Tuomas, Matti Lehtimäki e Aimo Taipale. "Filter Clogging by Bimodal Aerosol". Aerosol Science and Technology 40, n. 4 (aprile 2006): 255–60. http://dx.doi.org/10.1080/02786820500543282.
11
Redner, S., e Somalee Datta. "Clogging Time of a Filter". Physical Review Letters 84, n. 26 (26 giugno 2000): 6018–21. http://dx.doi.org/10.1103/physrevlett.84.6018.
12
Ismail, Nova Risdiyanto, Agung Suprapto, Dadang Hermawan, Purbo Suwandono e Leo Hutri Wicaksono. "Implementation of sediment separator core hole in an effort to reduce the filter clogging rate of CAT 16M Grader". ARMATUR : Artikel Teknik Mesin & Manufaktur 5, n. 1 (22 marzo 2024): 192–99. http://dx.doi.org/10.24127/armatur.v5i1.5347.
Abstract (sommario):
The Cat 16M Grader is a heavy equipment that is widely used to support mining operations. The development of this heavy equipment is required to use biodesel fuel (B30). The problem with B30 fuel is oxidation which results in the formation of sediment and can cause filter clogging. Filter clogging can affect engine power and filter replacement time. From these problems, the researcher proposed to modify the number of sediment separator core holes to reduce the filter clogging rate on the Cat 16M grader. Modified number of sediment separator core holes are 40, 20 and 10 holes with 8 mm hole dimension. Data was collected experimentally by implementing the modified sediment separator core on a Cat 16M grader for 250 hours of operation. The research resulted in the number of sediment separator core holes 10 at 250 hours of operation producing the highest sediment volume of 92 ml, the filter with the lowest clogging rate and the lowest fuel pressure difference. In addition, using the number of sediment separator cores 10 at 250 hours of operation produces the highest engine power, the highest filter clogging efficiency and has a high economic value.
13
Шурайц, А. Л., А. В. Бирюков e А. П. Усачев. "DEVELOPMENT OF A CALCULATION METHOD FOR TWO-STAGE NATURAL GAS PURIFICATION PLANTS FROM MECHANICAL IMPURITIES". НАУЧНЫЙ ЖУРНАЛ СТРОИТЕЛЬСТВА И АРХИТЕКТУРЫ, n. 3(59) (1 ottobre 2020): 32–42. http://dx.doi.org/10.36622/vstu.2020.59.3.003.
Abstract (sommario):
Состояние проблемы. В настоящее время отсутствует методика расчета степени засорения многослойного фильтрующего картриджа, учитывающая недопущение осаждения механических примесей в зазоре между цилиндрическими фильтрующими картриджами грубой и тонкой очистки. В этой связи разработка такой методики является актуальной задачей. Результаты. В данной работе предложена методика расчета по определению среднеинтегральной степени засорения многослойных цилиндрических фильтрующих картриджей механическими примесями и потери давления на них, которые учитывают недопущение осаждения механических примесей в зазоре между цилиндрическими фильтрующими картриджами грубой и тонкой очистки. Выводы. Полученные результаты позволяют определить величины потерь давления и среднеинтегральной степени засорения многослойного фильтрующего картриджа в зависимости от величины уменьшения живого сечения всех фильтрующих сеток в процессе их засорения и предотвратить осаждение механических примесей в зазоре между цилиндрическими фильтрующими картриджами грубой и тонкой очистки. Statement of the problem. Currently, there is no methodology for calculating the degree of clogging of a multilayer filter cartridge taking into account the prevention of deposition of mechanical impurities in the gap between the coarse and fine filter cylindrical filter cartridges. In this regard, the development of such a technique is an urgent task. Results. In this paper, we propose a calculation method for determining the average integral degree of clogging of multilayer cylindrical filter cartridges with mechanical impurities and pressure loss on them which take into account the prevention of sedimentation of mechanical impurities in the gap between the coarse and fine filter cartridges. Conclusions. The results obtained make it possible to determine the pressure loss and the average integral degree of clogging of the multilayer filter cartridge depending on the decrease in the living cross-section of all filter grids in the process of clogging and to prevent the deposition of solids in the gap between the coarse and fine filter cartridges. Statement of the problem. Currently, there is no methodology for calculating the degree of clogging of a multilayer filter cartridge taking into account the prevention of deposition of mechanical impurities in the gap between the coarse and fine filter cylindrical filter cartridges. In this regard, the development of such a technique is an urgent task. Results. In this paper, we propose a calculation method for determining the average integral degree of clogging of multilayer cylindrical filter cartridges with mechanical impurities and pressure loss on them which take into account the prevention of sedimentation of mechanical impurities in the gap between the coarse and fine filter cartridges. Conclusions. The results obtained make it possible to determine the pressure loss and the average integral degree of clogging of the multilayer filter cartridge depending on the decrease in the living cross-section of all filter grids in the process of clogging and to prevent the deposition of solids in the gap between the coarse and fine filter cartridges.
14
Zenfira Huseynli, Ali Mansurov, Zenfira Huseynli, Ali Mansurov, e Gulshad Aghayeva, Rovshana Aliyeva Gulshad Aghayeva, Rovshana Aliyeva. "INCREASING THE PERFORMANCE OF CHRISTMAS TREES IN SANDY CONDITIONS". ETM - Equipment, Technologies, Materials 18, n. 06 (10 dicembre 2023): 108–14. http://dx.doi.org/10.36962/etm18062023-108.
Abstract (sommario):
The key reason to make this research is to find solutions for mechanical impurities, or commonly sand clogging in christmas trees. As it’s known, christmas trees are equipment made for controlling flow of oil and gas, which consists of several gauges and valves for specific purposes. This equipment installed on wells are constantly clogged with various impurities. These mechanical consistency interrupt christmas tree’s work and cause wears and tears which leads to failure of system and overall oil production delay. Thus, frequent maintenance is required. There are two main ways to release the clogging in wells: mechanical and chemical. In this research, mechanical way is applied. To improve and increase the performance of christmas trees, various types of filters are considered with their advantages and disadvantages according to previous experiences. Studies show that, for different type of wells different type of filters, separators etc. are used. Filters used to prevent sand particles are gravel filter, slot filter, perforated filter, wire well filter, well mesh filter, frame-rod filter, slot filter, support element filters and other filters which are considered in this research. According to the mesh principle, the filters which are a component of the ESP - are intended to prevent sand particles from entering the production stream by holding big particles and filtering the resulting liquid. To choose a filter with the best permeation rate and to stop particles larger than a specific size from penetrating, the size of the channels must be calculated. Modification and other movable factors are used to separate each group of filters. Keywords: Christmas tree (oil and gas), mechanical impurities, sand, filter, oil well, separators.
15
McIsaac, Reagan, e R. Kerry Rowe. "Effect of filter–separators on the clogging of leachate collection systems". Canadian Geotechnical Journal 43, n. 7 (1 luglio 2006): 674–93. http://dx.doi.org/10.1139/t06-030.
Abstract (sommario):
This paper reports the results obtained after 6 years operation of nine mesocosm experiments that simulate the 50 cm of the drainage layer closest to the leachate collection pipe in a landfill. Five different design configurations were examined involving a 300 mm thick layer of coarse (38 mm) gravel. The designs differed in terms of the presence, nature, and location of a filter–separator layer either at the waste–gravel interface or partway through the gravel. A nonwoven geotextile filter–separator (GTF/S) is shown to reduce clogging of the gravel relative to the no filter–separator or woven GTF/S designs. Some clogging of the geotextiles is reported, with reductions in geotextile hydraulic conductivity of 23% for the woven GTF/S, 74%–89% for the nonwoven GTF/S, and 75%–94% for the nonwoven geotextile partway through the gravel. The clogged nonwoven geotextile filter–separator maintained a higher hydraulic conductivity than the extracted woven geotextile. Of the designs with a filter–separator between the waste and gravel, the granular filter–separator most effectively reduced clogging of the gravel but at the expense of leachate mounding above the sand once the sand layer clogs. The design with a nonwoven geotextile partway through the gravel (GTMF) provides better protection of the underlying gravel from clogging than other designs involving a geotextile.Key words: landfill, waste, leachate, clogging, biofilm, geotextile.
16
Wang, Jun, Yongli Yang, Hongtao Fu, Yuanqiang Cai, Xiuqing Hu, Xiaoming Lou e Yawei Jin. "Improving consolidation of dredged slurry by vacuum preloading using prefabricated vertical drains (PVDs) with varying filter pore sizes". Canadian Geotechnical Journal 57, n. 2 (febbraio 2020): 294–303. http://dx.doi.org/10.1139/cgj-2018-0572.
Abstract (sommario):
Prefabricated vertical drains (PVDs) have been used extensively to accelerate the consolidation rate of dredged slurry. While some fine particles from dredged slurry can easily squeeze through the filter into the drainage channel, many cannot. As such, these soil particles deposit on the filter surface causing partial clogging of the drainage path. Although the pore size of filter is recognized as an important factor that influences PVD clogging, the standards for determining the pore size of the filter are lacking. To this end, the traditional gradient ratio tests with four different filter pore sizes were conducted, and the results show that the permeability of the filter at a given head increases with the increase in the pore size of the filter. To remove the effect of the difference between static hydraulic gradient and vacuum pressure, the vacuum preloading tests with varying pore sizes of filters were further conducted. Through these vacuum preloading tests, the degree of vacuum, settlement, pore-water pressure, water content, vane shear strength, and other parameters of PVDs with various filter pore sizes were obtained, and the optimal pore size of filter was determined.
17
Hatt, B. E., N. Siriwardene, A. Deletic e T. D. Fletcher. "Filter media for stormwater treatment and recycling: the influence of hydraulic properties of flow on pollutant removal". Water Science and Technology 54, n. 6-7 (1 settembre 2006): 263–71. http://dx.doi.org/10.2166/wst.2006.626.
Abstract (sommario):
Improved urban water management in Australia is of national importance. Water resources are stretched and urban runoff is a recognized leading cause of degradation of urban waterways. Stormwater recycling is an option that can contribute to easing these problems. Biofilters are effective structural stormwater pollution control measures with the potential for integration into stormwater treatment and recycling systems. However, premature clogging of biofilters is a major problem, with resulting decreased infiltration capacity (and hence the volume of stormwater the system can detain) and increased detention time. This paper presents preliminary findings with respect to the effect of clogging on pollutant removal efficiency in conventional stormwater filter media. A one-dimensional laboratory rig was used to investigate the impact of clogging on pollutant removal efficiency in a conventional biofiltration filter media (gravel over sand). Both the individual gravel layer and the overall multi-filter were highly efficient at removing suspended solids and particulate-associated pollutants. This removal efficiency was consistent, even as the filters became clogged. Removal of dissolved nutrients was more variable, with little reduction in concentrations overall. Although preliminary, these results challenge the concept that increased detention time improves the treatment performance of stormwater filtration systems.
18
Wakelin, S. A., D. W. Page, P. Pavelic, A. L. Gregg e P. J. Dillon. "Rich microbial communities inhabit water treatment biofilters and are differentially affected by filter type and sampling depth". Water Supply 10, n. 2 (1 aprile 2010): 145–56. http://dx.doi.org/10.2166/ws.2010.570.
Abstract (sommario):
Factors affecting microbial diversity (richness) and community structure in biofilter columns were investigated. At a pilot filtration plant, granular activated carbon (GAC), anthracite and sand-based filters were used to treat stormwater from an urban catchment. After 12 weeks operation, sand media filters clogged (hydraulic conductivity declining by 90%) and all filters were destructively sampled. All biofilters had similar levels of polysaccharide in the surface layer, however only the sand columns clogged. This clogging may have been due to a combination of polysaccharide and small particle size, the development of a sand-specific microbial community, or other biogeochemical interactions. DNA fingerprinting was used to show that bacterial, archaeal and eukaryotic communities were present in all filter types and at all sampling depths (to 45 cm). The bacterial community was far richer (Margalefs index, d, 1.5–2) than the other groups. This was consistent across filter types and sampling depths. The structure of the bacteria and archaea communities in sand filters differed to those in GAC and anthracite filters (P<0.05). In contrast, eukaryotic communities were similar in surface biofilm layers, irrespective of filter type. As such, physicochemical properties of filters differentially influence the microbial community. Furthermore, we have established that archaea are distributed throughout biofilters; the role of these microorganisms in water treatment and filter function, particularly clogging, requires attention.
19
Song, Zhi Xin, Shao Yuan Bai e Jian Xu. "Effect of Flow Field Distribution on the Clogging of Subsurface Flow Constructed Wetlands". Advanced Materials Research 610-613 (dicembre 2012): 1349–53. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.1349.
Abstract (sommario):
this review summarizes an important factor of clogging in subsurface flow constructed wetlands ¬(SSF)—field distribution. The efficiency of filter media and the spatial distribution of biological growth are determined by the flow field distribution directly. If the flow field distribution is un-uniform, it would accelerate the clogging of substrate. The influencing factors for flow field distribution, including hydraulic loads, properties of filter media, filling structures and root distribution were investigated, and the clogging reasons were discussed additionally. At last, this study showed some corresponding research methods, and helping in the process of research and development of subsurface flow constructed wetlands in solving clogging problem.
20
Lee, D. J. "Filter medium clogging during cake filtration". AIChE Journal 43, n. 1 (gennaio 1997): 273–76. http://dx.doi.org/10.1002/aic.690430132.
21
Oota-Ishigaki, Akiko, Takashi Yamane, Daisuke Sakota, Ryo Kosaka, Osamu Maruyama e Masahiro Nishida. "In vitro hemocompatibility investigation for the development of low-flow centrifugal blood pumps with less platelet clogging". International Journal of Artificial Organs 45, n. 4 (18 ottobre 2021): 431–37. http://dx.doi.org/10.1177/03913988211052570.
Abstract (sommario):
Low-flow blood pumps rated under 1 L/min are emerging for new medical applications, such as hemofiltration in acute use. In those pumps, platelet adhesion and aggregation have to be carefully considered because of clogging risk in the filter part. To find an acceptable hemocompatibility that can be applied to low-flow centrifugal blood pump design, the platelet aggregation index, clogging on a micromesh filter, and the hemolysis index were investigated using a low-flow blood pump designed for hemofiltration use. We conducted circulation testing in vitro using fresh porcine blood and two centrifugal pumps with different impeller inlet shapes. The Negative Log Platelet Aggregation Threshold Index (NL-PATI), which reflects the ability of residual platelets to aggregate, and flow rate were measured during reflux for 60 min, and the Normalized Index of Hemolysis (NIH (g/20 min)) was calculated. In addition, blood cell clogging after reflux was observed on the micromesh filter by SEM, and the adhesion rate was calculated. Our results showed that the platelet clogging on the micromesh filter occurred when the average NL-PATI was greater than 0.28 and the average NIH (g/20 min) was greater than 0.01. In contrast, platelet clogging on the micromesh was suppressed when NL-PATI was less than 0.17 and the NIH (g/20 min) was less than 0.003. These values might be used as acceptable hemocompatibility of low-flow centrifugal blood pumps with suppressed platelet clogging for hemofiltration pumps.
22
Xu, QiaoLing, Li Wang, Ping Wang, XueYuan Wen e Feng Zhang. "Clogging in Vertical Flow Constructed Wetlands: Causes for Clogging and Influence of Decontamination". Ecological Chemistry and Engineering S 29, n. 1 (1 marzo 2022): 65–75. http://dx.doi.org/10.2478/eces-2022-0007.
Abstract (sommario):
Abstract With the continuous operation of constructed wetlands, substrate clogging is issue. In order to solve the problem, there is practical significance to understand the causes for clogging in constructed wetlands. Two pilot-scale vertical flow constructed wetlands were established, namely, CW-B and CW-C. By studying the relationship between the accumulation of different substances and the banked-up water area, it was found that the accumulation of non-filter substances and total solids was an important reason for the clogging of the substrate, and the accumulation degree of non-filter inorganic substances was more obvious than that of non-filter organic substances, and the blockage was mainly located in the 10-20 cm layer. In the vertical flow constructed wetland with river sand as the main substrate, water accumulation will occur when the content of total solid and non-filter substances exceeds 67.233 g and 101.228 g per cubic meter of substrate, respectively. Therefore, it is important to pay attention to the substrate particle size matching of 0-20 cm layer to reduce the clogging in the vertical flow constructed wetland. The clogging has little effect on chemical oxygen demand (COD) removal, but great effect on total phosphorus (TP) removal. Compared with the control wetland (CW-C), the biomass content in the CW-B with biochar increased by 334.26 nmol P/g, which can improve the removal efficiency of total nitrogen (TN) and total phosphorus (TP), but also increase the risk of clogging in the vertical flow constructed wetland. Future research should try to combine the anti-blocking research results of biochar constructed wetlands to improve the purification effect, which is of great significance to promote the sustainable development of constructed wetlands.
23
Sultana, Sarmin, e Kazi Matin Ahmed. "Assessing risk of clogging in community scale managed aquifer recharge sites for drinking water in the coastal plain of south-west Bangladesh". Bangladesh Journal of Scientific Research 27, n. 1 (4 gennaio 2016): 75–86. http://dx.doi.org/10.3329/bjsr.v27i1.26226.
Abstract (sommario):
Community scale managed aquifer recharge (MAR) has been implemented by infiltrating pond and rooftop rainwater into shallow, locally confined brackish aquifers in the southern deltaic plains of Bangladesh for providing safe drinking water. This paper mainly deals with the risks of physical clogging and the issues of clogging related to aquifer material, design, drilling and construction methods at 20 sites. Risk of chemical and biochemical clogging has also been briefly discussed. High turbidity in the source pond water is mainly responsible for physical clogging. In order to reduce the turbidity MAR system has been designed with an over ground double chambered filtration tank with a graded sand filter in one chamber. Pond water is pumped into the filtration tank to pass through sand filter. Efficiency of turbidity removal is assessed by measuring turbidity of water at the source pond, after passing though the sand filter and at the abstraction well. The turbidity of source (pond) water ranges from 50 to 150 NTU decreases to 5 NTU after passing through the sand filter in most of the sites. Clogging is assessed by performing falling head tests at each recharge well at number of times during the operation of the test sites. A maximum infiltration rate of 6m3/day has been achieved at a number of sites where the average is about 3m3/day. Relatively high nutrient content present both in source and groundwater water could cause biological clogging. Probability of clogging due to clay swelling should be considered due to salinity difference of source and groundwater although sodium adsorption ratio has been observed to be reduced which reduce the risk of reduction of permeability. There is possibility of chemical plugging in the aquifer and around the well from the precipitation of iron bearing minerals as iron concentration has been observed to be reduced.Bangladesh J. Sci. Res. 27(1): 75-86, June-2014
24
Spychala, M., e R. Blazejewski. "Sand filter clogging by septic tank effluent". Water Science and Technology 48, n. 11-12 (1 dicembre 2004): 153–59. http://dx.doi.org/10.2166/wst.2004.0828.
Abstract (sommario):
The aim of this study was to characterise conditions and factors affecting fine sand clogging by septic tank effluent on the basis of physical modelling. The physical model consisted of 12 sand columns dosed with sewage from one household (5 persons), preliminary treated in a septic tank. Hydraulic loadings of the sand filters were equal to 82 mm/d. The mean discharge from sand columns, measured as the effluent volume collected during 10 minutes, decreased significantly over the experiment period from 34 cm3/min in August 2000 to 20 cm3/min in August 2001 at the same temperature of about 20°C. First the columns clogged almost completely after 480 days in December 2001, however six columns had remained unclogged till the end of the experiment (March 2002). The temperature had a significant impact on hydraulic conductivity. A vertical distribution of accumulated mass and biomass was investigated in partly clogged sand. Microscopic survey of the clogging layer showed a presence of live micro-organisms, residuals of dead micro-organisms, particularly pieces of small animal armour and many fibres. These particles accelerated the accumulation of solids in the upper clogging layer. The study indicated that temperature impact on the filter hydraulic conductivity was more significant for biological activity, than for sewage viscosity.
25
Kalore, Shubham, e G. L. Sivakumar Babu. "Recent developments in design criteria for granular and geotextile filters". E3S Web of Conferences 368 (2023): 02015. http://dx.doi.org/10.1051/e3sconf/202336802015.
Abstract (sommario):
Granular and geotextile filters are commonly provided in several hydrological infrastructures to limit soil erosion and allow unimpeded water seepage. The success of a filter depends on forming a bridging structure, which is governed by the grain size distribution of soil and the constriction size distribution of filter. Currently, the retention requirement is satisfied considering representative grain and opening size, whereas the hydraulic conductivity requirement is satisfied considering empirical factors for avoiding excessive clogging. In this paper, the design criteria for granular and geotextile filters are reviewed, and improved design criteria are presented. A probabilistic retention criterion is developed, considering the grain size and constriction size as random variables. The influence of filter thickness is incorporated into the criterion by considering the number of constrictions in a filtration path. A hydraulic conductivity criterion is developed theoretically based on governing flow equations and the expected partial clogging of geotextiles. The limit states for the developed criteria are evaluated based on the wide range of experimental data. The developed design criteria are applicable to granular and nonwoven geotextiles, which offers an improvement in design compared to the existing criteria in practice.
26
Wang, Xu, Yonghong Zhang, Liqin Fan e Jingli Shen. "Salt Drainage Efficiency and Anti-Clogging Effects of Subsurface Pipes Wrapped with Geotextiles". Water 16, n. 10 (14 maggio 2024): 1392. http://dx.doi.org/10.3390/w16101392.
Abstract (sommario):
Subsurface drainage pipes covered with filters and geotextiles are the key to preventing clogging and ensuring efficient drainage. To improve the salt discharge efficiency of these subsurface drainage pipes, different layers of geotextiles were set outside the pipes with the aid of uniform gravel filters. This paper reports our findings from laboratory simulation of subsurface drainage pipes and experiments. The study examined the influence of different layers of geotextiles on the drainage efficiency, salt discharge effects of subsurface drainage pipes, and the effect of superimposed geotextiles on the salt drainage efficiency as well as the anti-clogging effect of subsurface drainage pipes. The results are as follows: (1) The geotextile and filter material wrapped around the subsurface pipe facilitated the movement of water towards the subsurface pipe, which could promote the salt discharge of the subsurface pipe. However, in the single leaching experiment, the reduction in soil pH was not significant for different scenarios. (2) The salt removal rate of the geotextile-wrapped subsurface pipes was more than 95%. The salt removal rate of the double-layer geotextile scenario was the highest (96.7%), and the total salt content of soil profiles was 8.3% and 31.3% lower than those of the single-layer and triple-layer geotextile scenarios, respectively. The drainage efficiency of the double-layer geotextile scenario was the highest, and the salt distribution in the 0–60 cm profile was relatively uniform, ranging from 2.3 to 3.0 g∙kg−1. (3) The clogging in the triple-layer geotextile scenario was caused by the geotextile, i.e., a dense filter cake layer formed on the surface of the geotextile. The clogging in the single-layer and double-layer geotextile scenarios was the clogging of the geotextile itself, i.e., soil particles retained in the fiber structure of geotextiles. (4) In the case of the single-layer and double-layer geotextile scenarios, the soil particles failed to completely clog the selected geotextiles, and there were still a large number of pores retained. The double-layer geotextiles integrate filtration, clogging prevention, and drainage promotion to provide the best salt drainage with the subsurface pipe. This study reveals the influence of the filter on soil water salt and salt discharge and provides a theoretical explanation and technical justification for the application of the subsurface pipes salt discharge technology in saline soil ameliorate.
27
Salwa, M. Z. M., Muaz Mohd Zaini Makhtar e Mohammad Tamizi Selimin. "Predicting physical clogging of modular paver equipped with filter media". IOP Conference Series: Earth and Environmental Science 1135, n. 1 (1 gennaio 2023): 012012. http://dx.doi.org/10.1088/1755-1315/1135/1/012012.
Abstract (sommario):
Abstract Porous pavements are simple to retrofit, good at improving the hydrology and quality of the water, but prone to clogging. There is little knowledge on the physical clogging processes through these systems, even though they play a significant role in the lifespan of porous pavements. This study’s objectives were to comprehend the primary physical mechanisms that control physical clogging and create a straightforward hexagonal modular (HM) model that can forecast physical congestion. A filtration system with a layered filter media granular activated carbon (GAC) and sand was installed. The clogging agent was found trapped only on the mesh because of the sizes of some of the material being larger than the size of mesh opening, while the voids of the media material were found to be not of a major effect in this respect. With the GAC and sand layers combined, the hydraulic conductivity was determined to be 0.097 cm/s and this k value can be considered low for the purpose.
28
Ribeiro, Túlio Assunção Pires, José Euclides Stipp Paterniani, Rogério Pereira da Silva Airoldi e Marcelo Jacomini Moreira da Silva. "Performance of non woven synthetic fabric and disc filters for fertirrigation water treatment". Scientia Agricola 61, n. 2 (aprile 2004): 127–33. http://dx.doi.org/10.1590/s0103-90162004000200001.
Abstract (sommario):
Obstruction of emitters caused by the presence of solid particles in the water raises the cost and maintenance of trickle irrigation systems, and might compromise their utilization. This research was performed through test fields, with the objective of evaluating the performance of a disc filter (130 microns) and a non woven synthetic fabric filter on the removal of physical, chemical and biological impurities from the irrigation water, which may cause emitter obstruction during fertirrigation processes. The evaluation criteria of the impurities present in the irrigation water, were based on studies performed on trickle irrigation systems. Specifically, physical, chemical and biological parameters analyzed in the inflow and outflow water from both filters were: pH, turbidity, total suspended solids, salinity, total iron, sulphites, manganese, algae and bacteria. Results pointed to chemical factors, which presented medium clogging risks to the emitters; those factors were: pH, total iron and sulphite concentration. All the other parameters of water quality did not present clogging risks. A comparative analysis of head loss evolution, according to the filtered volume, was also atempted Non woven synthetic fabric filter presented a higher evolution when compared to the disc filter.
29
Bari, S., C. W. Yu e T. H. Lim. "Filter clogging and power loss issues while running a diesel engine with waste cooking oil". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 216, n. 12 (1 dicembre 2002): 993–1001. http://dx.doi.org/10.1243/095440702762508245.
Abstract (sommario):
As with other vegetable oils, the high viscosity of waste cooking oil (WCO) poses some challenges to engine operation. One of them is filter clogging. In this research, it was found that heating to above 55°C was effective in preventing clogging. However, the head loss across the filter was about 6 times higher than that of diesel. Generally, the lower calorific values of vegetable oils are held responsible for the reduction in maximum power of the engine. While running with WCO, the maximum power of the engine was reduced by 10.9 per cent from that with diesel. Raising the fuel tank level and dividing the flow through two filters to compensate for the higher head loss across the filter reduced the maximum power loss to 5.0 and 8.8 per cent respectively. Therefore, higher head loss in the filter is also responsible for the loss of maximum power. In terms of combustion, WCO had a shorter ignition delay compared with diesel, resulting in a less intense premixed combustion phase. The CO and NO emissions were on the average 8.4 and 16.2 per cent higher than those for diesel.
30
Ehlinger, F., J. M. Audic, D. Verrier e G. M. Faup. "The Influence of the Carbon Source on Microbiological Clogging in an Anaerobic Filter". Water Science and Technology 19, n. 1-2 (1 gennaio 1987): 261–73. http://dx.doi.org/10.2166/wst.1987.0207.
Abstract (sommario):
Using two different substrates, glucose and a mixture of volatile fatty acids, the influence of the types of bacteria on the appearance of microbiological clogging in anaerobic filters was studied. The clogging was detected by lithium tracings and head-loss profiles. The composition of the biofilm and the electron-microscopy were used to illustrate the phenomenon. The clogging is due to polysaccharides secreted by acidogenic bacteria.
31
Khomutov, A. O., A. V. Biryukov, A. P. Usachev e O. A. Kutsigina. "THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF IDENTIFYING PRESSURE LOSS IN FILTER ELEMENTSOF COARSE AND FINE GAS PURIFICATION WHEN PLACED IN ONE BODY". Russian Journal of Building Construction and Architecture, n. 1(53) (21 febbraio 2022): 29–38. http://dx.doi.org/10.36622/vstu.2022.53.1.003.
Abstract (sommario):
Statement of the problem. Reliable operation of modern high-precision gas flow reduction and control systems located in cabinet, block and capital gas distribution points calls for the use of two-stage cylindrical gas purification plants containing preliminary and fine filters. An urgent task is to design and scientifically substantiate the use of cost-effective two-stage natural gas purification devices located at gas distribution points as well as the development of analytical calculation methods for identifying pressure losses in the filter elements of two-stage cylindrical installations and the timing of their regeneration.Results. Theoretical and experimental identification of pressure losses depending on the degree of clogging of a multilayer filter element with mechanical impurities is given.Conclusions. Analytical equations for identifying pressure losses are obtained which differ from the known solutions in that the effect of clogging with mechanical impurities in a multilayer filter cloth is first presented as the sum of pressure losses on a number of clean calibrated grids located one after another, with the cell sizes of each subsequent grid less than the previous one.
32
Kayser, K., e S. Kunst. "Processes in vertical-flow reed beds: nitrification, oxygen transfer and soil clogging". Water Science and Technology 51, n. 9 (1 maggio 2005): 177–84. http://dx.doi.org/10.2166/wst.2005.0314.
Abstract (sommario):
Vertical-flow reed beds (VF) with intermittent feeding are extremely reliable regarding aerobic processes. For a save operation with high nitrification rates and without soil clogging it is essential to preserve aerobic conditions in the filter. The challenge is to keep aerobic conditions in the filter without oversizing the system (economical aspects). It is very difficult to determine the current oxygen content in the filters because it ultimately results from complex interactions of a large number of different influencing parameters such as loading rate, degree of clogging, temperature, and hydraulic behaviour of the reed bed. To gain better knowledge of this complex system, different tests and examinations were carried out over several years. Focusing on the questions of identification and the description of conversion and transport processes (water/gas), a full-scale treatment plant under clogged and non-clogged conditions was investigated in detail. Additionally soil column test were carried out. The results make it possible to describe some of the processes and their interactions in the filter body. Recommendations for a safe and controlled operation can be derived.
33
Davis, Goldie, Edwin I. Ekwue e Hazi Md Azamathulla. "Examination of the Efficiency of Fabric Filter Media in Two-Stage Crossflow Pre-Filtration of Turbid Surface Water Using the Davies Flow Equation". West Indian Journal of Engineering 46, n. 2 (gennaio 2024): 57–63. http://dx.doi.org/10.47412/uixv2590.
Abstract (sommario):
Clogging of rapid sand filters during heavy rainfall causes surface water treatment plants to stop their operations until the river water turbidity decreases to a level that the rapid sand filter is capable of filtering. As clogging of rapid sand filters is impediment in surface water treatment, two-stage crossflow pre-filtration with fabric filter media (linen, crepe-backed satin, burlap, and cotton) was considered in a previous study by Davis and Ekwue (2020) as a possible solution. Pre-filtration with linen fabric filter medium was found to be the most efficient at retaining particles. The present paper incorporated properties of various fabrics previously measured and identified by Davis and Ekwue (2020) with the aim of identifying ideal fabric properties that were effective in removing particles from turbid water. Mechanisms of filtration (surface straining, depth filtration and cake filtration) depicted by each selected fabric during two-stage crossflow pre-filtration were identified and compared to the operation of standard filter media (absorbent, adsorbent, biological and woven). The Davies equation was used to calculate the flow of water through single layer and four layers of fabric filter media. Results indicate that no one specific fabric property could be used to proclaim a fabric as the ideal filter media, but rather all properties of the various fabric contribute to their performance during filtration.Linen fabric was once again determined as the fabric type most efficacious at retaining particles during two-stage crossflow pre-filtration of turbid river water and is therefore recommended.
34
Lee, Byungsik. "A Neural Network Model to Estimate the Clogging of Ash Mixed Sand Filter". Journal of the Korean Society of Hazard Mitigation 23, n. 3 (30 giugno 2023): 147–53. http://dx.doi.org/10.9798/kosham.2023.23.3.147.
Abstract (sommario):
Infiltration filters of LID facilities are frequently confronted with clogging of pores by contaminants. To avoid malfunctioning of LID facilities, filters should be maintained according to the degree of clogging. In this study, clogging was characterized by curves representing the correlation between infiltration rate (<i>Q</i>) and infiltration quantity (<i>IR</i>). To estimate the degree of clogging, a regression neural network model was developed to estimate the label (infiltration quantity) corresponding to the selected features (ash mix ratio, infiltration rate, and variation of infiltration rate). According to the results obtained from the evaluation of accuracy and applicability of the final model trained over the whole training dataset, the following conclusions were drawn: 1) the training of the final model was verified to be correct according to mean absolute errors of 0.00445 and 0.00491 for the training and test datasets, respectively; 2) the final model could be applied to estimate multiple, multivariate clogging curves for arbitrary ash mixing ratios and trained range of time series in terms of infiltration rate; 3) given that the final model could not estimate the clogging curve for future time steps for which the model was not trained, a CNN model or LSTM-RNN model are suggested as an alternative.
35
Wang, Dong-bo, Zi-yun Zhang, Xiao-ming Li, Wei Zheng, Yan Ding, Bo Yang, Qi Yang et al. "Effects of earthworms on surface clogging characteristics of intermittent sand filters". Water Science and Technology 61, n. 11 (1 giugno 2010): 2881–88. http://dx.doi.org/10.2166/wst.2010.180.
Abstract (sommario):
Intermittent sand filters (ISFs) are effective and economical in treating wastewater, but they are easy to clog up. To explore a feasible and simple method to alleviate clogging, two pilot-scale ISFs were constructed, one of which contained earthworms and the other did not. During the operation, the effects of earthworms on the hydraulic behaviour of ISFs were investigated. The results showed that both ISFs exhibited good performance in wastewater treatment. However, they showed different hydraulic characteristics although operated at the same organic loading rate (approximately 300 g m−2 d−1). The ISF without earthworms clogged only after 53 d operation, and was partially recovered after 7 d resting, but after that, clogging occurred again, and more rapidly than the initial clogging event (40 d). However, water on the medium surface of the ISF with earthworms was not observed during the whole experiments. In addition, 11–13% of effective porosity and 0.015–0.026 cm s−1 of infiltration rate were measured in the upper 20 cm of the ISF at the end of the experiments. The facts demonstrated that earthworms played a positive role in alleviating clogging and earthworms fed filter could alleviate surface clogging effectively.
36
Pucher, Bernhard, e Guenter Langergraber. "The State of the Art of Clogging in Vertical Flow Wetlands". Water 11, n. 11 (15 novembre 2019): 2400. http://dx.doi.org/10.3390/w11112400.
Abstract (sommario):
Clogging in vertical flow (VF) wetlands is an important process influencing water purification processes. The main contributing factors are the growth of microorganisms within the filter media, the accumulation of suspended solids on top of the wetland, as well as within the filter media. Both processes lead to a decrease of the available pore space, hence changing the soil’s hydraulic properties. This will alter the water flow and cause malfunctioning of the system. This paper summarizes the state of the art of the prevailing physical, biological and chemical processes influencing clogging in VF wetlands. Different design and operational parameters are discussed to give a better understanding on their influence to prevent malfunctioning. Based on a literature review, a detailed overview on experimental as well as modelling studies carried out is presented. The main conclusions are that on the one hand, important insights on clogging processes in VF wetlands have been gained but, on the other hand, design parameters such as intermittent loading operation and the grain size of the filter media are not well represented in those studies. Clogging models use different conceptual approaches ranging from black box models to process based models.
37
Jonsson, Lena, Elzbieta Plaza e Bengt Hultman. "Experiences of nitrogen and phosphorus removal in deep-bed filters in the Stockholm area". Water Science and Technology 36, n. 1 (1 luglio 1997): 183–90. http://dx.doi.org/10.2166/wst.1997.0042.
Abstract (sommario):
Experimental studies of nutrient removal in a discontinuous downflow two-media filter on a pilot plant scale are described and compared with previously reported results from a continuous upflow filter (DynaSand) studied at full scale. Under controlled conditions both filters show low effluent values of total nitrogen and phosphorus. Removal mechanisms were more complex in the discontinuous downflow filter owing to the use of two media, deposition of sludge on the filter surface, and changes of the biological activity over time after backwashing. The discontinuous downflow filter was much influenced by the formation of nitrogen gas bubbles clogging the filter, while the influence of nitrogen gas formation in the DynaSand filter was minor. Multivariate methods were used to evaluate factors influencing nitrate and phosphate removal and the time passing before the filter became clogged.
38
Franco, Monalisa, Gabriela K. e. Silva e José E. S. Paterniani. "Water treatment by multistage filtration system with natural coagulant from Moringa oleifera seeds". Engenharia Agrícola 32, n. 5 (ottobre 2012): 989–97. http://dx.doi.org/10.1590/s0100-69162012000500018.
Abstract (sommario):
This study presents an evaluation of a pilot multistage filtration system (MSF) with different dosages, 131 mg L-1 and 106 mg L-1, of the natural coagulant extracted from Moringa oleifera seeds in pre-filtration and slow filtration stages, respectively. The system was comprised by a dynamic pre-filter unit, two upflow filters in parallel and four slow filters in parallel, and in one of the four filters had the filter media altered. The performance of the system was evaluated by monitoring some water quality parameters such as: turbidity, apparent color and slow filter load loss. The stages that have received the coagulant solution had better treatment efficiency compared with the steps without it. However, the direct application of the coagulant solution in the slow filter caused rapid clogging of the non-woven blanket and shorter career length.
39
Ménoret, C., C. Boutin, A. Liénard e F. Brissaud. "Use of recycling through medium size granular filters to treat small food processing industry effluents". Water Science and Technology 45, n. 12 (1 giugno 2002): 225–32. http://dx.doi.org/10.2166/wst.2002.0430.
Abstract (sommario):
Currently there are no suitable wastewater treatment systems for effluents from small food processing industries (dairy, cheese, wine production). Such raw sewages are characterized by high organic matter concentrations (about 10 g COD L−1) and relatively low daily volumes (about 2 m3). An adaptation of attached-growth cultures on fine media processes, known to be easy and inexpensive to use, could fit both the technical and economical context of those industries. Coarser filter particle size distributions than those normally used allow a better aeration and reduce clogging risk. The transit time of the effluent through the porous filter materials is shortened and requires recycling to increase the contact time between the biomass and the substrate. A pilot plant was built to compare the efficiency of two kinds of filter materials, gravel (2-5 mm) and pozzolana (3-7 mm). Two measurement campaigns were undertaken on a full-scale unit dealing with cheese dairy effluents. Both pilot-scale and full-scale plants show high COD removal rates (>95%). Pilot-scale experiments show that accumulation of organic matter leads to the clogging of the recycling filter. To prevent early clogging, a better definition of feeding cycles is needed.
40
Bao, Shufeng, Lingfeng Guo, Zhiliang Dong, Ruibo Zhou, Shuangxi Zhou e Jian Chen. "Clogging Behaviors in PVD and Their Evaluation Criteria for Dredged Mud Slurry". Water 15, n. 24 (5 dicembre 2023): 4206. http://dx.doi.org/10.3390/w15244206.
Abstract (sommario):
During the consolidation period of vacuum preloading drainage of dredged mud slurry, the clogging behaviors of the filter drainage structural layers and the core boards of prefabricated vertical drains (PVD) determine the drainage capacities of PVD. However, currently, there is a lack of comprehensive research on the evaluation criteria for these two clogging behaviors. Therefore, based on typical dredged mud slurry, typical geomembranes, and raw material core boards with different bending forms, relevant macro and micro-scale experimental studies have been carried out in this study. The research results show that (1) with the application of the gradient ratio test method, the clogging behaviors of filter membranes of PVD under graded vacuum preloading can be effectively simulated. Also, in the design of graded vacuum preloading, characteristics of equivalent pore sizes and pore structures should be emphasized to investigate the suitability of filtration and drainage performance of PVD filter membranes. (2) The compressive yield strength of core board grooves is a key factor influencing the reduction rate of flow capacity. The reduction rate of flow capacity and well resistance increment can be used as comprehensive indicators reflecting the clogging behaviors of core boards, while the bending angles and bending rates of core boards can be used as specific technical indicators. (3) The proposed clogging evaluation criteria for PVD are as follows: a filter membrane gradient ratio (GR) > 4.0, a core board bending rate >60% and a core board bending angle < 45°, or a reduction rate of flow capacity of bending drainage board > 90% or well-resistance increment > 9. Also, these criteria can be incorporated into the control indicators for drainage performance of PVD used in such types of foundations.
41
Ahn, Jaeyoon, Dongseop Lee, Shinin Han, Youngwook Jung, Sangwoo Park e Hangseok Choi. "Experimental study on performance of sand filter layer to remove non-point source pollutants in rainwater". Water Supply 17, n. 6 (9 maggio 2017): 1748–63. http://dx.doi.org/10.2166/ws.2017.056.
Abstract (sommario):
Abstract Clogging characteristics of conventional sand filter layers with different grain-size distributions were experimentally studied to estimate their filtration capacity to capture non-point source pollutants in an artificial rainwater reservoir. A series of laboratory-scale chamber tests was conducted for artificial urban runoff synthesized with non-point source pollutants collected from a real road in Seoul, Korea. In addition, an analytical filtration model for estimating removal of non-point source pollutants was adopted considering the clogging characteristics. To evaluate the performance of three types of sand filter layers with different grain size characteristics, the pollutant concentration was measured in terms of total suspended solids and chemical oxygen demand. The lumped parameter (θ) related to the clogging property was estimated by comparing the accumulated weight of pollutant particles obtained from the laboratory chamber experiments and the theoretical estimation from the analytical filtration model. Based on the experimental study and theoretical consideration, a double-sand-filter layer consisting of two separate layers is proposed as the optimum system for removing non-point source pollutants in the pilot-scale rainwater reservoir.
42
Zhou, Yuan, Ling Yun Zhang e Zhi Hao Lu. "Effects of Anti-Clogging in Ultra-Soft Soils Using Different Composite Filter Material". Advanced Materials Research 1101 (aprile 2015): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1101.3.
Abstract (sommario):
An experimental study on drainage of different composite filter material in Wenzhou ultra-soft soils was carried out, to investigate the effects of anti-clogging for these composite material. A new instrument was designed to simulate draining process of the ultra-soft soils under vacuum loadings. Based on the experimental results in the form of pump quantity of water, the average settlement of the sludge, the pumping rate and the water content, a comparison was made among six composite filter material (e.g., PVA-1, PVA-2, SAP, superfine fiber, coral cashmere fiber and bamboo fiber) and a traditional non-woven fabric material. The results demonstrate that, PVA-2 composite material is the best way to keep from clogging in the ultra-soft soils. The effects of the anti-clogging is depended on the characteristics of the water absorbency and retention.
43
Kandra, Harpreet Singh, Ana Deletic e David McCarthy. "Assessment of Impact of Filter Design Variables on Clogging in Stormwater Filters". Water Resources Management 28, n. 7 (11 aprile 2014): 1873–85. http://dx.doi.org/10.1007/s11269-014-0573-7.
44
Wang, H. Y., X. W. Tang, Q. Tang e B. Bai. "Analytical solutions for soil flushing through geotextiles considering filter cake and clogging". Lowland Technology International 17, n. 1 (2015): 11–18. http://dx.doi.org/10.14247/lti.17.1_11.
45
Calisir, Mehmet D., Melike Gungor, Ali Toptas, Utkay Donmez, Ali Kilic e Semistan Karabuga. "Clogging performance of micro/nanofibrous laminated composite air filter media". Journal of Industrial Textiles 52 (agosto 2022): 152808372211130. http://dx.doi.org/10.1177/15280837221113084.
Abstract (sommario):
The performance of fibrous filter media relies on factors such as particle capture efficiency, pressure drop and clogging time. Fiber diameter, porosity and packing density are important web-based factors to improve final filtration performance. In this study, composite nonwoven webs were produced using spunbonded, meltblown and electroblown mats to obtain filter media with different fiber diameter, porosity and packing density. Such a layered composite approach caused huge differences in porosity and packing density, which resulted with improved clogging performance. The average fiber diameter was found to be 65 ± 19.4 nm for electroblown layer ( N), while that was 1.17 ± 0.38 μm for meltblown (M) and 17.64 ± 2.65 μm for spunbond (S) layers. NM (nanofiber+meltblown) configuration provided 12–13% lower mean flow pore size, which resulted in faster clogging compared to NS (nanofiber + spunbond) mats. The thicker nanofibrous layer resulted in lower pore size and quality factor. Additionally, the composite samples showed a faster-rising pressure drop than the thick microfibrous mats due to smaller pores that clogged quickly. It was also shown that nanofiber coating causes a linear increase in pressure drop with dust loading, while microfibrous samples exhibited smooth plateau and linear increase after clogging point. Nanofiber layer facilitates cake formation which causes more difficult airflow, and lower dust holding capacity. Among the layered composite mats, the NM configurations were found to be more advantageous due to higher initial filtration efficiency and almost similar dust loading performance.
46
Rodgers, M., J. Mulqueen e M. G. Healy. "Surface Clogging in an Intermittent Stratified Sand Filter". Soil Science Society of America Journal 68, n. 6 (novembre 2004): 1827–32. http://dx.doi.org/10.2136/sssaj2004.1827.
47
Eker, Omer F., Fatih Camci e Ian K. Jennions. "Physics-based prognostic modelling of filter clogging phenomena". Mechanical Systems and Signal Processing 75 (giugno 2016): 395–412. http://dx.doi.org/10.1016/j.ymssp.2015.12.011.
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Kaplan, C., J. Wang e J. W. Gentry. "Condition numbers, Monte Carlo simulations and filter clogging". Journal of Aerosol Science 17, n. 3 (gennaio 1986): 418–22. http://dx.doi.org/10.1016/0021-8502(86)90120-5.
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Le Tallec, X., A. Vidal e D. Thornberg. "Upflow biological filter: modeling and simulation of filtration". Water Science and Technology 39, n. 4 (1 febbraio 1999): 79–84. http://dx.doi.org/10.2166/wst.1999.0192.
Abstract (sommario):
One of the most important operating parameters for the operation and the design of biofilters is the headloss due to clogging of the system leading to a semi-continuous operation with filtration cycles and backwashes. Some basic aspects of the filtration operation have been studied. The work consists in understanding and modelling the clogging phenomena due to the suspended solids retention, and validating the simulation results by calibration with experimental and full-scale results. Tracer experiments allowed us to simplify the hydrodynamics within the Biofilters into a plug-flow reactor with axial diffusion. Mass balances for the suspended solids have been therefore written accordingly, including solids retention represented as a mass transfer from the liquid to the solid phase. This affects the porosity of the system, leading on one hand to a modification of the filtration coefficient (responsible for the transfer of SS from liquid to “solid” phase) and on the other hand to an increased clogging measured by the headloss in the system. The Kozeny-Carman equation could successfully be used and a linear relationship between the filter coefficient and the water porosity could be validated. Experimental work has been conducted to calibrate the model and in this paper validations from pilot scale unit to full-scale plant are shown.
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Essakhraoui, Meriem, Abdelhamid Nyassi, Aziz Boukhair, Hajar Bellefqih, Nils Haneklaus, Hamid Mazouz e Essaid Bilal. "Enhancing Molten Sulfur Filtration during Sulfuric Acid Manufacturing for Phosphate Fertilizer Production in Morocco with Cellulose-Based Filter Aids". Applied Sciences 13, n. 15 (1 agosto 2023): 8879. http://dx.doi.org/10.3390/app13158879.
Abstract (sommario):
The filtration of liquid sulfur is a key operation in the production of sulfuric acid that is used for phosphate fertilizer production in Morocco and elsewhere. The purpose of the filtration process is to remove solid impurities from liquid sulfur, which could clog the sulfur burner spray nozzles, leading to the reduction of the lifetime of the sulfuric acid production unit. The standard life cycle operation for sulfuric acid units is 24 months, while due to clogging, this lifetime can be reduced to less than 18 months, which is obviously a tremendous economic disadvantage. In the liquid sulfur filtration process, a precoat made of diatomaceous earth is usually used. In this work, the performance of a standard diatomaceous earth filter aid was compared to the performance of two commercial, inexpensive, cellulose-based filter aids, namely, FILTER-900 and FILTER-1100, which are distinguished by their respective Dalton numbers (900 Da and 1100 Da). The experiments were realized using an industrial sulfur filtration device, and the results indicated that all three of the filter aids yielded similar performance in terms of the impurity content in the filtered liquid sulfur. The cellulose-based filter aids did, however, show a lower specific filter-aid consumption, accompanied by an increase in operating cycle times from 24 to 72 h. In addition, the use of the cellulose-based filters allowed for the relatively easy removal of the filter cake without damaging the filter cloths (which is often an issue with the diatomaceous earth filter aids). It was further noticed that the filtered liquid sulfur obtained using the cellulose-based filter aids remained uncontaminated by silicate, which is one of the main elements that can result in clogging of the sulfur spray nozzles. The first experimental data presented here are therefore promising, and further industrial tests as well as economic analysis for using cellulose-based filter aids in industrial sulfuric acid production are encouraged.