Journal articles: 'Spent filter backwash water'

1

Leible, Bob. "Optimize Spent-Filter Backwash Water." Opflow 34, no. 11 (November 2008): 16–17. http://dx.doi.org/10.1002/j.1551-8701.2008.tb02005.x.

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Arora, Harish, George Di Giovanni, and Mark Lechevallier. "SPENT filter backwash water CONTAMINANTS AND TREATMENT STRATEGIES." Journal - American Water Works Association 93, no. 5 (May 2001): 100–112. http://dx.doi.org/10.1002/j.1551-8833.2001.tb09211.x.

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Adin, A., L. Dean, F. Bonner, A. Nasser, and Z. Huberman. "Characterization and destabilization of spent filter backwash water particles." Water Supply 2, no. 2 (April 1, 2002): 115–22. http://dx.doi.org/10.2166/ws.2002.0053.

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Inorganic and organic particles, including bacteria, viruses and parasites, which are retained within a granular filter during surface water filtration, are removed by backwashing the filter with clean water or water and air. The objective of the study was to characterize SFBW and determine its treatability by coagulation. Microbial and physical-chemical characterization of SFBW collected from a number of different water treatment plants was performed. Experiments to determine the impact of coagulation/flocculation on the SFBW samples were also conducted. SFBW was collected from six different water treatment plants and analyzed for microbial and physical parameters. Physical characterization was done on SFBW collected from all of the treatment plants. Turbidity and pH measurements were taken over the course of the backwash run, and the backwash samples were collected in two to four 20 L containers. A number of parameters were measured for the samples in each container, as well as for SFBW composites made by mixing equal portions of the container contents. The measured parameters included: turbidity, pH, TSS, DOC, UV-254 and alkalinity. Jar tests were carried out on individual containers, on SFBW composite and on SFBW composite that was allowed to settle for one hour. Turbidity and particle count data was collected for both settled and filtered samples.

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Mueller, Uwe, Gerhard Biwer, and Guenther Baldauf. "Ceramic membranes for water treatment." Water Supply 10, no. 6 (December 1, 2010): 987–94. http://dx.doi.org/10.2166/ws.2010.536.

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Ceramic membranes, different in pore size and membrane material, were applied to remove particulate and dissolved matter from different spent filter backwash water types as well as from dam water. The study was conducted in pilot scale under conditions typical for waterworks at a dam water treatment plant. A comparison of different ceramic membranes implied that total membrane resistance was more influenced by feed water type and by operation than by membrane type for the waters tested. Nevertheless, ceramic membranes seem to accumulate during operation less organic foulants especially polysaccharides compared to organic membranes leading to lower total membrane resistances for ceramic membranes during filtration process. Ceramic membranes may be considered to be applicable to treat spent filter backwash water as well as source water in public water supply.

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Eades, A., B. J. Bates, and M. J. MacPhee. "Treatment of spent filter backwash water using dissolved air flotation." Water Science and Technology 43, no. 8 (April 1, 2001): 59–66. http://dx.doi.org/10.2166/wst.2001.0465.

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There is increasing interest in treating recovered spent filter backwash water in the drinking water industry. In the USA the Filter Backwash Recycling Rule will come into effect in the near future. The purpose of the Rule is to prevent the concentrated pathogenic agents, potentially in the filter backwash water, from being returned to the head of the water treatment works without some form of treatment or dilution. By treating this flow both public health and financial liability can be better managed by the operating utility. Dissolved Air Flotation (DAF) was investigated as a possible technology alternative to simple or advanced sedimentation techniques. This application is not widespread but sits somewhere in between the two normal applications of DAF as a high solids sludge thickener and a low turbidity clarification system. Given this a pilot plant program, supported by jar testing, was undertaken to determine the process capability and the design parameters for this application. DAF proved to be very suitable for backwash water recovery. DAF effluent turbidities of <1.0 NTU could be easily obtained, when raw water turbidities were in excess of 50 NTU. Chemical requirements were low with only a single low dose of polymer required to bind the floc particles to form a solids matrix suitable for flotation. Flocculation contact times ranged from 0–10 minutes depending on the nature of the raw water. Recycle rates as low as 5% performed satisfactorily with no significant improvement when increased to 20%. Sludge solids of 3.5–9.6% dry solids were found and very low volumes of sludge, <0.1% of the incoming flow make the DAF solids handling system very compact.

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Li, Wei, Xinran Liang, Jinming Duan, Simon Beecham, and Dennis Mulcahy. "Influence of spent filter backwash water recycling on pesticide removal in a conventional drinking water treatment process." Environmental Science: Water Research & Technology 4, no. 7 (2018): 1057–67. http://dx.doi.org/10.1039/c7ew00530j.

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7

Reissmann, Florian G., and Wolfgang Uhl. "Ultrafiltration for the reuse of spent filter backwash water from drinking water treatment." Desalination 198, no. 1-3 (October 2006): 225–35. http://dx.doi.org/10.1016/j.desal.2006.03.517.

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Saravia, F., C. Zwiener, and F. H. Frimmel. "Application of submerged membranes for the treatment of spent filter backwash water." Water Supply 7, no. 5-6 (December 1, 2007): 157–65. http://dx.doi.org/10.2166/ws.2007.133.

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The application of membrane filtration in the treatment of spent filter backwash water (SFBW) permits efficient removal of microorganisms, suspended particles and organic substances, depending on the used membrane molecular weight cut-off. However, flux decline, due to deposits and adsorption of substances (salts, colloids, organics, particles, microorganisms, etc.) tends to limit the use of membranes. Characterization of SFBW samples from different waterworks showed that three major factors contribute to the SFBW properties: the raw water itself, the time interval of sand filter operation and additional treatment steps. The main differences between SFBW samples were found principally in DOC, TOC and turbidity. Experiments with submerged membranes (lab- and pilot- scale modules) showed that there was a clear correlation between DOC concentration of the feed and the flux decline: when the DOC-concentration increased, the flux decline increased. Additionally, the presence of calcium led not only to an important flux decline but to high adsorption of NOM on the membrane surface. Iron concentrations in the micromolar range resulted in a considerably decline of flux. Filtration of SFBW revealed that the decline of permeability is mainly determined by DOC, calcium and iron concentrations. A decisive effect of biofouling on membrane performance is expected for long term experiments.

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Ebrahimi, Afshin, Mokhtar Mahdavi, Meghdad Pirsaheb, Fariborz Alimohammadi, and Amir Hossein Mahvi. "Dataset on the cost estimation for spent filter backwash water (SFBW) treatment." Data in Brief 15 (December 2017): 1043–47. http://dx.doi.org/10.1016/j.dib.2017.10.040.

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Osouleddini, Noushin, Mohammad Abdollahzadeh, Maryam Safaei, and Raheleh Sajadipoor. "Re-use of Spent Filter Backwash Water by Micro strainer in Water Treatment Plants." Eurasian Journal of Analytical Chemistry 12, no. 5b (July 5, 2017): 599–606. http://dx.doi.org/10.12973/ejac.2017.00194a.

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Ćurko, Josip, Ivan Mijatović, Dean Rumora, Vlado Crnek, Marin Matošić, and Mladen Nežić. "Treatment of spent filter backwash water from drinking water treatment with immersed ultrafiltration membranes." Desalination and Water Treatment 51, no. 25-27 (May 14, 2013): 4901–6. http://dx.doi.org/10.1080/19443994.2013.774142.

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Kommineni, S. N., J. Bryck, C. Stringer, C. Stevens, N. Meyers, B. Karnik, R. Hoffman, and L. Sullivan. "Evaluation of an emerging water treatment technology: ceramic membranes." Water Supply 10, no. 5 (December 1, 2010): 765–70. http://dx.doi.org/10.2166/ws.2010.175.

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Historically, low-pressure membranes (microfiltration (MF) and ultrafiltration (UF)) used in potable water treatment are made of polymers (polysulfone (PS), polypropylene (PP), polyethersulfone (PES), polyvinylidene fluoride (PVDF) etc). Recently, membranes made of ceramic materials (aluminium oxide) have been developed by MetaWater (Japan), Kubota (Japan) and others and is being marketed in the United States (US) by Krüger, Inc. (Cary, NC). Ceramic membranes offer several potential advantages over polymeric membranes, including higher mechanical robustness and ability to handle higher loading of particulates, higher resistance to oxidants and membrane cleaning chemicals, higher membrane integrity, longer service life and compact footprint. The authors conducted collaborative evaluations of this emerging technology at two different places; (i) Elm Fork Water Treatment Plant (WTP) of Dallas Water Utilities (DWU), Dallas, Texas, USA and (ii) Graham Mesa WTP, City of Rifle, Rifle, Colorado, USA. The evaluations included pilot testing of ceramic membranes in direct filtration mode (i.e. without clarification) and with coagulant addition. The water streams that were pilot tested at Elm Fork WTP included Trinity River water, spent filter backwash wastewater and lagoon recycle water (spent filter backwash water combined with clarifier blow down water). The City of Rifle pilot testing was conducted on Colorado River water. This paper presents the key results of these two pilot studies. Results of pilot testing were used to define the potential membrane flux, backwash protocols (interval and duration), chemical enhanced backwash (CEB) and clean-in-place (CIP) protocols. Pilot test results and engineering judgment were used for developing concept-level sizing and outlining parameters for future evaluation. This paper will discuss the key technical and economic considerations of the emerging treatment technology and its potential applications for potable water treatment. This paper will be of interest to water providers that are considering alternatives to treat challenging source waters (waters with high particulates and under heavy microbial influence), build new compact water treatment plants, increase plant capacity through membrane retrofits and treat recycle streams at existing WTPs.

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Mahdavi, Mokhtar, Afshin Ebrahimi, Hossein Azarpira, Hamid Reza Tashauoei, and Amir Hossein Mahvi. "Dataset on the spent filter backwash water treatment by sedimentation, coagulation and ultra filtration." Data in Brief 15 (December 2017): 916–21. http://dx.doi.org/10.1016/j.dib.2017.10.062.

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14

Mahdavi, Mokhtar, Mohammad Mehdi Amin, Amir Hossein Mahvi, Hamidreza Pourzamani, and Afshin Ebrahimi. "Metals, heavy metals and microorganism removal from spent filter backwash water by hybrid coagulation-UF processes." Journal of Water Reuse and Desalination 8, no. 2 (February 8, 2017): 225–33. http://dx.doi.org/10.2166/wrd.2017.148.

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Abstract Spent filter backwash water (SFBW) reuse has attracted particular attention, especially in countries that experience water scarcity. It can act as a permanent water source until the water treatment plant is working. In this study, the concentrations of Fe, Al, Pb, As, and Cd with total and fecal coliform (TC/FC) were investigated in raw and treated SFBW by hybrid coagulation-UF processes. The pilot plant consisted of pre-sedimentation, coagulation, flocculation, clarification, and ultrafiltration (UF) units. Poly-aluminum ferric chloride (PAFCL) and ferric chloride (FeCl3) were used as pretreatment. The results showed that, at the optimum dose of PAFCl, the average removal of TC and FC was 88 and 79% and with PAFCl-UF process, it reached 100 and 100%, respectively. For FeCl3, removal efficiency of TC and FC were 81 and 72% and by applying FeCl3-UF process, it reached 100 and 100%, respectively. In comparison with FeCl3, PAFCl showed better removal efficiency for Fe, Pb, As, and Cd, except residual Al concentration. Coagulation-UF process could treat SFBW efficiently and treated SFBW could meet the US-EPA drinking water standard. Health risk index values of Fe, AL, Pb, AS, and Cd in treated SFBW indicate no risk of exposure to the use of this water.

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15

Ladeia, Winni Alves, Felippe Danyel Cardoso Martins, Camila Fernanda Rosolen e Silva, and Roberta Lemos Freire. "Molecular surveillance of Cryptosporidium and Giardia duodenalis in sludge and spent filter backwash water of a water treatment plant." Journal of Water and Health 16, no. 5 (July 20, 2018): 857–60. http://dx.doi.org/10.2166/wh.2018.040.

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Abstract The purpose of this study was to monitor the presence of Cryptosporidium spp. and Giardia duodenalis in a water treatment plant (WTP) using settling sludge and backwash water (BW) samples in previous and post the deflocculation of polyaluminium chloride (PAC) flacks. Eleven collections were performed. BW and settling sludge (SSF) were concentrated by calcium carbonate flocculation, and another aliquot of settling sludge (SSC) by centrifugation. The samples were divided as follows: Group A, containing 33 samples without degradation of PAC flakes, and Group B, with degradation by alkalinization with 10 M NaOH. Sample DNA was extracted with a commercial kit, and nested polymerase chain reaction (PCR) was used to detect Cryptosporidium and G. duodenalis. All samples from Group A were negative for Cryptosporidium spp., and 6.1% (2/33) were positive for G. duodenalis in SSC samples. While the absence of Cryptosporidium may be due to a low contamination level of the water resource, the presence of G. duodenalis indicates contamination of the raw water. The detection of G. duodenalis in SSC samples indicates that this detection method was the most effective. The 33 samples from Group B were negative for both protozoa, probably due to the presence of aluminium and humic substances.

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16

Mahdavi, Mokhtar, Mohammad Mehdi Amin, Yaghoub Hajizadeh, Hossein Farrokhzadeh, and Afshin Ebrahimi. "Removal of Different NOM Fractions from Spent Filter Backwash Water by Polyaluminum Ferric Chloride and Ferric Chloride." Arabian Journal for Science and Engineering 42, no. 4 (December 3, 2016): 1497–504. http://dx.doi.org/10.1007/s13369-016-2364-3.

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17

Huang, Chihpin, Jr-Lin Lin, Wen-Shan Lee, Jill R. Pan, and Bingqing Zhao. "Effect of coagulation mechanism on membrane permeability in coagulation-assisted microfiltration for spent filter backwash water recycling." Colloids and Surfaces A: Physicochemical and Engineering Aspects 378, no. 1-3 (March 2011): 72–78. http://dx.doi.org/10.1016/j.colsurfa.2011.01.054.

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18

Nasser, A., Z. Huberman, L. Dean, F. Bonner, and A. Adin. "Coagulation as a pretreatment of SFBW for membrane filtration." Water Supply 2, no. 5-6 (December 1, 2002): 301–6. http://dx.doi.org/10.2166/ws.2002.0183.

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Granular filtration has been incorporated as a major barrier to prevent the dissemination of disease-causing agents by drinking water. Particles and pathogens such as Giardia lamblia and Cryptosporidium parvum retained in the filters are then washed by utilizing clean water. This study was conducted, primarily, to evaluate coagulation as a pretreatment for the Spent Filter Backwash Water (SFBW) treatment by ultrafiltration (UF). SFBW Samples were collected from four different water treatment plants and carefully analyzed. Jar-tests and backwash pilot studies were performed in the laboratory. Depending on the water source, protozoan parasites and viruses were found to be prevalent in SFBW. The results show that turbidity cannot serve as a surrogate for the microbial load of the SFBW. Alum flocculation pretreatment of SFBW was found to be effective in reducing turbidity, particle count, viruses and parasites, consequently it may also reduce membrane fouling. Settling the SFBW prior to flocculation did not enhance the removal of turbidity and particle count as compared to the unsettled SFBW samples. This finding might imply that settling would not be required prior to UF. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles and may result in extending the filtration cycle by reducing the SFBW fouling potential.

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Huang, Chihpin, Jr-Lin Lin, C. L. Wu, and C. P. Chu. "Recycling of spent filter backwash water using coagulation-assisted membrane filtration: effects of submicrometre particles on membrane flux." Water Science and Technology 61, no. 8 (April 1, 2010): 1923–29. http://dx.doi.org/10.2166/wst.2010.146.

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Membrane separation technology has been widely used for recycling of spent filter backwash water (SFBW) in water treatment plant. Membrane filtration performance is subject to characteristics of the particles in the SFBW. A bench-scale microfiltration (MF) coupled with pre-coagulation was set up to evaluate the recovery efficiency of SFBW. Effect of particle size distribution and zeta potential of the coagulated SFBW on the membrane filtration as well as the coagulation strategies were investigated. Pore clogging was more severe on the membrane with 1.0 μm pore size than on the membrane with 0.5 μm pore size due to the fact that submicrometre particles are dominant and their diameters are exactly closed to the pore size of the MF membrane. Pre-settling induced more severe irreversible fouling because only the submicrometre particles in the water become predominant after settling, resulting in the occurrence of more acute pore blocking of membrane. By contrast, pre-coagulation mitigates membrane fouling and improves membrane flux via enlarging particle size on membrane surface. The variations of zeta potential in response to coagulant dosing as well as fractal dimension were also compared with the performance of the subsequent filtration. The result showed that pre-coagulation induced by charge neutralization at the optimum dosage where the zeta potential is around zero leads to the optimal performance of the subsequent membrane filtration for SFBW recycling. At such condition, the fractal dimension of coagulated flocs reached minimum.

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Wiercik, Paweł, Karolina Matras, Ewa Burszta-Adamiak, and Magdalena Kuśnierz. "Analysis of the Properties and Particle Size Distribution of Spent Filter Backwash Water from Groundwater Treatment at Various Stages of Filters Washing." Engineering and Protection of Environment 19, no. 1 (January 2016): 149–61. http://dx.doi.org/10.17512/ios.2016.1.12.

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Adin, A. "Particle count and size alteration for membrane fouling reduction in non-conventional water filtration." Water Science and Technology 50, no. 12 (December 1, 2004): 273–78. http://dx.doi.org/10.2166/wst.2004.0723.

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If coagulation is not completely successful and produces aggregates which are too small, fouling may increase. In some cases, a deep-bed filter could perhaps provide a solution. The paper examines these effects using experimental results for different waters. Activated sludge effluents, stormy seawater containing microalgae and spent filter backwash water (SFBW) were coagulated by alum or ferric chloride. Sand filtration tests were carried out. Tests were performed in a membrane filtration stirred cell, filtration pilot plant equipped with SDI analyzer (seawater) and pilot UF plant (SFBW). For activated sludge effluent, alum residual ratio curves of turbidity and total particle count (TPC) followed one another. With ferric chloride, low coagulant dosage showed negative turbidity removal. Contact granular filtration reduced membrane fouling intensity. Increasing the dose resulted in higher improvement in membrane flux. For seawater, a filter run period under storm conditions reached 35 hours with satisfactory filtrate quality. An iron chloride dose of 0.3 mg/l during normal conditions and 0.5 mg/l for stormy condition should be injected, mixed well before the filters, while maintaining 10 m/hr filtration rate and pH 6.8 value. For SFBW, alum flocculation pretreatment of SFBW was effective in reducing turbidity, TPC, viruses and protozoa. SFBW settling prior to flocculation did not enhance turbidity and TPC removal. The largest remaining particle fraction after alum flocculation was 3-10 μm in size, both Cryptosporidium and Giardia are found in this size range. Coagulation enhanced the removal of small size particles, a positive impact on reducing membrane fouling potential.

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Sardari, Reza, and Noushin Osouleddini. "The data on the removal of turbidity and biological agents in spent filter backwash by bed ceramic in water treatment process." Data in Brief 19 (August 2018): 1794–98. http://dx.doi.org/10.1016/j.dib.2018.06.037.

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23

Pontius, Frederick W. "Regulating Filter Backwash Water." Journal - American Water Works Association 89, no. 8 (August 1997): 14–16. http://dx.doi.org/10.1002/j.1551-8833.1997.tb08271.x.

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Arendze, S., and M. Sibiya. "Filter backwash water treatment options." Journal of Water Reuse and Desalination 4, no. 2 (December 16, 2013): 85–91. http://dx.doi.org/10.2166/wrd.2013.131.

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Filtration acts as the final step in the removal of suspended matter and protozoa. The accumulated residue is removed during the backwash process and any subsequent recycling of filter backwash water could potentially re-introduce these contaminants into the main treatment process. By separating the filter backwash water from the main treatment process, factors that could interfere with the integrity of the primary treatment barriers, will be eliminated. Treatment and recovery of the filter backwash water would be beneficial in terms of water reuse, by replacing a proportion of the freshwater demand. The aim of this study was to investigate possible treatment options for the filter backwash water at Rand Water. Treatment options for filter backwash water treatment plants usually consist of a solids removal process and a disinfection process. Three solid removal processes for filter backwash water from Rand Water's filtration systems were selected for testing on an experimental basis: (1) sedimentation without flocculation, (2) sedimentation with flocculation, and (3) dissolved air flotation with flocculation. Flocculation with sedimentation produced the best results when compared to the other two treatment options evaluated. It is a simple and effective option for the treatment of filter backwash water.

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Ke, Zhao, Zhu Gang, Zhang Yu, and Kong Zheng. "Study on Backwash of Biological Aerated Filter." Applied Mechanics and Materials 448-453 (October 2013): 429–33. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.429.

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Backwash was very important for ensuring the successful performance of biological aerated filter (BAF). Through the experiment, combined air-water backwash mode were taken in BAF backwash and water backwash were 5~7L/(m2·s) and air backwash 13~17L/(m2·s) with the backwash period 24h and the backwash time 15min. It took 5~6h to recover to the optimal performance after backwash.

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Cornwell, David A., and Michael J. Macphee. "Effects of SPENT FILTER BACKWASH recycle ON CRYPTOSPORIDIUM REMOVAL." Journal - American Water Works Association 93, no. 4 (April 2001): 153–62. http://dx.doi.org/10.1002/j.1551-8833.2001.tb09185.x.

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Hall, D., and C. S. B. Fitzpatrick. "A mathematical filter backwash model." Water Science and Technology 37, no. 12 (June 1, 1998): 371–79. http://dx.doi.org/10.2166/wst.1998.0563.

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A mathematical model for deposit detachment and removal during the backwash of rapid gravity filters has been derived for a fluidising water wash. The model consists of two parts; part 1 determines the volume of deposit dislodged into suspension at any instant, and part 2 determines the change in concentration emerging from the filter bed at any stage during the backwash. Initial conditions for the backwash model are determined from a filtration model.

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Vigneswaran, S., S. Boonthanon, and H. Prasanthi. "Filter backwash water recycling using crossflow microfiltration." Desalination 106, no. 1-3 (August 1996): 31–38. http://dx.doi.org/10.1016/s0011-9164(96)00089-6.

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Akgiray, Ömer, and Ahmet M. Saatçı. "A new look at filter backwash hydraulics." Water Supply 1, no. 2 (March 1, 2001): 65–72. http://dx.doi.org/10.2166/ws.2001.0022.

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A new approach to model media expansion during filter backwash is presented. The proposed approach is based on the assumption that the Ergun equation remains valid after fluidization. Mathematical formulas are derived for predicting expanded porosity for a given backwash velocity or backwash velocity for a given expanded porosity. These formulas can be easily used by the engineer. Values predicted using the proposed approach are in good agreement with experimental measurements.

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Han, S. J., C. S. B. Fitzpatrick, and A. Wetherill. "Simulation on combined rapid gravity filtration and backwash models." Water Science and Technology 59, no. 12 (June 1, 2009): 2429–35. http://dx.doi.org/10.2166/wst.2009.308.

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Combined rapid gravity filtration and backwash models have been applied to simulate filtration and backwash cycles. The simulated results from the backwash model suggest that an optimum air flow rate exists to maximise particle removal efficiency in the backwash operation for a certain backwash system. The simulation of combined rapid gravity filtration and backwash models suggests that the filter shouldn't be completely cleaned up in the backwash and a certain amount of particles retained on filter grains after backwash can be beneficial for subsequent filtration runs. This is consistent with the experimental results in the literature.

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Edzwald, J. K., and J. E. Tobiason. "Fate and removal of Cryptosporidium in a dissolved air flotation water plant with and without recycle of waste filter backwash water." Water Supply 2, no. 2 (April 1, 2002): 85–90. http://dx.doi.org/10.2166/ws.2002.0049.

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Pilot plant research focused on the removal of Cryptosporidium oocysts by dissolved air flotation (DAF) clarification and by dual media filtration and on the impacts of the recycle of waste filter backwash water containing oocysts. No impacts from recycle of filter backwash (10% rate) were found for turbidity, particle counts (2-15 μm), and UV254 on DAF and filtration performance. DAF achieved Cryptosporidium log removals of 1.6 to 2.2 without or with recycle of filter backwash. No impacts of recycle were found on filtration, and cumulative (DAF plus filtration) log oocyst removals exceeded 4 log. Model predictions show that the fate of Cryptosporidium and the build-up of oocysts in the plant influent depend on: DAF performance, the percent of filtered water production used for backwashing, and the percent of filter backwash recycle flow. A DAF plant using 2.5% of filtered water production for backwashing and achieving 1.6 log removal or greater of oocysts by DAF clarification will not have a build-up of oocysts in the plant influent regardless of the recycle rate.

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Ngo, H. H., and S. Vigneswaran. "Process optimisation of a combined system of floating medium and sand filter in prawn farm effluent treatment." Water Science and Technology 38, no. 4-5 (August 1, 1998): 87–93. http://dx.doi.org/10.2166/wst.1998.0588.

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A treatment technology known as “a combined system of floating medium and sand filter (FMSF)” was developed and tested successfully with prawn farm effluent. This system has a remarkable techno-economical advantages. Laboratory and semi pilot-scale studies were carried out to optimise the filter bed depth, backwash method and other operating conditions. The dewatering characteristics of sludge from filter backwash was also analysed. The filter was operated at a high rate. The experimental results indicated that: (i) in case of no in-line chemical addition, the smaller ratio between floating medium and sand filter depth gave rise better filter performance. At the filtration rate of 7.5–20 m3/m2.h and with an in-line chemical addition, the suitable depth of floating medium varied from 400–1000 mm for a sand filter depth of 400 mm; (ii) frequent (once in every 90–120 minutes) but short duration of backwash (not more than 60 seconds) was found to be suitable. During the backwash, the water and air were sent for 30 seconds in upward direction and then followed with upflow of water for another 30 seconds. Backwash water amount comprised only 1.2–1.8% of the filtered water production. A mechanical backwash system using rotating paddles is a promising alternative for floating medium filter; and (iii) the filterability of the sludge from filter backwash was low in case of no in-line chemical addition (specific resistance, r = 9.34 × 1010 m/kg) but improved with in-line flocculant addition (r = 3.07 × 109 − 1.29 × 1010 m/kg).

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Song, H., X. Fan, Y. Zhang, T. Wang, and Y. Feng. "Application of microfiltration for reuse of backwash water in a conventional water treatment plant - a case study." Water Supply 1, no. 5-6 (June 1, 2001): 199–206. http://dx.doi.org/10.2166/ws.2001.0115.

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In conventional drinking water treatment processes, the amount of the filter backwash water covers nearly 3% of the total production. To reduce the water loss and waste discharge in the conventional drinking water treatment process, the Macao Water Supply Co. Ltd (SAAM) plans to recover the backwash water by Microfiltration (MF) membrane process as water resources are scarce and new environmental regulations are mandated in Macao. Generally, the filter backwash water from the conventional water treatment plant with sedimentation process is recycled to the source water to be treated again under certain conditions, and the sedimentation tank discharges most of the sludge. However, it is possible to recycle the backwash water directly to the inlet for direct filtration process due to the limitation of inlet turbidity. This paper describes how to apply MF technology to treat the backwash water of the direct filtration plant and to optimize MF operation. Without pre-treatment of the settling basin for backwash water, the operation of the MF pilot plant is proved to be stable and the permeate quality can meet EU drinking water standards. The pilot study shows that it is both economically and technically feasible to adopt MF technology in backwash water treatment. The main parameters to test MF process include flux, chemical cleaning duration and transmembrane pressure (TMP). They are 150-200 L/m2.h, 20 days and <1 bar respectively. The estimated cost including O&M and investment for a 1320-1760 m3/d backwash water treatment plant is USD 0.126-0.168/m3.

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Samuel, Michelle, Kimberly Jones, and Sudhir Murthy. "Treatment of Spent Filter Backwash Wastewater using Dissolved Air Flotation Process." Proceedings of the Water Environment Federation 2006, no. 11 (January 1, 2006): 1638–39. http://dx.doi.org/10.2175/193864706783750178.

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Schöntag, Juliana M., and Maurício L. Sens. "Effective production of rapid filters with polystyrene granules as a media filter." Water Supply 15, no. 5 (June 1, 2015): 1088–98. http://dx.doi.org/10.2166/ws.2015.072.

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In conventional water treatment stations, the filter cleaning is performed with the use of filtered water. To save water and obtain higher production, the use of polystyrene (PS) beads has been proposed as a granular filter element because it is a granular element with a low specific mass. By being lightweight, this material requires a lower water velocity during backwash. The PS beads were applied in a descending rapid filter and compared to a conventional sand and anthracite filter, and its hydraulic performance was evaluated during the backwash with air and water interspersed. Although it presents a high fluidity, with lower rates (compared to conventional filters) of backwash, this fact does not necessarily represent an economy of backwash water, because it requires more time for cleaning. It was also observed that there is an optimal value for the removal of particles collected during the filtration without loss of material.

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Brügger, A., K. Voßenkaul, T. Melin, R. Rautenbach, B. Golloing, U. Jacobs, and P. Ohlenforst. "Reuse of filter backwash water by implementing ultrafiltration technology." Water Supply 1, no. 5-6 (June 1, 2001): 207–14. http://dx.doi.org/10.2166/ws.2001.0116.

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Membrane filtration allows safe retention of microorganisms when treating filter backwash water from conventional drinking water filters. The permeate of the membrane plant can thus be reused to produce drinking water. The benefits are a higher yield of the drinking water treatment plant and a minimised wastewater production. This paper discusses the results of a pilot study, cost data and full-scale operation experiences concerning the application of ultrafiltration to treat filter backwash water. The effectiveness of ultrafiltration was assessed with regard to flux, cost and permeate quality.

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X-Flow, B. V. "Reuse of sand filter backwash water using membranes." Filtration & Separation 34, no. 1 (January 1997): 28–29. http://dx.doi.org/10.1016/s0015-1882(97)84820-3.

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Tan, Feng Xun, Rong Zhen Zhou, Dao Ji Wu, Ning Wang, Nan Lu, and Xiao Xiang Cheng. "Application of Aerated Activated Carbon Filter for Advanced Treatment." Advanced Materials Research 864-867 (December 2013): 2090–95. http://dx.doi.org/10.4028/www.scientific.net/amr.864-867.2090.

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The objective of this research was to study the treatment effect of micro-polluted water usingconventional activated carbon filter(CACF) andaeration activated carbon filter(AACF), test the effect of backwashing on the performance of carbon filters, and provide a reference for water plant upgrading. The removal efficiency of pollutants and the impact of backwash of AACF was studied and compared with CACF. The results showed that, with an influent turbidity of 0.67 versus 0.44NTU, CODMnof 2.48 versus 2.74mg / L, UV254of 0.045versus 0.045cm-1and NH4+-N of 0.15 versus 0.11mg / L, the removal effect of turbidity, CODMn, UV254,and NH4+-N are 36.19% versus 33.67%, 30.63% versus 21.53%, 23.06% versus 26.57% and 34.34% versus 19.62% . AACF improved the treatment of CODMn,and NH4+-N by 26.66% and 60%. Backwash is found to enhance the performance of AACF on CODMnwith the removal efficiency increases from the 25.82% to 29.75% after 2 hr backwash, and stabilizes at approximately 30% at the consequent 6 hrs; Backwash decreases UV254removal from 17.51% to 16.64% after 2 hr backwash, increases it to 19.64% to after 4 hr treatment, and drops to 13.44% after 8 hrs. Additionally, backwash has no significant effect on NH4+-N.

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Jibhakate, Mangesh L., M. P. Bhorkar, A. G. Bhole, and P. K. Baitule. "Reuse & Recirculation of Filter Backwash Water of Water Treatment Water." International Journal of Engineering Research and Applications 07, no. 04 (April 2017): 60–63. http://dx.doi.org/10.9790/9622-0704016063.

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Zhang, Wen Yi, Ning Han, Gang Yan, Xia Xu, and Xiao Liang Chen. "Study on Biological Aerated Filter (BAF) of Algae-Contained Micropolluted Water." Advanced Materials Research 340 (September 2011): 311–17. http://dx.doi.org/10.4028/www.scientific.net/amr.340.311.

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Using NaCl modified zeolite with high specific surface area as filter media, algae-contained micropolluted water was treated with biological aerated filter (BAF) process. The removal efficiencies of the process on micro-pollutants and removal mechanism of algae-contained micropolluted water were investigated and studied. The results showed that better removal efficiency was obtained in turbidity, Chlorophyll-a, UV254, and CODMn when algae-contained micropolluted water was treated by BAF. The optimal process parameters of the treatment of algae-contained micropolluted water with BAF were gases/water ratio of 0.5~2.5, backwash cycle of 3~5 d, air/water backwash strength of 5~7 L/(m2·s), air backwash strength of 13~17 L/(m2·s), backwash time of 15~20min, temperature of 25~30°C, pH value of 7.8~8.5 and hydraulic load of 0.23~0.35 m3/(m2·h). The results of continuous running for 21 days showed that the removal efficiency of turbidity, Chlorophyll-a, UV254, and CODMn were up to 71.61%, 81.35%, 28.34% and 32.97% respectively under the conditions of these optimal parameters, and the effluent water could meet Grade II of the Drinking Water Quality Standards (CJ 3020~1993). This study could provide technical information for town water plant reconstruction of Taihu Lake and Chaohu Lake basin.

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Mkhonto, S., H. Ewerts, A. Swanepoel, and G. C. Snow. "The efficacy of a recovered wash water plant in removing cyanobacteria cells and associated organic compounds." Water Supply 20, no. 5 (May 8, 2020): 1776–86. http://dx.doi.org/10.2166/ws.2020.086.

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Abstract The treatment works under investigation uses a recovered wash water plant (RWWP) to remove impurities prior to recycling filter backwash water. Filter backwash water (raw water) is characterized by high quantities of cyanobacteria cells and associated organic compounds; a potential threat when recovered water is recycled. The aim of this study is to identify the cyanobacteria cells and associated organic compounds in the filter backwash water and to subsequently evaluate the effectiveness of the RWWP in removing these organic impurities during the following periods; autumn-winter and spring-summer. Results showed that at least six major phytoplankton groups were present in the filter backwash water with turbidity levels (59 and 46 NTU; autumn-winter and spring-summer, respectively) being much higher than the drinking water productions standard of ≤5 NTU. Cyanobacteria were a dominant group (mean of 80% and above) in the total phytoplankton composition of the raw water and consisted of three genera (Anabaena sp., Microcystis sp. and Oscillatoria sp.), which were effectively removed by the RWWP (up to 99%). However, associated organic compounds such as geosmin, total organic carbon (TOC), dissolved organic carbon (DOC) and microcystin were not effectively removed during the different seasonal periods but were of such low concentrations that they posed no major risk to the drinking water quality, meeting the RWWP water quality standard.

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Scharfenaker, Mark A. "Usepa Adopts Streamlined Filter Backwash Recycling Rule." Journal - American Water Works Association 93, no. 8 (August 2001): 24–30. http://dx.doi.org/10.1002/j.1551-8833.2001.tb09258.x.

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Hou, Bingwei, Tao Lin, and Wei Chen. "Evaluation of a drinking water treatment process involving directly recycling filter backwash water using physico-chemical analysis and toxicity assay." RSC Advances 6, no. 80 (2016): 76922–32. http://dx.doi.org/10.1039/c6ra14912j.

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Di Giovanni, George D., F. Helen Hashemi, Nancy J. Shaw, Felicia A. Abrams, Mark W. LeChevallier, and Morteza Abbaszadegan. "Detection of Infectious Cryptosporidium parvum Oocysts in Surface and Filter Backwash Water Samples by Immunomagnetic Separation and Integrated Cell Culture-PCR." Applied and Environmental Microbiology 65, no. 8 (August 1, 1999): 3427–32. http://dx.doi.org/10.1128/aem.65.8.3427-3432.1999.

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ABSTRACT A new strategy for the detection of infectiousCryptosporidium parvum oocysts in water samples, which combines immunomagnetic separation (IMS) for recovery of oocysts with in vitro cell culturing and PCR (CC-PCR), was field tested with a total of 122 raw source water samples and 121 filter backwash water grab samples obtained from 25 sites in the United States. In addition, samples were processed by Percoll-sucrose flotation and oocysts were detected by an immunofluorescence assay (IFA) as a baseline method. Samples of different water quality were seeded with viable C. parvum to evaluate oocyst recovery efficiencies and the performance of the CC-PCR protocol. Mean method oocyst recoveries, including concentration of seeded 10-liter samples, from raw water were 26.1% for IMS and 16.6% for flotation, while recoveries from seeded filter backwash water were 9.1 and 5.8%, respectively. There was full agreement between IFA oocyst counts of IMS-purified seeded samples and CC-PCR results. In natural samples, CC-PCR detected infectious C. parvum in 4.9% (6) of the raw water samples and 7.4% (9) of the filter backwash water samples, while IFA detected oocysts in 13.1% (16) of the raw water samples and 5.8% (7) of the filter backwash water samples. All CC-PCR products were confirmed by cloning and DNA sequence analysis and were greater than 98% homologous to the C. parvum KSU-1hsp70 gene product. DNA sequence analysis also revealed reproducible nucleotide substitutions among the hsp70fragments, suggesting that several different strains of infectiousC. parvum were detected.

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Zhou, Yang Min, Chao Li, Li Li Xu, Si Yi Luo, and Chui Jie Yi. "The Design and Experimental Study of Automatic Backwash Fiber Bundle Filter." Advanced Materials Research 339 (September 2011): 130–33. http://dx.doi.org/10.4028/www.scientific.net/amr.339.130.

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A kind of automatic backwash fiber bundle filter which is used for filtering the washing BFS water is designed and its properties have been studied. The high density particles in washing BFS water and suspended slag wool are the key factors for the filtering effect. By optimization design of structure, the filter has properties of big particles precipitation, automatic discharge of floating sludge and fixed pressure backwash. Through experimental tests, the results show that: the high density particles precipitation and filter layer regeneration rate are quicker; the ability of automatic discharge floating sludge is higher. Compared with the traditional fiber filters, this kind filter efficiency of this kind filters increases 15%.

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Zhytsianiou, Barys N., and Lyudmila E. Yordanova. "Backwash water treatment by coagulation in the presence of phosphates at underground water iron removal stations." Vestnik MGSU, no. 4 (April 2020): 553–68. http://dx.doi.org/10.22227/1997-0935.2020.4.553-568.

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Introduction. The analysis of the present-day condition of water resources has proven the relevance and expediency of developing highly effective backwash water treatment methods to be used at iron removal stations designated for groundwater treatment. In accordance with effective technical regulations, backwash water must be reused. The operation of iron removal stations has proven the inefficiency of backwash water treatment facilities. Water and wastewater treatment companies stop using backwash water treatment facilities and refrain from reusing backwash water. Highly concentrated iron-bearing backwash water is discharged into sewage networks, nearby water bodies or onto the terrain, which means irrational use of high-quality groundwater and environmental pollution with iron compounds. Materials and methods. The results of experimental research efforts and statistical processing of data on the qualitative and quantitative composition of backwash water at iron removal stations are presented. The chemical nature of the components and the principle underlying the formation of the backwash water composition in the process of groundwater deferrization have been studied. It’s been identified that if backwash water supplied by iron removal stations is treated by sodium phosphate reagent Na3PO4 and aluminum sulphate Al2(SO4)3 as a coagulant, precipitation of iron compounds intensifies, as colloidal particles FePO4 are formed. They have very low solubility, and they are effectively removed by coagulation. It has been theoretically proven and experimentally confirmed that anions H2 PO4– and PO4 3– fformed in the process of hydrolysis of sodium phosphate Na3PO4 help to reduce the electrokinetic charge of the colloidal particle of iron hydroxide Fe(OH)3, and high purification efficiency reaching 99.0–99.9 % is attained by attaching iron compounds to the surface of the colloidal particle of aluminum hydroxide Al(OH)3. Conclusions. The co-authors have developed a math-and-stats model simulating the backwash water treatment process that employs coagulation in the presence of phosphates. It describes the dependence between the concentration of residual iron, doses of sodium phosphate Na3PO4, aluminum sulphate Al2(SO4)3 and the settling time. A backwash water treatment technology has been developed. It employs coagulation in the presence of phosphates, and it is designated for use at iron removal stations. This technology comprises a chemical plant for sodium phosphate and aluminum sulphate used as a coagulant, a post-treatment filter, and sludge dewatering facilities. The application of this technology enables to reduce iron concentration to 0.05–0.20 mg/l, to reuse backwash water for drinking and other household purposes, or to have this water reused by iron removal stations, this, preventing pollution of water sources with iron compounds.

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Wicaksono, Ikhsan, Tri Joko Wibowo, and M. Jihan Shofa. "Analisis Pengurangan Cooling Water Loss Menggunakan Six Sigma dan Failure Mode Effect Analysis (FMEA)." Jurnal INTECH Teknik Industri Universitas Serang Raya 3, no. 2 (December 28, 2017): 67. http://dx.doi.org/10.30656/intech.v3i2.882.

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Loss on a working system is one of the causes of the cost of the process to swell. The loss that reaches more than 450 tons/month on a cooling water system at a chemical company in the Serang area causes the company's expenses to swell. This study aims to determine the cause of cooling water wash as a basis for process improvement by using Six Sigma and Failure Mode Effect Analysis (FMEA). Data analysis results showed that cooling water loss is too little backwash filter duration, service filter duration is not optimum, and flow unreadable side stream. Improvements by increasing the length of the backwash, raising the service time of the sand filter to every two days, and cleaning the rotameter can increase the sigma value from 3.5 to 4.5.

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Zielina, Michał, and Wojciech Dąbrowski. "Energy and Water Savings during Backwashing of Rapid Filter Plants." Energies 14, no. 13 (June 23, 2021): 3782. http://dx.doi.org/10.3390/en14133782.

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This paper describes an analysis of the effects of adjusting the intensity of filter backwash to the water temperature. The consequences of the lack of such adjustment for the life of filter beds, the amount of water used for backwashing, the amount of energy used for backwashing and the quality of the first filtrate are presented. In order to determine the losses and profits resulting from controlling the intensity of backwash water depending on its temperature, an analysis was carried out at a water treatment plant in southern Poland. Laboratory measurements were used to determine the granulation and specific gravity of sand grains filling the filtration beds. On the basis of measurements on a semi-technical scale, the magnitudes of filter bed expansion were determined for average monthly wash water temperatures. They were first calculated from the Richardson–Zaki equation, using different formulae for the value of the exponent of the power in this equation. Due to significant differences in the density and shape of grains covered with a permanent deposit after several years of filter operation, a satisfactory match between the formulae known from the literature and the results of expansion measurements was not obtained. Therefore, an new formula for the bed expansion was developed based on the Richardson–Zaki equation. A good fit of this formula to the experimental results was obtained. Monthly average values of water temperature were compiled, and on this basis the required amount of backwash water and energy was computed. The computations were made for 25% of fluidized bed expansion. Possible energy and water savings were estimated, as well as further gains from keeping the required expansion of the porous bed constant regardless of the wash water temperature.

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Cocchia, Sergio, Kenneth H. Carlson, and Fred Marinelli. "Use of Total Suspended Solids in Characterizing the Impact of Spent Filter Backwash Recycling." Journal of Environmental Engineering 128, no. 3 (March 2002): 220–27. http://dx.doi.org/10.1061/(asce)0733-9372(2002)128:3(220).

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Parsons, Michael G., and Richard W. Harkins. "Full Scale Particle Removal Performance of Three Types of Mechanical Separation Devices for the Primary Treatment of Ballast Water." Marine Technology and SNAME News 39, no. 04 (October 1, 2002): 211–22. http://dx.doi.org/10.5957/mt1.2002.39.4.211.

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The Great Lakes Ballast Technology Demonstration Project has undertaken a multi-year program to demonstrate and evaluate ballast treatment methodologies that might minimize the potential for the introduction of additional nonindigenous aquatic species into the Great Lakes and other U.S. waters. Full-scale mechanical and biological testing of primary and secondary treatment options has been performed on both operating vessels and a ballast treatment testing barge facility located in Duluth and Two Harbors, Minnesota. Mechanical testing results for three candidate primary mechanical separation devices obtained over a four-year period on the barge installation are presented and compared. Results are presented for the particle removal efficiency at a nominal 340 m3 /h (1500 U.S. gpm) for a 50 micron (µm) screen-type surface automatic backwash filter, a 100 µm rated cyclonic separation device, and a 100 µm disk-type depth automatic backwash filter. The screen-type and disk-type automatic backwash filters showed particle removal efficiencies at and above their removal rating of over 90%. Although more complicated, the disk-type depth filter exhibited a significant advantage through a longer time between backwash cycles and, thus, a greater net filtration throughput. The hydrocyclone demonstrated significantly lower effectiveness (about 30%) in removing particles that included both neutrally buoyant biota and other materials such that, while much simpler, these devices are not considered appropriate for this application requiring the effective removal of both particulate material and larger biota.

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Journal articles on the topic 'Spent filter backwash water'

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