FilmTec Technical Manual - Chester Paul Company

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3.9 Membrane System Design GuidelinesThe factor which has the greatest influence on the membrane system design is the fouling tendency of the feed water.Membrane fouling is caused by particles and colloidal material which are present in the feed water and are concentrated atthe membrane surface. The Silt Density Index (SDI) value of the pretreated feed water correlates fairly well with the amountof fouling material present. The concentration of the fouling materials at the membrane surface increases with increasingpermeate flux (the permeate flow rate per unit membrane area) and increasing FILMTEC element recovery (the ratio ofpermeate flow rate to feed flow rate for a single element). A system with high permeate flux rates is, therefore likely toexperience higher fouling rates and more frequent chemical cleaning.A membrane system should be designed such that each element of the system operates within a frame of recommendedoperating conditions to minimize the fouling rate and to exclude mechanical damage. These element operating conditions arelimited by the maximum recovery, the maximum permeate flow rate, the minimum concentrate flow rate and the maximumfeed flow rate per element. The higher the fouling tendency of the feed water the stricter are the limits of these parameters.The proposed limits are recommended guidelines based on many years of experience with FILMTEC membranes.The average flux of the entire system, i.e. the system permeate flow rate related to the total active membrane area of thesystem, is a characteristic number of a design. The system flux is a useful number to quickly estimate the required number ofelements for a new project. Systems operating on high quality feed waters are typically designed at high flux values whereassystems operating on poor quality feed waters are designed at low flux values. However, even within the same feed watercategory, systems are designed with higher or lower flux values, depending on the focus being either on minimizing the capitalexpenses or minimizing the long term operational expenses. The ranges of flux values given in the tables below are typicalnumbers for the majority of systems, but they are not meant to be limits.A continuous RO/NF process designed according to the system design guidelines and with a well-designed and operatedpretreatment system will show stable performance with no more than about four cleanings per year in standard applications.Exceeding the recommended limits may result in more frequent cleanings, reduced capacity, increased feed pressure andreduced membrane life. A moderate violation of the limits for a short time may be acceptable as long as the physical limits –the maximum pressure drop and the maximum feed pressure – are not exceeded. On the other hand, a conservativeapproach is to anticipate a higher fouling tendency and to design the system according to the stricter limits in order to enjoy atrouble free system operation and an increased membrane life.Page 80 of 180 ® Trademark of The Dow Chemical <strong>Company</strong> ("Dow") or an affiliated company of Dow Form No. 609-00071
3.9.1 Membrane System Design Guidelines for 8-inch FILMTEC ElementsThe following tables show the recommended guidelines for designing RO systems with 8-inch FILMTEC elements accordingto feed water type.Table 3.4 Design guidelines for 8-inch FILMTEC elements in water treatment applicationsFeed source RO Permeate Well Water Surface Supply Wastewater (FilteredSeawaterMunicipal Effluent)MF 1 Conventional Well or MF 1 Open intakeFeed silt density index SDI < 1 SDI < 3 SDI < 3 SDI < 5 SDI < 3 SDI < 5 SDI < 3 SDI < 5Average gfd 21-25 16-20 13-17 12-16 10-14 8-12 8-12 7-10system flux l/m 2 h 36-43 27-34 22-29 20-27 17-24 14-20 13-20 11-17Maximum element recovery % 30 19 17 15 14 12 15 13Active Membrane AreaMaximum permeate flow rate, gpd (m 3 /d)320 ft 2 elements 9,000 (34) 7,500 (28) 6,500 (25) 5,900 (22) 5,300 (20) 4,700 (18) 6,700 (25) 6,100 (23)365 ft 2 elements 10,000 (38) 8,300 (31) 7,200 (27) 6,500 (25) 5,900 (22) 5,200 (20)380 ft 2 elements 10,600 (40) 8,600 (33) 7,500 (28) 6,800 (26) 5,900 (22) 5,200 (20) 7,900 (30) 7,200 (27)390 ft 2 elements 10,600 (40) 8,900 (34) 7,700 (29) 7,000 (26) 6,300 (24) 5,500 (21)400 ft 2 elements 11,000 (42) 9,100 (34) 7,900 (30) 7,200 (27) 6,400 (24) 5,700 (22)440 ft 2 elements 12,000 (45) 10,000 (38) 8,700 (33) 7,900 (30) 7,100 (27) 6,300 (24)Element typeMinimum concentrate flow rate 2 , gpm (m 3 /h)BW elements (365 ft 2 ) 10 (2.3) 13 (3.0) 13 (3.0) 15 (3.4) 16 (3.6) 18 (4.1)BW elements (400 ft 2 and 440 ft 2 ) 10 (2.3) 13 (3.0) 13 (3.0) 15 (3.4) 18 (4.1) 20 (4.6)NF elements 10 (2.3) 13 (3.0) 13 (3.0) 15 (3.4) 18 (4.1) 18 (4.1)Full-fit elements 25 (5.7) 25 (5.7) 25 (5.7) 25 (5.7) 25 (5.7) 25 (5.7)SW elements 10 (2.3) 13 (3.0) 13 (3.0) 15 (3.4) 16 (3.6) 18 (4.1) 13 (3.0) 15 (3.4)Element typeActive areaft 2 (m 2 )Maximum feed flow rate 2 , gpm (m 3 /h)BW elements 365 (33.9) 65 (15) 65 (15) 63 (14) 58 (13) 52 (12) 52 (12)BW or NF elements 400 (37.2) 75 (17) 75 (17) 73 (17) 67 (15) 61 (14) 61 (14)BW elements 440 (40.9) 75 (17) 75 (17) 73 (17) 67 (15) 61 (14) 61 (14)Full-fit elements 390 (36.2) 85 (19) 75 (17) 73 (17) 67 (15) 61 (14) 61 (14)SW elements 320 (29.7) 65 (15) 65 (15) 63 (14) 58 (13) 52 (12) 52 (12) 63 (14) 56 (13)SW elements 380 (35.3) 72 (16) 72 (16) 70 (16) 64 (15) 58 (13) 58 (13) 70 (16) 62 (14)1 MF: Microfiltration - continuous filtration process using a membrane with pore size of
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DowWater SolutionsFILMTEC Reverse O
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2.6 Biological Fouling Prevention .
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1. Basics of Reverse Osmosis and Na
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Nanofiltration (NF)Nanofiltration r
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How to Use Reverse Osmosis and Nano
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1.4 Membrane DescriptionThe FILMTEC
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Membrane systems are typically desi
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1.8 Element CharacteristicsFILMTEC
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2. Water Chemistry and Pretreatment
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SeawaterSeawater with TDS of 35,000
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Table 2.5 Water analysis for RO/NFS
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Table 2.7 Solubility products of sp
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In this process, only Ca 2+ , Ba 2+
Page 29 and 30: For the concentration ranges presen
Page 31 and 32: The conditions for CaCO 3 scale con
Page 33 and 34: Figure 2.3 Langelier saturation ind
Page 35 and 36: These computations have been descri
Page 37 and 38: Figure 2.5 “K” versus ionic str
Page 39 and 40: Figure 2.6 Ksp for CaSO 4 versus io
Page 41 and 42: 2.4.6 Calcium Fluoride Scale Preven
Page 43 and 44: Figure 2.8 K sp for SrSO 4 versus i
Page 45 and 46: 2.4.7 Silica Scale PreventionDissol
Page 47 and 48: Table 2.10 Solubility of SiO 2 vers
Page 49 and 50: 2.4.8 Calcium Phosphate Scale Preve
Page 51 and 52: Table 2.9 Various fouling indicesIn
Page 53 and 54: Frequent shutdowns and start-ups sh
Page 55 and 56: If the differential pressure across
Page 57 and 58: 1. Intake (surface) or well, before
Page 59 and 60: or combined residual chlorine (CRC)
Page 61 and 62: 2.6.5 DBNPADBNPA (2,2, dibromo-3-ni
Page 63 and 64: 2.6.11 Use of Fouling Resistant Mem
Page 65 and 66: 2.11 Treatment of Feedwater Contain
Page 67 and 68: 2.13 Summary of Pretreatment Option
Page 69 and 70: 26. Handbook of Industrial Membrane
Page 71 and 72: Table 3.1 System design information
Page 73 and 74: 3.2 Batch vs. Continuous ProcessAn
Page 75 and 76: 3.4 Single-Stage SystemIn a single-
Page 77 and 78: The apparent salt passage of the sy
Page 79: Instead of having a separate high-p
Page 83 and 84: In Table 3.6, the small commercial
Page 85 and 86: Table 3.8 Number of stages of a sea
Page 87 and 88: 3.11 System Performance Projection3
Page 89 and 90: 3.11.2 Design Equations and Paramet
Page 91 and 92: Table 3.10 Design equations for pro
Page 93 and 94: 3.11.3 Comparing Actual Performance
Page 95 and 96: The high-pressure concentrate is fe
Page 97 and 98: If the product water from an RO sys
Page 99 and 100: Besides the above recommendations,
Page 101 and 102: 4. Loading of Pressure VesselsThis
Page 103 and 104: The process of shimming is performe
Page 105 and 106: 4.5.2 Summary of Large Element Inte
Page 107 and 108: 5. System Operation5.1 Introduction
Page 109 and 110: 5.2.3 Start-Up SequenceProper start
Page 111 and 112: 5.2.4 Membrane Start-Up Performance
Page 113 and 114: 5.5.3 SeawaterIn principle, the ope
Page 115 and 116: Table 5.1 Reverse osmosis operating
Page 117 and 118: A. Normalized Permeate FlowQS=ΔPsP
Page 119 and 120: For the operating conditions we hav
Page 121 and 122: 4. During recirculation of cleaning
Page 123 and 124: 2. The cleaning pump should be size
Page 125 and 126: 6.7 Effect of pH on Foulant Removal
Page 127 and 128: Cleaning ProcedureThere are seven s
Page 129 and 130: If the organic fouling is the resul
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There are two factors that greatly
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7. Handling, Preservation and Stora
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7.4 Preservation of RO and NF Syste
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If the normalized actual performanc
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8.3.3 Localization of High Solute P
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Figure 8.2 Permeate probing apparat
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8.4.5 Performance TestThe standard
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8.5.1.1 Low Flow and Normal Solute
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. Metal Oxide FoulingMetal oxide fo
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. Organic FoulingThe adsorption of
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8.5.3 High Pressure DropHigh differ
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In case of fullfit or heat sanitiza
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Breakpoint chlorinationBreak tankBr
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FeedThe input solution to a treatme
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Milligram per litre (mg/L)Mixed-bed
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SBS Sodium bisulfite, NaHSO 3.Scale
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9.2 Specific Conductance of Sodium
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Figure 9.1 Conductivity of ionic so
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9.6 Temperature Correction FactorTa
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9.9 Osmotic Pressure of Sodium Chlo
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Details - TestEquipment andSpecific
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satisfactory for such a determinati
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case for almost all tested biocides
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9.12 Key Word IndexAbrasion - 150 B
Page 179 and 180:
Positive displacement pump - 95 Shu
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