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galvis

Water treatment

aw water. The red colour

aw water. The red colour is used for the zone indicating that the filter is being operated at either an extremely high or low velocity. The scale is constructed of aluminium or acrylic. Figure A1-2: Triangular weir (A) and rectangular weir (B). Outlet rectangular weir in a DyGF unit which combines constant (headloss ≤ s) and declining filtration rates. Figure A1-3. Example of a measuring scale (to be used in vertical position) A1.1.4. Movable overflow and drainage device for SSF This movable device is also called “goose neck” because it can be pulled up to be used as an overflow facility during SSF runs and push down to drain the supernatant water. Details of this device are presented in Figure A1-4. Figure A1-4: Details of the movable overflow and drainage (goose neck) device for SSF. A1-2

A1.2 Maintenance facilitating devices A1.2.1 Fast drainage valve The fast drainage valves are connected to the drainage system to facilitate the periodic hydraulic cleaning of CGF units. By quickly opening and closing the valves, changes of flow pattern are produced which assist in removing the material accumulated on the gravel. In Figure A1-5 two early designs for these types of valves are presented, one (A) based on experience in Peru by Pardón (1989) and the other (B) developed in Colombia by Cinara (Galvis et al, 1989) using a model which is also applied for milk cans. In both designs the operator faces the risk of becoming in contact with biologically active wash water, so the use of this type of valve is now discouraged. The commercially available butterfly valve is equipped with a handle, as shown in Figure A2-5. The house of the valve is made of cast iron, stainless steel or bronze. Its main characteristics include easy handling, complete sealing of the flow, low headloss and easy instalment and replacement. It can be easily connected to the outlet of the drainage system and an extension pipe can be installed after the fast opening valve to avoid the contact of the operator with the wash-water. It is now recommended that this valve be used in treatment units both first and second CGF stages. C Figure A1-5: Fast opening valves. (A) After experiences of Pardón (1989); (B) after experiences of Cinara (Galvis et al, 1989); (C) Commercial (“butterfly”) valve. References Galvis, G., Visscher, J.T., Quiroga, E., Latorre, J., Galvis, A., Duque, R., Cruz, C. (1989) Proyecto Integrado de Investigación y Demostración en Filtración Lenta en Arena. Informe Final. Versión Resumida. Cali, Colombia: Cinara. The Hague, The Netherlands, IRC International Water and Sanitation Centre. Pardon, M.O. (1989) Treatment of Turbid Surface Water for Small Community Supplies: PhD Thesis. University of Surrey. United Kingdom. A1-3

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    Development and Evaluation of Multi

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    ACKNOWLEDGEMENTS To my supervisor,

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    ABBREVIATIONS ABNT: Acuavalle: ACV:

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    SOCs: Synthetic Organic Chemicals S

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    u c V V f Vs uniformity coefficient

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    TABLE OF CONTENTS 1. INTRODUCTION 1

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    4 MULTISTAGE FILTRATION EXPERIENCIE

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    1 INTRODUCTION Water is essential f

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    Table 1.2 Access to WS&S in Colombi

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    Table 1.5 Safe drinking water cover

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    1.2 Multiple Barriers Strategy and

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    2 OVERCOMING THE LIMITATIONS OF SLO

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    adjustment, are among the technolog

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    On January 14, 1829, Simpson’s on

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    With increasing life expectancy, en

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    Table 2.2 Treatments steps recommen

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    In table 2.3, WHO guideline values

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    2.5 The Slow Sand Filtration Proces

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    When the particles are very close t

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    in which p 0 is the clean media por

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    Yao et al (1971) related the remova

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    compensate for the increase in the

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    can be applied, but intermittent op

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    Table 2.4 Comparison of design crit

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    Although accepted as indirect indic

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    50% when the temperature falls from

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    Figure 2.9 Flow diagram of the wate

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    ut higher running costs, since more

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    Headloss and flow control. Final he

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    Figure 2.13 Influence of flow condi

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    Operation and maintenance (O & M).

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    in parallel (Galvis, 1983; Smet et

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    cleaning simple, DyGF should behave

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    case of Dortmund (Germany), the HGF

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    Table 2.9 Data about three experien

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    Some points of discussion about HGF

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    and 600-800 NTU) and different filt

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    the HGF units of Aesch (see table 2

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    in spite of the low removal efficie

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    order to overcome the water quality

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    full-scale units. In this research,

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    3 MULTISTAGE FILTRATION STUDIES WIT

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    in the case of UGFL. Initially, it

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    • Bigger and better-instrumented

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    l Figure 3.7 Plan view of Cinara's

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    The present research work was divid

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    Table 3.1. Design parameters, grave

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    Figure 3.9. Piezometer distribution

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    were used to collect samples for DO

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    were poured into a funnel using fil

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    H 0 : H a : Treatment levels workin

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    3.2 Results and Specific Discussion

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    3.2.2 Dynamic gravel filtration (Dy

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    Mean faecal coliform removal effici

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    Table 3.10 Comparative analysis of

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    DyGF-A had flow reductions in the r

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    The experimental data used to produ

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    Previous observations were further

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    ates (figure 3.17 B). However, at t

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    Longer “initial-ripening” perio

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    Table 3.17. Descriptive statistics

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    100 Filtration rate = 0.3 mh -1 100

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    After the present experience, faeca

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    nature of the organic matter and th

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    Table 3.24 Comparative analyses of

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    3.2.4.3. Filtration run lengths and

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    deep bed filter (data not included

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    and operational considerations Pard

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    than in sand samples from other SSF

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    Step dose tracer tests were made at

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    for HGFS and from 3 to 5 for HGF. T

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    Constant and declining filtration r

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    The efficiency levels summarised be

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    Surface area of CGF and SSF units.

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    community based organisations and l

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    systems. All these systems were fed

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    Parts of the suburban settlements o

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    Figure 4.2. Layout of Retiro MSF pl

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    Traditionally, in the WS&S of Colom

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    Photo 4.10. Partial cleaning activi

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    Figure 4.3 Location of full-scale M

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    4.4.1.3 Main characteristics of mul

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    Figure 4.4 Layout of Restrepo MSF p

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    Figure 4.6 Layout of Javeriana MSF

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    Figure 4.9 Layout of Cañasgordas M

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    Figure 4.11. Layout of Ceylan MSF p

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    Table 4.4 Descriptive statistics fo

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    Water sources in the coffee region

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    Filterability results seem to under

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    Table 4.8 Mean removal efficiencies

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    The length of this ripening period

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    in Peru (Pardon, 1989) and Colombia

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    Photo 4.24 Drainage facilities in u

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    the Cauca Valley. This is not the c

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    Pardon (1989) reports similar evide

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    5. COST OF MULTI-STAGE FILTRATION P

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    ecame formally established as WS en

  • Page 200 and 201: Models for assessing construction q
  • Page 202 and 203: MSF system can then be calculated o
  • Page 204 and 205: 5.7 Cost Model for the Cali Area an
  • Page 206 and 207: Table 5.8. Annual labour costs due
  • Page 208 and 209: 5.8 General Discussion The followin
  • Page 210 and 211: systems. The differences between MS
  • Page 212 and 213: guideline for colour is < 15 PCU (W
  • Page 214 and 215: Table 6.1. Individual (at each trea
  • Page 216 and 217: Table 6.3. Individual (at each trea
  • Page 218 and 219: As shown in tables 6.1 and 6.3, col
  • Page 220 and 221: UGFL 0.45 UGFS 0.45 (32;51;85) (44;
  • Page 222 and 223: Table 6.4. An example of identifica
  • Page 224 and 225: MSF technology showed great flexibi
  • Page 226 and 227: In harmony with the new development
  • Page 228 and 229: epresents the risk the community ha
  • Page 230 and 231: The selection of MSF alternatives i
  • Page 232 and 233: scouring and transporting away prev
  • Page 234 and 235: REFERENCES ABNT, (1989) NB-592 Proj
  • Page 236 and 237: Craun, G.F., Bull, R.J., Clark, R.M
  • Page 238 and 239: Drinking Water Disinfection, ed. by
  • Page 240 and 241: Huisman, L. (1989) Plain Sedimentat
  • Page 242 and 243: Mendenhall, W. and Sincich, T. (199
  • Page 244 and 245: Ridley, J.E. (1967) Experience in t
  • Page 246 and 247: Visscher, J.T. and Galvis, G. (1992
  • Page 248 and 249: ANNEXES Annex 1: Accessories for Mu
  • Page 252 and 253: Annex 2: Design of Manifolds Manifo
  • Page 254 and 255: + q 2 Q1 (1.2 qn + qn) (2.2 qn) = =
  • Page 256 and 257: R 1 = (total orifice area / lateral
  • Page 258 and 259: 0.30 0.25 0.20 0.15 0.10 0.05 0.00
  • Page 260 and 261: Table A.4-2 General notation for th
  • Page 262 and 263: Box A4-3. Sum of Square Error (SSE)
  • Page 264 and 265: Annex 5: Residence times in coarse
  • Page 266 and 267: Table A5-1 Percentage of incoming w
  • Page 268 and 269: Annex 6 Number and Type of Valves N
  • Page 270: Table A7-1. Descriptive statistics
  • Page 274 and 275: Tables A7-3 Removal efficiencies of
  • Page 276 and 277: Tables A7-5 Removal efficiencies of
  • Page 278 and 279: Construction quantities of DyGF com
  • Page 280: Net present value (US$) of MSF and