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galvis

Water treatment

5.5.2 Operation,

5.5.2 Operation, maintenance, and administration costs 181 5.5.3 Cost comparison with conventional RF technology 182 5.6 Results 182 5.6.1 Initial investment cost 182 5.6.2 Operation and maintenance 183 5.6.3 Administration 184 5.6.4 Estimating overall cost 184 5.7 Cost Model for Cali Area and Cauca Valley 185 5.7.1 Construction cost model 185 5.7.2 Operation, maintenance and administration costs 186 5.7.3 Comparison of MSF and conventional RF alternatives 187 5.8 General Discussion 189 6 SELECTION OF MULTISTAGE FILTRATION ALTERNATIVES 190 6.1 Basic Parameters of Sanitary Significance in Surface Water Sources 191 6.2 Treatment Efficiencies of Multistage Filtration Alternatives 193 6.3 Water Treatment Concepts and Treatment Objectives in MSF Alternatives 199 6.4 Selection of MSF Alternatives 200 6.4.1 Example of a selection guide for MSF alternatives 202 6.4.2 Examples to illustrate level of performance achieved by MSF plants 205 6.5 Sustainability of Development Projects Including MSF Alternatives 206 7 CONCLUSIONS AND RECCOMMENDATIONS 210 REFERENCES 215 ANNEXES 229 Annex 1: Accessories for Multistage Filtration Plants Annex 2: Design of Manifolds Annex 3: Information on Analytical Techniques Annex 4: Example of F-Test (Analysis of Variance) Application Annex 5: Residence Times in Coarse Gravel Filtration Units Annex 6: Number and Type of Valves needed for MSF Systems Annex 7: Descriptive Statistics and Removal Efficiencies Based on Adjusted Databases of MSF Plants Fulfilling Treatment Objectives Proposed in Section 6.3 xiii

1 INTRODUCTION Water is essential for all forms of life. However, excess water, scarcity and poor water quality all affect human health and well being. Safe drinking water supply and basic sanitation (WS&S), together with hygiene education, are considered fundamental components to improve the quality of life and productivity in human settlements. These components of the water sector reduce the sanitary risks associated with the environment and interact with different areas of development also relevant to health, such as employment, agriculture and housing (Esrey et al, 1990; WASH, 1993; Traverso, 1996). Accordingly, substantial efforts to improve WS&S have been made in recent decades. For example, in the 1980s, during the International Drinking Water and Sanitation Decade (IDWSSD), over 1,350 million people were covered with new water supply (WS) facilities and 750 million with sanitation services. However, these efforts were not sufficient, since by the end of the Decade around 1,600 million people were still lacking access to WS and some 2,600 million in need of adequate sanitation services as shown in table 1.1 (WHO, 1996). Table 1.1 Water supply and sanitation coverage at global and Latin American and the Caribbean in 1990 and 1994 (adapted from WHO, 1996). 1990 (Population in millions) 1994 (Population in millions) Area Total Access Coverage (%) Total Access Coverage (%) Water Sanitat. Water Sanitat. Water Sanitat. Water Sanitat. GLOBAL Urban 1,389 1,145 931 82 67 1,594 1,315 1,005 82 63 Rural 2,682 1,342 536 50 20 2,789 1,953 505 70 18 Total 4,071 2,487 1,467 61 36 4,383 3,268 1,510 75 34 LATIN AMERICA AND THE CARIBBEAN Urban 314 282 262 90 83 348 306 254 88 73 Rural 126 64 42 51 33 125 70 42 56 34 Total 440 346 304 79 69 473 376 296 79 63 The people served with WS in the period 1990 -1994 increased but the effects of high population growth and accelerating urbanisation surpassed facilities development and the coverage values remained the same at global level and became 2% lower in Latin America and the Caribbean (LAC). While changes in the definitions of “adequate” sanitation (WHO, 1996) had an impact (the number of people considered to be covered fell by 31 million at global level), the comparison with WS progress shows that sanitation are being given a lower priority in development programmes. This tendency appears to be stronger in the case of the LAC region. Whereas comparative coverage figures are increasingly being used to report water sector improvements at global, regional, and national levels, they are not easy to analyse since the values presented do not necessarily correspond to the same type of service in each country. For example, the target time or distance necessary to go to collect the water are not reported in a standard way and the target quantities of water per capita to be provided or the type of sanitation facility installed also vary from one country to another. Without standardised 1

  • Page 1 and 2: Development and Evaluation of Multi
  • Page 3 and 4: ACKNOWLEDGEMENTS To my supervisor,
  • Page 5 and 6: ABBREVIATIONS ABNT: Acuavalle: ACV:
  • Page 7 and 8: SOCs: Synthetic Organic Chemicals S
  • Page 9 and 10: u c V V f Vs uniformity coefficient
  • Page 11 and 12: TABLE OF CONTENTS 1. INTRODUCTION 1
  • Page 13: 4 MULTISTAGE FILTRATION EXPERIENCIE
  • Page 17 and 18: Table 1.2 Access to WS&S in Colombi
  • Page 19 and 20: Table 1.5 Safe drinking water cover
  • Page 21 and 22: 1.2 Multiple Barriers Strategy and
  • Page 23 and 24: 2 OVERCOMING THE LIMITATIONS OF SLO
  • Page 25 and 26: adjustment, are among the technolog
  • Page 27 and 28: On January 14, 1829, Simpson’s on
  • Page 29 and 30: With increasing life expectancy, en
  • Page 31 and 32: Table 2.2 Treatments steps recommen
  • Page 33 and 34: In table 2.3, WHO guideline values
  • Page 35 and 36: 2.5 The Slow Sand Filtration Proces
  • Page 37 and 38: When the particles are very close t
  • Page 39 and 40: in which p 0 is the clean media por
  • Page 41 and 42: Yao et al (1971) related the remova
  • Page 43 and 44: compensate for the increase in the
  • Page 45 and 46: can be applied, but intermittent op
  • Page 47 and 48: Table 2.4 Comparison of design crit
  • Page 49 and 50: Although accepted as indirect indic
  • Page 51 and 52: 50% when the temperature falls from
  • Page 53 and 54: Figure 2.9 Flow diagram of the wate
  • Page 55 and 56: ut higher running costs, since more
  • Page 57 and 58: Headloss and flow control. Final he
  • Page 59 and 60: Figure 2.13 Influence of flow condi
  • Page 61 and 62: Operation and maintenance (O & M).
  • Page 63 and 64: 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

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    Models for assessing construction q

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    MSF system can then be calculated o

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    5.7 Cost Model for the Cali Area an

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    Table 5.8. Annual labour costs due

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    5.8 General Discussion The followin

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    systems. The differences between MS

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    guideline for colour is < 15 PCU (W

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    Table 6.1. Individual (at each trea

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    Table 6.3. Individual (at each trea

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    As shown in tables 6.1 and 6.3, col

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    UGFL 0.45 UGFS 0.45 (32;51;85) (44;

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    Table 6.4. An example of identifica

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    MSF technology showed great flexibi

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    In harmony with the new development

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    epresents the risk the community ha

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    The selection of MSF alternatives i

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    scouring and transporting away prev

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    REFERENCES ABNT, (1989) NB-592 Proj

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    Craun, G.F., Bull, R.J., Clark, R.M

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    Drinking Water Disinfection, ed. by

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    Huisman, L. (1989) Plain Sedimentat

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    Mendenhall, W. and Sincich, T. (199

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    Ridley, J.E. (1967) Experience in t

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    Visscher, J.T. and Galvis, G. (1992

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    ANNEXES Annex 1: Accessories for Mu

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    aw water. The red colour is used fo

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    Annex 2: Design of Manifolds Manifo

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    + q 2 Q1 (1.2 qn + qn) (2.2 qn) = =

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    R 1 = (total orifice area / lateral

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    0.30 0.25 0.20 0.15 0.10 0.05 0.00

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    Table A.4-2 General notation for th

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    Box A4-3. Sum of Square Error (SSE)

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    Annex 5: Residence times in coarse

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    Table A5-1 Percentage of incoming w

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    Annex 6 Number and Type of Valves N

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    Table A7-1. Descriptive statistics

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    Tables A7-3 Removal efficiencies of

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    Tables A7-5 Removal efficiencies of

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    Construction quantities of DyGF com

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    Net present value (US$) of MSF and

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