WATER SUPPLY Fifth Edition Alan C. Twort

725 Pages·2007·60.35 MB·English

WATER SUPPLY
Fifth Edition
This Page Intentionally Left Blank
WATER SUPPLY
Fifth Edition
Alan C. Twort
BSc, FICE, FCIWEM
Don D. Ratnayaka
BSc, DIC, MSc, FIChem E, FClWEM
Malcolm J. Brandt
BSc, MICE, MCIWEM
L~E 1 N E M A N N
Publishing
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Contents
Preface ix
Contributing authors, reviewers and advisors xi
Abbreviations used in bibliographies xiii
Public water supply requirement and its measurement 1
Consumption categories- difficulties of measuring household consump-
tion - components of domestic demand - fittings usage - standpipe
demand -industrial, commercial and agricultural demand - supply meter
accuracies - amount of leakage and wastage - distribution losses - price
elasticity of demand- growth trends- demand constraint measures- peak
consumption rates.
The organisation and financing of public water supplies. 36
,
Control of public supplies - privatisation in UK- role of Director General of
Water Services - the UK Environment Agency- pollution control measures
- public water supplies in USA- functions of USEPA- private sector
participation- organisation and staffing of undertakings- charging for
water- financing of capital works - depreciation and asset managment -
short- and long-term marginal costing - UK water prices.
Hydrology and surface supplies
11
Part I- Hydrological considerations. 63
Catchment areas- streamflow and rainfall measurement- evaporation and
transpiration - soil moisture measurement- catchment losses- stream-
flow naturalisation - minimum and maximum rainfalls and runoffs - flood
estimation methods.
Part II- Yield of surface sources. 87
Definitions of 'yield'- aspects of yield failure risk- river intake yields - use
of probability paper- direct supply impounding reservoir .yields- yield
failure risk by probability methods- pumped storage yields - producing
design drought daily flows - regulating reservoir yield - catchwater yields -
conjunctive use and operating rules - computer modelling - rainwater
collecting systems.
vi Contents
Groundwater supplies 114
11
Aquifer sources - yield uncertainties - potential yield of an aquifer-
assessing aquifer characteristics- recharge assessment- use of Jacob's
equation - groundwater modelling - test pumping - geophysical and other
investigation methods- borehole linings and gravel packs - borehole
construction and development- pollution prevention- artificial recharge-
island water supplies - collector wells - borehole and well layouts.
Dams, impounding reservoirs and river intakes 152
|
Essential reservoir conditions- historic dam failures- design of overflow
and outlet works- estimating probable maximum flood- spillway flood
routing- drawoff arrangements- earth dam design- gravity dams of
concrete and masonry- uplift problems- arch dams- buttress, rockfill and
composite dams - seismic considerations - statutory controls - dam
deterioration signs - reservoir sedimentation - fish passes - river intakes.
Chemistry, microbiology and biology of water
9
Part I- Significant chemicals and physico-chemical parameters in water 197
Key substances in water and water quality parameters- their derivation,
incidence and implications.
Part II- Water quality standards for chemical and physical parameters 221
WHO, EC, UK and USEAP Drinking water standards- comment on their
application - classification of raw waters - sampling frequencies - priorities
in testing - methods to be used - UK standards for waterworks materials.
Part III- Water microbiology 240
Waterborne bacterial diseases--cholera, typhoid, dysentery, Legionnaire's
disease - protozoal diseases - amoebic dysentery, Cryptosporidiosis,
Giardiasis - viral diseases. Use of coliforms for testing - bacteriological
standards- tests for total and faecal coliforms- frequency of sampling-
test kits - protozoai and virological examinations - nuisance organisms.
Part IV- Water biology 254
Range of living organisms found in natural waters - algae growth and types
-eutrophication effect- problems created in pipelines, treatment works
and distribution system.
Part V- New and emerging issues. 260
Substances and microbiological aspects subject to further evaluation, e.g.
MTBE, perchlorate, endocrine disrupters, BSE; and aeromonas, arcobac-
ter, enterovirulent E.Coli and other viruses.
Storage, clarification and filtration of water
11
Part 1 - Storage, screening, sedimentation and clarification 267
Raw water storage- screening - sedimentation and settling tanks -
chemically assisted clarification- clarifier design- dissolved air flotation-
sludge removal- chemical dosing equipment and layout- coagulants and
coagulant aids.
Part II- Water filtration methods and sludge disposal. 317
Rapid filters- design and operation- multilayer filtration- use of anthracite
media - granular activated carbon - upward flow filtration - membrane
Contents vii
filtration - slow sand filtration -cryptosporidium oocysts and giardia cysts
removal- disposal of sludge from treatment works.
11 Specialised and advanced water treatment processes 370
Softening of water- demineralisation -iron and manganese removal-
arsenic, lead and aluminium removal- defluoridation and fluoridation-
aeration methods - nitrate and ammonia removal by ion exchange,
biological or membrane processes- removal of VOC compounds by
packed tower aerators, GAC or chemical oxidation- taste and odour
removal- micropollutants removal- advanced oxidation processes -
corrosion causes and prevention- desalination- removal of radionuclides.
el Disinfection of water 429
Chlorine and chloramine processes of disinfection -chlorine compounds
produced - disinfection efficiency and contact time requirements -
production of trihaiomethanes - breakpoint and superchlorination -
chlorine-ammonia application- chlorine production plant and application
- hypochlorite production by electrolysis - chlorine dioxide use - calcium
hypochlorite powder- disinfection by ozone- ozone production plant-
disinfection by UV radiation - disinfection of water mains and tanks -
control of aftergrowth in mains.
10. Hydraulics 463
Energy equation of flow- boundary layer effect - Colebrook-White pipe
flow formula - empirical formulae Hazen and Manning's - fittings loss -
open channel flow critical depth of flow- weirs, flumes and gates - non-
uniform flow- measurement weirs - measurement flumes - venturi and
orifice meters - other flow meters.
11. Service reservoirs 499
Functions and capacity required- economic shape and depth- covering
and protecting - structural design of jointed and monolithic reservoirs-
drainage and waterproofing - access and protection - pipework- testing
for watertightness - searching for leaks - ventilation and instrumentation
requirements - water towers.
12. Pumping plant: electrical, control and instrumentation systems 522
Types of centrifugal pumps - characteristics - specific speed - axial flow
pumps - reciprocating pumps - electric motor drives - the AC induction
motor- starting methods - motor protection - speed control devices -
boosting flow or pressure - plant layouts - water hammer protection -
suction design and cavitation- efficiencies and fuel consumptions-
thermodynamic monitoring of performance- instrumentation and control
systems.
13. Pipes, pipeline construction and valves 559
Types of pipes and standard setting organisations- ductile iron pipes and
joints - steel pipes - internal and external protection - cathodic protection -
polyethylene pipes- PVC pipes- glass reinforced plastic pipes- concrete
pipes - asbestos cement pipes - choice of pipes - pipeline construction
viii Contents
and testing - submarine pipelines - sluice and butterfly valves- flow or
pressure control valves -jet dispersers - air valve and washout
requirements.
14. Pipeline and distribution system design and analysis 613
Functional classification of pipelines - asset management requirements for
pipelines- levels of service- economics of pumping main design- gravity
main design - break pressure tank - pipeline route planning - distribution
system characteristics- design of networks and feed mains- computer
modelling of distribution system and network flows - modelling of water
quality through distribution system.
15. Distribution practice 638
Distribution organisation - fire demand requirements - service pipe
materials in use- lead being replaced- copper, steel, PVC, polyethylene
- supply meter types, semi-positive and inferential- domestic flow rates
for service pipes - fittings headlosses - Regulation requirements -
distribution system maintenance and checking performance- mains
cleaning, relining, replacing- leakage levels experienced- active leakage
control- measurement of field flows -leak location and repair-
rehabilitation of systems in disrepair with intermittent supplies.
Conversion factors 667
Index 669
Preface
A number of key specialists in the water industry have contributed to the production of
this fifth edition of Water Supply and as a result most chapters have been re-written,
extended and updated.
The text gives up-to-date national and international standards for drinking water
quality set by the UK and EC regulatory bodies plus the World Health Organization and
the US Environmental Protection Agency. It describes the incidence and significance of
the main chemical constituents found in raw waters, and the types of bacteria, viruses and
protozoan organisms which present a hazard to human health. New matters of concern
with respect to chemical and microbiological contaminants are listed. The design is given
of treatment works and the equipment used for chemical coagulation, clarification
methods including dissolved air flotation, rapid gravity filtration, slow sand filtration and
membrane filtration. Sludge disposal methods are presented with design parameters and
tables of relevant data.
The new 1999 UK regulations with respect to monitoring for cryptosporidium oocysts
are given, and treatment practices recommended to reduce the risk of oocysts passing into
supply are described.
Advanced and specialised treatments are described for iron, arsenic and manganese
removal, plumbosolvency control, defluoridation and fluoridation, nitrate and ammonia
removal. Taste and odour causes and removal; and reduction of volatile organic
compounds and micropollutants by use of granular activated carbon (GAC) and advanced
oxidation processes are dealt with. Further material is added on desalination by ion
exchange, electrodialysis, reverse osmosis and thermal processes.
The new approach to the management of distribution systems is described. Zoning of
supplies, telemetered monitoring of district flows, computer modelling of flows and water
quality modelling, together with geographic information systems are increasingly being
used to provide data on system performance, levels of service to consumers and the
condition of assets for the development of asset management plans. Methods of
rehabilitating pipelines are discussed. An extended chapter on pipes and pipelines gives
additional information on the design of steel, polyethylene and PVC pipes according to
numerous international and in-country standards.
Material on the yield of sources has been remodelled to emphasize the important role
played by underground water supplies throughout the world. New approaches to
definitions of 'yield' are discussed; and reference is directed to the new Flood Estimation
Handbook 1999 for estimating flood magnitudes.
Experience with privatization of the water industry in England and Wales is reported
together with a consideration of the growth of private sector participation in public water
supply overseas. Levels of staffing of waterworks undertakings in UK and other countries