Water Supply Engineering Notes PDF

College of Engineering A’Sharqiyah University Place photo here WATE211 Introduction to Water Quality Chapter 1: Introduction Dr. Motasem Alazaiza Associate Professor Fresh wa...

College of Engineering A’Sharqiyah University Place photo here WATE211 Introduction to Water Quality Chapter 1: Introduction Dr. Motasem Alazaiza Associate Professor Fresh water source Fresh water source Water obtained from reclamation  Thank you DISTRIBUTION OF GLOBAL WATER  Access to safe water Water Distribution System Typical new system pipe Thermoplastic or ductile iron Reinforced concrete in larger mains Older system pipe Cast-iron or asbestos cement Typical distribution pressure of 65 – 75 psi File:Largediapvc.jpg Designed for less than 150 psi  Water Distribution System Consists of water lines, fittings, valves, service lines, meters, and fire hydrants Loop system more desirable than branch system Isolation valves Water flows in more than LOOP BRANCH one direction SYSTEM SYSTEM The hydrological cycle Sun The hydrological cycle The water cycle describes the existence and movement of water on, in, and above the Earth Water Storage Pumped to Storage Tank Storage Water pressure o psi o 1 psi = 2.31 feet of water NOAA http://www.csc.noaa.gov/alternatives/infrastructure.html  Factors to be considered ❖ Quality of water. The analysis of the raw water quality should be made to know the various impurities present in it, and to decide on the required treatment processes. ❖ Treatment works. sizes and number of treatment units ❖ Pumping units for treated water. ❖ Storage. The entire city or town should be divided into several pressure zones and storage facility should be provided in each zone. ❖ Distribution system. The distribution system should be designed according to the master plan of the town, keeping in mind the future development. ❖ Economy and reliability. should be economical and reliable Sources of Water Surface Water Lakes, reservoirs, rivers Rivers dammed to create reservoirs Reservoirs store water during heavy rain/snow  Surface Water Rain water ✓Rain water might contain dust, smoke, bacteria, carbon dioxide… as falling from high altitude. ✓RW Harvesting- roofs are most effective and can be integrated with tanks Factors to be considered ❖ Population. Factors affecting the future increase in the population. ❖ Per capita Requirement. the various factors and living standard and the number and type of industries, number and type of the commercial establishments in the town etc. ❖ Public places, parks, institutions etc. ❖ Industries. existing industries as well as future ❖ Sources of water. Detailed survey. ❖ Conveyance of water. from source to water treatment units depend on the relative levels.  Water supply system planning Water supply system planning involves Identification of service needs Evaluation of options Determination of optimal strategy to meet services development of implementation strategies The planning exercise involves: collection of applicable and relevant data consideration of relevant factors, and preparation of project documents and cost estimates Surface Water Rain water  Surface Water Lakes and reservoirs Store water in wet seasons for usage in dry seasons. It is a standing water; because of this: -Quality is very low: turbidity, bacteria and pollutants -Thermal stratification (i.e. for deep lakes/reservoirs) Water Supply Components: Water Supply Components The system comprises the following major elements: Source(groundwater or surface water) Raw water collection structures (intake structure, transmission line) Treatment plant Distribution systems (pipes, pumps, reservoir, different appurtenances) Surface Water River water A stream or river is a body of running water on the surface of the earth, from higher to lower ground. Their capacity is dependent on minimum flow per day Development of rivers requires : submerged intake structure OR small diversion dams (i.e. for small streams) Surface Water Permanent streams and rivers having adequate flow throughout the year, can be continuously used for water supply The safe yield from a stream/river is its lowest dry weather run-off in a critical year From non perennial sources, excessive flood water are stored in reservoirs for use during dry seasons Construction of an impounding reservoir is necessary to store water sufficient to annual requirement Lakes, and ponds are larger water bodies on earth’s surface, which can serve as water supply for a small town (unsuitable for big city) Water Supply System Objectives Safe and wholesome water Adequate quantity Readily available to encourage personal and household hygiene  Water Supply Planning, design, construction, operation and maintenance of water supply systems. Planning should be economical, socially acceptable, and environmentally friendly that meet the present as well as future requirement. The quality of water is different for a river depending whether it is upstream or downstream Parameter Upstream Downstream General quality Good – not Poor- very polluted affected from WTPs Bacteria content low high Toxic and heavy Not affected As, Pb, etc metals content Colour Due to organic and Highly colored – inorganics construction activity Turbidity Generally clear Turbid due to high SS - rain  Sources of Water Aquifers (Groundwater) Primary source of drinking water Porous consolidated rock or unconsolidated soil Groundwater fills spaces Wells and pumps used to remove water Aquifer This image was reproduced from groundwater.org with the permission of The Groundwater Foundation. © 2010 The Groundwater Foundation. All Rights Reserved Courtesy USGS at http://pubs.usgs.gov/circ/circ1139/htdocs/boxa.htm Lets save Water! The challenges faced by water supply engineer? To maintain the Quality and Quantity of water supply for next generation Groundwater sources Advantages : It is likely to be free of pathogenic bacteria free from turbidity and color It can be used without further treatment It can be found in the close vicinity It is economical to obtain and distribute The water-bearing stratum provides a natural storage at the point of intake. Aquifer also may be called a water-bearing stratum Groundwater sources Disadvantages often have high in mineral content; It usually requires pumping. CATIONS: calcium, sodium, magnesium, iron and manganese ANIONS: bicarbonate, carbonate, and chloride Water Supply Today.. Traditional Water Supply Groundwater The quality – influence by: ❖ Infiltration : leachate from landfills. ❖ Distance : nearer to the sea will be slightly salty. ❖ Type of aquifer : igneous, sedimentary or metamorphic – influence is in term of iron content, hardness and pH. Igneous: rock having solidified from lava or magma Groundwater sources  Introduction: Water Supply Engineering.. http://harrye11.edublogs.org/files/2010/11/image-wshiwq.gif Groundwater sources Gravity springs GW flows over an impervious stratum onto the ground surface The yield varies with the position of the water table May dry up during or immediately after a dry season Gravity overflow spring Gravity depression spring  Groundwater sources Artesian springs High quality water due to confinement High discharge due to high pressure in the confinement Yield is likely uniform and nearly constant over the seasons of the year Introduction: Water Supply Engineering.. Such supply systems did not distribute water to individual residences, but rather brought it to a few central locations from which the citizens could carry it to their homes. Until the mid of 17th century, pipes which could withstand significant pressures were not available Introduction: Water Supply Engineering.. Groundwater sources  Groundwater sources Introduction: Water Supply Engineering.. Provision of an adequate quantity of water has been a matter of concern since the beginning of civilization Even in ancient cities, local supplies were inadequate. Aqueducts were built to convey water from distant sources  Criteria for selecting a source of water supply Distance of source: must be nearby township (save a lot of operation money!) → size and length of pipes, less valves, use gravity, easy routine maintenance Topographical condition: flat, avoid mountainous, hilly, swampy area to save operation cost. Height of water source: must be high contour so that water can flow via gravity force. (Waterfalls… ) Water Treatment Amount of treatment depends on quality of the source. Ground water requires less treatment than surface water Criteria for selecting a source of water supply Quantity ❖ must be sufficient to fulfill the increasing water demand Quality ❖ Harmless. ❖ the sources must be at least can be treated. ❖ the water must be easily treated (not very contaminated)