MODULE 2 - Fundamentals of Water Supply and System.pdf

School of Architecture ADVISOR ABUTILS1 National University Fairview AR. STEPHANIE Y. SABAREZ Plumbing and Sanitary Systems Fundamentals of Wa...

School of Architecture ADVISOR ABUTILS1 National University Fairview AR. STEPHANIE Y. SABAREZ Plumbing and Sanitary Systems Fundamentals of Water Supply and System Sources and uses of water; Physical, chemical and biological properties of water; Water treatment methods; Water storage and distribution systems (Hot and Cold Water)  I Water Supply and Distribution The Water Supply System These are infrastructure for the collection, transmission, treatment, storage, and distribution of water for homes, commercial establishments, industry, and irrigation, as well as for such public needs as firefighting and street flushing. Of all municipal services, provision of potable water is perhaps the most vital. Water supply systems must also meet requirements for public, commercial, and industrial activities. In all cases, the water must fulfill both quality and quantity requirements. I Water Supply and Distribution Historical Background Developments in supply systems Water was an important factor in the location of the earliest settled communities, and the evolution of public water supply systems is tied directly to the growth of cities. In the development of water resources beyond their natural condition in rivers, lakes, and springs, the digging of shallow wells was probably the earliest innovation. As the need for water increased and tools were developed, wells were made deeper. Brick-lined wells were built by city dwellers in the Indus River basin as early as 2500 BCE, and wells almost 500 metres (more than 1,600 feet) deep are known to have been used in ancient China. I Water Supply and Distribution Historical Background Developments in supply systems Construction of qanāts, slightly sloping tunnels driven into hillsides that contained groundwater, probably originated in ancient Persia about 700 BCE. From the hillsides the water was conveyed by gravity in open channels to nearby towns or cities. The use of qanāts became widespread throughout the region, and some are still in existence. Until 1933 the Iranian capital city, Tehrān, drew its entire water supply from a system of qanāts. I Water Supply and Distribution Historical Background Developments in supply systems The need to channel water supplies from distant sources was an outcome of the growth of urban communities. Among the most notable of ancient water-conveyance systems are the aqueducts built between 312 BCE and 455 CE throughout the Roman Empire. Some of these impressive works are still in existence. The writings of Sextus Julius Frontinus (who was appointed superintendent of Roman aqueducts in 97 CE) provide information about the design and construction of the 11 major aqueducts that supplied Rome itself. I Water Supply and Distribution Historical Background Developments in supply systems Extending from a distant spring-fed area, a lake, or a river, a typical Roman aqueduct included a series of underground and aboveground channels. The longest was the Aqua Marcia, built in 144 BCE. Its source was about 37 km from Rome. The aqueduct itself was 92 km long, however, because it had to meander along land contours in order to maintain a steady flow of water. In fact, most of the combined length of the aqueducts supplying Rome (about 420 km ) was built as covered trenches or tunnels. When crossing a valley, aqueducts were supported by arcades comprising one or more levels of massive granite piers and impressive arches. I Water Supply and Distribution Historical Background Developments in supply systems The aqueducts ended in Rome at distribution reservoirs, from which the water was conveyed to public baths or fountains. A few very wealthy or privileged citizens had water piped directly into their homes, but most of the people carried water in containers from a public fountain. Water was running constantly, the excess being used to clean the streets and flush the sewers. I Water Supply and Distribution Historical Background Developments in supply systems Ancient aqueducts and pipelines were not capable of withstanding much pressure. Channels were constructed of cut stone, brick, rubble, or rough concrete. Pipes were typically made of drilled stone or of hollowed wooden logs, although clay and lead pipes were also used. I Water Supply and Distribution Historical Background Developments in supply systems Cast iron pipes with joints capable of withstanding high pressures were not used very much until the early 19th century. The steam engine was first applied to water- pumping operations at about that time, making it possible for all but the smallest communities to have drinking water supplied directly to individual homes. Asbestos cement, ductile iron, reinforced concrete, and steel came into use as materials for water supply pipelines in the 20th century. I Water Supply and Distribution Developments in water treatment In addition to quantity of supply, water quality is also of concern. Even the ancients had an appreciation for the importance of water purity. Sanskrit writings from as early as 2000 BCE tell how to purify foul water by boiling and filtering. But it was not until the middle of the 19th century that a direct link between polluted water and disease (cholera) was proved, and it was not until the end of that same century that the German bacteriologist Robert Koch proved the germ theory of disease, establishing a scientific basis for the treatment and sanitation of drinking water. I Water Supply and Distribution Developments in water treatment Water treatment is the alteration of a water source in order to achieve a quality that meets specified goals. At the end of the 19th century and the beginning of the 20th, the main goal was elimination of deadly waterborne diseases. The treatment of public drinking water to remove pathogenic, or disease-causing, microorganisms began about that time. Treatment methods included sand filtration as well as the use of chlorine for disinfection. The virtual elimination of diseases such as cholera and typhoid in developed countries proved the success of this water-treatment technology. In developing countries, waterborne disease is still the principal water quality concern. I Water Supply and Distribution Developments in water treatment In industrialized countries, concern has shifted to the chronic health effects related to chemical contamination. For example, trace amounts of certain synthetic organic substances in drinking water are suspected of causing cancer in humans. Lead in drinking water, usually leached from corroded lead pipes, can result in gradual lead poisoning and may cause developmental delays in children. The added goal of reducing such health risks is seen in the continually increasing number of factors included in drinking-water standards. I Water Supply and Distribution Water Sources GLOBAL DISTRIBUTION Water is present in abundant quantities on and under Earth’s surface, but less than 1 percent of it is liquid fresh water. Most of Earth’s estimated 1.4 billion cubic km (326 million cubic miles) of water is in the oceans or frozen in polar ice caps and glaciers. Ocean water contains about 35 grams per litre (4.5 ounces per gallon) of dissolved minerals or salts, making it unfit for drinking and for most industrial or agricultural uses. I Water Supply and Distribution Water Sources GLOBAL DISTRIBUTION There is ample fresh water—water containing less than 3 grams of salts per litre, or less than one-eighth ounce of salts per gallon—to satisfy all human needs. It is not always available, though, at the times and places it is needed, and it is not uniformly distributed over the globe, sometimes resulting in water scarcity for susceptible communities. In many locations the availability of good-quality water is further reduced because of urban development, industrial growth, and environmental pollution. I Water Supply and Distribution Water Sources SURFACE WATER AND GROUNDWATER Surface water and groundwater are both important sources for community water supply needs. Groundwater is a common source for single homes and small towns, and rivers and lakes are the usual sources for large cities. Although approximately 98 percent of liquid fresh water exists as groundwater, much of it occurs very deep. This makes pumping very expensive, preventing the full development and use of all groundwater resources. I Water Supply and Distribution Water Sources SURFACE WATER SOURCES The total land area that contributes surface runoff to a river or lake is called a watershed, drainage basin, or catchment area. The volume of water available for municipal supply depends mostly on the amount of rainfall. It also depends on the size of the watershed, the slope of the ground, the type of soil and vegetation, and the type of land use. I Water Supply and Distribution Water Sources SURFACE WATER SOURCES The flow rate or discharge of a river varies with time. Higher flow rates typically occur in the spring, and lower flow rates occur in the winter, though this is often not the case in areas with monsoon systems. When the average discharge of a river is not enough for a dependable supply of water, a conservation reservoir may be built. The flow of water is blocked by a dam, allowing an artificial lake to be formed. Conservation reservoirs store water from wet weather periods for use during times of drought and low streamflow. I Water Supply and Distribution Water Sources SURFACE WATER SOURCES A water intake structure is built within the reservoir, with inlet ports and valves at several depths. Since the quality of water in a reservoir varies seasonally with depth, a multilevel intake allows water of best quality to be withdrawn. Sometimes it is advisable, for economic reasons, to provide a multipurpose reservoir. A multipurpose reservoir is designed to satisfy a combination of community water needs. In addition to drinking water, the reservoir may also provide flood control, hydroelectric power, and recreation. I Water Supply and Distribution Water Sources TYPES OF SURFACE WATER STREAMS RIVERS LAKES I Water Supply and Distribution Water Sources TYPES OF SURFACE WATER WETLANDS RESERVOIRS CREEKS I Water Supply and Distribution Water Sources GROUNDWATER SOURCES The value of an aquifer as a source of groundwater is a function of the porosity of the geologic stratum, or layer, of which it is formed. Water is withdrawn from an aquifer by pumping it out of a well or infiltration gallery. An infiltration gallery typically includes several horizontal perforated pipes radiating outward from the bottom of a large-diameter vertical shaft. Wells are constructed in several ways, depending on the depth and nature of the aquifer. I Water Supply and Distribution Water Sources GROUNDWATER SOURCES Wells used for public water supplies, usually more than 30 metres deep and from 10 to 30 cm in diameter, must penetrate large aquifers that can provide dependable yields of good-quality water. They are drilled using impact or rotary techniques and are usually lined with a metal pipe or casing to prevent contamination. The annular space around the outside of the upper portion of the casing is filled with cement grout, and a special sanitary seal is installed at the top to provide further protection. At the bottom of the casing, a slotted screen is attached to strain silt and sand out of the groundwater. I Water Supply and Distribution Water Sources GROUNDWATER SOURCES A submersible pump driven by an electric motor can be used to raise the water to the surface. Sometimes a deep well may penetrate a confined artesian aquifer, in which case natural hydrostatic pressure can raise the water to the surface. I Water Supply and Distribution Water Requirements DRINKING WATER QUALITY Water has a strong tendency to dissolve other substances that it is rarely found in nature in a pure condition. When it falls as rain, small amounts of gases such as oxygen and carbon dioxide become dissolved in it; raindrops also carry tiny dust particles and other substances. As it flows over the ground, water picks up fine soil particles, microbes, organic material, and soluble minerals. In lakes, bogs, and swamps, water may gain colour, taste, and odour from decaying vegetation and other natural organic matter. I Water Supply and Distribution Water Requirements DRINKING WATER QUALITY Groundwater usually acquires more dissolved minerals than does surface runoff because of its longer direct contact with soil and rock. It may also absorb gases such as hydrogen sulfide and methane. In populated areas the quality of surface water as well as groundwater is directly influenced by land use and by human activities. I Water Supply and Distribution Water Requirements HEALTH CONCERNS Five general types of impurities are of public health concern. These are organic chemicals, inorganic chemicals, turbidity, microorganisms, and radioactive substances. Organic contaminants include various pesticides, industrial solvents, and trihalomethanes such as chloroform. Inorganic contaminants of major concern include arsenic, nitrate, fluoride, and toxic metals such as lead and mercury. A low concentration of fluoride, however, has been proved to promote dental health. Some communities add fluoride to their water for this purpose. I Water Supply and Distribution Water Requirements AESTHETIC CONCERNS Colour, taste, and odour are physical characteristics of drinking water that are important for aesthetic reasons rather than for health reasons. Colour in water may be caused by decaying leaves or by algae, giving it a brownish yellow hue. Taste and odour may be caused by naturally occurring dissolved organics or gases. I Water Supply and Distribution Water Requirements HARDNESS This is a term used to describe the effect of dissolved minerals (mostly calcium and magnesium). Minerals cause deposits of scale in hot water pipes, and they also interfere with the lathering action of soap. Hard water does not harm human health, but the economic problems it causes make it objectionable to most people. I Water Supply and Distribution Water Requirements STANDARDS Water quality standards set limits on the concentrations of impurities allowed in water. Standards also affect the selection of raw water sources and the choice of treatment processes. Modern testing methods now allow the detection of contaminants in extremely low concentrations—as low as one part contaminant per one billion parts water or even, in some cases, per one trillion parts water. Water quality standards are continually evolving, usually becoming more stringent. I Water Supply and Distribution Water Requirements STANDARDS Drinking-water regulations in the United States include two types of standards: primary and secondary. Primary standards are designed to protect public health, whereas secondary standards are based on aesthetic factors rather than on health effects. Secondary standards are guidelines or suggested maximum levels of colour, taste, odour, hardness, corrosiveness, and certain other factors. I Water Supply and Distribution Water Treatment The primary objective of water treatment is to protect the health of the community. Potable water must, of course, be free of harmful microorganisms and chemicals, but public supplies should also be aesthetically desirable so that consumers will not be tempted to use water from another, more attractive but unprotected source. The water should be crystal clear, with almost no turbidity, and it should be free of objectionable colour, odour, and taste. I Water Supply and Distribution Water Treatment Water is treated in a variety of physical and chemical methods. Treatment of surface water begins with intake screens to prevent fish and debris from entering the plant and damaging pumps and other components. Conventional treatment of water primarily involves clarification and disinfection. I Water Supply and Distribution Water Treatment Sedimentation Impurities in water are either dissolved or suspended. The suspended material reduces clarity, and the easiest way to remove it is to rely on gravity. Under quiescent conditions, suspended particles that are denser than water gradually settle to the bottom of a basin or tank. In a treatment plant, sedimentation (settling) tanks are built to provide a few hours of storage or detention time as the water slowly flows from tank inlet to outlet. I Water Supply and Distribution Water Treatment Coagulation and flocculation Suspended particles cannot be removed completely by plain settling. Large, heavy particles settle out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all. Because of this, the sedimentation step is usually preceded by a chemical process known as coagulation. Chemicals (coagulants) are added to the water to bring the nonsettling particles together into larger, heavier masses of solids called floc. Aluminum sulfate (alum) is the most common coagulant used for water purification. I Water Supply and Distribution Water Treatment Coagulation and flocculation Coagulation is usually accomplished in two stages: rapid mixing and slow mixing. Rapid mixing serves to disperse the coagulants evenly throughout the water and to ensure a complete chemical reaction. Usually, a small flash-mix tank provides about one minute of detention time. After the flash mix, a longer period of gentle agitation is needed to promote particle collisions and enhance the growth of floc. This gentle agitation, or slow mixing, is called flocculation; I Water Supply and Distribution Water Treatment Filtration Filtration is a physical process that removes impurities from water by percolating it downward through a layer or bed of porous, granular material such as sand. Suspended particles become trapped within the pore spaces of the filter media, which also remove harmful protozoa and natural colour. Most surface water supplies require filtration after the coagulation and sedimentation steps. For surface waters with low turbidity and colour, however, a process of direct filtration, which is not preceded by sedimentation, may be used. I Water Supply and Distribution Water Treatment Disinfection Disinfection destroys pathogenic bacteria and is essential to prevent the spread of waterborne disease. Typically the final process in drinking-water treatment, it is accomplished by applying either chlorine or chlorine compounds, ozone, or ultraviolet radiation to clarified water. I Water Supply and Distribution Water Treatment CHLORINATION The addition of chlorine or chlorine compounds to drinking water is called chlorination. Chlorine compounds may be applied in liquid and solid forms—for instance, liquid sodium hypochlorite or calcium hypochlorite in tablet or granular form. However, the direct application of gaseous chlorine from pressurized steel containers is usually the most economical method for disinfecting large volumes of water. I Water Supply and Distribution Water Treatment OZONE Ozone gas may be used for disinfection of drinking water. However, since ozone is unstable, it cannot be stored and must be produced on-site, making the process more expensive than chlorination. Ozone has the advantage of not causing taste or odour problems; it leaves no residual in the disinfected water. The lack of an ozone residual, however, makes it difficult to monitor its continued effectiveness as water flows through the distribution system. I Water Supply and Distribution Water Treatment ULTRAVIOLET RADIATION Ultraviolet radiation destroys pathogens, and its use as a disinfecting agent eliminates the need to handle chemicals. It leaves no residual, and it does not cause taste or odour problems. But the high cost of its application makes it a poor competitor with either chlorine or ozone as a disinfectant. I Water Supply and Distribution Additional Water Treatment MEMBRANE FILTRATION Several types of synthetic semipermeable membranes can be used to block the flow of particles and molecules while allowing smaller water molecules to pass through under the effect of hydrostatic pressure. They can provide increased assurances of safe drinking water because the microbial contaminants (viruses, bacteria, and protozoa) can be completely removed by a physical barrier. I Water Supply and Distribution Additional Water Treatment WATER SOFTENING Softening is the process of removing the dissolved calcium and magnesium salts that cause hardness in water. It is achieved either by adding chemicals that form insoluble precipitates or by ion exchange. I Water Supply and Distribution Additional Water Treatment AERATION Aeration is a physical treatment process used for taste and odour control and for removal of dissolved iron and manganese. It consists of spraying water into the air or cascading it downward through stacks of perforated trays. Dissolved gases that cause tastes and odours are transferred from the water to the air. I Water Supply and Distribution Additional Water Treatment CARBON ADSORPTION An effective method for removing dissolved organic substances that cause tastes, odours, or colours is adsorption by activated carbon. Adsorption is the capacity of a solid particle to attract molecules to its surface. Powdered carbon mixed with water can adsorb and hold many different organic impurities. When the carbon is saturated with impurities, it is cleaned or reactivated by heating to a high temperature in a special furnace. I Water Supply and Distribution Additional Water Treatment FLUORIDATION Many communities reduce the incidence of tooth decay in young children by adding sodium fluoride or other fluorine compounds to filtered water. The dosage of fluoride must be carefully controlled. Low concentrations are beneficial and cause no harmful side effects, but very high concentrations of fluoride may cause discoloration of tooth enamel. I Water Supply and Distribution Additional Water Treatment DESALINATION Desalination, or desalting, is the separation of fresh water from salt water or brackish water. Desalted water is the main source of municipal supply in areas of the Caribbean, the Middle East, and North Africa, and its use is increasing in the southeastern United States. There are two basic types of desalting techniques: thermal processes and membrane processes. Thermal methods involve heat transfer and a phase change of the water from liquid into vapour or ice. Membrane methods use very thin sheets of special plastic that act as selective barriers, allowing pure water to be separated from the salt. I Water Supply and Distribution Thermal Processes DISTILLATION a thermal process that includes heating, evaporation, and condensation, is the oldest and most widely used of desalination technologies. Modern methods for the distillation of large quantities of salt water rely on the fact that the boiling temperature of water is lowered as air pressure drops, significantly reducing the amount of energy needed to vaporize the water. Systems that utilize this principle include multistage flash distillation, multiple-effect distillation, and vapour-compression distillation. I Water Supply and Distribution Thermal Processes SOLAR HUMIDIFICATION Salt water is collected in shallow basins in a “still,” a structure similar to a greenhouse. The water is warmed as sunlight enters through inclined glass or plastic covers. Water vapour rises, condenses on the cooler covers, and trickles down to a collecting trough. Thermal energy from the sun is free, but a solar still is expensive to build, requires a large land area, and needs additional energy for pumping water to and from the facility. Solar humidification units are suitable for providing desalted water to individual families or for very small villages where sunlight is abundant. I Water Supply and Distribution Water Distribution System A water distribution system is a network of pumps, pipelines, storage tanks, and other appurtenances. It must deliver adequate quantities of water at pressures sufficient for operating plumbing fixtures and firefighting equipment, yet it must not deliver water at pressures high enough to increase the occurrence of leaks and pipeline breaks. Pressure-regulating valves may be installed to reduce pressure levels in low-lying service areas. I Water Supply and Distribution Water Distribution System A water distribution system is a network of pumps, pipelines, storage tanks, and other appurtenances. It must deliver adequate quantities of water at pressures sufficient for operating plumbing fixtures and firefighting equipment, yet it must not deliver water at pressures high enough to increase the occurrence of leaks and pipeline breaks. Pressure-regulating valves may be installed to reduce pressure levels in low-lying service areas. I Water Supply and Distribution Water Distribution System A water distribution system is a network of pumps, pipelines, storage tanks, and other appurtenances. It must deliver adequate quantities of water at pressures sufficient for operating plumbing fixtures and firefighting equipment, yet it must not deliver water at pressures high enough to increase the occurrence of leaks and pipeline breaks. Pressure-regulating valves may be installed to reduce pressure levels in low-lying service areas. I Water Supply and Distribution Design Principles of Water Distribution System 1. The distribution system must be capable of supplying water to all the water required areas with sufficient pressure heads. 2. It should be designed in such a way; the water supply must not be disturbed while carrying out any repair or maintenance work in any section of the system. 3. It must be capable of supplying the required amount of water during firefighting. 4. The system must be water-tight to reduce leakage chances. 5. The quality of water must not be compromised in the distribution pipes. 6. The distribution pipe must be laid one meter away or above the sewer lines. 7. Factors like water pressure, initial capital cost, and maintenance and operational cost must consider while designing. I Water Supply and Distribution Types of Water Distribution System DEAD END SYSTEM In this type of water distribution system, many sub-main pipelines are connected to a single main pipeline that runs along the center of the building. Dead end water distribution system is also known as the Tree system. The sub-main pipelines are further divided from both sides into branches that connect various service areas of the building. This system is most suitable for unsystematic areas like old towns and cities with definite patterns of roads. I Water Supply and Distribution Types of Water Distribution System ADVANTAGES This system is cost-effective Pipe laying is easy, no skilled laborers are required Determination of discharge and pressure quantity can be done easily due to a smaller number of valves. DISADVANTAGES The chances of Stagnation of water in pipes are high due to many dead ends. The pipes should have a large diameter and longer length due to high circulating flow from all directions. The available water pressure is low, so a pumping system is required to meet the supply pressure requirement. Because of high head loss in the system, the discharge availability for firefighting is very limited. High risk, Due to only one main water supply pipeline to the entire building. I Water Supply and Distribution Types of Water Distribution System RADIAL SYSTEM In a radial system, the area is divided into various zones. The main water supply pipeline is connected to the distribution reservoir or storage tank which is kept in the middle of each zone. Then supply pipes are laid radially (as shown in the figure) from the distribution reservoir to households. I Water Supply and Distribution Types of Water Distribution System ADVANTAGES This type of water distribution is most suitable for high-rise buildings. Disruption of water supply during any maintenance or repair work is very low. The radial system supplies water with high discharge and with minimum head loss. This system offers quick service. DISADVANTAGES It is not economical as the number of distribution reservoirs is more. Due to more connections, this system requires more length of pipe laying system. I Water Supply and Distribution Types of Water Distribution System GRID-IRON SYSTEM In a grid-iron system, the main pipeline, Sub main pipeline, and branch pipelines are interconnected to each other in the form of a grid system. A Grid-iron water distribution system is also known as an interlaced system or reticulation system. The requirement of the total length of the pipeline is more due to more connections and it helps to maintain water pressure evenly. A Grid-iron water distribution system is best suited for modern well-planned cities as the water main pipeline and branches are laid in a rectangle layout. I Water Supply and Distribution Types of Water Distribution System ADVANTAGES Due to no dead ends water is continuously flowing through pipelines. Maintenance and repair work can be carried without out disrupting water flow. This water distribution system provides the required discharge quantity for firefighting. There is a minimum head loss because of the interconnection of pipes. DISADVANTAGES In the grid-iron system, the requirement for cut-off valves is high. It is not cost-effective due to more requirements of pipe length for laying. This system requires longer pipe lengths with a larger diameter. I Water Supply and Distribution Types of Water Distribution System RING DISTRIBUTION SYSTEM In this water distribution system, the whole system is enclosed by the main pipeline in a radial or rectangular shape. As you can see in the above fig. smaller areas are enclosed by the sub-main pipeline. In case of any failure of one system, a very small area will be affected. The area ahead of the affected area can get water from other system points. The ring distribution system requires a higher number of valves. In this system, water can be supplied to any point from two directions. I Water Supply and Distribution Types of Water Distribution System ADVANTAGES The discharge rate is high when compared to other distribution methods. Maintenance and repair work can be carried without out disrupting water flow. Due to a smaller number of interconnections, the head loss is minimum. Due to no endpoints, stagnation of water is minimal or zero. DISADVANTAGES It is not cost-effective, because the requirement of pipe length for laying is more. The requirement for cut-off valves is more. This system requires skilled laborers for laying pipelines. I Water Supply and Distribution Methods of Water Distribution System For an efficient distribution system, adequate water pressure is required in various points. Depending on the level of source, topography of the area, and other local conditions, the water may be forced into distribution systems in the following ways: 1. GRAVITY SYSTEM 2. PUMPING SYSTEM 3. COMBINED GRAVITY AND PUMPING SYSTEM I Water Supply and Distribution Methods of Water Distribution System For an efficient distribution system, adequate water pressure is required in various points. Depending on the level of source, topography of the area, and other local conditions, the water may be forced into distribution systems in the following ways: 1. GRAVITY SYSTEM 2. PUMPING SYSTEM 3. COMBINED GRAVITY AND PUMPING SYSTEM I Water Supply and Distribution Methods of Water Distribution System GRAVITY SYSTEM Suitable when source of supply is sufficient in height Most reliable and economical distribution system The water head required for the consumers is just minimum required. The remaining water head is consumed by surface friction and other losses I Water Supply and Distribution Methods of Water Distribution System PUMPING SYSTEM In the pumping water distribution system, water is supplied to the consumers with the help of pumps. Some extra pumps are also installed for emergency causes like fire hazards, peak water demand, etc. This method is suitable if the source is at a lower elevation than the target community. I Water Supply and Distribution Methods of Water Distribution System COMBINED GRAVITY AND PUMPING SYSTEM Combined Gravity and Pumping Water Distribution System is a combination of a gravity system and a pumping system. In this system, the treated water is pumped and stored in an elevated reservoir, from where it is supplied to the consumer by the action of gravity. I Water Supply and Distribution Distribution Reservoirs I Water Supply and Distribution Distribution Reservoirs I Water Supply and Distribution Distribution Reservoirs I Water Supply and Distribution Types of Reservoir Surface Reservoir Surface reservoirs are built structures for water storage that help improve water security for local communities. The types and sizes of reservoirs vary, from damming natural water bodies for storage to ground excavation in low-lying plains fed either by rainwater or diverted rivers. I Water Supply and Distribution Types of Reservoir Elevated Reservoir An elevated reservoir stores clean water in a steel tank on a raised stand or tower. The elevation of the tank provides the water pressure to all points in the pressure zone of the distribution system. Tanks may be cylindrical, rectangular or any other convenient shape I Water Supply and Distribution Types of Tanks REINFORCED CONCRETE CEMENT (RCC) TANKS RCC water tanks are constructed for storing water. The tanks can be made of reinforced concrete or even of steel. The overhead tanks (elevated tanks) are usually elevated from the rooftop through column. On the other hand the underground tanks are rested on the foundation. I Water Supply and Distribution Types of Tanks GALVANIZED IRON (GI) TANKS Galvanized tanks are an economical way of storing liquids and are primarily used for the storage of oil and gas, fire water, industrial liquids, potable water and wastewater applications. I Water Supply and Distribution Types of Tanks HIGH DENSITY POLYETHELENE (HDPE) TANKS Polyethylene storage tanks are rotationally molded from high density linear polyethylene (HDPE) or high density cross linked polyethylene (XLPE). Rotationally molded plastic tanks have increased structural integrity and durability against impact, puncture, or tears. They are also resistant to rust and corrosion. School of Architecture ADVISOR ABUTILS1 National University Fairview AR. STEPHANIE Y. SABAREZ Plumbing and Sanitary Systems Good day! Fundamentals of Water Supply and System REQUIRED ADDITIONAL READINGS FOR THE CLASS: Chapter 6 of The Revised National Plumbing Code of the Philippines