Basics Course. Montana. Introduction to Drinking Water Systems. for small public drinking water systems serving less than 3,300 people

Transcription

1 Basics Course for small public drinking water systems serving less than 3,300 people Montana Montana Basics Course for Small Public Drinking Water Systems -1

2 Introduction to Drinking Water Systems Welcome to Lesson 1: Introduction to Drinking Water Systems! To operate a public water system, you need to understand the fundamentals of water. This lesson will introduce you to the characteristics, sources, and classification of water. What is Water? What is Water?... Is a brief discussion of water and its important properties. Basic Definition of Water Water is the most abundant and common material on Earth. It covers 70% of the surface of the Earth as water and ice. Water is the life blood of the world. Without water there could be no life. 2 - Montana Basics Course for Small Public Drinking Water Systems

3 Water Content in the Human Body Our bodies also contain 70% water. Water carries nutrition throughout our bodies and rids us of waste. Without drinking water for four to seven days our blood becomes thick and contains a high concentration of toxic waste materials. We become delirious and unable to function. Death is not far behind. Universal Solvent Water is often called the UNIVERSAL SOLVENT. Given enough time it will dissolve almost everything that it comes in contact with. Dissolved Minerals As water flows through gravels, fissures, and sands in the Earth s crust and flows over the top of the ground it picks up minerals, microorganisms, dirt and bits of plants. Some of these materials are carried along by the water due to its speed. Others, such as minerals are dissolved in the water. Montana Basics Course for Small Public Drinking Water Systems -3

4 Dissolved Gases Water, like many other fluids, also has the ability to dissolve gases, such as oxygen (02) and carbon dioxide (CO2). Water as a Chemical The water molecule is composed of one atom of oxygen and two atoms of hydrogen. This molecule is given the chemical symbol H2O (H2 for two hydrogen atoms and O for one oxygen atom). Notice that the two hydrogen atoms are at one end of the molecule. The hydrogen atoms are positively charged. The Water Molecule When the hydrogen atoms attach to the oxygen molecule the whole molecule effectively becomes polarized with negative and positive poles, much like a battery or a magnet. Because it has both negative and positive charges, it is much easier for it to attract other material. This is one of the reasons it is the Universal Solvent. 4 - Montana Basics Course for Small Public Drinking Water Systems

5 States of Water A unique property of water is that it is the only material found on Earth as a solid, a liquid, and as a gas at standard temperatures. Water Molecules in Motion The water molecule, like other molecules, is in constant motion. The rate of this motion is directly related to the temperature of the water. As the temperature is reduced, the rate of movement of the water molecules slows and the molecules get closer and closer together. The water molecule moves slowest when the water is in the form of ice, and fastest when the water is a vapor. Water at 4 C At 4 C water molecules are as close together as they are ever going to be. The volume that a set amount of water occupies is at a minimum at this point. Montana Basics Course for Small Public Drinking Water Systems -5

6 Introduction to Drinking Water Systems Water Below 4 C Below 4 C (39 F), the molecules are moving so slowly that their electrical charges begin to cause the molecules to line up in a pattern and form crystals. Water at 0 C At 0 C (32 F) and below, water crystals are fully formed. This crystal formation allows the molecules to line up so that they occupy a greater space than they did before freezing. This expansion is what causes water to break a bottle or pipe when it is frozen. Temperature Related Properties of Water Explore the temperature-related properties of water by adjusting the slider to each temperature set-point. 6 - Montana Basics Course for Small Public Drinking Water Systems

7 Where is Water? Where is Water?...summarizes water sources and the distribution of water nationally and statewide. Water Sources The sources of water on Earth are divided into two categories; surface water and groundwater. Surface Water Surface water is water that is found in the oceans, lakes, streams, springs, and ponds. This is the source of drinking water for some of our largest communities. Surface water is exposed to the atmosphere and is affected by ambient conditions. Montana Basics Course for Small Public Drinking Water Systems -7

8 Groundwater Groundwater is the water below the Earth s surface. Hydrologic Cycle How It Works The amount of water in the atmosphere, lithosphere, and hydrosphere remains constant. This water is continually recycled by the action of plants and the sun. Let s follow a drop of precipitation through the hydrologic cycle to learn about the process. Hydrologic Cycle - Precipitation Precipitation in the form of rain, snow, or sleet falls toward the Earth. As the precipitation falls toward the Earth it can pick up contamination in the form of minerals and toxic materials from industrial air pollution and natural pollution such as dust from a volcanic eruption. 8 - Montana Basics Course for Small Public Drinking Water Systems

9 Hydrologic Cycle - Evaporation On its fall toward the Earth some of the precipitation evaporates. The amount of evaporation is dependent upon several factors such as humidity, air temperature and the amount of wind. There is a significant amount of precipitation that is recycled back to the atmosphere before it ever strikes the ground. Hydrologic Cycle Water Flow Precipitation hits the forest canopy, brush and grass. Some of the water evaporates directly from the leaves. While other water flows down the outside of plants to the ground or strikes the ground directly, then runs downhill. This water flow picks up contamination from organic or inorganic matter. Hydrologic Cycle Surface Water The water flow accumulates in lakes, streams, ponds and rivers. Most rivers will eventually run into the ocean. These sources are referred to as surface water. A large quantity of the water that forms surface water will be evaporated back into the atmosphere. In fact in most of the world this is the largest single loss of surface water. Montana Basics Course for Small Public Drinking Water Systems -9

10 Hydrologic Cycle - Infiltration Some of the water that is running along the earth s surface seeps into the soil. This process is called infiltration. Hydrologic Cycle - Transpiration As the water infiltrates the soil and moves downward some is taken up by the roots of trees and other plants. The water that is taken in by plants moves upward and is given off into the atmosphere through the leaves of the plants in a process called transpiration. Hydrologic Cycle - Evapotranspiration This transpired moisture mixes with the moisture that is evaporated from surface waters. This combined process is referred to as evapotranspiration Montana Basics Course for Small Public Drinking Water Systems

11 Hydrologic Cycle - Aquifer The water not taken up by plants continues to move downward in a process called percolation. This water continues to move downward until it collects in gravel and sands called aquifers. Hydrologic Cycle Spring Water The water continues to slowly move toward and into adjacent lakes, streams and the ocean where it is evaporated back into the atmosphere. Springs are formed when the edge of an aquifer is exposed to the surface. Water can exit the hillside or mountain, run along the ground surface and eventually mix with surface water. Hydrologic Cycle Water Vapor Groundwater and surface water eventually mix and are evaporated back into the atmosphere and form water vapor. This vapor is condensed by atmospheric conditions and forms precipitation which falls to the ground and the cycle begins again, providing us with clean fresh water for our water systems. Montana Basics Course for Small Public Drinking Water Systems -11

12 Hydrologic Cycle Water Vapor Groundwater and surface water eventually mix and are evaporated back into the atmosphere and form water vapor. This vapor is condensed by atmospheric conditions and forms precipitation which falls to the ground and the cycle begins again, providing us with clean fresh water for our water systems. Usable Water Supply The total of all water in the world is approximately 306 million cubic miles. Of this total supply 296 million cubic miles are in the world s oceans and about ten million cubic miles or 3% of all water in the world is available as fresh water. Total Fresh Water Supply About 75% of the fresh water is tied up in polar ice caps, soil moisture and atmosphere. While 25% of the fresh water is in the groundwater supply, leaving 0.3% of the fresh water in the lakes and streams Montana Basics Course for Small Public Drinking Water Systems

13 Total Groundwater Supply The total usable groundwater supply is estimated at 1.06 million cubic miles. The lakes and rivers represent 0.03 million cubic miles of fresh water. This gives a total of 1.1 million cubic miles of usable fresh water. Total Usable Fresh Water Supply Of the usable fresh water, 97% is in the groundwater supply and 3% is in the surface water supply. Water in the Continental United States Within the continental United States 77.3% of the public water systems use groundwater and 18% of the systems use surface water. 4.7% of the systems in the U.S. use a combination of surface water and groundwater. On the other hand, 68% of the population is served by surface water supplies while only 32% of the population relies on groundwater supplies. Montana Basics Course for Small Public Drinking Water Systems -13

14 United States Surface Water Supplies In the continental United States, 37 of the 100 largest communities use surface water. This is because the majority of these communities are built next to surface water sources, including ten that are built next to the Great Lakes. In the West, communities such as Los Angeles, San Francisco, Portland and Seattle all utilize surface water. Water Availability in Montana In Montana, approximately 11% of the public water systems use surface water while 89% use groundwater. Some cities and towns in Montana use a combination of surface water and groundwater, but most use only groundwater. How is Water Used? How is water used?... will help you understand typical uses and demands for water within a community drinking water system Montana Basics Course for Small Public Drinking Water Systems

15 Categories of Water Use The consumption of water is often divided into categories depending on its intended use. Typical categories are: industrial use, agriculture use and domestic use. Did you Know? Industry in the United States uses an average of 150 billion gallons of water each day in order to produce the products that we all use. Industrial Use 270 tons of water to make one ton of steel, 250 tons of water to make one ton of paper and 10 gallons of water to produce each gallon of gasoline. The processing of seafood requires large volumes of high quality water. Agricultural Use Even the food we eat requires water to grow and process. Each loaf of bread requires 115 gallons of water to produce and each gallon of milk requires 16 gallons of water for processing. Montana Basics Course for Small Public Drinking Water Systems -15

16 Domestic Use Laundry, 20 to 40 gallons per load; showers, 20 to 30 gallons each; baths, 30 to 40 gallon each; flushing toilets, 1.6 to 7 gallons per flush and, drinking, one to two quarts of water a day. Average Daily Demand The average daily demand for your utility should be determined for each month and recorded as part of the routine records for the water system. Minimizing the average daily demand can reduce the cost of upgrading the system. Water Demands - Peak Hour and Peak Day The water system s pumps, storage and treatment must be designed so that the system can meet peak hour demands and fire flows without stressing the system. The peak hourly demand is best determined from a chart recorder. Normally a peak day ranges from 1.5 to 3 times the average day Montana Basics Course for Small Public Drinking Water Systems

17 Introduction to Drinking Water Systems What Is a Drinking Water System? What is a drinking water system?... defines drinking water systems based on type, purpose and the population served. Composition of a Water System Three primary components of a water system are the source, treatment, and distribution subsystems. Operators manage and maintain these system components in a safe manner that meets the needs of the customers Source Components Water source components for a public drinking water supply can include dams, intake structures, screens, pumps, and piping. Montana Basics Course for Small Public Drinking Water Systems -17

18 Treatment Process The treatment process varies from community to community, but typically includes turbidity and microorganism removal, possibly color removal, and nuisance chemical removal. Distribution Most distribution systems will include pipes, valves, fire hydrants, storage tanks, pumps, and house service connections. Waterborne Diseases Did you know? On a worldwide scale, one person dies every nine seconds from a waterborne disease. At the turn of the century there were 360 typhoid deaths out of every one million people. With the installation of water treatment plants and disinfection, the number of deaths was reduced to one. This reduction was enhanced by improvements in personal hygiene. Diseases that are carried by the water are called waterborne. The organisms that cause these diseases do not normally live in the water, but are transported by the water. Examples of typical waterborne diseases are; cholera, typhoid, dysentery, polio, hepatitis and giardiasis. All of these diseases can be prevented from spreading through the water system with a proper treatment and disinfection system Montana Basics Course for Small Public Drinking Water Systems

19 Alternative Supplies When the water produced by a system is objectionable because of odor, taste, or appearance, the customer will often seek another source for their drinking water. While looking, tasting and smelling good, another source could contain microorganisms and/or chemicals that are harmful. This last point is critical but often overlooked in the operation and management of a public water system. Purpose of a Public Water Supply The primary purpose of a public water system is the protection of public health. The water system serves as a line of defense between disease and the public. Properly operated systems protect public health by the: -the removal and/or inactivation of pathogenic microorganisms including bacteria, viruses and protozoa; -the reduction and/or removal of chemicals that can be detrimental to health such as arsenic, nitrates, lead and copper; -and providing quality water thus discouraging the customer from seeking better tasting or better looking water but which may be from a contaminated source. Classification of Systems Water systems are classified using various methods and criteria. The most common criteria for classification are type of source and population. In addition to this classification, water systems are classified based on the state and EPA specifications. Montana Basics Course for Small Public Drinking Water Systems -19

20 Classification by Source Common source classifications are surface water, groundwater and groundwater under the direct influence of surface water. Classification by Population The U.S. EPA has classified systems according to population. This classification was developed to allow the EPA to phase in regulations so that systems serving the largest segments of the population were addressed first. Typical population classifications include: below 3,300 people, 3,300 to 10,000 people and above 10,000 people. EPA Classification In order to apply drinking water regulations uniformly across the United States the EPA classified systems into three categories: community water systems, non-community water systems and non-transient non-community water systems Montana Basics Course for Small Public Drinking Water Systems

21 Introduction to Drinking Water Systems State Specific Classification Many states have their own classification system including Montana. In Montana, a public water system means any community well, water hauler for cisterns, water bottling plants, water dispenser, or other water supply that has at least 15 service connections or that regularly serves at least 25 persons daily for a period of at least 60 days in a calendar year. Montana Classification of Systems In Montana there are three types of public water supplies. Community Water Systems Community water systems are PWS s that serves the same people year round. Most residences including homes, apartments, and condominiums in cities, small towns, and mobile home parks are served by Community Water Systems. Montana Basics Course for Small Public Drinking Water Systems -21

22 Non-Transient Non-Community Water Systems A non-transient non-community Water System is a water system that serves the same people more than six months per year. For example, a school with its own water supply is considered a non-transient system. Transient Non-Community Water Systems A transient non-community water system is a water system that serves the public but not the same individuals for more than six months; for example, a rest area or campground may be considered a transient water system 22 - Montana Basics Course for Small Public Drinking Water Systems