GNE 335 Lecture 3 - Water Quality Impacts PDF

CIE 355 – Introduction to Sustainable Engineering Fall 2024 Dr. Miriam Tawk  Lecture 3 Water Quality Impacts 2 Chapter Outline 1. Introduction 2. The Hydrologic Cycle 3. Watershed and Runoff 4. Water Budget 5. Water Footprint 6. T...

CIE 355 – Introduction to Sustainable Engineering Fall 2024 Dr. Miriam Tawk  Lecture 3 Water Quality Impacts 2 Chapter Outline 1. Introduction 2. The Hydrologic Cycle 3. Watershed and Runoff 4. Water Budget 5. Water Footprint 6. The Water Crisis 7. Water Treatment 8. Wastewater Treatment 3 Introduction Every year more people die from unsafe water than from all forms of violence, including war. The most significant sources of water pollution are lack of adequate treatment of human wastes and inadequately managed and treated industrial and agricultural waste. Every day, 2 million tonnes of sewage and other effluents drain into the world’s waters. The quality of water necessary for each human use varies, as do the criteria used to assess water quality. 4 The Hydrologic Cycle Definitions The atmosphere is a mixture of gases Hydrology is “the science that treats the waters of extending from the surface of the Earth the Earth, their occurrence, circulation, and toward space distribution, their chemical and physical properties, and their reaction with the environment, including the relations to living The lithosphere is the soil crust that lies on things” the surface of the planet where we live The hydrosphere is the portion of the Earth that accounts for most of the water storage and consists of oceans, lakes, streams, and shallow groundwater bodies. 5 The Hydrologic Cycle The hydrologic cycle, or water cycle, describes the movement of water from one biogeochemical cycle to another. 6 The Hydrologic Cycle Oceans contain 97% of the water on the planet The largest repository of freshwater on the planet lies in the Arctic and Antarctic ice caps Groundwater is the largest source of freshwater actively used by the human species: 30.1% of freshwater on the planet and 99% of the freshwater available for human use Only 0.3% of the world’s total freshwater is available in surface waters. 7 The Hydrologic Cycle Precipitation Water moves from the atmosphere to the surface of the planet through precipitation. Precipitation may occur when the atmosphere becomes completely saturated with water (100% humidity) and the droplets have enough mass to fall from the atmosphere. Evaporation from the oceans and eventual cooling of the water vapor from the oceans account for approximately 90% of the Earth’s precipitation. 8 The Hydrologic Cycle Precipitation 9 The Hydrologic Cycle Infiltration Some fraction of precipitation seeps into the ground through a process called infiltration. Groundwater tables are replenished and sustainable when the rate of infiltration is equal to or greater than the rate of withdrawal from the groundwater table. 10 The Hydrologic Cycle Infiltration Water table, also called groundwater table, upper level of an underground surface in which the soil or rocks are permanently saturated with water. The upper surface of this zone of saturation is called the water table. The saturated zone beneath the water table is called an aquifer, and aquifers are huge storehouses of water. 11 The Hydrologic Cycle Infiltration Wells can be drilled into the aquifers and water can be pumped out. Precipitation eventually adds water (recharge) into the porous rock of the aquifer. The rate of recharge is not the same for all aquifers, though, and that must be considered when pumping water from a well. Pumping too much water too fast draws down the water in the aquifer and eventually causes a well to yield less and less water and even run dry. 12 The Hydrologic Cycle Key components of the hydrologic cycle Green Water Soil Moisture (nonproductive green Grey Water Recycled, reusable water is evaporated from soil and wastewater open water surfaces) Blue Water Groundwater, Lakes, Rivers, Virtual Water Water embodied in Groundwater Recharge, Surface production of goods and Runoff, Streamflow services Blue Water Diversions, including reservoirs Desalination Augmentation in water- (engineered) scarce areas 13 Watershed and Runoff The watershed is the region that collects rainfall. When the height of the groundwater table is equal to the surface, a stream is formed. The precipitation may also flow over saturated land through runoff in small rivulets that may be collected into intermittent streams. The intermittent streams flow into groundwater-based stream or river systems. The river systems transport the water back to the oceans. 14 Watershed and Runoff Drainage basins, catchments, and watersheds are 3 synonymous terms that refer to the topographic area that collects and discharges surface stream flow through one outlet. All the runoff within a watershed exits a single point downhill or downstream from all other points in the watershed 15 Water Budget The water budget balances the flows of water Inputs = Outputs + Storage into and out of a watershed or system. P=R+I+E+T+S The watershed boundaries determine the boundaries for the system of concern. Precipitation (P) is the input into the watershed In natural watersheds, the highest points in those on the left-hand side of the water budget watersheds create the watershed boundaries. equation. Water is removed from the watershed by evaporation (E), transpiration (T), runoff (R), and infiltration (I) into the soil. Water stored (S) in the system is also accounted for on the right-hand side of the equation 16 Water Budget Consumptive water use Inputs = Outputs + Storage + Consumption “water removed from available supplies without return to a water resources system (e.g., water used P=R+I+E+T+S+C in manufacturing, agriculture, and food preparation that is not returned to a stream, river, or water Precipitation (P) is the input into the watershed treatment plant)” on the left-hand side of the water budget equation. Withdrawal use Water is removed from the watershed by “the use of water for any purpose which requires evaporation (E), transpiration (T), runoff (R), that it be physically removed from the source” and infiltration (I) into the soil. Nonwithdrawal use Water stored (S) in the system is also “the use of water for any purpose which does not accounted for on the right-hand side of the require that it be removed from the original source, equation such as water used for navigation” 17 Water Budget Case Study - Malta You are asked to evaluate the urgency of water management measures for the island nation of Malta. Referring to the data you are provided with (handout): a. Determine how much water is available per person if all the rainfall in Malta could be collected and used? (provide answer in liters/day) b. Determine the water storage per person? Hint: determine groundwater and surface storage available for use c. What is your assessment of the situation? :) Given: Assume area of Malta = 316 km2 Population = 398000 18 Water Budget General Notes Engineers are currently examining water availability and have identified many water-scarce areas in both the developed and developing worlds where there are existing or expected water shortages. A sustainable level of consumption is one where the net storage term is greater than zero for a watershed. When the consumption terms increase from human demand to the point where the storage term becomes negative in value, then there is non-sustainable water use in the watershed. Archaeologists believe that water shortages have been a significant factor in the collapse of many civilizations. Today in regions where consumptive withdrawals are greater than inputs into the watershed, water must be acquired from beyond the watershed boundaries, or water-rationing measures can be adopted to prevent the degradation and disruption of ecosystems and human systems within the watershed of concern. 19 Water Budget General Notes “The rapid global rise in living standards combined with population growth presents the major threat to sustainability of water resources and environmental services.” (World Water Assessment Programme, 2009). Technological advances in water development and energy development have the potential to help meet the growing water demand. At the same time, technological and industrial development may also increase the demand for water associated with agriculture, energy demand, and industrialization. Engineers, scientists, and policymakers must work across regional and national boundaries to meet the future demand for water in many water-scarce areas. 20 Water Footprint Everything we use, wear, buy, sell and eat takes water to make. The water footprint measures the amount of water used to produce each of the goods and services we use. It can be measured for a single process, such as growing rice, for a product, such as a pair of jeans, for the fuel we put in our car, or for an entire multi-national company. The water footprint can also tell us how much water is being consumed by a particular country – or globally – in a specific river basin or from an aquifer. The water footprint is a measure of humanity’s appropriation of fresh water in volumes of water consumed and/or polluted. https://youtu.be/b1f-G6v3voA 21 Water Footprint Three types of water footprints Green Water Footprint Water from precipitation that is stored in the root zone of the soil and evaporated, transpired or incorporated by plants. It is particularly relevant for agricultural, horticultural and forestry products. Blue Water Footprint Water that has been sourced from surface or groundwater resources and is either evaporated, incorporated into a product or taken from one body of water and returned to another, or returned at a different time. Irrigated agriculture, industry and domestic water use can each have a blue water footprint. Grey Water Footprint The amount of fresh water required to assimilate pollutants to meet specific water quality standards. The grey water footprint considers point-source pollution discharged to a freshwater resource directly through a pipe or indirectly through runoff or leaching from the soil, impervious surfaces, or other diffuse sources. 22 The Water Crisis 1.1 billion people without access to a protected well or spring Far more people endure the Nearly half of the people within reasonable walking largely preventable effects of in the world do not have distance of their homes poor sanitation and access to improved sanitation and one quarter lack water supply than are access to improved safe affected by war, terrorism, drinking water and weapons of mass destruction combined. A silent humanitarian crisis kills an estimated 3,900 children every day 23 The Water Crisis 1. Water-related diseases are Water Crisis in low- income populations among the most common causes of illness and death in developing countries, especially in sub- Saharan Africa. Symptom and cause of Poverty Sickness Lost educational opp. Lost Employment opp. Early Death 24 The Water Crisis What is your role as an engineer? Water and sanitation systems may be costly to construct. The operation and maintenance (O&M) expenses Remember for water and sanitation systems are often “Appropriate overlooked and may cause failure due to the inability to collect revenue, which is especially Technology”? problematic in low-income countries. Growing urban centres challenge engineers, scientists, and policymakers to implement appropriate use of technology. 25 The Water Crisis What is your role as an engineer? Low- to medium-income countries lack adequately trained staff to operate and manage facilities in urban and rural areas 26 The Water Crisis What is your role as an engineer? Low- to medium-income countries lack adequately trained staff to operate and manage facilities in urban and rural areas 27 Water Treatment Few diseases are spread by water in highly economically developed countries. In contrast, in less economically developed countries, a safe, reliable supply of water may be unavailable, and a sanitation infrastructure is often absent. Your Role as an Engineer Environmental engineers apply the basic principles of science and engineering to design water treatment systems for drinking water and treating human and industrially contaminated wastewater. 28 Water Treatment Design water treatment systems to protect public health The engineer’s goal while balancing environmental, economic, social, and political constraints. knowledge of the constituents of concern the impact of these constituents The transformation and fate of the constituents treatment methods to remove or reduce the toxicity of the constituents methods to dispose of or recycle treatment byproducts 29 Water Treatment Importance of Adopting Water Treatment Technologies Cholera and typhoid outbreaks did not begin to decrease until chlorination for treating drinking water received widespread acceptance in 1908–1911. Mortality and water supply records kept by the Commonwealth of Massachusetts show how improved water filtration and chlorination led to a rapid decline in typhoid fever deaths Check Figure on the left :) 30 Water Demand Management Many developing communities and many large urban areas are in regions of the world where water is scarce. Water Demand management Engineers now consider Think of water as a limited considers the total quantity of both the supply and resource and use water water abstracted from a demand of water demand management source of supply using resources strategies. measures to control waste and excessive consumption. Consider efficiency, effectiveness, and demand management VS. providing for maximum possible demand 31 Wastewater Treatment Wastewater is discharged from homes, commercial establishments, and industrial plants by means of sanitary sewers. The system of sewers has to be designed so that the collecting sewers, which collect the wastewater from homes and industries, all converge to a central point where the water flows by trunk sewers to the wastewater treatment plant. Sometimes it is impossible or impractical to install gravity sewers, so the waste has to be pumped by pumping stations through force mains or pressurized pipes. 32 Wastewater Treatment Water reuse provide a more sustainable approach to meeting the demand for water in many growing communities. 33 Wastewater Treatment The shift toward reused and recycled drinking water is occurring in many water-scarce areas throughout the world. The advantages to recycling water include: Lower costs Reliable water source Fewer impacts from excessive water withdraw to ecosystems Less costly infrastructure investments needed compared to building large reservoirs or conveyance systems 34  End of Lecture 3 Water Quality Impacts Study Well :) 35