Environmental Engineering I III Year/ V Sem Civil Engineering A Course Material on Environmental Engineering I By Mr. S.Elaiyarasu ASSISTANTPROFESSOR DEPARTMENT OFCIVIL ENGINEERING SASURIE COLLEGE OF ENGINEERING VIJAYAMANGALAM–638 056 Environmental Engineering I III Year/ V Sem Civil Engineering QUALITY CERTIFICATE This is to certify that the e-course material Subject Code : CE6503 Scubject :Environmental Engineering I Class :III Year Civil Being prepared by me and it meets the knowledge requirement of the university curriculum. Signature of the Author Name: Designation: This is to certify that the course material being prepared by Mr.S.Elaiyarasu is of adequate quality. He has referred more than five books amont them minimum one is from aborad author. Signature of HD Name: SEAL CE6503 ENVIRONMENTAL ENGINEERING I L T P C 3 0 03 OBJECTIVES: To make the students conversant with principles of water supply, treatment and distribution UNIT I PLANNING FOR WATER SUPPLY SYSTEM 8 Public water supply system -Planning - Objectives -Design period - Population forecasting - Water demand -Sources of water and their characteristics -Surface and Groundwater- Impounding Reservoir Well hydraulics -Development and selection of source - Water quality - Characterization and standards- Impact of climate change. UNIT II CONVEYANCE SYSTEM 7 Water supply -intake structures -Functions and drawings -Pipes and conduits for water- Pipe materials - Hydraulics of flow in pipes -Transmission main design -Laying, jointing and testing of pipes - Drawings appurtenances - Types and capacity of pumps -Selection of pumps and pipe materials. UNIT III WATER TREATMENT 12 Objectives - Unit operations and processes - Principles, functions design and drawing of Chemical feeding, Flash mixers, flocculators, sedimentation tanks and sand filters - Disinfection- Residue Management - Construction annd Operation & Maintenance aspects of Water Treatment Plants. UNIT IV ADVANCED WATER TREATMENT 9 Principles and functions of Aeration - Iron and manganese removal, Defluoridation and demineralization -Water softening -Desalination - Membrane Systems -Recent advances. UNITV WATER DISTRIBUTION AND SUPPLY TO BUILDINGS 9 Requirements of water distribution -Components -Service reservoirs -Functions and drawings - Network design -Economics -Computer applications -Analysis of distribution networks - Appurtenances -operation and maintenance -Leak detection, Methods. Principles of design of water supply in buildings -House service connection -Fixtures and fittings -Systems of plumbing and drawings of types of plumbing. TOTAL: 45 TEXT BOOKS: 1. Garg, S.K., "Environmental Engineering", Vol.1 Khanna Publishers, New Delhi, 2005. 2. Modi, P.N. "Water Supply Engineering", Vol. I Standard Book House, New Delhi, 2005. 3. Punmia, B.C., Ashok K Jain and Arun K Jain, "Water Supply Engineering", Laxmi Publications Pvt. Ltd., New Delhi, 2005 REFERENCES: 1. Government of India, "Manual on Water Supply and Treatment", CPHEEO, Ministry of Urban Development, New Delhi, 2003 2. Syed R. Qasim and Edward M. Motley Guang Zhu, "Water Works Engineering Planning", Design and Operation, Prentice Hall of India Private Limited, New Delhi, 2006. CONTENTS PAGE NO CHAPTER 1 PLANNING FOR WATER SUPPLY SYSTEM 1.1 PRE REQUISTE DISCUSSION 1 1.2 CONCEPTS 1 1.3 SIGNIFICANT 5 1.4 APPLICATIONS 2 1.5 WATER SUPPLY 1.6 SOURCES OF WATER 7 1.7 POPULATION FORECASTINGMETHODS 8 1.8 ESTIMATION OFWATER DEMAND 12 1.9 MERITS OF SURFACE SOURCES 14 1.10 TYPES OF RESERVOIRS AND CONSTRUCTION 16 CHAPTER 2 CONVEYANCE SYSTEM 21 PRE REQUISTE DISCUSSION 18 2.2 CONCEPTS 18 2.3 2.3 SIGNIFICANT 19 2.4 TOPOLOGIES OF WATER DISTRIBUTION NETWORKS 21 2.5 WATER NETWORK MAINTENANCE 21 2.6 HYDRAULICS OF FLOW IN PIPES 23 2.7 PIPES AND CONDUITS FOR WATER-PIPE MATERIALS 24 2.8 TRANSMISSION MAIN DESIGN 28 CHAPTER 3 WATER TREATMENT 3.1 PRE REQUISTE DISCUSSION 30 3.2 CONCEPTS 30 3.3 SIGNIFICANT 30 3.4 OBJECTIVES AND PRINCIPLES 31 3.5 PREFILTRATION 31 3.6 SEDIMENTATION 31 3.7 FLOCCULATORS 32 3.8 SAND FILTRATION 32 3.9 SLOW SAND FILTERS 33 3.10 RAPID SAND FILTERS 33 3.11 DISINFECTION 34 3.12 OTHER TREATMENT PROCESSES 34 3.13 SELECTING TECHNOLOGY 35 3.14 WATER TREATMENT PLAN 35 3.15 TREATMENT PLANT ASSESSMENTS 36 3.16 PRINCIPLES OF UNIT OPERATIONS AND PROCESSES 37 3.17 WATER PURIFICATION 39 3.18 ADVANCED WASTE WATER TREATMENT-REMOVAL OF 40 SUSPENDED SOLIDS CHAPTER 4 ADVANCED WATER TREATMENT 4.1 PRE REQUISTE DISCUSSION 41 4.2 PRINCIPLES AND FUNCTIONS OF AERATION 41 4.3 METHODS OF AERATION 41 4.4 IRON AND MANGANESE REMOVAL 43 4.5 LIMITATIONS 45 4.6 WATER SOFTENNING 50 4.7 DEMINERALIZATION 67 4.8 DEALKALIZATION 70 4.9 OTHER DEMINERALIZATION PROCESSES 72 4.10 COMMON ION EXCHANGE SYSTEM PROBLEMS 74 4.11 RESIN FOULING AND DEGRADATION 74 4.12 MEMBRANE PROCESSES 78 CHAPTER 5 WATER DISTRIBUTION AND SUPPLY TO BUILDINGS 5.1 PRE REQUISTE DISCUSSION 81 5.2 CONCEPTS 83 5.3 COMPONENTS OF WATER DISTRIBUTION SYSTEM 84 5.4 HYDROLOGY 85 5.5 GEOMORPHOLOGY 86 5.6 RESERVOIR 88 5.7 SERVICE RESERVOIR 90 5.8 WATER DISTRIBUTION SYSTEM POLICIES 92 5.9 DISTRIBUTION SYSTEM PRESSURE 93 5.10 LEAKS 94 5.11 DISTRIBUTION SYSTEM WATER STORAGE FACILITIES 94 5.12 DISTRIBUTION SYSTEM APPURTENANCES 95 5.13 DISTRIBUTION SYSTEM MAINTENANCE 96 5.14 FITTINGS AND ACCESSORIES 98 2MARKS AND 16 MARK QUESTIONS AND ANSWERS Environmental Engineering I III Yr/V Sem Civil Engineering CHAPTER 1 PLANNING FOR WATER SUPPLY SYSTEM 1.1 PRE REQUISTE DISCUSSION It is the application of scientific and engineering principles to the environmental issues and their solutions. Generally, it includes supply of water, disposal and recycling of wastes, drainage of communities, control of water, soil, atmospheric pollution and environmental impacts of different activities carried out on earth. The practice and application of engineering laws in compliance with the safety of environment and the code of ethics prescribed as standards. Some of those are as below 1.2 CONCEPTS Environmental engineering is the application of science and engineering principles to improve the natural environment (air, water, and/or land resources), to provide healthy water, air, and land for human habitation and for other organisms, and to remediate polluted sites. It involves waste water management and air pollution control, recycling, waste disposal, radiation protection, industrial hygiene, environmental sustainability, and public health issues as well as a knowledge of environmental engineering law. It also includes studies on the environmental impact of proposed construction projects. Environmental engineers conduct hazardous-waste management studies to evaluate the significance of such hazards, advise on treatment and containment, and develop regulations to prevent mishaps. Environmental engineers also design municipal water supply and industrial wastewater treatment systems as well as address local and worldwide environmental issues such as the effects of acid rain, global warming, ozone depletion, water pollution and air pollution from automobile exhausts and industrial sources. At many universities, Environmental Engineering programs follow either the Department of Civil Engineering or The Department of Chemical Engineering at Engineering faculties. Environmental "civil" engineers focus on hydrology, water resources management, bioremediation, and water treatment plant design. Environmental "chemical" engineers, on the other hand, focus on environmental chemistry, advanced air and water treatment technologies and separation processes 1.3 SIGNIFICANT Ever since people first recognized that their health and well-being were related to the quality of their environment, they have applied thoughtful principles to attempt to improve the quality of their environment. The ancient Harappan civilization utilized early sewers in some cities. The Romans constructed aqueducts to prevent drought and to create a clean, healthful water supply for the metropolis of Rome. In the 15th century, Bavaria created laws restricting the development and degradation of alpine country that constituted the region's water supply. 1 S.Elaiyarasu 2015-16 Environmental Engineering I III Yr/V Sem Civil Engineering The field emerged as a separate environmental discipline during the middle third of the 20th century in response to widespread public concern about water and pollution and increasingly extensive environmental quality degradation. However, its roots extend back to early efforts in public health engineering. Modern environmental engineering began in London in the mid-19th century when Joseph Bazalgette designed the first major sewerage system that reduced the incidence of waterborne diseases such as cholera. The introduction of drinking water treatment and sewage treatment in industrialized countries reduced waterborne diseases from leading causes of death to rarities. In many cases, as societies grew, actions that were intended to achieve benefits for those societies had longer-term impacts which reduced other environmental qualities. One example is the widespread application of DDT to control agricultural pests in the years following World War II. While the agricultural benefits were outstanding and crop yields increased dramatically, thus reducing world hunger substantially, and malaria was controlled better than it ever had been, numerous species were brought to the verge of extinction due to the impact of the DDT on their reproductive cycles. The story of DDT as vividly told in Rachel Carson's "Silent Spring" is considered to be the birth of the modern environmental movement and the development of the modern field of "environmental engineering. Conservation movements and laws restricting public actions that would harm the environment have been developed by various societies for millennia. Notable examples are the laws decreeing the construction of sewers in London and Paris in the 19th century and the creation of the U.S. national park system in the early 20th century. 1.4 APPLICATIONS Briefly speaking, the main task of environmental engineers is to protect public health by protecting (from further degradation), preserving (the present condition of), and enhancing the environment. Environmental engineering is the application of science and engineering principles to the environment. Some consider environmental engineering to include the development of sustainable processes. There are several divisions of the field of environmental engineering. Environmental impact assessment and mitigation In this division, engineers and scientists use a systemic identification and evaluation process to assess the potential impacts of a proposed project , plans, programs, policies, or legislative actions upon the physical-chemical, biological, cultural, and socioeconomic components on environmental conditions.They apply scientific and engineering principles to evaluate if there are likely to be any adverse impacts to water quality, air quality, habitat quality, flora and fauna, agricultural capacity, traffic impacts, social impacts, ecological impacts, noise impacts, visual (landscape) impacts, etc. If impacts are expected, they then develop mitigation measures to limit or prevent such impacts. An example of a mitigation measure would be the creation of wetlands in a nearby location to mitigate the filling in of wetlands necessary for a road development if it is not possible to reroute the road. The practice of environmental assessment was intitiated on January 1, 1970, the effective date of the National Environmental Policy Act (NEPA) in the United States. Since that time, more than 100 developing and developed nations either have planned specific analogous laws or have 2 S.Elaiyarasu 2015-16 Environmental Engineering I III Yr/V Sem Civil Engineering adopted procedure used elsewhere. NEPA is applicable to all federal agencies in the United States. Water supply and treatment Engineers and scientists work to secure water supplies for potable and agricultural use. They evaluate the water balance within a watershed and determine the available water supply, the water needed for various needs in that watershed, the seasonal cycles of water movement through the watershed and they develop systems to store, treat, and convey water for various uses. Water is treated to achieve water quality objectives for the end uses. In the case of potable water supply, water is treated to minimize the risk of infectious disease transmission, the risk of non-infectious illness, and to create a palatable water flavor. Water distribution systems are designed and built to provide adequate water pressure and flow rates to meet various end-user needs such as domestic use, fire suppression, and irrigation. Wastewater conveyance and treatment Water pollution Most urban and many rural areas no longer discharge human waste directly to the land through outhouse, septic, and/or honey bucket systems, but rather deposit such waste into water and convey it from households via sewer systems. Engineers and scientists develop collection and treatment systems to carry this waste material away from where people live and produce the waste and discharge it into the environment. In developed countries, substantial resources are applied to the treatment and detoxification of this waste before it is discharged into a river, lake, or ocean system. Developing nations are striving to obtain the resources to develop such systems so that they can improve water quality in their surface waters and reduce the risk of water-borne infectious disease. Sewage treatment plant, Australia. There are numerous wastewater treatment technologies. A wastewater treatment train can consist of a primary clarifier system to remove solid and floating materials, a secondary treatment system consistingof an aeration basin followed by flocculation and sedimentation or an activated sludge system and a secondary clarifier, a tertiary biological nitrogen removal system, and a final disinfection process. The aeration basin/activated sludge system removes organic material by growing bacteria (activated sludge). The secondary clarifier removes the activated sludge from the water. The tertiary system, although not always included due to costs, is becoming more prevalent to remove nitrogen and phosphorus and to disinfect the water before discharge to a surface water stream or ocean outfall. Air quality management Engineers apply scientific and engineering principles to the design of manufacturing and combustion processes to reduce air pollutant emissions to acceptable levels. Scrubbers, electrostatic precipitators, catalytic converters, and various other processes are utilized to remove particulate matter, nitrogen oxides, sulfur oxides, volatile organic compounds (VOC), reactive organic gases (ROG) and other air pollutants from flue gases and other sources prior to allowing their emission to the atmosphere. 3 S.Elaiyarasu 2015-16 Environmental Engineering I III Yr/V Sem Civil Engineering Scientists have developed air pollution dispersion models to evaluate the concentration of a pollutant at a receptor or the impact on overall air quality from vehicle exhausts and industrial flue gas stack emissions. To some extent, this field overlaps the desire to decrease carbon dioxide and other greenhouse gas emissions from combustion processes. OTHER APPLICATIONS 1.Environmental policy and regulation development Contaminated land management and site remediation Environment, Health and Safety Hazardous waste management Natural resource management Noise pollution Risk assessment Solid waste management Public water supply system -Planning-Objectives Water supply and sanitation in India continue to be inadequate, despite longstanding efforts by the various levels of government and communities at improving coverage. The level of investment in water and sanitation, albeit low by international standards, has increased during the 2000s. Access has also increased significantly. For example, in 1980 rural sanitation coverage was estimated at 1% and reached 21% in 2008.Also, the share of Indians with access to improved sources of water has increased significantly from 72% in 1990 to 88% in 2008.[1] At the same time, local government institutions in charge of operating and maintaining the infrastructure are seen as weak and lack the financial resources to carry out their functions. In addition, no major city in India is known to have a continuous water supply[7] and an estimated 72% of Indians still lack access to improved sanitation facilities. A number of innovative approaches to improve water supply and sanitation have been tested in India, in particular in the early 2000s. These include demand-driven approaches in rural water supply since 1999, community-led total sanitation, a public-private partnerships to improve the continuity of urban water supply in Karnataka, and the use of micro-credit to women in order to improve access to water In 2008, 88% of the population in India had access to an improved water source, but only 31% had access to improved sanitation. In rural areas, where 72% of India‘s population lives, the respective shares are 84% for water and only 21% for sanitation. In urban areas, 96% had access to an improved water source and 54% to improved sanitation. Access has improved substantially since 1990 when it was estimated to stand at 72% for water and 18% for sanitation.[1] According to Indian norms, access to improved water supply exists if at least 40 liters/capita/day of safe drinking water are provided within a distance of 1.6 km or 100 meter of elevation 4 S.Elaiyarasu 2015-16 Environmental Engineering I III Yr/V Sem Civil Engineering difference, to be relaxed as per field conditions. There should be at least one pump per 250 persons. Service quality Water and sanitation service quality in India is generally poor, although there has been some limited progress concerning continuity of supply in urban areas and access to sanitation in rural areas. 1.5 WATER SUPPLY Challenges. None of the 35 Indian cities with a population of more than one million distribute water for more than a few hours per day, despite generally sufficient infrastructure. Owing to inadequate pressure people struggle to collect water even when it is available. According to the World Bank, none have performance indicators that compare with average international standards.A 2007 study by the Asian Development Bank showed that in 20 cities the average duration of supply was only 4.3 hours per day. No city had continuous supply. The longest duration of supply was 12 hours per day in Chandigarh, and the lowest was 0.3 hours per day in Rajkot.In Delhi residents receive water only a few hours per day because of inadequate management of the distribution system. This results in contaminated water and forces households to complement a deficient public water service at prohibitive 'coping' costs; the poor suffer most from this situation. For example, according to a 1996 survey households in Delhi spent an average of 2,182 (US$48.4) per year in time and money to cope with poor service levels.This is more than three times as much as the 2001 water bill of about US$18 per year of a Delhi household that uses 20 cubic meters per month. Achievements. Jamshedpur, a city in Jharkhand with 573,000 inhabitants, provided 25% of its residents with continuous water supply in 2009.[10] Navi Mumbai, a planned city with more than 1m inhabitants, has achieved continuous supply for about half its population as of January 2009.[11] Badlapur, another city in the Mumbai Conurbation with a population of 140,000, has achieved continuous supply in 3 out of 10 operating zones, covering 30% of its population.[12] Thiruvananthapuram, the capital of Kerala state with a population of 745,000 in 2001, is probably the largest Indian city that enjoys continuous water supply.[13] Sanitation Most Indians depend on on-site sanitation facilities. Recently, access to on-site sanitation have increased in both rural and urban areas. In rural areas, total sanitation has been successful (see below). In urban areas, a good practice is the Slum Sanitation Program in Mumbai that has provided access to sanitation for a quarter million slum dwellers.[14] Sewerage, where available, is often in a bad state. In Delhi the sewerage network has lacked maintenance over the years and overflow of raw sewage in open drains is common, due to blockage, settlements and inadequate pumping capacities. The capacity of the 17 existing wastewater treatment plants in Delhi is adequate to cater a daily production of waste water of less than 50% of the drinking water produced.[8] Of the 2.5 Billion people in the world that defecate openly, some 665 million live in India. This is of greater concern as 88% of deaths from diarrhea occur because of unsafe water, inadequate sanitation and poor hygiene. 5 S.Elaiyarasu 2015-16