Principles of Environmental Science & Technology This page intentionally left blank Pri nciples of Environmental Science & Technology Or.~ NEW AGE INTERNATIONAL (P) liMITED, PUBUSHERS New Delhi .i • Ron<hi Copyright © 2005, New Age International (P) Ltd., Publishers Published by New Age International (P) Ltd., Publishers All rights reserved. No part of this ebook may be reproduced in any form, by photostat, microfilm, xerography, or any other means, or incorporated into any information retrieval system, electronic or mechanical, without the written permission of the publisher. All inquiries should be emailed to rights@newagepublishers.com ISBN (13) : 978-81-224-2341-9 PUBLISHING FOR ONE WORLD NEW AGE INTERNATIONAL (P) LIMITED, PUBLISHERS 4835/24, Ansari Road, Daryaganj, New Delhi - 110002 Visit us at www.com PREFACE This book is meant to be an introductory text on the Fundamentals of Environmental Science and Engineering. Today, knowledge of Environmental Science is essential for students as well as practicing engineers and scientists of all disciplines.
Here an attempt has been made to provide precise and upta date infoIlllation on the fundamental aspects of Environmental Science and Engineering without going much in-depth in to specific areas, so as to be useful for a cross section of fields of study. Indian technical universities are making the study of Environmental Science and Engineering mandatory for all courses and hence a 'comprehensive textbook covering all domains of this field (including the policy aspects and management practices) is the need of the hour. The book adopts a simple narrative style keeping in mind both the knowledge requirements and the examination needs of university students. The authors wish to profusely thank all those who have supported them in their effort viz.
the Management, the Principal, teachers, professors and students of our institution Kongu Engineering College, Perundurai, Erode. The authors also thank Mis New Age International (P) Ltd. for having accepted to publish the work and the wonderful way they have brought out this book in such a short time. Feedback and corrective action is the only way to progress.
As students of science the authors most humbly seek feed back from the readers of this book. The authors can be reached in any of the following e~ mail addresses - sar_rumisivaesh@yahoo.com, jeyramrad@yahoo.com, naturebaskar@yahoo.in -Authon This page intentionally left blank CONTENTS Prefaee eY) Introduction 1 1 Components and Subcomponents of Environment 3 2. Science of Environment 33 3. Cum:nt Environmental Issues 50 4.
Engineering Interventions to Reduce Environmental Stresses 61 5. Waste Minimization and Clean Technology 104 6. Environment and Development lIS 7. Tools for Environmental Management 139 8.
Environmental Perfonnance Standards 173 Review Questions 186 Selected Bibliography 193 This page intentionally left blank INTRODUCTION The objective of this book is to promote an understating among Engineers of different disci- plines the concept and principles of environmental science and Engineering. Earth is a member of the solar system orbiting the Sun. The Sun is one ofthe millions ofstars in the Milky Way. When the Earth was formed there was no life in it.
Mixtures of methane, ammonia, water vapour and hydrogen wefe converted into life generating compounds by electrical discharge. Thus life came in to the Earth. With the passage of time the evolution of life and Ecosystems took place. The planet as we see today is the result of millions of years of evolution.
The modem man with. his high level of intellect became the most dominant animal in the entire planet. SOME FACTS ABOUT THE EARTH The earth is the third planet from the Sun at a distance of about 150 million kilometers, which is called an "astronomic unit", The earth is 12760 kilometers in diameter. It is not an ideal globe.
At the equator there are little bumps and at the poles it is flatter than it is at the rest of the world. The southern part has more bumps than the northern part. The Earth's circumference is 40070 kilometers. Some basic facts about our planet is dli:tailed below : Average Diameter 12760kms Average Circumference 40070kms Surface Area 510Million sq.kms Land Area 149 Million sq.2%) Ocean Area 361 Million sq.8 %) Mass 5973 trillion tons Human Population AroWld 7 Billion Average surface temperature 14.6 billion years The surface temperatures on OUT planet fluctuate between - 88 degrees Celsius (in Siberia) and + 58 degrees Celsius (in Death Va1ley.
The temperature in the Earth's core is about 10000-12000 degrees Celsius at a pressure ofabaut 3 millions times our air pressure at sea level. About 70% of the Earth's surface consi sts of the ocean's water and hence Earth is called "the blue planet". The oceans contain about 97% of all the water on our planet. The oceans have high salt content.
The Earth is the only planet in our solar system that has an atmosphere consisting 2 PRINCIPLES Of ENVIRONMENTAL SCIENCE AND TECHNOl.OGY of21% oxygen and 78% nitrogen. The Earth rotates at a speed of30 kilometers per second around the Sun. This rotation is made in an elliptical form. MAN EARTH INTERFACE Man's quest for improvement and progress is eternal.
In order to meet his natural and acquired needs he started utilizing the planet's resources indiscriminately. The stress of these efforts in- creased phenomenally due to the increase in population and industrial revolution. The environmental damage that we have done in the last 200 years is much more than the total damage done in the entire period of human existence in this planet. The stress on the resources became so acute that nature started reacting in an adverse fashion.
The world population woke up to this scenario and started systematizing and controlling the indiscriminate use of natural resources. hence the study, research and application in Environmental Science and Engineering has become overwhelm- ingly relevant especially for engineering professionals. 1 COMPONENTS AND SUBCOMPONENTS OF ENVIRONMENT 1.1 CLASSIFICATION OF ENVIRONMENT The term Environment can be broadly defined as one’s surroundings. To be more specific we can say that it is the physical and biological habitat that surrounds us, which can be felt by our physical faculties (seen, heard, touched, smelled and tasted.) The two major classifications of environment are : (A) Physical Environment: External physical factors like Air, Water, and Land etc.
This is also called the Abiotic Environment. (B) Living Environment: All living organisms around us viz. plants, animals, and microorganisms. This is also called the Biotic Environment.
Earth’s environment can be further subdivided into the following four segments: (1) Lithosphere (2) Hydrosphere (3) Atmosphere (4) Biosphere. LITHOSPHERE The earth’s crust consisting of the soil and rocks is the lithosphere. The soil is made up of inorganic and organic matter and water. The main mineral constituents are compounds or mixtures derived from the elements of Si, Ca, K, Al, Fe, Mn, Ti, O etc.
The organic constituents are mainly polysaccharides, organo compounds of N, P and S. The organic constituents even though form only around 4% – 6% of the lithosphere, they are responsible for the fertility of the soil and hence its productivity. HYDROSPHERE This comprises all water resources both surface and ground water. The world’s water is found in oceans and seas, lakes and reservoirs, rivers and streams, glaciers and snowcaps in 3 4 PRINCIPLES OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY the Polar Regions in addition to ground water below the land areas.
The distribution of water among these resources is as under Table 1.1 Oceans and Seas 96–97 % Glaciers and polar icecaps 2–3 % Fresh water < 1% The water locked up in the Oceans and Seas are too salty and cannot be used directly for human consumption, domestic, agriculture or Industrial purposes. Only less than 1% of water resources are available for human exploitation. Water is considered to be a common compound with uncommon properties. These uncommon properties (e.
anomalous expansion of water) are mainly responsible for supporting terrestrial and aquatic life on earth. BIOSPHERE The biosphere is a capsule encircling the earth’s surface wherein all the living things exist. This portion extends from 10000 m below sea level to 6000 m above sea level. Life forms do not exist outside this zone.
The biosphere covers parts of other segments of the environment viz. Lithosphere, Hydrosphere and Atmosphere. Life sustaining resources like food, water and oxygen present in the biosphere are being withdrawn and waste products in increasing quantities are being dumped. The biosphere has been absorbing this and assimilating them.
However the rate of waste dumping has gone beyond the assimilating capability of the biosphere and signals of this stress is becoming evident. ATMOSPHERE It is the gaseous envelope surrounding the earth and extends upto 500 kms above the earth’s surface. The composition of the atmosphere is given in Table 1.2 Constituent Volume % Nitrogen 78.03 Trace constituents* Balance *The trace constituents include Helium, Neon, Krypton, xenon, SO2, NO2, Ammonia, Ozone, and Carbon monoxide etc. The atmosphere, which is a gaseous cover, protects the earth from cosmic radiations and provides life sustaining Oxygen, the macronutrient Nitrogen and Carbon dioxide needed for photosynthesis.
The atmosphere screens the dangerous UV radiations from the sun and allows only radiations in the range of 300 nm – 2500 nm (near UV to near IR) and radio waves. The atmosphere plays a major role in maintaining the heat balance of the earth by absorbing the COMPONENTS AND SUBCOMPONENTS OF ENVIRONMENT 5 re-emitted radiation from the earth. In addition the atmosphere is the medium of carriage of water from the oceans to the land in the hydrological cycle. The Structure of the Atmosphere The atmosphere is broadly divided into four major zones viz.
Troposphere, Stratosphere, Mesosphere and Thermosphere. Characteristics of these zones are pictorially represented below in Fig.1 TROPOSPHERE Troposphere is the layer of air nearest to the ground. Temperature decreases with height. The average temperature drops from 15ºC at sea level to –56.5ºC at 11,000 m above sea level.
Mixing of the air molecules due to their constant movement (winds) keeps the composition of the gases more or less same throughout the troposphere. An exception to this is water vapor. Most water vapor evaporates from the surface of the Earth and is found in the lower troposphere. Most of the weather occurs in the troposphere.
Tropopause is the top of the troposphere, which is a transition layer between Troposphere and Stratosphere 6 PRINCIPLES OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY STRATOSPHERE Stratosphere is the layer of air above the troposphere where temperature increases with height. The average temperature rises to –2.5ºC at 50,000 m above sea level. Ozone is found in higher concentrations between 20 and 30 km above the surface. Hence sometimes this layer is referred to as the “ozone layer”.
Ozone absorbs radiant energy from the sun and hence warmer temperatures are encountered in the stratosphere. Stratopause is the top of the stratosphere, which is a transition layer between Stratosphere and Mesosphere. MESOSPHERE Mesosphere is the layer of air above the stratosphere where temperature decreases with height. The average temperature decreases to –90°C at 90,000 m.
This is the coldest layer of the atmosphere. Mesopause is the top of the mesosphere, which is a transition layer between Mesosphere and Thermosphere. THERMOSPHERE Thermosphere is the layer of air above the mesosphere. The temperatures in the thermosphere increase with increasing height, but there are not many molecules in this layer.
The air becomes less and less dense as we reach space.2 INTER-RELATIONSHIP BETWEEN THE COMPONENTS AND SUBCOMPONENTS Matter (chemicals) as well as living beings on earth are distributed among the four major Environmental Components viz. Lithosphere, Hydrosphere, Atmosphere and Biosphere. While for the purpose of studying and understanding the Global Environment this division may be convenient, constant interaction by way of mass and energy transfer between these components and subcomponents is constantly taking place. This is pictorially indicated in Fig.2 Every sphere has a flow of matter and energy to every other sphere, which is a two- way linkage as shown in the figure.
Such two-way interactions are also taking place within individual spheres.