To our presentation of class VIII

Chemistry Group Work

PPrreesseennttss…………

1. INTRODUCTION 2. CONTENT -WATER POLLUTION -AIR POLLUTION -CONSERVING METHODS OF WATER 3. CONCLUSION

INTRODUCTIONLife is existing on earth because of:-• The presence of air, water, soil, and minerals are

presentation the earth. they are required by living things.

• The right temperature on earth which is suitable for life to exist.

plants need carbon dioxide ,water, minerals and sunlight to exist.

Animals require oxygen,water,and food to surviveAll these requiring things are now being polluted by

humans.Here,we are going to learn more about the pollution of air and water, since all living things mainly need air and water.

CONTENCONTENTT

AIR POLLUTION

What Is Air Pollution?• Air pollution is the introduction of particulates, biological molecules,

or other harmful materials into the Earth's atmosphere, possibly causing disease, death to humans, damage to other living organisms such as food crops, or the natural or built environment.

• The atmosphere is a complex natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has been recognized as a threat to human health as well as to the Earth's ecosystems.

• Indoor air pollution and urban air quality are listed as two of the world's worst toxic pollution problems in the 2008 Blacksmith Institute World's Worst Polluted Places report. According to the 2014 WHO report, air pollution in 2012 caused the deaths of around 7 million people worldwide.

POLLUTANTSAn air pollutant is a substance in the air that can have adverse effects

on humans and the ecosystem. The substance can be solid particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made. Pollutants are classified as primary or secondary. Primary pollutants are usually produced from a process, such as ash from a volcanic eruption. Other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant. Some pollutants may be both primary and secondary: they are both emitted directly and formed from other primary pollutants

Major primary pollutants produced by human activity include:

• Sulfur oxides (SOx) - particularly sulfur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain.[2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.

• Nitrogen oxides (NOx) - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion, and are also produced during thunderstorms by electric discharge. They can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a chemical compound with the formula NO2. It is one of several nitrogen oxides. One of the most prominent air pollutants, this reddish-brown toxic gas has a characteristic sharp, biting odor.

• Carbon monoxide (CO) - CO is a colorless, odorless, toxic yet non-irritating gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.

• Volatile organic compounds - vocs are a well-known outdoor air pollutant. They are categorized as either methane (ch4) or non-methane (nmvocs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon vocs are also significant greenhouse gases because of their role in creating ozone and prolonging the life of methane in the atmosphere. This effect varies depending on local air quality. The aromatic nmvocs benzene, toluene and xylene are suspected carcinogens and may lead to leukemia with prolonged exposure. 1,3-butadiene is another dangerous compound often associated with industrial use.

• Particulates, alternatively referred to as particulate matter (pm), atmospheric particulate matter, or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to combined particles and gas. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged worldwide, anthropogenic aerosols—those made by human activities—currently account for approximately 10 percent of our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease, altered lung function and lung cancer.

• Persistent free radicals connected to airborne fine particles are linked to cardiopulmonary disease.

• Toxic metals, such as lead and mercury, especially their compounds.• Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from products

are currently banned from use. These are gases which are released from air conditioners, refrigerators, aerosol sprays, etc. CFC's on being released into the air rises to stratosphere. Here they come in contact with other gases and damage the ozone layer. This allows harmful ultraviolet rays to reach the earth's surface. This can lead to skin cancer, disease to eye and can even cause damage to plants.

• Ammonia (NH3) - emitted from agricultural processes. Ammonia is a compound with the formula NH3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous. In the atmosphere, ammonia reacts with oxides of nitrogen and sulfur to form secondary particles.

• Odors — such as from garbage, sewage, and industrial processes• Radioactive pollutants - produced by nuclear explosions, nuclear events, war

explosives, and natural processes such as the radioactive decay of radon.

Secondary pollutants include:• Particulates created from gaseous primary pollutants and compounds in

photochemical smog. Smog is a kind of air pollution. Classic smog results from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide. Modern smog does not usually come from coal but from vehicular and industrial emissions that are acted on in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also combine with the primary emissions to form photochemical smog.

• Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is a key constituent of the troposphere. It is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer. Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night. At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog.

• Peroxyacetyl nitrate (PAN) - similarly formed from NOx and VOCs.

Minor air pollutants include:

• A large number of minor hazardous air pollutants are regulated in USA under the Clean Air Act and in Europe under the Air Framework Directive

• A variety of persistent organic pollutants, which can attach to particulates

Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potentially significant impacts on human health and the environment

SourcesThere are various locations, activities or factors which are responsible for releasing

pollutants into the atmosphere. These sources can be classified into two major categories.

Anthropogenic (man-made) sources:• These are mostly related to the burning of multiple types of fuel.• Stationary sources include smoke stacks of power plants, manufacturing facilities

(factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices. In developing and poor countries, traditional biomass burning is the major source of air pollutants; traditional biomass includes wood, crop waste and dung.

• Mobile sources include motor vehicles, marine vessels, and aircraft.• Controlled burn practices in agriculture and forest management. Controlled or

prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest.

Fumes from paint, hair spray, varnish, aerosol sprays and other solvents

Waste deposition in landfills, which generate methane. Methane is highly flammable and may form explosive mixtures with air. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19.5% by displacement.

Military resources, such as nuclear weapons, toxic gases, germ warfare and rocketry

Dust from natural sources, usually large areas of land with few or no vegetation

Methane, emitted by the digestion of food by animals, for example; cattle Radon gas from radioactive decay within the Earth's crust. Radon is a

colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking.

Vegetation, in some regions, emits environmentally significant amounts of VOCs on warmer days. These VOCs react with primary anthropogenic pollutants—specifically, NOx, SO2, and anthropogenic organic carbon compounds — to produce a seasonal haze of secondary pollutants. Black gum, poplar, oak and willow are some examples of vegetation that can produce abundant VOCs. The VOC production from these species result in ozone levels up to eight times higher than the low-impact tree species.

Volcanic activity, which produces sulfur, chlorine, and ash particulates Smoke and carbon monoxide from wildfires

Wild fire in Georgia

Emission factors• Air pollutant emission factors are representative values that people

attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per tonne of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.

• There are 12 compounds in the list of POPs. Dioxins and furans are two of them and intentionally created by combustion of organics, like open burning of plastics. The POPs are also endocrine disruptors and can mutate the human genes.

• The United States Environmental Protection Agency has published a compilation of air pollutant emission factors for a multitude of industrial sources. The United Kingdom, Australia, Canada and many other countries have published similar compilations, as well as the European Environment Agency.

Indoor air quality (IAQ)• A lack of ventilation indoors concentrates air pollution where people often spend

the majority of their time. Radon (Rn) gas, a carcinogen, is exuded from the Earth in certain locations and trapped inside houses. Building materials including carpeting and plywood emit formaldehyde (H2CO) gas. Paint and solvents give off volatile organic compounds (VOCs) as they dry. Lead paint can degenerate into dust and be inhaled. Intentional air pollution is introduced with the use of air fresheners, incense, and other scented items. Controlled wood fires in stoves and fireplaces can add significant amounts of smoke particulates into the air, inside and out. Indoor pollution fatalities may be caused by using pesticides and other chemical sprays indoors without proper ventilation.

• Carbon monoxide (CO) poisoning and fatalities are often caused by faulty vents and chimneys, or by the burning of charcoal indoors. Chronic carbon monoxide poisoning can result even from poorly-adjusted pilot lights. Traps are built into all domestic plumbing to keep sewer gas and hydrogen sulfide, out of interiors. Clothing emits tetrachloroethylene, or other dry cleaning fluids, for days after dry cleaning.

• Though its use has now been banned in many countries, the extensive use of asbestos in industrial and domestic environments in the past has left a potentially very dangerous material in many localities. Asbestosis is a chronic inflammatory medical condition affecting the tissue of the lungs. It occurs after long-term, heavy exposure to asbestos from asbestos-containing materials in structures. Sufferers have severe dyspnea (shortness of breath) and are at an increased risk regarding several different types of lung cancer. As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to the World Health Organization (WHO), these may defined as; asbestosis, lung cancer, and Peritoneal Mesothelioma (generally a very rare form of cancer, when more widespread it is almost always associated with prolonged exposure to asbestos).

• Biological sources of air pollution are also found indoors, as gases and airborne particulates. Pets produce dander, people produce dust from minute skin flakes and decomposed hair, dust mites in bedding, carpeting and furniture produce enzymes and micrometer-sized fecal droppings, inhabitants emit methane, mold forms on walls and generates mycotoxins and spores, air conditioning systems can incubate Legionnaires' disease and mold, and houseplants, soil and surrounding gardens can produce pollen, dust, and mold. Indoors, the lack of air circulation allows these airborne pollutants to accumulate more than they would otherwise occur in nature.

Health Effects

Air pollution is a significant risk factor for a number of health conditions including respiratory infections, heart disease, COPD, stroke and lung cancer. The health effects caused by air pollution may include difficulty in breathing, wheezing, coughing, asthma and worsening of existing respiratory and cardiac conditions. These effects can result in increased medication use, increased doctor or emergency room visits, more hospital admissions and premature death. The human health effects of poor air quality are far reaching, but principally affect the body's respiratory system and the cardiovascular system. Individual reactions to air pollutants depend on the type of pollutant a person is exposed to, the degree of exposure, and the individual's health status and genetics.The most common sources of air pollution include particulates, ozone, nitrogen dioxide, and sulfur dioxide. Children aged less than five years that live in developing countries are the most vulnerable population in terms of total deaths attributable to indoor and outdoor air pollution.

Effects of Air pollution• 1. Respiratory and heart problems: The effects of Air pollution are alarming. They are

known to create several respiratory and heart conditions along with Cancer, among other threats to the body. Several millions are known to have died due to direct or indirect effects of Air pollution. Children in areas exposed to air pollutants are said to commonly suffer from pneumonia and asthma.

• 2. Global warming: Another direct effect is the immediate alterations that the world is witnessing due to Global warming. With increased temperatures world wide, increase in sea levels and melting of ice from colder regions and icebergs, displacement and loss of habitat have already signaled an impending disaster if actions for preservation and normalization aren’t undertaken soon.

• 3. Acid Rain: Harmful gases like nitrogen oxides and sulfur oxides are released into the atmosphere during the burning of fossil fuels. When it rains, the water droplets combines with these air pollutants, becomes acidic and then falls on the ground in the form of acid rain. Acid rain can cause great damage to human, animals and crops.

• 4. Eutrophication: Eutrophication is a condition where high amount of nitrogen present in some pollutants gets developed on sea’s surface and turns itself into algae and and adversely affect fish, plants and animal species. The green colored algae that is present on lakes and ponds is due to presence of this chemical only.

• 5. Effect on Wildlife: Just like humans, animals also face some devastating affects of air pollution. Toxic chemicals present in the air can force wildlife species to move to new place and change their habitat. The toxic pollutants deposit over the surface of the water and can also affect sea animals.

• 6. Depletion of Ozone layer: Ozone exists in earth’s stratosphere and is responsible for protecting humans from harmful ultraviolet (UV) rays. Earth’s ozone layer is depleting due to the presence of chlorofluorocarbons, hydro chlorofluorocarbons in the atmosphere. As ozone layer will go thin, it will emit harmful rays back on earth and can cause skin and eye related problems. UV rays also have the capability to affect crops.

Regulations

1 2 3 4 5 6 7 8 9 10 +

Risk: Low (1-3) Moderate (4-6) High (7-10) Very high (above 10)

As it is now known that even low levels of air pollution can trigger discomfort for the sensitive population, the index has been developed as a continuum: The higher the number, the greater the health risk and need to take precautions. The index describes the level of health risk associated with this number as 'low', 'moderate', 'high' or 'very high', and suggests steps that can be taken to reduce exposure.

Health Risk

Air Quality Health Index

Health Messages

At Risk population General Population

Low 1-3 Enjoy your usual outdoor activities.

Ideal air quality for outdoor activities

Moderate 4-6

Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms.

No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.

High 7-10

Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy.

Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.

Very high Above 10

Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion.

Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

Most polluted world cities by PM(particulate matter)

Particulatematter,

μg/m³ (2004)City

168 Cairo, Egypt150 Delhi, India128 Kolkata, India (Calcutta)125 Tianjin, China123 Chongqing, China109 Kanpur, India109 Lucknow, India104 Jakarta, Indonesia101 Shenyang, China

Solutions for Air Pollution

• 1. Use public mode of transportation: Encourage people to use more and more public modes of transportation to reduce pollution. Also, try to make use of car pooling. If you and your colleagues come from the same locality and have same timings you can explore this option to save energy and money.

• 2. Conserve energy: Switch off fans and lights when you are going out. Large amount of fossil fuels are burnt to produce electricity. You can save the environment from degradation by reducing the amount of fossil fuels to be burned.

• 3. Understand the concept of Reduce, Reuse and Recycle: Do not throw away items that are of no use to you. In-fact reuse them for some other purpose. For e.g. you can use old jars to store cereals or pulses.

• 4. Emphasis on clean energy resources: Clean energy technologies like solar, wind and geothermal are on high these days. Governments of various countries have been providing grants to consumers who are interested in installing solar panels for their home. This will go a long way to curb air pollution.

• 5. Use energy efficient devices: CFL lights consume less electricity as against their counterparts. They live longer, consume less electricity, lower electricity bills and also help you to reduce pollution by consuming less energy.

Several attempts are being made world wide on a personal, industrial and governmental levels to curb the intensity at which Air Pollution is rising and regain a balance as far as the proportions of the foundation gases are concerned. This is a direct attempt at slacking Global warming. We are seeing a series of innovations and experiments aimed at alternate and unconventional options to reduce pollutants. Air Pollution is one of the larger mirrors of man’s follies, and a challenge we need to overcome to see a tomorrow.

Before flue-gas desulfurization was installed, the emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide.

Schematic drawing, causes and effects of air pollution: (1) greenhouse effect, (2) particulate contamination, (3) increased UV radiation, (4) acid rain, (5) increased ground

level ozone concentration, (6) increased levels of nitrogen oxides.

In the future it will be like this:

otherwise……

WWATATEER R PPOLOLLULUTITIOONN

What is water pollution?• Water pollution is the contamination of water

bodies (e.g. lakes, rivers, oceans, ponds, and ground water). This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.

• Water pollution affects the entire biosphere that is the plants and organisms living in the water bodies. In almost all cases the effect is damaging not only to individual species and population, but also to the natural biological communities

• Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels. It has been suggested that water pollution is the leading worldwide cause of deaths and diseases, and that it accounts for the deaths of more than 14,000 people daily. An estimated 580 people in India die of water pollution related illness every day. Around 90% the water in the cities of China is polluted, and as of 2007, half a billion Chinese had no access to safe drinking water. In addition to the acute problems of water pollution in developing countries, developed countries also continue to struggle with pollution problems. For example, in the most recent national report on water quality in the United States, 45 percent of streams , 47% of lakes, and 32 percent of bays were classified as polluted. The head of China's national development agency said in 2007 that one quarter the length of China's seven main rivers were so poisoned the water harmed the skin.

• Water is typically referred to as polluted when it is filled with contaminants and either does not support a human use, such as drinking water, or undergoes a shift in its ability to support its constituent biotic communities, such as fish. Natural phenomena such as volcanoes, algaes, storms, and earthquakes also cause major changes in water quality and the ecological status of water

Pollution in the Lachine Canal, Canada

What are the Categories?

Point source pollution – Point source pollution – Shipyard – Rio de JaneiroShipyard – Rio de Janeiro..• Point sourcesPoint sources • Point source water pollution refers to contaminants that enter a waterway from a single,

identifiable source, such as a pipe or ditch. Examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U.S. Clean Water Act (CWA) defines point source for regulatory enforcement purposes. The CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites.

• Nonpoint sources Nonpoint source pollution refers to diffuse contamination that does not originate from a single

discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. A common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from "sheet flow" over an agricultural field or a forest are also cited as examples of NPS pollution.

• Contaminated storm water washed off of parking lots, roads and highways, called urban runoff, is sometimes included under the category of NPS pollution. However, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source.

What is Ground water pollution?

• Interactions between groundwater and surface water are complex. Consequently, groundwater pollution, sometimes referred to as groundwater contamination, is not as easily classified as surface water pollution. By its very nature, groundwater aquifers are susceptible to contamination from sources that may not directly affect surface water bodies, and the distinction of point vs. non-point source may be irrelevant. A spill or ongoing release of chemical or radioactive contaminants into soil (located away from a surface water body) may not create point or non-point source pollution but can contaminate the aquifer below, creating a toxic plume. The movement of the plume, called a plume front, may be analyzed through a hydrological transport model or groundwater model. Analysis of groundwater contamination may focus on soil characteristics and site geology, hydrogeology, hydrology, and the nature of the contaminants.

What are the Causes? The specific contaminants leading to pollution in water include a wide spectrum of chemicals, pathogens, and physical changes such as elevated temperature and discoloration. While many of the chemicals and substances that are regulated may be naturally occurring (calcium, sodium, iron, manganese, etc.) the concentration is often the key in determining what is a natural component of water and what is a contaminant. High concentrations of naturally occurring substances can have negative impacts on aquatic flora and fauna.Oxygen-depleting substances may be natural materials such as plant matter (e.g. leaves and grass) as well as man-made chemicals. Other natural and anthropogenic substances may cause turbidity (cloudiness) which blocks light and disrupts plant growth, and clogs the gills of some fish species.Many of the chemical substances are toxic. Pathogens can produce waterborne diseases in either human or animal hosts. Alteration of water's physical chemistry includes acidity (change in pH), electrical conductivity, temperature, and eutrophication. Eutrophication is an increase in the concentration of chemical nutrients in an ecosystem to an extent that increases in the primary productivity of the ecosystem. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia (oxygen depletion) and severe reductions in water quality may occur, affecting fish and other animal populations.

PATHOGENSDisease-causing microorganisms are referred to as pathogens. Although the vast majority of

bacteria are either harmless or beneficial, a few pathogenic bacteria can cause disease. Coliform bacteria, which are not an actual cause of disease, are commonly used as a bacterial indicator of water pollution. Other microorganisms sometimes found in surface waters that have caused human health problems include:

o Burkholderia pseudomalleio Cryptosporidium parvum• Giardia lamblia• Salmonella• Norovirus and other viruses• Helminths (parasitic worms)

High levels of pathogens may result from inadequately treated sewage discharges.This can be caused by a sewage plant designed with less than secondary treatment (more typical in less-developed countries). In developed countries, older cities with aging infrastructure may have leaky sewage collection systems (pipes, pumps, valves), which can cause sanitary sewer overflows. Some cities also have combined sewers, which may discharge untreated sewage during rain storms. Pathogen discharges may also be caused by poorly managed livestock operations.

What is THERMAL POLLUTION?

• Thermal pollution is the rise or fall in the temperature of a natural body of water caused by human influence. Thermal pollution, unlike chemical pollution, results in a change in the physical properties of water. A common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers. Elevated water temperatures decrease oxygen levels, which can kill fish and alter food chain composition, reduce species biodiversity, and foster invasion by new thermophilic species.

• Urban runoff may also elevate temperature in surface waters.• Thermal pollution can also be caused by the release of very cold

water from the base of reservoirs into warmer rivers.

MEASURING OF POLLUTIONWater pollution may be analyzed through several broad categories of methods: physical, chemical and biological. Most

involve collection of samples, followed by specialized analytical tests. Some methods may be conducted in site, without sampling, such as temperature. Government agencies and research organizations have published standardized, validated analytical test methods to facilitate the comparability of results from disparate testing events.

Sampling• Sampling of water for physical or chemical testing can be done by several methods, depending on the accuracy needed

and the characteristics of the contaminant. Many contamination events are sharply restricted in time, most commonly in association with rain events. For this reason "grab" samples are often inadequate for fully quantifying contaminant levels. Scientists gathering this type of data often employ auto-sampler devices that pump increments of water at either time or discharge intervals.

Sampling for biological testing involves collection of plants and/or animals from the surface water body. Depending on the type of assessment, the organisms may be identified for biosurveys (population counts) and returned to the water body, or they may be dissected for bioassays to determine toxicity.

• Physical testing Common physical tests of water include temperature, solids concentrations (e.g., total suspended solids (TSS)) and

turbidity.• Chemical testing Water samples may be examined using the principles of analytical chemistry. Many published test methods are available

for both organic and inorganic compounds. Frequently used methods include pH, biochemical oxygen demand (BOD),chemical oxygen demand (COD),nutrients (nitrate and phosphorus compounds), metals (including copper, zinc, cadmium, lead and mercury), oil and grease, total petroleum hydrocarbons (TPH), and pesticides.

• Biological testing• Biological testing involves the use of plant, animal, and/or microbial indicators to monitor the health of an aquatic

ecosystem. They are any biological species or group of species whose function, population, or status can reveal what degree of ecosystem or environmental integrity is present. One example of a group of bio-indicators are the copepods and other small water crustaceans that are present in many water bodies. Such organisms can be monitored for changes

• (biochemical, physiological, or behavioral) that may indicate a problem within their ecosystem.

HOW TO CONTROL THE WATER POLLUTION?

• Domestic sewage Domestic sewage is typically 99.9 percent water with 0.1 percent pollutants. Although found in low

concentrations, these pollutants pose risk on a large scale. In urban areas, domestic sewage is typically treated by centralized sewage treatment plants. Well-designed and operated systems (i.e., secondary treatment or better) can remove 90 percent or more of these pollutants. Some plants have additional systems to remove nutrients and pathogens. Most municipal plants are not specifically designed to treat toxic pollutants found in industrial waste water.

Cities with sanitary sewer overflows or combined sewer overflows employ one or more engineering approaches to reduce discharges of untreated sewage, including:

• utilizing a green infrastructure approach to improve storm water management capacity throughout the system, and reduce the hydraulic overloading of the treatment plant• repair and replacement of leaking and malfunctioning equipment• increasing overall hydraulic capacity of the sewage collection system (often a very expensive option). A household or business not served by a municipal treatment plant may have an individual septic tank,

which treats the waste water on site and discharges into the soil. Alternatively, domestic waste water may be sent to a nearby privately owned treatment system.

Deer Island Waste Water Treatment Plant serving Boston, Massachusetts and vicinity

What are Industrial sewages?• Some industrial facilities generate ordinary domestic sewage that can be treated by

municipal facilities. Industries that generate waste water with high concentrations of conventional pollutants (e.g. oil and grease), toxic pollutants (e.g. heavy metals, volatile organic compounds) or other non-conventional pollutants such as ammonia, need specialized treatment systems. Some of these facilities can install a pre-treatment system to remove the toxic components, and then send the partially treated waste water to the municipal system. Industries generating large volumes of waste water typically operate their own complete on-site treatment systems. Some industries have been successful at redesigning their manufacturing processes to reduce or eliminate pollutants, through a process called pollution prevention.

• Heated water generated by power plants or manufacturing plants may be controlled with:o cooling ponds, man-made bodies of water designed for cooling by evaporation,

convection, and radiationo cooling towers, which transfer waste heat to the atmosphere through evaporation and/or

heat transfero cogeneration, a process where waste heat is recycled for domestic and/or industrial

heating purposes.

Dissolved air flotation system for treating industrial wastewater.

WATER CONSERVATION

What is WATER CONSERVATION?• Water conservation encompasses the policies, strategies and activities to

manage fresh water as a sustainable resource, to protect the water environment, and to meet current and future human demand. Population, household size and growth and affluence all affect how much water is used. Factors such as climate change will increase pressures on natural water resources especially in manufacturing and agricultural irrigation.

The goals of water conservation efforts include as follows:• To ensure availability for future generations, the withdrawal of fresh water

from an ecosystem should not exceed its natural replacement rate.• Energy conservation. Water pumping, delivery and waste water treatment

facilities consume a significant amount of energy. In some regions of the world over 15% of total electricity consumption is devoted to water management.

• Habitat conservation. Minimizing human water use helps to preserve fresh water habitats for local wildlife and migrating waterfowl, as well as reducing the need to build new dams and other water diversion infrastructures.

Water conservation programs involved in social solutions are typically initiated at the local level, by either municipal water utilities or regional governments. Common strategies include public outreach campaigns, tiered water rates (charging progressively higher prices as water use increases), or restrictions on outdoor water use such as lawn watering and car washing. Cities in dry climates often require or encourage the installation of natural landscaping in new homes to reduce outdoor water usage.

One fundamental conservation goal is universal metering. The prevalence of residential water metering varies significantly worldwide. Recent studies have estimated that water supplies are metered in less than 30% of UK households, and about 61% of urban Canadian homes (as of 2001).Although individual water meters have often been considered impractical in homes with private wells or in multifamily buildings, the U.S. Environmental Protection Agency estimates that metering alone can reduce consumption by 20 to 40 percent. In addition to raising consumer awareness of their water use, metering is also an important way to identify and localize water leakage. Water metering would benefit society in the long run it is proven that water metering increases the efficiency of the entire water system, as well as help unnecessary expenses for individuals for years to come. One would be unable to waste water unless they are willing to pay the extra charges, this way the water department would be able to monitor water usage by public, domestic and manufacturing services.

METHODS OF WATER CONSERVATION

•SOCIAL SOLUTIONS Water conservation programs involved in social solutions are typically initiated at the local level, by

either municipal water utilities or regional governments. Common strategies include public outreach campaigns,[4] tiered water rates (charging progressively higher prices as water use increases), or restrictions on outdoor water use such as lawn watering and car washing.[5] Cities in dry climates often require or encourage the installation of natural landscaping in new homes to reduce outdoor water usage.[6]

One fundamental conservation goal is universal metering. The prevalence of residential water metering varies significantly worldwide. Recent studies have estimated that water supplies are metered in less than 30% of UK households,[7] and about 61% of urban Canadian homes (as of 2001).[8] Although individual water meters have often been considered impractical in homes with private wells or in multifamily buildings, the U.S. Environmental Protection Agency estimates that metering alone can reduce consumption by 20 to 40 percent.[9] In addition to raising consumer awareness of their water use, metering is also an important way to identify and localize water leakage. Water metering would benefit society in the long run it is proven that water metering increases the efficiency of the entire water system, as well as help unnecessary expenses for individuals for years to come. One would be unable to waste water unless they are willing to pay the extra charges, this way the water department would be able to monitor water usage by public, domestic and manufacturing services.

Some researchers have suggested that water conservation efforts should be primarily directed at farmers, in light of the fact that crop irrigation accounts for 70% of the world's fresh water use.[10]

New technology poses a few new options for consumers, features such and full flush and half flush when using a toilet are trying to make a difference in water consumption and waste. Also available in our modern world is shower heads that help reduce wasting water, old shower heads are said to use 5-10 gallons per minute. All new fixtures available are said to use 2.5 gallons per minute and offer equal water coverage.

•HOUSEHOLD APPLICATIONSThe Home Water Works website contains useful information on household water conservation.Contrary to

popular view, experts suggest the most efficient way is replacing toilets and retrofitting washers.Water-saving technology for the home includes:• Low-flow shower heads sometimes called energy-efficient shower heads as they also use less energy• Low-flush toilets and composting toilets. These have a dramatic impact in the developed world, as

conventional Western toilets use large volumes of water• Dual flush toilets created by Caroma includes two buttons or handles to flush different levels of water. Dual

flush toilets use up to 67% less water than conventional toilets• Faucet aerators, which break water flow into fine droplets to maintain "wetting effectiveness" while using

less water. An additional benefit is that they reduce splashing while washing hands and dishes• Raw water flushing where toilets use sea water or non-purified water• Wastewater reuse or recycling systems, allowing:

– Reuse of gray water for flushing toilets or watering gardens– Recycling of wastewater through purification at a water treatment plant.

• Rainwater harvesting• Weather-based irrigation controllers• Garden hose nozzles that shut off water when it is not being used, instead of letting a hose run.• Low flow taps in wash basins• Swimming pool covers that reduce evaporation and can warm pool water to reduce water, energy and

chemical costs.• Automatic faucet is a water conservation faucet that eliminates water waste at the faucet. It automates the

use of faucets without the use of hands.

•COMMERCIAL APPLICATIONS

• Many water-saving devices (such as low-flush toilets) that are useful in homes can also be useful for business water saving. Other water-saving technology for businesses includes:

• Waterless urinals• Waterless car washes• Infrared or foot-operated taps, which can save water by using short bursts of

water for rinsing in a kitchen or bathroom• Pressurized water brooms, which can be used instead of a hose to clean sidewalks• X-ray film processor re-circulation systems• Cooling tower conductivity controllers• Water-saving steam sterilizers, for use in hospitals and health care facilities• Rain water harvesting• Water to Water heat exchangers.

Simple ways you can practise• Turn off water while you are brushing your teeth and open it when you

need to rinse your mouth.• Take shallow baths and plug the drain before you run water. Keep showers

short with pressure at low force. Re-use bath water to water your lawn or shrubs or for heavy cleaning jobs like floors or cars.

• Install Dual Flush toilets in the home.• Buy the washing machines or dishwashers that have AAA ratings and that

are ranked as energy efficient.• Get rain tanks and collect the rainwater in them. That water can be used for

gardening and washing cars.• Use mulch around the trees and plants in your lawn. This keeps in moisture

longer so that use will need less water to keep your lawn and plants healthy.

Minimum water network target and design

The cost effective minimum water network is a holistic framework/guide for water conservation that helps in determining the minimum amount of freshwater and wastewater target for an industrial or urban system based on the water management hierarchy i.e. it considers all conceivable methods to save water. The technique ensure that the designer desired payback period is satisfied using Systematic Hierarchical Approach for Resilient Process Screening (SHARPS) technique.

Water -saving devices

Spray tap

Aerator tap

Low-flow shower with shut off valve

US postage stamp advocating ‘water conservation’

Drip irrigation: a way of conserving water