M1 ME

UNIT - 4

ENVIRONMENT- TRADITIONAL AND FUTURISTIC METHODS

The environment refers to the totality of resources and the total planetary inheritance we have received. It includes biotic (animals, plants, birds etc.) and abiotic (sun, land, water and mountains etc.) components. It explains the inter relationship that exists between the abiotic and biotic components.

The environment performs four crucial functions

Supplying resources: the environment contains both renewable (air, water and land) and non renewable resources (fossil fuels). While the former are reusable and do not get depleted soon, non renewable resources come with the fear of depletion.

Assimilating waste: economic activities generate waste which the environment absorbs through the natural processes.

Sustenance of life: the environment comprises abiotic components that aid the living of biotic components. In the absence of elements such as air, water, land etc. there would be no life on the planet.

Aesthetic value: the environment adds aesthetic value to life. The mountains, oceans, seas, landmasses and other sceneries of the environment enhance the quality of life.

4.1 Environmental conservation

Environmental conservation is the practice of us humans saving the environment from the loss of species, and the destruction of the ecosystem, primarily due to pollution and human activities. Conservation is vital in saving and helping both animals and trees as we are all dependent on one another for survival.

Environmental conservation is an umbrella term that defines anything we do to protect our planet and conserve its natural resources so that every living thing can have an improved quality of life.

Environmental conservation and preservation are two terms that are often used interchangeably, although they are quite different. Conservation refers to the responsible management of the environment and its resources for present and future use. Preservation, on the other hand, is a much stricter approach where the environment, lands and natural resources are put away, not to be consumed by humans, but are instead maintained in their pristine form. If the land is to be used by humans, it should only be utilized for its natural beauty and inspiration.

4.2 METHODS

Forest conservation

Afforestation and reforestation help in conserving the forests, which are responsible for trapping absorbing a huge amount of carbon dioxide from reaching the atmosphere. We should make it our life mission to plant trees as much as possible, both on public and private lands, and take care of them. Additionally, legislation that protects the forests should be highlighted, so that we help in environmental conservation.

 Soil conservation

Soil conservation helps control erosions and improves the soil for agricultural purposes. We should plant more trees, protect pasture lands, and grow cover crops which regulate the blowing away of soils. We should also minimize the use of chemicals, use compost fertilizers and terrace farms on slopy lands.

Managing waste

Solid waste is produced by market areas, industries, homes, settlement areas and many other locations. We should therefore manage our solid waste and help keep the environment healthy. Municipalities should also conduct program that manages solid wastes designating litter bins all over the towns and collecting the waste regularly. Additionally, we should teach ourselves how to manage our waste without littering all over.

Recycling

We should learn to recycle everything we can for as long as it is possible. Glass, paper, plastic and even metals are reusable, and should not be thrown away after its original use. About 90% of all plastic bottles do not reach recycling units and this is unfortunate. They are not biodegradable and about 500 billion of them are used every year. Reusing these bottles, containers, bags and more will help in environmental conservation.

Reducing our water consumption

Clean, fresh and safe water is precious and not easily available. It is therefore very crucial to save as much water as possible, and prevent water pollution, otherwise, it will be scarce in years to come. Reduce the number of baths, take showers, use the washing machine only, do not discard waste in bodies of fresh water, and recycle, so that we conserve the little freshwater we have now.

Control pollution

We should regularly maintain our cars and leave them at home for as much as it is possible as they are a primary source of air pollution. Using rechargeable batteries helps the environment as we will not be prone to throwing them away once they are empty.

Composting also avoids littering, and not only does it protect the environment, but is also a reliable source of natural manure. Avoid chemical fertilizers, herbicides, pesticides and insecticides that pollute the environment. We should control pollution in as much as it is possible, to conserve the environment.

Create public awareness

Make people aware of the consequences of our activities through the various means available such as social media, seminars and the traditional media. Also, discuss environmental protection with your friends and family members so that everyone is made aware of environmental conservation, ways to conserve the environment and potential consequences if we do not take care of the environment.

4.3 SOLID WASTE

Solid waste comprises of all the waste arising from human and animal waste that are typically solid and that are discarded as useless or unwanted.

Commonly used synonyms for the solid waste

Refuse

Garbage: consists of kitchen waste.

Rubbish: wastes with high ash.

Debris: bulky wastes such as construction waste.

Scrap: wastes that have high metal content.

4.4 SOLID WASTE MANAGEMENT

Solid waste management is a term that is used to refer to the process of collecting and treating solid wastes. It also offers solutions for recycling that do not belong to garbage or trash. As long as people have been living in settlements and residential areas, garbage or solid waste has been an issue. Waste management is all about how solid waste can be changed and used as a valuable resource.

METHODS OF SOILD WASTE MANAGEMENT

SANITARY LANDFILL

This is the most popular solid waste disposal method used today. Garbage is basically spread out in thin layers, compressed and covered with soil or plastic foam. 

Modern landfills are designed in such a way that the bottom of the landfill is covered with an impervious liner, which is usually made of several layers of thick plastic and sand. This liner protects the groundwater from being contaminated because of leaching or percolation.

When the landfill is full, it is covered with layers of sand, clay, topsoil and gravel to prevent seepage of water.

Advantage: If landfills are managed efficiently, it is an ensured sanitary waste disposal method.

Constraint: It requires a reasonably large area.

 INCINERATION

This method involves the burning of solid wastes at high temperatures until the wastes are turned into ashes. Incinerators are made in such a way that they do not give off extreme amounts of heat when burning solid wastes. 

Incinerators that recycle heat energy through furnace and boiler are called waste-to-energy plants. These waste-to-energy systems are more expensive to set up and operate compared to plain incinerators because they require special equipment and controls, highly skilled technical personnel, and auxiliary fuel systems.

This method of solid waste management can be done by individuals, municipalities and even institutions. The good thing about this method is the fact that it reduces the volume of waste up to 20 or 30% of the original volume.

Advantage: The volume of combustible waste is reduced considerably by burning waste. In the case of off-site pits, it is an appropriate method to minimize scavenging.

Constrain: It can cause smoke or fire hazard and also emits gaseous pollutants

RECYCLING

Recycling or recovery of resources is the process of taking useful but discarded items for the next use. Plastic bags, tins, glass and containers are often recycled automatically since, in many situations, they are likely to be scarce commodities.

Traditionally, these items are processed and cleaned before they are recycled. The process aims at reducing energy loss, consumption of new material and reduction of landfills. The most developed countries follow a strong tradition of recycling to lower volumes of waste.

Advantage: Recycling is environmentally friendly.

Constraint: It is expensive to set up, and in most emergencies, there is limited potential.

 

COMPOSTING

Due to a lack of adequate space for landfills, biodegradable yard waste is allowed to decompose in a medium designed for the purpose. Only biodegradable waste materials are used in composting. 

It is a biological process in which micro-organisms, specifically fungi and bacteria, convert degradable organic waste into substances like humus. This finished product, which looks like soil, is high in carbon and nitrogen. Good quality environmental friendly manure is formed from the compost that is an excellent medium for growing plants and can be used for agricultural purposes

Advantage: Composting is environmental friendly as well as beneficial for crops.

Constrain: It requires intensive management and experienced personnel for large scale operation.

PYROLYSIS

This is a method of solid waste management whereby solid wastes are chemically decomposed by heat without the presence of oxygen. It usually occurs under pressure and at temperatures of up to 430 degrees Celsius. The solid wastes are changed into gasses, solid residue of carbon and ash and small quantities of liquid.

Advantage: This will keep the environment cleaned reduce health and settlement problems.

Constraint: The systems that destroy chlorinated organic molecules by heat may create incomplete combustion products, including dioxins and furans. These compounds are highly toxic in the parts per trillion ranges. The residue it generates may be hazardous wastes, requiring proper treatment, storage, and disposal.

4.5 WATER PURIFICATION

Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water fit for specific purposes. These standards usually include minimum and maximum concentrations of contaminants, depending on the intended use of the water.

METHODS

1. Boiling

The simplest method to purify water is to boil it for a good amount of time. High temperatures cause the bacteria and virus to dissipate, removing all impurities from the water. In doing so, chemical additions cease to exist in the water as well. However, the dead micro-organisms and impurities settle at the bottom of the water, and boiling does not help eliminate all the impurities. You must strain the water through a micro-porous sieve to completely get rid of the impurities.

2. Water Purifier

An electric water purifier is the most trusted form of water purification that can be found in most houses today. A water purifier uses a multi-stage process that involves UV and UF filtration, carbon block, and modern water filtration technology that eliminates a majority of the chemicals and impurities making it the purest drinking water.

3. Reverse Osmosis

An RO Purifier proves to be one of the best methods of purifying water. Reverse Osmosis forces water through a semi-permeable membrane and removes contaminants. The TDS Controller and Mineraliser Technology like the one found in an A. O. Smith RO UV Water Purifier help retain the necessary nutrients while doing away with harmful impurities.

4. Water Chlorination

This is an older technique used usually during an emergency, wherein a mild bleach with approximately 5% chlorine is added to the water. This mixture works as an oxidant and quickly kills microorganisms, making water safe for consumption.

5. Distillation

Distillation is a water purification process that involves collecting the condensed water after evaporation, which ensures that water is free of contaminants. However, this isn’t as effective as an RO filter because it is time-consuming and eliminates minerals as well.

6. Iodine Addition

Iodine is a red chemical that is easily available as a tablet or a liquid. It is extremely powerful as it kills bacteria and viruses. However, it adds an unpleasant taste and can be fatal if taken in high doses. Therefore, it should only be used if you don’t have access to a better method of purification like an electric water purifier.

7. Solar Purification

An alternative to the UV filtration is solar purification which involves treating water with the ultraviolet radiation of the sun. The process involves filling a plastic bottle with water, shaking it to activate the oxygen and leaving it horizontally in the sunlight. This effectively kills bacteria and viruses present in the water, making it safe for consumption.

8. Clay Vessel Filtration

Way before people had access to an RO or UV Purifier, they used clay pots which purified muddy water, by blocking out the mud and allowing pure, potable water to pass through. This method is still used in some rural regions.

9. UV Radiation

Water is exposed to a UV Light that kills microorganisms, thereby preventing it from breeding further. But if not coupled with an RO Filter, UV Radiation alone cannot remove impurities and heavy metals.

10. Desalination

4.6 WASTEWATER TREATMENT

Wastewater is water that has been used and must be treated before it is released into another body of water, so that it does not cause further pollution of water sources. Wastewater comes from a variety of sources. Everything that you flush down your toilet or rinse down the drain is wastewater. Rainwater and runoff, along with various pollutants, go down street gutters and eventually end up at a wastewater treatment facility. Wastewater can also come from agricultural and industrial sources. Some wastewaters are more difficult to treat than others; for example, industrial wastewater can be difficult to treat, whereas domestic wastewater is relatively easy to treat (though it is increasingly difficult to treat domestic waste, due to increased amounts of pharmaceuticals and personal care products that are found in domestic wastewater.

Process

There are several levels of wastewater treatment; these are primary, secondary and tertiary levels of treatment. Most municipal wastewater treatment facilities use primary and secondary levels of treatment, and some also use tertiary treatments.

Primary level

The primary level of treatment uses screens and settling tanks to remove the majority of solids. This step is extremely important, because solids make up approximately 35 percent of the pollutants that must be removed. The screens usually have openings of about 10 millimetres, which is small enough to remove sticks, garbage and other large materials from the wastewater. This material is removed and disposed of at the landfill.

The water is then put into settling tanks (or clarifiers), where it sits for several hours, allowing the sludge to settle and a scum to form on the top. The scum is then skimmed off the top, the sludge is removed from the bottom, and the partially treated wastewater moves on to the secondary treatment level. The primary treatment generally removes up to 50 percent of the Biological Oxygen Demand (BOD; these are substances that use up the oxygen in the water), around 90 percent of suspended solids, and up to 55 percent of fecal coliforms. While primary treatment removes a significant amount of harmful substances from wastewater, it is not enough to ensure that all harmful pollutants have been removed.

Secondary level

Secondary treatment of wastewater uses bacteria to digest the remaining pollutants. This is accomplished by forcefully mixing the wastewater with bacteria and oxygen. The oxygen helps the bacteria to digest the pollutants faster. The water is then taken to settling tanks where the sludge again settles, leaving the water 90 to 95 percent free of pollutants. The picture below shows the settling tanks in the Winnipeg Wastewater Treatment Plant. Secondary treatment removes about 85 to 90 percent of BOD and suspended solid, and about 90 to 99 percent of coliform bacteria.

Some treatment plants follow this with a sand filter, to remove additional pollutants. The water is then disinfected with chlorine, ozone, or ultraviolet light, and then discharged.

The sludge that is removed from the settling tanks and the scum that is skimmed off the top during the primary steps are treated separately from the water. Anaerobic bacteria (anaerobic bacteria do not require oxygen) feed off of the sludge for 10 to 20 days at temperatures around 38 degrees Celsius. This process decreases the odour and organic matter of the sludge, and creates a highly combustible gas of methane and carbon dioxide, which can be used as fuel to heat the treatment plant. Finally, the sludge is sent to a centrifuge, like the one shown in the picture below. A centrifuge is a machine that spins very quickly, forcing the liquid to separate from the solid. The liquid can then be processed with the wastewater and the solid is used as fertilizer on fields.

Tertiary level

Tertiary (or advanced) treatment removes dissolved substances, such as colour, metals, organic chemicals and nutrients like phosphorus and nitrogen. There are a number of physical, chemical and biological treatment processes that are used for tertiary treatment. One of the biological treatment processes is called Biological Nutrient Removal (BNR).

 

Water Recycling Process Diagram

4.7 WATER RECYCLING

Recycling water allows us to continually reuse one of our most vital resources. Water recycling removes contaminants from wastewater and allows it to re-enter local water systems for use in homes and businesses. Recycling water ensures that the water is safe for consumption and other practical uses. 

4.8 HAZARDOUS WASTE

Hazardous waste is any unwanted material the disposal of which poses a threat to the environment, i.e. it is explosive, flammable, oxidising, poisonous/infectious, radioactive, corrosive and/or toxic/ecotoxic.

Sources of hazardous waste include hospitals, timber treatment, petrol storage, metal finishing, paint manufacture, vehicle servicing, tanneries, agriculture/horticulture, electricity distribution and dry cleaning.

4.9 TREATMENT OF HAZARDOUS WASTES

Chemical methods

1. NEUTRALISATION: Waste acid with an alkali e.g. sulfuric acid with sodium carbonate: H2SO4 + CO3 2- → SO4 2- + CO2 + H2O

2. Oxidation: Using common oxidising substances such as hydrogen peroxide or calcium hypochlorite e.g. cyanide waste with calcium hypochlorite: CN- + OCl- → OCN- + ClOCN- + H3O+ → CO2 + NH3

3. Reduction Used to convert inorganic substances to a less mobile and toxic form e.g. reducing Cr(VI) to Cr(III) by the use of ferrous sulphate: 14H+ + Cr2O7 2- + 6Fe2+ → 6Fe3+ + 2Cr3+ + 7H2O

4. Hydrolysis: Decomposition of hazardous organic substances e.g. decomposing certain organophosphorus pesticides with sodium hydroxide.

5. Precipitation Particularly useful for converting hazardous heavy metals to a less mobile, insoluble form prior to disposal to a landfill e.g. precipitation of cadmium as its hydroxide by the use of sodium hydroxide: Cd2+(aq) + 2OH- → Cd(OH)2(s)

Physical Methods

1. Encapsulation Immobilising hazardous materials by stabilisation and incorporation within a solid matrix such as cement concrete or proprietary organic polymers prior to and filling. e.g. encapsulating beryllium in concrete

2. Filtration/Centrifuging/Separation Physically separating phases containing hazardous substances from other nonhazardous constituents e.g. separation of oils from ships bilge waters.

Biological Methods These involve the use of microorganisms under optimised conditions to mineralise hazardous organic substances e.g. the use of pseudomonas under aerobic conditions break down phenols.

Thermal Methods These are the treatment processes which involve the application of heat to convert the waste into less hazardous forms. It also reduces the volume and allows opportunities for the recovery of energy from the waste..

High Temperature Incineration In North America and Europe the treatment method most commonly used to destroy hazardous organic wastes, including organochlorines such as polychlorinated biphenyls (PCBs), is high temperature incineration.

4.10 FLOOD CONTROL

Flood control methods are used to reduce or prevent the detrimental effects of flood waters. Flood relief methods are used to reduce the effects of flood waters or high water levels.

Causes of floods

Floods are caused by many factors or a combination of any of these generally prolonged heavy rainfall (locally concentrated or throughout a catchment area), highly accelerated snowmelt, sever winds over water, unusual high tides, tsunamis or failure of dams, levees, retention periods or other structures that retained the water.

Periodic floods occur on many rivers, forming a surrounding region known as flood plain.

During times of rain, some of the water is retained in ponds or soil, some is absorbed by grass and vegetation, some evaporates and the rest travels over the land as surface runoff. Flood occurs when ponds, lakes, riverbeds, soil and vegetation cannot absorb all the water.

Effects of flood

Flooding has many impacts. It damages property and endangers the lives of humans and other species. Rapid water runoff causes soil erosion and concomitant sediment deposition elsewhere (such as further downstream or down a coast). The spawning grounds for fish and other wildlife habitats can become polluted or completely destroyed. Some prolonged high floods can delay traffic in areas which lack elevated roadways. Floods can interfere with drainage and economical use of lands, such as interfering with farming. Structural damage can occur in bridge abutments, bank lines, sewer lines, and other structures within floodway. Waterway navigation and hydroelectric power are often impaired. Financial losses due to floods are typically millions of dollars each year, with the worst floods in recent U.S. history having cost billions of dollars.

Benefits of flooding

There are many disruptive effects of flooding on human settlements and economic activities. However, flooding can bring benefits such as making soil more fertile and providing nutrients in which in many ways it is deficient. Periodic flooding was essential to the well being of ancient communities. The viability for hydrologically based renewable energy sources of energy is higher in flood prone regions.

Methods of flood management

Some methods of flood control have been practiced since ancient times. These methods include planting vegetation to retain extra water, terracing hillsides to slow flow downhill, and the construction of floodway (man-made channels to divert floodwater). Other techniques include the construction of levees, lakes, dams, reservoirs, retentions ponds to hold extra water during times of flooding.

DAMS

Many dams and their associated reservoirs are designed completely or partially to aid in flood protection and control. Many large dams have flood-control reservations in which the level of a reservoir must be below a certain elevation before the onset of the rainy/summer melt season to allow a certain amount of space in which floodwaters can fill. Other beneficial uses of dam created reservoirs include hydroelectric power generation, water conservation and recreation. Reservoir and dam construction and design are based upon standard typically set out by the government. In the U.S, dams and reservoir design is regulated by the US army corps of engineers (USACE). Design of a dam and reservoir follows guidelines set by the USACE and covers topics such as design flow rates in consideration to meteorological, topographic, stream-flow and soil data for the watershed above the structure.

The term dry dam refers to a dam that serves purely for flood control without any conservation storage.

Diversion canals

Floods can be controlled by redirecting excess water to purpose built canals or flood-ways, which in turn divert the water to temporary holding ponds or other bodies of water where there is lower risk or impact to flooding.

Floodplains and groundwater replenishment

Excess water can be used for groundwater replenishment by diversion onto land that can absorb the water. This technique can reduce the impact of later droughts by using the ground as a natural reservoir. It is being used in California, where orchards and vineyards can be flooded without damaging crops or in other places wilderness areas have been re-engineered to act as floodplains.

River defences

In many countries, rivers are prone to floods and are often carefully managed defences such as levees, bunds, reservoirs and weirs are used to prevent rivers form bursting their banks. A weir also known as low-head dam is more often used to create millponds.

The Leeds flood alleviation scheme uses movable weirs which are lowered during periods of high water to reduce the chances of flooding upstream. They are designed to reduce potential flood levels by up to one meter.

4.11 MULTI PURPOSE WATER PROJECTS

A multipurpose project is that which simultaneously serves several purposes. A dam built across a river often serves more than one purpose at a time and is termed as a multipurpose project. Flood control, irrigation, hydroelectric generation, navigation, fishing and tourism etc are some of the chef aims of multipurpose project.   

ADVANTAGES OF MULTI PURPOSE PROJECTS

1. Irrigation Facility:

Extension of irrigation facility is one of the important objectives and advantage of multipurpose projects. These projects can stimulate the agricultural productivity for meeting the growing requirement of food and raw materials required for increasing non-farm activities.

2. Flood Control:

Another important objective of such projects is to control the occurrence of floods creating havocs on the economy.

3. Generating Electricity:

Multi-purpose projects help to generate hydro-electricity on a large scale basis, which is very much important for the development of industry.

4. Navigation:

Such projects can create navigation facility in the country by developing ferrying services for transportation, raise fleet capacity and thereby can reduce the traffic load on rail and road transport.

5. Forests and Fisheries:

These projects can help to raise forestry on the banks of the canals. Moreover, it can also encourage the development of fisheries in the reservoirs.

6. Drinking Water:

Such projects facilitate the development of safe drinking water projects for the adjoining areas.

7. Development of Industry and Employment Generation:

Such projects can create a favourable climate for the development of industry by offering the facilities like cheaper power, better water transport, availability of raw materials at cheaper rates for agro-based industries etc.

Moreover, by developing agriculture, industry and infrastructural services, these projects can generate adequate volume of employment opportunities in the farm and non-farm sector. All these would help to raise the standard of living of the people of those adjoining regions reaping benefits from such projects.

8. Recreation:

Multi-purpose projects can also facilitate to develop recreation facilities in the form of picnic resorts, holiday resorts etc. which are having much commercial viability nowadays.

DEMERITS OF MULTIPURPOSE PROJECTS

1. Exaggerated Benefits on Irrigation:

It has been argued that irrigation benefits derived out of multi-purpose projects are exaggerated because the actual area irrigated by these projects is much less due to delay in the construction of field channels and water routes. Moreover delay in completion of these projects has resulted in high escalation of its cost.

2. Higher Cost of Hydropower:

Although hydro power is having the advantage of low operating cost, renewable source and eco-friendly but at the same time it is also subjected to long gestation period, delay in commissioning the project resulting escalation of project cost and higher initial cost. All these have resulted in a comparatively higher unit cost of generation in respect of hydro power.

3. Least Flood Control Benefit:

The multi-purpose projects have also failed to derive maximum benefit in respect of flood control as the embankments, drainage channels and flood protection schemes have failed miserably to achieve results.

4. Adverse Environmental Impact:

Finally, the multi-purpose projects have resulted serious adverse environmental impact in respect of degradation of soil content arising out of water-logging and soil salinity in its command areas.

4.12 ATMOSPHERIC POLLUTION

Air pollution occurs in many forms but can generally be thought of as gaseous and particulate contaminants that are present in the earth’s atmosphere. Chemicals discharged into the air that have a direct impact on the environment are called primary pollutants. These primary pollutants sometimes react with other chemicals in the air to produce secondary pollutants.

Common Air Pollutants

The most commonly found air pollutants are particulate matter, ground-level ozone, carbon monoxide, sulphur oxides, nitrogen oxides, and lead. These pollutants can harm health and the environment, and cause property damage. Of the six pollutants, particle pollution and ground-level ozone are the most widespread health threats. The U.S. Environmental Protection Agency (EPA)  regulates them by developing criteria based on considerations of human and environmental health.

1. Ground-level ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight. Emissions from industrial facilities and electric utilities, motor vehicle exhaust, gasoline vapors, and chemical solvents are some of the major sources of NOx and VOC. Breathing ozone can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. Ground level ozone can also have harmful effects on sensitive vegetation and ecosystems. (Ground-level ozone should not be confused with the ozone layer, which is high in the atmosphere and protects Earth from ultraviolet light; ground-level ozone provides no such protection).

2. Particulate matter, also known as particle pollution, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles. The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.

3. Carbon monoxide (CO) is a colourless, odourless gas emitted from combustion processes.  Nationally and, particularly in urban areas, the majority of CO emissions to ambient air come from mobile sources.  CO can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues. At extremely high levels, CO can cause death.

4. Nitrogen dioxide (NO2) is one of a group of highly reactive gasses known as “oxides of nitrogen,” or nitrogen oxides (NOx). Other nitrogen oxides include nitrous acid and nitric acid. EPA’s National Ambient Air Quality Standard uses NO2 as the indicator for the larger group of nitrogen oxides. NO2 forms quickly from emissions from cars, trucks and buses, power plants, and off-road equipment. In addition to contributing to the formation of ground-level ozone, and fine particle pollution, NO2 is linked with a number of adverse effects on the respiratory system.

5. Sulphur dioxide (SO2) is one of a group of highly reactive gasses known as “oxides of sulphur.”  The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%).  Smaller sources of SO2 emissions include industrial processes such as extracting metal from ore, and the burning of high sulphur containing fuels by locomotives, large ships, and non-road equipment. SO2 is linked with a number of adverse effects on the respiratory system.

6. Lead is a metal found naturally in the environment as well as in manufactured products. The major sources of lead emissions have historically been from fuels in on-road motor vehicles (such as cars and trucks) and industrial sources.  As a result of regulatory efforts in the U.S. to remove lead from on-road motor vehicle gasoline, emissions of lead from the transportation sector dramatically declined by 95 percent between 1980 and 1999, and levels of lead in the air decreased by 94 percent between 1980 and 1999. Today, the highest levels of lead in air are usually found near lead smelters. The major sources of lead emissions to the air today are ore and metals processing and piston-engine aircraft operating on leaded aviation gasoline.

4.13 GLOBAL WARMING

Global warming is the phenomenon of increasing average air temperatures near the surface of Earth over the past one to two centuries. Climate scientists have since the mid-20th century gathered detailed observations of various weather phenomena (such as temperatures, precipitation, and storms) and of related influences on climate (such as ocean currents and the atmosphere’s chemical composition). These data indicate that Earth’s climate has changed over almost every conceivable timescale since the beginning of geologic time and that the influence of human activities since at least the beginning of the Industrial Revolution has been deeply woven into the very fabric of climate change.

4.14 CAUSES OF GLOBAL WARMING

Global warming occurs when carbon dioxide (CO2) and other air pollutants and greenhouse gases collect in the atmosphere and absorb sunlight and solar radiations that have bounced off the earth’s surface. Normally, this radiation would escape into space—but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. That's what's known as the greenhouse effect.

The burning of fossil fuels to make electricity is the largest source of heat-trapping pollution, producing about two billion tons of CO2 every year. Coal-burning power plants are by far the biggest polluters. The second-largest source of carbon pollution is the transportation sector, which generates about 1.7 billion tons of CO2 emissions a year.

4.15 POLLUTION MITIGATION MEASURES

Mitigation measures include policies concerning energy, transportation, food and agriculture, and land use that will reduce GHG emissions. They include:

• Energy policies that can promote development and use of renewable energy, decrease production and use of fossil fuels, and reduce overall energy demand

• Transportation policies that promote fuel efficiency and active transport, such as walking and bicycling

• Food and agriculture policies that can promote sustainable practices, enhance food security, promote growth and consumption of fruits and vegetables, and decrease consumption of meat

• Land-use policies that aim to protect existing forests and promote growth of new forests

As of 2013, fossil fuels accounted for 67% of energy generation in the United States; nuclear power, 20%; hydroelectric power, 7%; wind power, 4%; and solar, geothermal, and other sources of energy, 2%. However, the proportion of energy generated by wind and solar power is progressively increasing.

There are many health co-benefits of mitigation policies. As examples, reducing use of fossil fuels, decreases air pollution and improves health; and promoting active transport reduces GHG emissions, increases physical activity, and helps to prevent cardiovascular disease.

 

4.16 ENVIRONMENTAL METRICS

Environmental metrics are designed to assess the environmental impact of technology or activity. Such impacts are primarily related to using natural resources (lifecycle INPUTS) and generating waste and emissions (lifecycle OUTPUTS). The ultimate sustainability goal is to minimize the environmental impacts due to using non-renewable resources and minimizing waste and pollution. Since the complete elimination of these impacts is hardly possible (any technology has its environmental costs!), it is also important to evaluate the rate at which environment can absorb the impacts and become remediated.

There are a number of common metrics designed to characterize the lifecycle inputs and outputs. Some examples are given below:

Environmental metrics related to lifecycle inputs

 Metric

 Units*

 What it measures

 Water use

 m3

 

Amount of water consumed in the process of extraction, processing, manufacturing, maintenance and use of the product

 Land use

 Acre

 

Land area required (not available for other needs) for extraction, processing, manufacturing, use, and disposal of the product

 Embodied energy

 J

 

Sum of all energy inputs to produce the product. This metric may include both technological and natural transformations.

 Total lifecycle energy

 J

 

Sum of all energy spent to produce the product, extract and process the initial materials, use the product, and disposed off the waste

Environmental metrics related to lifecycle outputs

 Metric

 Units

 What it measures

 Global Warming Potential (GWP)

 kgCO2-eq

Contribution to global warming due to emissions of greenhouse gases to the atmosphere

 

Ozone Depletion Potential (ODP)

 kgCFC11-eq

Contribution to stratospheric ozone layer depletion

 

Water/Soil Acidification Potential (AP)

 kgSO2-eq

Contribution to acidification of soils and water due to the release of gases such as nitrogen oxides and sulfur oxides

 

Smog / Tropospheric Ozone Creation Potential (SCP)

 kgNO2-eq

Contribution to air pollution, creation of tropospheric ozone (smog) by releasing nitrogen oxides and particulates

Eutrophication Potential (EP)

 kg N-eq

Enrichment of the aquatic ecosystems with nutritional elements (nitrogen or phosphorus)

Human Toxicity Potential (HTP)

 

1,4-DCB-eq

Impact on humans of toxic substances emitted to the environment (health / cancer /non-cancer impacts)

ENVIRONMENTAL MONITORING

Environmental monitoring is a tool to assess environmental conditions and trends, support policy development and its implementation, and develop information for reporting to national policymakers, international forums and the public.

4.17 AIR MONITORING

The air pollutants indicator assesses pressures from specific pollutants on atmospheric air across individual countries, but also identifies pressures from particular national sectors like energy, transport, industrial processes, agriculture and waste management.

On the basis of this indicator, public authorities can adjust the national environmental policy by, for instance, revising emission standards and emission limit values, strengthening permitting of potentially polluting activities and improving the application of economic instruments. Information on pollutant emissions is necessary for the assessment of transboundary air pollution and for international cooperation to address this problem.

WATER MONITORING

Renewable freshwater resources have major environmental and economic value. Their distribution varies widely among and within countries. Pressures on freshwater resources are exerted by overexploitation and by pollution. Relating resources abstraction to renewal of stocks is a central issue in sustainable freshwater resource management. If a significant share of a country's water comes from trans-boundary rivers, tensions between countries can arise, especially if water availability in the upstream country is greater than in the downstream one. Countries are quite interdependent with regard to water resources.

The Convention on the Protection and Use of Transboundary Watercourses and International Lakes requires that the Parties introduce sustainable water management, including an ecosystem approach and the rational and fair use of trans-boundary waters.

WASTE MONITORING

Waste represents a considerable loss of resources in the form of materials and energy. The treatment and disposal of waste may cause environmental pollution and expose humans to harmful substances and infectious organisms. Waste generation is closely linked to the level of economic activity in a country, and reflects the society's production and consumption patterns. The waste intensity represents a driving force indicator and shows response to anthropogenic activities. A reduction in the volume of waste generated is therefore an indication of an economy's move towards less material-intensive production and consumption patterns. 

The main purpose of the waste indicator is to measure the pressure on the environment of the total amount of generated waste and waste by category.

Innovations and methodologies for ensuring sustainability

Sustainable innovation has been defined as covering the spectrum of levels of innovation from incremental to radical. Whilst there are no absolute or quantifiable definitions and boundaries, four main level of innovation can be defined in the context of environmental improvement:

Level 1(incremental): incremental or small, progressive improvements to existing products.

Level 2(re-design or green limits): major re-design of existing product(but limited the level of improvement that is technically feasible).

Level 3(functional or product alternatives): new product or service concepts to satisfy the same functional need e.g. teleconferencing as an alternative to travel.

Level 4(systems): design for a sustainable society.

Top sustainable technologies in green construction

Green technology makes building more energy efficient and sustainable. They thus have a lower carbon footprint and a reduced impact on the environment. In new buildings, green building construction plays a role in every phase of development. Every aspect of the structure, including siting, design, construction materials and the systems used to run and maintain operations are chosen to be as sustainable and energy efficient as possible.

References:

1. Žiga Turk (2014), Global Challenges and the Role of Civil Engineering, Chapter 3 in: Fischinger M. (eds) Performance-Based Seismic Engineering: Vision for an Earthquake Resilient Society. Geotechnical, Geological and Earthquake Engineering, Vol. 32. Springer, Dordrecht

2. Brito, Ciampi, Vasconcelos, Amarol, Barros (2013) Engineering impacting Social, Economical and Working Environment, 120th ASEE Annual Conference and Exposition

3. NAE Grand Challenges for Engineering (2006), Engineering for the Developing World, The Bridge, Vol 34, No.2, Summer 2004.

4. Allen M. (2008) Cleansing the city. Ohio University Press. Athens Ohio.

5. Ashley R., Stovin V., Moore S., Hurley L., Lewis L., Saul A. (2010). London Tideway Tunnels Programme – Thames Tunnel Project Needs Report – Potential source control and SUDS applications: Land use and retrofit options

6. http://www.thamestunnelconsultation.co.uk/consultation-documents.aspx

7. Ashley R M., Nowell R., Gersonius B., Walker L. (2011). Surface Water Management and Urban Green Infrastructure. Review of Current Knowledge. Foundation for Water Research FR/R0014

8. Barry M. (2003) Corporate social responsibility – unworkable paradox or sustainable paradigm? Proc ICE Engineering Sustainability 156. Sept Issue ES3 paper 13550. p 129-130

9. Blackmore J M., Plant R A J. (2008). Risk and resilience to enhance sustainability with application to urban water systems. J. Water Resources Planning and Management. ASCE. Vol. 134, No. 3, May.

10. Bogle D. (2010) UK’s engineering Council guidance on sustainability. Proc ICE Engineering Sustainability 163. June Issue ES2 p61-63

11. Brown R R., Ashley R M., Farrelly M. (2011). Political and Professional Agency Entrapment: An Agenda for Urban Water Research. Water Resources Management. Vol. 23, No.4. European Water Resources Association (EWRA) ISSN 0920-4741.

12. Brugnach M., Dewulf A., Pahl-Wostl C., Taillieu T. (2008) Toward a relational concept of uncertainty: about knowing too little, knowing too differently and accepting not to know. Ecology and Society 13 (2): 30

13. Butler D., Davies J. (2011). Urban Drainage. Spon. 3rd Ed.

14. Cavill S., Sohail M. (2003) Accountability in the provision of urban services. Proc. ICE. Municipal Engineer 156. Issue ME4 paper 13445, p235-244.

15. Centre for Water Sensitive Cities (2012) Blueprint for a water sensitive city. Monash University.

16. Charles J A. (2009) Robert Rawlinson and the UK public health revolution. Proc ICE Eng History and Heritage. 162 Nov. Issue EH4. p 199-206