On-line Post Graduate Programme in Project Management for Working

Professionals Batch 2 (2021 - 2022)

Health, Safety &

Environment Management
- Assignment
Faculty: Dr. Abhijat Abhyankar

Jobin Raj B S
Reg. No.: 221-07-51-13146-2224
Mobile: +91 – 8281544453
 CONTENTS

Q1.The society demanded products which were produced by industry that

lead to impact on environment. List and discuss any five products. ..........3

Q2.Define EIA? Discuss stepwise procedure for conducting an EIA of a

building? 4

Q3.Discuss the major issues related to dam projects in India. Demonstrate

with an example the impact of any large dam project. ........................ 10

Q4.Define: Water pollution? Depict the sources and effects of water

pollution. Discussthe treatment options in detail. ............................. 13

Q5.List the major and minor component of Construction and Demolition (C&

D) waste. Discuss the opportunities available to reduce burden of these

kind of waste on secured landfill. .................................................24

Q1. The society demanded products which were produced by industry
that lead to impact on environment. List and discuss any five products.
Answer:

Over the past 50 years consumerism has run riot, evolving to create a culture in which
individuals lean towards items which are convenient, disposable and low-cost. Suppliers are
meeting this demand with products that are intentionally designed and manufactured to
have a limited lifespan after which they are discarded or replaced, giving rise to single-use
items

Let us see some of such products and its impact.

 Many brands of hand soap contain the controversial chemical triclosan, which is linked
to serious health conditions and causes cancer in mice. The chemical is also extremely
resilient and can survive water treatment, enabling it to reach the ocean and destroy
bacteria that form the base of the food chain
 Many toothpaste brands have been discovered to contain plastic micro beads, a leading
contributor to the 8 million tons of plastic that enters the ocean each year, with
devastating consequences for wildlife and the marine environment. Micro beads do not
biodegrade and are too small to be caught in clean-up exercises, and they attract toxic
chemicals as they travel.
 Disposable chopsticks are stripping Asian forests bare. Almost 4 million trees are
sacrificed to produce 57 billion pairs of disposable chopsticks each year, according to
Greenpeace, and they are treated with chemicals that can cause respiratory disorders.
 Wet wipes are increasingly popular for use on skin or household surfaces, which is
causing problems further down the line. Although labeled as "Flush-able," they contain
plastic and don't break down easily like toilet paper. When disposed via the toilet, the
non-biodegradable products cause blockages and "fatbergs" in sewers and wash up in
huge volumes on beaches.
 Plastic bags are one of the most damaging sources of everyday pollution. By some
estimates, 1 trillion non-biodegradable plastic bags are disposed of each year, breaking
down in waterways, clogging landfill sites and releasing toxic chemicals when burned.
Q2. Define EIA? Discuss stepwise procedure for conducting an EIA of a
building?
Answer:

Development projects in the past were undertaken without any consideration to their
environmental consequences. In view of the colossal damage to the environment,
governments and public are now concerned about the environmental impacts of
developmental activities. Thus, to assess the environmental impacts, the mechanism of EIA
was introduced.

EIA is a tool to anticipate the likely environmental impacts that may arise out of the
proposed developmental activities and suggest mitigation measures and strategies. EIA
was introduced in India in 1978, with respect to river valley projects. Later the EIA
legislation was enhanced to include other developmental sections. EIA comes
under Notification on Environmental Impact Assessment (EIA) of developmental projects
1994 under the provisions of Environment (Protection) Act, 1986. Besides EIA, the
Government of India under Environment (Protection) Act 1986 issued a number of other
notifications, which are related to environmental impact assessment.

EIA is now mandatory for more than 30 categories of projects, and these projects
get Environmental Clearance (EC) only after the EIA requirements are fulfilled.
Environmental clearance or the ‘go ahead’ signal is granted by the Impact Assessment
Agency in the Ministry of Environment and Forests, Government of India.

All projects that require clearance from central government can be broadly categorized
into the following:

1. Individual projects that need require clearance from central government,

2. Nuclear power and related projects,
3. River valley projects including hydel power, major irrigation and flood control,
4. Ports, harbours, airports (except minor ports and harbours),
5. Petroleum refineries including crude and product pipelines,
6. Chemical fertilizers and pesticides,
7. Petrochemical complexes and petrochemical intermediates and production of basic
plastics,
8. Bulk drugs and pharmaceuticals,
9. Exploration for oil and gas and their production, transportation and storage,
10. Synthetic rubber,
11. Asbestos and asbestos products,
12. Hydrocyanic acid and its derivatives,
13. Primary metallurgical industries (such as production of iron and steel, aluminium,
copper, zinc, lead, and ferro-alloys),
14. Chlor-alkali industry,
15. Integrated paint complex including manufacture of resins and basic raw materials
required in the manufacture of paints,
16. Viscose staple fibre (biodegradable fibre similar to cotton) and filament yarn,
17. Storage batteries integrated with manufacture of oxides of lead and lead antimony
alloy,
18. All tourism projects between 200m-500 metres of High Water Line and at locations
with an elevation of more than 1000 metres with investment of more than Rs. 5 crores,
19. Thermal power plants,
20. Mining projects (with lease more than 5 hectares),
21. Highway projects except projects relating to improvement work provided it does not
pass through ecologically sensitive areas such as National Parks, Sanctuaries, Tiger
Reserves, Reserve Forests,
22. Tarred roads in the Himalayas and forest areas,
23. Distilleries,
24. Raw skins and hide,
25. Pulp, paper and newsprint, dyes,
26. Cement,
27. Electroplating,
28. Meta aminophenol, etc.

The important aspects of EIA are

 risk assessment,
 environmental management and
 post product monitoring.

EIA is to

 serve as a primary environmental tool with clear provisions.

 apply consistently to all proposals with potential environmental impacts.
 use scientific practice and suggest strategies for mitigation.
 address all possible factors such as short term, long term, small scale and large scale
effects.
 consider sustainable aspects such as capacity for assimilation, carrying
capacity, biodiversity protection.
 lay down a flexible approach for public involvement.
 have in built mechanism of follow up and feedback.
 include mechanisms for monitoring, auditing and evaluation.
Environmental Components Of EIA

The EIA process looks into the following components of the environment.
Air environment

 Quality of ambient air present and predicted.

 Meteorological data: Wind speed, direction, humidity etc.
 Quantity of emission likely from project.
 Impact of the emission on the area.
 Pollution control desires/air quality standards.

Noise

 Levels of noise present and predicted

 Strategies for reducing noise pollution.

Water environment

 Existing ground and surface water resources, their quality and quantity within the zone.
 Impact of proposed project on water resources.

Biological environment

 Flora and fauna in impact zone.

 Potential damage (likely) due to project, due to effluents, emissions and landscaping.
 Biological stress (prediction).

Land environment

 Study of soil characteristics, land use, and drainage pattern, and the likely adverse
impact of the project.
 Impact on historical monuments and heritage site.

EIA Process and Procedures

Steps in EIA process

EIA involves the steps mentioned below. However, EIA process is cyclical with interaction
between the various steps.

 Screening: The project plan is screened for scale of investment, location and type of
development and if the project needs statutory clearance.
 Scoping: The project’s potential impacts, zone of impacts, mitigation possibilities and
need for monitoring.
 Collection of baseline data: Baseline data is the environmental status of study area.
 Impact prediction: Positive and negative, reversible and irreversible and temporary
and permanent impacts need to be predicted which presupposes a good understanding
of the project by the assessment agency.
 Mitigation measures and EIA report: The EIA report should include the actions and
steps for preventing, minimizing or by passing the impacts or else the level of
compensation for probable environmental damage or loss.
 Public hearing: On completion of the EIA report, public and environmental groups
living close to project site may be informed and consulted.
 Decision making: Impact Assessment Authority along with the experts consult the
project-in-charge along with consultant to take the final decision, keeping in mind EIA
and EMP (Environment Management Plan).
 Monitoring and implementation of environmental management plan: The various
phases of implementation of the project are monitored.
 Assessment of Alternatives, Delineation of Mitigation Measures and Environmental
Impact Assessment Report: For every project, possible alternatives should be
identified, and environmental attributes compared. Alternatives should cover both
project location and process technologies.
 Once alternatives have been reviewed, a mitigation plan should be drawn up for the
selected option and is supplemented with an Environmental Management Plan (EMP) to
guide the proponent towards environmental improvements.
 Risk assessment: Inventory analysis and hazard probability and index also form part of
EIA procedures.

Steps in Preparation of EIA report

 Collection of baseline data from primary and secondary sources;

 Prediction of impacts based on past experience and mathematical modelling;
 Evolution of impacts versus evaluation of net cost benefit;
 Preparation of environmental management plans to reduce the impacts to the
minimum;

Quantitative estimation of financial cost of monitoring plan and the mitigation measures.

Environment Management Plan

Delineation of mitigation measures including prevention and control for each environmental
component and rehabilitation and resettlement plan.
Environmental Appraisal

 An Appraisal Committee constituted by the Ministry of Environment and Forests will

first scrutinized a project based on the data presented by the project authorities.
 If necessary, the MoEF may also hold consultations with the investors and experts on
specific issues as and when necessary.
 After considering all the facets of a projects, environmental clearance is accorded
subject to implementation of the stipulated environmental safeguards.
 In case of projects where the project proponents have submitted complete information,
a decision is taken within 90 days.
 The six regional offices of the Ministry functioning at Shillong, Bhubaneshwar,
Chandigarh, Bangalore, Lucknow and Bhopal undertake monitoring of cleared projects.

EIA of Coasts

 Coastal Zone Management Plans (CZMPs) are prepared by coastal states or Union
Territories as per rules set by CRZ notification 1991.
 CZMPs are prepared based on identification and categorization of coastal areas for
different activities and then submitted to the MoEF for approval.
 The ministry then forms a task force for examining their plans.

Single window clearance

 Environmental clearance + Forestry clearance.

 When a project requires both environmental clearance as well as approval under
the Forest (Conservation) Act, 1980, proposals for both are required to be given
simultaneously to the concerned divisions of the Ministry.
 The processing is done simultaneously for clearance or rejection.
 If the project does not involve diversion of forestland, the case is processed only for
environmental clearance.

The Main Participants Of EIA

 EIA applies to public and private sections. The six main players are:
 Those who propose the project
 The environmental consultant who prepare EIA on behalf of project proponent.
 Pollution Control Board (State or National).
 Public has the right to express their opinion.
 The Impact Assessment Agency.
 Regional centre of the Ministry of Environment and Forest.
Composition of the expert committees for EIA

The Committees will consist of experts in the following disciplines:

 Eco-system management
 Air/water pollution control
 Water resource management
 Flora/fauna conservation and management
 Land use planning
 Social Sciences/Rehabilitation
 Project appraisal
 Ecology
 Environmental Health
 Subject Area Specialists
 Representatives of NGOs/persons concerned with environmental issues
 The Chairman will be an outstanding and experienced ecologist or environmentalist
or technical professional with wide managerial experience in the relevant
development.
 The representative of Impact Assessment Agency will act as a Member-Secretary.
 Chairman and members will serve in their individual capacities except those
specifically nominated as representatives.
 The membership of a committee shall not exceed 15 members.
Q3. Discuss the major issues related to dam projects in India.
Demonstrate with an example the impact of any large dam project.
Answer:

Around 80% of country’s 5000 dams are over 25 years old and are confronted with grave
safety challenges. Apart from ageing, unabated wear and tear and sub-par maintenance are
also disrupting the safety of the dams.
Worryingly, about 170 dams in the country are more than 100 years old and are basically
earthen structures that have been built with obsolete technologies. These earthern dams
pose a grave danger to life and property and are particularly susceptible to dam related
mishaps given the fact that bulk of the landmass in which these dams are present are
susceptible to frequent earthquakes. This vulnerability has increased manifold with water
flows into reservoirs turning highly unpredictable.
Though, outright dam failures are very rare, it cannot be completely ruled out. So far, at
least 36 such incidents with respect to the earthern dams are on record. More importantly,
out of 36, about half of the dam failures were catastrophic causing extensive devastation.
Some examples of dam failures are: Jamunia dam in Madhya Pradesh (2002), Lawa-ka-bas
dam in Rajasthan (2003), Panchat and Khadakwasala dams (1961), Nanak Sagar (1967)Tigra
(1970) and Chikkahole (1972).
Issues

Though, India has world’s third largest count of dams after China and the US, there is no
statutory framework to ensure dam safety. The UPA government introduced a bill in the
Parliament for fixing responsibility for dam maintenance and specifying mechanisms and
procedures for this purpose, but the bill got lapsed with the dissolution of the 15th Lok
Sabha.
State governments being the custodians of dams are primarily responsible for the dismal
condition of the dams. The Central Water Commission (CWC), which is the apex
organisation for water resources management, in 2006, asked the states to come up with an
emergency action plan for large dams and laid down guidelines for that purpose. But many
states had chosen to ignore such strategies. The ministry of water resources, too, in 2011
came up with crisis management plans for states to handle dam related contingencies and
asked them to set up dam safety organisations. But, so far, not even half of the states
complied with the directions of the water resources ministry.
Dams and Destruction

While dams can benefit society in many ways, they are also one of the biggest menaces to
river ecology, wildlife, the aquatic habitat of fish, and ultimately humans.
 Affect the Aquatic Life: Dams prevent fish migration and limit their ability to access
spawning habitat, seek out food resources, and escape predation. Aquatic organisms
 depend on steady flows to guide them while stagnant reservoir pools disorient
migrating fish and can significantly increase the duration of their migration.
 Dams block Rivers: Dams and reservoirs are physical barriers to the flow of water
bodies as they fragment them and reservoirs, which impact their seasonal flow. They
also change the way rivers function and trap sediment, burying rock riverbeds where
fish spawn. Gravel, logs, and other important food and habitat features can also
become trapped behind dams. This negatively affects the creation and maintenance of
more complex habitats downstream.
 A Hazardous Infrastructure: Large dams, even if structurally sound, are regarded as
“high hazard” infrastructure because of the potential for a massive loss of human lives,
livelihoods, and destruction in the event of failure. In the most recent Uttarakhand
flash floods, experts say the incident was induced by the effect of global warming on
melting glaciers but the effect was worsened by the construction of infrastructure
(Hydroelectric Power Projects, HEPs). HEPs which use large-scale blasting, tree felling,
and tunneling, most certainly added to the proportion of the impact. They became a
force multiplier in the destruction. The construction was against the recommendation
of the Chopra Committee which submitted a detailed report warning that a glacial
retreat in the state of Uttarakhand, coupled with structures built for hydroelectricity
generation and dams, could lead to large-scale disasters downstream.
 Reservoir Induced Seismicity: There is a strong relationship between the earthquakes
and the loading and unloading of water from the dam. The Koyna and Warna region is
possibly the best example of reservoir-induced seismicity (RIS). The Koyna and Warna
reservoirs are responsible for the earthquakes in the south Maharashtra region which
has experienced many earthquakes in five decades. This series of earthquakes have
occurred post the construction of dams in the region.
 Displacement of People: The land submergence and large-scale displacement of
people due to the construction of large dams is one prevailing issue which is often
overlooked by the authorities. Construction of dams such as Hirakud, Bhakra Nangal,
and Tehri had displaced a number of families many of which were not rehabilitated at
all. Even after rehabilitation, lack of livelihood opportunities and poor living conditions
are still observed. Sardar Sarovar Dam, the largest structure on the Narmada river, has
displaced over 3 lakh families.
 Older Dams are Greater Hazard: Older dams pose greater safety risks, cost higher in
terms of maintenance, and have declining functionality due to sedimentation. Globally,
over 1,115 large dams will be about 50 years old by 2025. China, the US, and India top
the list of countries with a significant number of large dams. China alone hosts 40% of
the world’s large dams (numbering 23,841), their average age being 45 years. India has
4,407 large dams of which more than 1,000 would be 50 years or older by 2025, a new
study has shown. India has 209 dams that are over 100-year-old, built when design
practices and safety were far below current norms.
Mullaperiyar Dam

The Mullaperiyar Dam, a gravity dam in Kerala is a 126-year-old barrage that has
dangerously outlived its 50 years of life. The dam is located in the Western Ghats, adjacent
to the Periyar wildlife sanctuary, built during the British colonial period. A gravity dam is
one that is designed to withstand water by its own weight and resistance. The weight and
width of the base prevent the dam from overturning when subjected to the force of
impounded water. The dam is considered hazardous, not only because of its age but also
for its location in an acknowledged seismic zone (zone-III). Decommission of the Dam: The
government of Kerala carried out hydrological review studies between 2006 and 2011 that
concluded that the Mullaperiyar Dam is unsafe for passing the estimated probable maximum
flood limit. Both IIT-Roorkee and IIT-Delhi have deemed the dam to be fit to be
decommissioned. However, decommissioning Mullaperiyar is strongly opposed by Tamil
Nadu state, which inherited a lease agreement between the former princely state of
Travancore (now Kerala) and the British government. The lease allows Tamil Nadu to
operate the dam and divert 640 million cubic meres of water annually for irrigation and
power generation through a tunnel bored into the Western Ghat mountains that form a wall
between the two states.

 Greenhouse Gas Emissions: Particularly in tropical regions, hydro power reservoirs

emit significant amounts of greenhouse gases. The water gathers behind the dam,
creates an unnatural, stagnant lake that often kills off a lot of the existing ecosystem.
Bacteria in the water decompose these plants and generate carbon dioxide and
methane (potent greenhouse gas). Methane from reservoirs accounts for more than 4%
of all human-caused climate change comparable to the climate impact of the aviation
sector. In some cases, hydro power projects are producing higher emissions than coal-
fired power generating the same amount of electricity plants.
Q4. Define: Water pollution? Depict the sources and effects of water
pollution. Discuss the treatment options in detail.
Answer:

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans and
groundwater). Water pollution affects plants and organisms living in these bodies of water
and in almost all cases the effect is damaging not only to individual species and populations,
but also to the natural communities.Water pollution occurs when pollutants are discharged
directly or indirectly into water bodies without adequate treatment to remove harmful
compounds.

Point source pollution refers to contaminants that enter a waterway through a discrete
conveyance, 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.

Non-point source pollution: Non-point source (NPS) 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. The
leaching out of nitrogen compounds from agricultural land which has been fertilized is a
typical example. 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, this runoff is
typically channeled into storm drain systems and discharged through pipes to local surface
waters, and is a point source. However where such water is not channeled and drains
directly to ground it is a non-point source.

Sources of Surface Water Pollution:

Sewage: Emptying the drains and sewers in fresh water bodies causes water pollution. The
problem is severe in cities.

Industrial Effluents: Industrial wastes containing toxic chemicals, acids, alkali, metallic
salts, phenol, cyanide, ammonia, radioactive substances, etc., are sources of water
pollution.They also cause thermal (heat) pollution of water.

Synthetic Detergents: Synthetic detergents used in washing and cleaning produce foam
and pollute water.
Agrochemical: Agrochemical like fertilizers (containing nitrates and phosphates) and
pesticides (insecticides, fungicides, herbicides etc.) washed by rain-water and surface
runoff pollute water.

Oil: Oil spillage into sea-water during drilling and shipment pollute it.

Waste heat: Waste heat from industrial discharges increases the temperature of water
bodies and affects distribution and survival of sensitive species.

Sources and Types of Water Pollutants:

Pathogens: Coliform bacteria are a commonly used bacterial indicator of water pollution,
although not an actual cause of disease. Other microorganisms sometimes found in surface
waters which have caused human health problems include:

 Burkholderia pseudomallei.
 Cryptosporidium parvum.
 Giardia lamblia.
 Salmonella.
 Novovirus and other viruses.
 Parasitic worms (helminths).

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.

Chemical and other contaminants: Contaminants may include organic and inorganic
substances.

Organic water pollutants include:

 Detergents.
 Disinfection by-products found in chemically disinfected drinking water, such as
chloroform.
 Food processing waste, which can include oxygen-demanding substances, fats and
grease.
 Insecticides and herbicides, a huge range of organohalides and other chemical
compounds.
 Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil)
and lubricants (motor oil), and fuel combustion by-products, from storm water runoff.
 Tree and bush debris from logging operations.
 Volatile organic compounds (VOCs), such as industrial solvents.
 Various chemical compounds found in personal hygiene and cosmetic products.

Inorganic water pollutants are:

 Pre-production industrial raw resin pellets.

 Heavy metals including acid mine drainage, chemical waste as industrial by-products.
 Acidity due to industrial discharges like sulphur dioxide.
 Silt in surface runoff due to logging, slash and burn practices, construction sites or land
clearing sites.
 Fertilizers in runoff from agriculture including nitrates and phosphates.

Other agents:

 The combustion of coal leads to the release of mercury in the atmosphere. This enters
the rivers, lakes and groundwater. This is very hazardous for pregnant women and
infants.
 Cattle and pig rearing causes a significant amount of nutrient-filled waste.
 Fertilizers having a large quantity of nitrogen and phosphorus cause a high biological
oxygen demand in the water. The high amount of BOD is responsible for oxygen
depletion in water bodies.
 Human settlement along the banks of rivers causes human, animal and industrial waste
to be discharged into it.

Effect of Water Pollution:

Disorders:

Some pollutants like sodium can cause cardiovascular diseases, while mercury and lead
cause nervous disorders.

Toxic Substances: DDT is toxic material which can cause chromosomal changes. Some of
these substances like pesticides, methyl mercury etc., move into the bodies of organisms
from the medium in which these organisms live. These substances tend to accumulate in
the organism’s body from the medium food. This process is called bio-accumulation or bio
concentration. The concentration of these toxic substances builds up at successive levels of
food chain. This process is called bio magnifications.
Water Pollution: Fluoride pollution causes defects in teeth and bones, a disease called
fluorosis while arsenic can cause significant damage to the liver and the nervous system. In
addition to all these, organic compounds present in the polluted water facilitate the growth
of algae and other weeds, which in turn use more oxygen dissolved in the water. This
reduces the amount of oxygen dissolved in the water and the consequent shortage of
oxygen for other aquatic life.

Asbestos: This pollutant is a serious health hazard and carcinogenic. Asbestos fibers can be
inhaled and cause illnesses such as asbestosis, mesothelioma, lung cancer, intestinal cancer
and liver cancer.

Mercury: This is a metallic element and can cause health and environmental problems. It is
a non-biodegradable substance so is hard to clean up once the environment is contaminated.
Mercury is also harmful to animal health as it can cause illness through mercury poisoning.

Phosphates: The increased use of fertilizers means that phosphates are more often being
washed from the soil and into rivers and lakes. This can cause eutrophication, which can be
very problematic to marine environments.

Oils: Oil does not dissolve in water; instead it forms a thick layer on the water surface. This
can stop marine plants receiving enough light for photosynthesis. It is also harmful for fish
and marine birds.

Petrochemicals: This is formed from gas or petrol and can be toxic to marine life.

Organic matter which reaches water bodies is decomposed by micro-organisms present in

water. For this degradation, oxygen dissolved in water is consumed. Dissolved oxygen (DO)
is the amount of oxygen dissolved in a given quantity of water at a particular temperature
and atmospheric pressure.

Amount of dissolved oxygen depends on aeration, photosynthetic activity in water,

respiration of animals and plants and ambient temperature.The saturation value of DO
varies from 8-15 mg/L. For active fish species (trout and Salmon) 5-8 mg/L of DO is
required whereas less desirable species like carp can survive at 3.0 mg/L of DO.Lower DO
may be harmful to animals especially fish population. Oxygen depletion (deoxygenating)
helps in release of phosphates from bottom sediments and causes eutrophication.

Addition of compounds containing nitrogen and phosphorus helps in the growth of algae
and other plants which when die and decay consume oxygen of water. Under anaerobic
conditions foul smelling gases are produced. Excess growth or decomposition of plant
material will change the concentration of CO2 which will further change pH of water.
Changes in pH, oxygen and temperature will change many physicochemical characteristics
of water.

Lead in water may be released from water pipes as lead is used in plumbing. Lead
poisoning affects kidneys reproductive system, liver, brain and central nervous system. It
also causes anaemia and mental retardation in children.

Nitrate ions present in the water are harmful to human health. From nitrogen fertilizers,
nitrate ions seep into water bodies from where these may bio accumulate in the bodies of
the consumers. In the stomach nitrate is reduced to nitrite and is responsible for blue baby
syndrome and stomach cancer.

Control of Water Pollution:

The following points may help in reducing water pollution from non-point sources.

 Judicious use of agro chemicals like pesticides and fertilizers which will reduce their
surface run-off and leaching. Use of these on sloped lands should be avoided.
 Use of nitrogen fixing plants to supplement the use of fertilizers.
 Adopting integrated pest management to reduce greater reliance on pesticides.
 Prevent run-off of manure. Divert such run-off to basin for settlement. The nutrient
rich water can be used as fertilizer in the fields.
 Separate drainage of sewage and rain water should be provided to prevent overflow of
sewage with rain water.
 Planting trees would reduce pollution by sediments and will also prevent soil erosion.

For controlling water pollution from point sources, treatment of waste waters is essential
before being discharged. Parameters which are considered for reduction in such water are:
Total solids, biological oxygen demand (BOD), chemical oxygen demand (COD), nitrates and
phosphates, oil and grease, toxic metals etc. Waste waters should be properly treated by
primary and secondary treatments to reduce the BOD, COD levels up to the permissible
levels for discharge.

Sewage treatment, or domestic wastewater treatment, is the process of removing

contaminants from wastewater and household sewage, both runoff (effluents) and domestic.
It includes physical, chemical, and biological processes to remove physical, chemical and
biological contaminants. Its objective is to produce an environmentally-safe fluid waste
stream (or treated effluent) and a solid waste (or treated sludge) suitable for disposal or
reuse (usually as farm fertilizer).

Sewage is created by residential, institutional, and commercial and industrial

establishments and includes household waste liquid from toilets, baths, showers, kitchens,
sinks and so forth that is disposed of via sewers. In many areas, sewage also includes liquid
waste from industry.

Sewage can be treated close to where it is created (in septic tanks, bio-fitter’s or aerobic
treatment systems), or collected and transported via a network of pipes and pump stations
to a municipal treatment plant.

Sewage collection and treatment is typically subject to local, state and federal regulations
and standards. Industrial sources of wastewater often require specialized treatment
processes (see Industrial wastewater treatment).

Conventional sewage treatment may involve three stages, called primary, secondary and
tertiary treatment. Primary treatment consists of temporarily holding the sewage in a
quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter
solids float to the surface. The settled and floating materials are removed and the
remaining liquid may be discharged or subjected to secondary treatment.

Secondary treatment removes dissolved and suspended biological matter. Secondary

treatment is typically performed by indigenous, water-borne micro-organisms in a managed
habitat. Secondary treatment may require a separation process to remove the
microorganisms from the treated water prior to discharge or tertiary treatment.

Tertiary treatment is sometimes defined as anything more than primary and secondary
treatment. Treated water is sometimes disinfected chemically or physically (for example,
by lagoons and micro filtration) prior to discharge into a stream, river, bay, lagoon or
wetland, or it can be used for the irrigation of a golf course, green way or park. If it is
sufficiently clean, it can also be used for groundwater recharge or agricultural purposes.
Pre - treatment removes materials that can be easily collected from the raw wastewater
before they damage or clog the pumps and skimmers of primary treatment clarifiers (trash,
tree limbs, leaves, etc.).

Screening: The influent sewage water is screened to remove all large objects carried in the
sewage stream. This is most commonly done with an automated mechanically raked bar
screen in modern plants serving large populations, whilst in smaller or less modern plants a
manually cleaned screen may be used.

The raking action of a mechanical bar screen is typically paced according to the
accumulation on the bar screens and/or flow rate. The solids are collected and later
disposed in a landfill or incinerated. Bar screens or mesh screens of varying sizes may be
used to optimize solids removal. If gross solids are not removed they become entrained in
pipes and moving parts.

Grit removal: Pre-treatment may include a sand or grit channel or chamber where the
velocity of the incoming wastewater is adjusted to allow the settlement of sand, grit,
stones, and broken glass. These particles are removed because they may damage pumps
and other equipment. For small sanitary sewer systems, the grit chambers may not be
necessary, but grit removal is desirable at larger plants.

Fat and grease removal: Fat and grease is removed by passing the sewage through a small
tank where skimmers collect the fat floating on the surface. Air blowers in the base of the
tank may also be used to help recover the fat as froth. In most plants however, fat and
grease removal takes place in the primary settlement tank using mechanical surface
skimmers.

Primary treatment: In the primary sedimentation stage, sewage flows through large tanks,
commonly called “primary clarifiers” or “primary sedimentation tanks.” The tanks are used
to settle sludge while grease and oils rise to the surface and are skimmed off.

Primary settling tanks are usually equipped with mechanically driven scrapers that
continually drive the collected sludge towards a hopper in the base of the tank where it is
pumped to sludge treatment facilities. Grease and oil from the floating material can
sometimes be recovered for saponification.

The dimensions of the tank should be designed to effect removal of a high percentage of
the floatables and sludge. A typical sedimentation tank may remove from 60 to 65 per cent
of suspended solids, and from 30 to 35 per cent of biochemical oxygen demand (BOD) from
the sewage.
Secondary treatment: Secondary treatment is designed to substantially degrade the
biological content of the sewage which is derived from human waste, food waste, soaps and
detergent. The majority of municipal plants treat the settled sewage liquor using aerobic
biological processes. To be effective, the biota requires both oxygen and food to live.

The bacteria and protozoa consume biodegradable soluble organic contaminants (e.g.
sugars, fats, organic short-chain carbon molecules, etc.) and bind much of the less soluble
fractions into floe. Secondary treatment systems are classified as fixed-film or suspended-
growth systems.

Fixed-film or attached growth systems include trickling filters and rotating biological
contactors, where the biomass grows on media and the sewage passes over its surface.
Suspended-growth systems include activated sludge, where the biomass is mixed with the
sewage and can be operated in a smaller space than fixed-film systems that treat the same
amount of water.

However, fixed-film systems are more able to cope with drastic changes in the amount of
biological material and can provide higher removal rates for organic material and
suspended solids than suspended growth systems.
Rotating biological contactors: Rotating biological contactors (RBCs) are mechanical
secondary treatment systems, which are robust and capable of withstanding surges in
organic load. RBCs were first installed in Germany in 1960 and have since been developed
and refined into a reliable operating unit.

The rotating disks support the growth of bacteria and micro-organisms present in the
sewage, which break down and stabilize organic pollutants. To be successful, micro-
organisms need both oxygen to live and food to grow. Oxygen is obtained from the
atmosphere as the disks rotate. As the micro-organisms grow, they build up on the media
until they are sloughed off due to shear forces provided by the rotating discs in the sewage.

Effluent from the RBC is then passed through final clarifiers where the micro-organisms in
suspension settle as sludge. The sludge is withdrawn from the clarifier for further
treatment. A functionally similar biological filtering system has become popular as part of
home aquarium filtration and purification.

The aquarium water is drawn up out of the tank and then cascaded over a freely spinning
corrugate fiber-mesh wheel before passing through a media filter and back into the
aquarium. The spinning mesh wheel develops a biofilm coating of microorganisms that feed
on the suspended wastes in the aquarium water and are also exposed to the atmosphere as
the wheel rotates. This is especially good at removing waste urea and ammonia urinated
into the aquarium water by the fish and other animals.

Biological aerated filters: The removal of nitrogen is effected through the biological
oxidation of nitrogen from ammonia (nitrification) to nitrate, followed by De-nitrification,
the reduction of nitrate to nitrogen gas. Nitrogen gas is released to the atmosphere and
thus removed from the water. Nitrification itself is a two-step aerobic process, each step
facilitated by a different type of bacteria.

The oxidation of ammonia (NH3) to nitrite (NO3) is most often facilitated by Nitrosomonas
spp. (nitroso referring to the formation of a nitroso functional group). Nitrite oxidation to
nitrate (NO3), though traditionally believed to be facilitated by Nitrobacter spp. (nitro
referring the formation of a nitro functional group), is now known to be facilitated in the
environment almost exclusively by Nitrospira spp.De-nitrification requires anoxic conditions
to encourage the appropriate biological communities to form. It is facilitated by a wide
diversity of bacteria.

Secondary sedimentation: The final step in the secondary treatment stage is to settle out
the biological floe or filter material through a secondary clarifier and to produce sewage
water containing low levels of organic material and suspended matter.
Tertiary treatment: The purpose of tertiary treatment is to provide a final treatment stage
to raise the effluent quality before it is discharged to the receiving environment (sea, river,
lake, ground, etc.). More than one tertiary treatment process may be used at any
treatment plant. If disinfection is practiced, it is always the final process. It is also called
“effluent polishing.”

Sand filtration removes much of the residual suspended matter. Filtration over activated
carbon, also called carbon adsorption, removes residual toxins.

Lagooning provides settlement and further biological improvement through storage in large
man-made ponds or lagoons. These lagoons are highly aerobic and colonization by native
macrophytes, especially reeds, is often encouraged. Small filter feeding invertebrates such
as Daphnia and species of Rotifera greatly assist in treatment by removing fine particulates.

Sludge treatment & disposal:

Anaerobic digestion: Anaerobic digestion is a bacterial process that is carried out in the
absence of oxygen. The process can either be thermophilic digestion, in which sludge is
fermented in tanks at a temperature of 55°C, or mesophilic, at a temperature of around
36°C.

Though allowing shorter retention time (and thus smaller tanks), thermophilic digestion is
more expensive in terms of energy consumption for heating the sludge. Anaerobic digestion
is the most common (mesophilic) treatment of domestic sewage in septic tanks, which
normally retain the sewage from one day to two days, reducing the BOD by about 35 to 40
percent.

This reduction can be increased with a combination of anaerobic and aerobic treatment by
installing Aerobic Treatment Units (ATUs) in the septic tank. One major feature of
anaerobic digestion is the production of biogas (with the most useful component being
methane), which can be used in generators for electricity production and/or in boilers for
heating purposes.

Aerobic digestion: Aerobic digestion is a bacterial process occurring in the presence of

oxygen. Under aerobic conditions, bacteria rapidly consume organic matter and convert it
into carbon dioxide. The operating costs used to be characteristically much greater for
aerobic digestion because of the energy used by the blowers, pumps and motors needed to
add oxygen to the process. Aerobic digestion can also be achieved by using diffuser systems
or jet aerators to oxidize the sludge.

Composting: Composting is also an aerobic process that involves mixing the sludge with
sources of carbon such as sawdust, straw or wood chips. In the presence of oxygen,
bacteria digest both the wastewater solids and the added carbon source and, in doing so,
produce a large amount of heat.

Incineration: Incineration of sludge is less common because of air emissions concerns and
the supplemental fuel (typically natural gases or fuel oil) required to burn the low calorific
value sludge and vaporize residual water.

Stepped multiple hearth incinerators with high residence time and fluidized bed
incinerators are the most common systems used to combust wastewater sludge. Co-firing in
municipal waste-to-energy plants is occasionally done, this option being less expensive
assuming the facilities already exist for solid waste and there is no need for auxiliary fuel.

Sludge disposal: When a liquid sludge is produced, further treatment may be required to
make it suitable for final disposal. Typically, sludge’s are thickened (dewatered) to reduce
the volumes transported off-site for disposal.

There is no process which completely eliminates the need to dispose of bio-solids. There is,
however, an additional step some cities are taking to super-heat sludge and convert it into
small pelleted granules that are high in nitrogen and other organic materials.
Q5. List the major and minor component of Construction and
Demolition (C& D) waste. Discuss the opportunities available to reduce
burden of these kind of waste on secured landfill.

Answer:

The growth in the construction industry triggers waste production to exponential levels.
The waste generated from the construction industry is commonly called as Construction &
Demolition Waste or C&D waste. Most of the waste materials in construction industries are
non-biodegradable and inert materials.

Construction waste materials are heavy, dense, bulky in characteristics and it needs more
storage space and cannot follow standard waste disposal methods. ‘Reduce – Reuse –
Recycle‘ are the most commonly adopted principles for waste management in the
construction industry (also in any other waste management sector).

The gap between demand and supply of building materials such as fine aggregate and
coarse aggregate in construction fields, especially in road construction is increasing day by
day. Construction industries in India generate an average of 10-13 million tons of waste per
year. By recycling the aggregate materials we can fill the gap between demand and supply,
and also reduce the cost of production.

Common waste materials formed during construction and demolition are listed below,

 Glass, wood, plastic, metals

 Asphalt, concrete, tiles, bricks, ceramics, gypsum, and cement

 Salvaged building components

 Paints and varnishes

 Adhesives and sealants

 Earth, stumps, trees, and rock from clearing sites

 Steel rebars and metals

 Aggregates

 Card boards, Gypsum board etc.

 Stones and other ceramic materials

 Bituminous materials

 Other materials like fiber materials, asbestos, electrical and wiring etc.

Classification of Construction & Demolition Waste

While we consider the global construction waste statistics, the contribution of C & D waste
by major construction industries are as below,

Project Type Percentage of C & D waste generated

High-rise buildings 33%

Industrial Projects 19%

Small Buildings 15%

Commercial Buildings 15%

Govt. projects 11%

Tunnel and Infrastructure 8%

Percentage of C & D waste generated in various types of Construction Projects

Construction wastes can be classified into following four major categories depending on the
nature of waste generated.

Reusable materials

The waste materials are re-used based on the following criteria, such as quality, dimension
and the amount of contamination. Bricks, timber, roof tiles, glass etc. are possible
materials that can be reused. Also these materials can be sold outside and can make a
revenue source. Main advantage of this method is we can save resources.

Recyclable materials

Most of the waste materials are recyclable and other useful products can be made.
Concrete, metals, plastic, timber, glass etc. some of the recyclable materials. A major
drawback in these fine aggregates products are, it consumes more water than conventional
fine aggregates. Metals (Including steel bars), plastic (PVC), glass can be recycled by
melting it.
The waste management system predominantly focuses on recycling principles. Recycled
aggregates can even be used for road construction. For example, during the demolition of
flats in Kochi, the concrete debris of volume 7620 tons was later crushed using the machine
called Rubble master into 6mm to12mm sized aggregates.

Unwanted waste

Every construction site holds up some amount of unwanted waste which is not useful.
Sometimes demolition debris is also categorized into unwanted waste. These waste
materials are commonly used for land filling purposes.

Hazardous waste

Contaminated water and spoil, fluorescent lamps, oils, solvents, materials, asbestos
materials, PFAS etc. comes under hazardous waste and can’t be disposed of in usual way.
These types of waste should be disposed of as per the environmental laws and regulations.

Benefits of Reducing the Disposal of C&D Materials

Reducing the C&D materials disposed of in landfills or incinerators has some benefits:

 Employment creation and an increase in economic activities in recycling industries.

This will also increase the business opportunities within the local community, in areas
where selective demolition and deconstruction are used.

 Fewer disposal facilities which reduce associated environmental problems.

 Reduction in overall building project expenses through avoided purchase costs and
donation of recovered materials to qualified charities, which offers a tax benefit.

 Offset the environmental effect associated with the extraction and consumption of
virgin resources and production of new materials

 Conserve landfill space.

Reduce:

Source reduction reduces life-cycle material and energy use, and waste generation. Source
reduction intercepts waste from being generated in the first place. Some examples of this
include optimizing the size of new buildings, designing new buildings for adaptability to
prolong their life, preserving existing buildings rather than constructing new ones, use of
construction methods that allow facilitating and disassembly reuse of materials. Reducing
C&D waste also reduces the environmental impact of producing new materials.
Reuse:
Construction and demolition materials can be diverted and used as a resource. Recovering
used construction and demolition waste for further use is effectively used to conserve
natural resources and save money.

Recycle:

Almost every building component and construction waste can be recycled. Rubble and
concrete are often recycled into aggregate and concrete products. Wood can
be recycled into engineered wood products like furniture. Metals like brass, copper, and
steel are also valuable resources to recycle. The benefits of recycling are now widely
recognized by the public, and participation in local recycling programs has become a way of
life for most citizens.

The construction industry is a significant contributor to extreme natural resource

consumption, waste generation and accumulation; degradation and depletion degradation;
and environmental impact and degradation. The amount of waste generated by C&D
activity is substantial. This is why construction and demolition industries need to find
suitable methods to manage the materials that generate waste during construction
activities. Managing C&D waste in an effective way is a critical component to save our
environment, natural resources, economy, society, etc.

Each type of waste generated by construction and demolition activities should be managed
based on efficient and proper mechanisms of waste prevention and business owners need to
build a smart and sustainable environment to make the C&D industry more efficient. So a
comprehensive waste management solution for the C&D industry is a must.