Coal Use and water pollution

1. Lakhan Lal, M.Tech stud
ENE17014
Coal use and water pollution
Submitted to:
Prof. Rupam Kataki
Deptt. of Energy, Tezpur
University

2. Introduction
 India’s energy sector is dominated by coal.It
contributes about 59% of total electricity
generation.
 Cement Industry requires coal in substantial
amount.
 It is also used for syn gas production.
Dankuni coal complex is producing syngas which
is piped to the industrial users in Calcutta.
 It is also used for production of coke which is a
popular reducing agent used in metallurgical
industries.

3. How coal use creates water pollution
 Coal Ash(all coal ash contains concentrated
amounts of toxic elements, including arsenic,
lead, and mercury.)
 Coal Mining(contaminate water in various ways)
 Water use in steam generation by coal fired
power plant(put excessive stress on existing
water resources in drought prone areas)

4. Coal Mining
 Coal mining pollutes near by water bodies and
rivers by contaminating them with highly acidic
water having heavy metals like arsenic, copper
and lead.
 The process is known as acid mine drainage. It
happens when certain substances (typically iron
sulfide, FeS2, or fool’s gold) is oxidized after
being exposed to air and water. Runoff can
change the pH of nearby streams.
 Mountain top removal mining process is a serious
threat to water body.

5.  The U.S. Environmental Protection Agency
estimates that mountaintop removal “valley fills”
are responsible for burying more than 2,000 miles
of vital Appalachian headwater streams, and
poisoning many more. As a result, water
downstream of mountaintop removal mines has
significantly higher levels of sulfate and selenium,
and increases in electrical conductivity, a
measure of heavy metals. These changes in
water quality can directly kill aquatic species, or
disrupt their life cycles so severely that
populations dwindle, or even disappear .
Source- Ecological Impacts of Mountaintop Removal, Applachian Voice

6.  Finally, after coal is mined, it is typically washed
with water and chemicals to remove impurities
before it’s burned. The resulting coal slurry must
then be stored, often with coal ash or in
improvised ponds that can leak, spill, or fail. In
2000, the bottom of a Kentucky coal slurry
impoundment gave way, contaminating more than
a hundred miles of rivers and streamswith more
than 300,000,000 gallons of thick black sludge—
30 times larger than the Exxon-Valdez oil spill.

7. Coal Ash
 When coal is burned it leaves behind a grey powder-like
substance known as coal ash. Although the exact
chemical composition depends on the type of coal
burned, all coal ash contains concentrated amounts of
toxic elements, including arsenic, lead, and mercury.
 Ash can be reused in some way (often in concrete); the
rest is stored in landfills, abandoned mines, and
hazardous, highly toxic ponds.
 Most coal ash is stored in unlined ponds or pits. Over
time, heavy metals in the ash can escape into nearby
waterways and contaminate drinking water.
 Exposure to coal ash is linked with a heightened risk for
cancer as well as heart damage, reproductive problems,
neurological disorders, and other serious health
conditions.

8. Coal Burning
 Burning coal emits large quantities of pollutants,
including sulfur dioxide, carbon dioxide, nitrous oxides,
and mercury. Sulfur dioxide and nitrous oxides can mix
with rain or snow to form acid rain. This mixture
increases the acidity of lakes and streams and can
harm or kill plants and animals.
 Pollution control equipment on power plants, called
“scrubbers," can reduce the emissions of sulfur dioxide
to the atmosphere by using a mixture of limestone and
water to absorb pollutants. This process produces
close to 200,000 tons of sludge waste per year for a
typical power plant.
Source-Union of Concerned Scientists. 2012. UCS EW3 Energy-Water Database
V.1.3.www.ucsusa.org/ew3database.

9. Water Use
 All coal plants rely on water. They function by heating
water to create steam, which then turns turbines,
generating electricity.
 “Once-through” coal plants pump the water directly
from a water source, heat it up, then discharge it
back. The waste water is typically hotter (by up to 20-
25° F) than the water that receives it, creating
"thermal pollution" that can decrease fertility and
increase heart rates in fish.
 These and other energy-water collisions may worsen
as the climate heats up. For example: droughts can
restrict the amount of water available to coal plants,
forcing them to shut down. And hot weather can make
water supplies too warm for cooling, forcing power
plants to reduce their electricity production when it’s
needed most (hot days are also peak electricity usage

10. Water pollution due to coal in
India
 The Water (Prevention and Control of Pollution)
Act 1974 (amended in 1988) is applicable to coal
industries.
 It consider impacts on water due to:-
a) Residues of explosives induce heavy metal
contamination into the surface water bodies
through run-offs & ground water.
b)Water spraying to reduce the fugitive emissions
gets contaminated and finds its way to surface
water bodies and ground water.
c)Water being used for domestic activities at mining
sites is contaminated.
Source- Central pollution control board’s report on pollution due to coal

11.  The implementation of environmental laws in
mining industry is governed by the conditions
imposed in environmental clearance issued by
Ministry of Environment and Forests and consent
to establish/operate issued by State Pollution
Control Board.
 In coal mining major environmental impacts on
surroundings are erosion & sedimentation, habitat
modification, surface & ground water 24
contamination and drawdown of ground water.
Drawdown is lowering of ground water table by
continuous pumping of ground water to prevent
ground water seepage in open cast mining.

12.  Possible events and the expected consequences
from various mining operations are as below:-
Event Consequences
Change in land use, land –
cover and land form
1.Disturbance in natural
watersheds & drainage
pattern of the region
2.Disturbance in wind
direction, flow and
temperature
3.Ultimately disturbance in
rivers/stream flow, agriculture
patterns etc.
4. Floods and loss of bio-
diversity
Waste products including
uranium, thorium and other
radioactive and heavy metal
contaminations
Air/water/soil/food grain
contamination or direct
exposure to flora/fauna

13. Event Consequences
Acid rain Contamination in
surface/ground water, soil,
agriculture
Acid mine drainage Contamination in
surface/ground water, soil and
agriculture
Disturbing recharge area Interference with groundwater
and water table level, surface
water
Disturbances in the drainage
and water-sheds of surface
water bodies
Causing change in flows and
discharges of rivers and
streams
Beneficiation of coal 1. Contamination of surface/
ground water, soil, agriculture
2. Air pollution health impact
and visibility hindrance.

14. Study of CPCB on coal mines
related water pollution
 The project “Impact of coal mine discharge on
surrounding with special reference to heavy
metals” was formulated by CPCB to conduct the
study in central zone.
 Field observation recorded by CPCB :
 There were no measuring devices installed in
coal mines for measurement of waste water
generated and discharged.
 The SPCB has recommended for zero discharge
from all coal mines but in most of mines zero
discharge in not complied.

15.  The treatment provided to waste water by coal
companies are need based only, wherever waste
water is to be used for domestic purpose in
townships, it being treated for proper settling followed
by pressure filtration.
 In many mines it was found that RCC tanks were
provided for settling with low retention time. The
waste water being pumped in that tanks are having
sufficient pressure for creating turbulence in settling
tanks.
 Treatment plants of many mines were found very old
or over aged and nor fit for it operation especially in
underground mines.
 In underground mines the left mined pits are being
used as storage pit and claimed as settling pit. This
water is pumped to ground level in RCC tanks and

16.  There were no sludge collection and with drawl
system in settling tanks. The fine coal particles
flowing in waste water was found deposited in
agricultural fields using this water for irrigation.
 The waste water discharged by mines finds its
way in perennial drain and ultimately joins the
rivers of that area. The heavier coal particles get
settled in way either in RCC tanks or in carrying
drain, 31 but very fine coal particles in
suspension decreases the sunlight permeability in
River water.
 In case of open cast mines the waste water
generated is collected in open pits and pumped in
to drains as and when required.

17.  The improper stacking and slope of top soil and
overburden increases the possibility of
contamination of ground water during rainy
season.
 Most of the coal mines have not provided catch
drain and catch pits for run-off collection from top
soil and over burden stacking.
 Garland drain for management of rain water was
found either not constructed and if constructed
not maintained properly.
 Huge deposition of fine coal particles were
observed in and around the coal mines on road
as well as on tree. This may be due to open
transportation of coal in the area. These fine coal
particles find its ways to drain and finally to River
in rainy season.

18. Outcomes of CPCB study
 The impact of coal mine discharge on
surroundings could not be ruled out.
 The mine waste water used for irrigation has
given an impact of fine coal particle deposition in
agricultural fields.
 The fine coal particles coming in mine discharge
are increasing turbidity of River water flowing very
near to mine area as in case of River Kelo and
River Rehar in Raigarh area of Chhattisgarh.
 The fluoride present in ground water is going to
Rivers through effluent of coal mines.

19.  Increasing the dependency of villagers on coal
mine discharge water by reducing ground water
table in the area.
 Increasing metal concentration in River water
especially in non-monsoon period.
 Decreasing plantation growth in the area by
emitting fine particles during its transportation.

20. Recommendation
 Strict compliance of zero discharge condition.
 Complete treatment of industrial wastewater to
confirm the prescribed standard and its in house
use.
 The treated water quality norms shall be stringent
up to portable water norms.
 Providing water meters to measure quantity of
waste water generation and discharge

21.  Construction of Catch drains, siltation ponds,
Garland drains and settling ponds.
 Providing artificial recharge measures, rain water
harvesting system and meeting water
requirement of nearby villages by permanent
water supply system.
 All internal roads shall be black topped and good
housekeeping shall be maintained.
 Coal shall be transported in duly covered
conveying system/vehicles to control fugitive
emission during transportation.
 The coal mines shall develop thick green belt
around the leased mine area.
 Top soil and overburden stacking shall strictly
follow the norms of its height and slope.

22. Conclusion
 Coal mining as well as its consumption directly
causes water pollution.
 Coal proudces water pollution during mining
stages as well as its burning and after burning
stage.
 Coal mining industries specially Indian industries
are not following zero emission standard as
prescribed by MoEF.
 Ground scale Implementation as well as time to
time monitoring is necessary for controlling
pollution from coal industry.