Waste-Water treatment in Thermal Power Plant

Syed Sajid Sohail,JNTUK

Pic: Mundra power plant, gujarat

MAIN PARTS IN THERMAL POWER PLANTS

1. COAL CONVEYER 10. CONDENSER

2. STOKER 11. TRANSFORMERS

3. PULVERIZER 12. COOLING TOWERS

4. BOILER 13. GENERATOR

5. COAL ASH 14. HIGH- VOLTAGE POWER LINE

6. AIR PREHEATER

7. ELECTROSTATIC PRECIPITATOR

8. SMOKE STACK

9. TURBINE

THERMAL POLLUTION : 1. Thermal pollution is the degradation of water quality by any process that changes ambient

water temperature.

2. When water used as a coolant is returned to the natural environment at a higher temperature, the change in temperature decreases oxygen supply and affects ecosystem composition.

3. When a power plant first opens or shuts down for repair or other causes, fish and other organisms adapted to particular temperature range can be killed by the abrupt change in water temperature known as “thermal shock”.

4. Stream temperature rises when trees and tall vegetation providing shade are cut.

5. Soil erosion caused due to construction also leads to thermal pollution

Effects of Thermal pollution

Reduction in dissolved oxygen: Concentration of Dissolved Oxygen (DO) decreases with increase in temperature.

Increase in toxicity: The rising temperature increases the toxicity of the poison present in water. A 10°C rise doubles the toxicity effect of potassium cyanide, while 80°C rise triples the toxic effects of o-xylene causing massive mortality to fish.

Interference in biological activity: Temperature is considered to be of vital significance to physiology, metabolism and biochemical processes that control respiratory rates, digestion, excretion, and overall development of aquatic organisms. Temperature changes cause total disruption to the entire ecosystem.

Interference in reproduction: In fishes, several activities like nest building, spawning, hatching, migration and reproduction depend on optimum temperature.

Direct mortality: Thermal pollution is directly responsible for mortality of aquatic organisms. Increase in temperature of water leads to exhaustion of microorganisms thereby shortening the life span of fish. Above a certain temperature, fish die due to failure of respiratory system and nervous system failure.

Food storage for fish: Abrupt changes in temperature alters the seasonal variation in the type and abundance of lower organisms leading to shortage of right food for fish at the right time.

WATER ENVIRONMENT:

• W/W FROM COOLING TOWERS ARE DISPOSED OFF AT TEMPERATURE 4-5°C ABOVE THE PREVALENT SURFACE TEMPERATURE( BETTER TO DISPOSE OFF BY LONG AND OPEN CHANNEL)

• WATER SLURRY IS USED TO TAKE THE ASH TO THE ASHPONDS FOR DISPOSAL. WATER SLOWLY SEEPS INTO GROUND WHILE CARRYING THE ASH LEECHATE AND POLLUTE THE GROUND WATER . THE RELEASE OF ASH POND DECENT ALSO AFFECT THE WATER ENVIRONMENT.

• WHEN THE WATER DRIES UP IT CREATES FUGITIVE DUST NUISENCE

LIQUID WASTE MANAGEMENT SYSTEM:

AFTER THE PRIMARY TREATMENT SENT TO E.T.P (EFFLUENT TREATMENT PLANT) WHICH IS DESIGNED TO TREAT CONDENSATE POLISHING UNIT(CPU) EFFLUENT, WATER TREATMENT PLANT, COAL HANDLING PLANT(CHP), FLOOR WASHING, SERVICE WATER DRAINDS ETC..

THIS WATER AFTER TREATMENT IS RECIRCULATED FOR VARIOUS PLANT USES.

“WASTING THE WASTE IS SUCH A WASTEFUL THING”

“NOTHING IS PARTICULARLY HARD IF U DIVIDE IT INTO SMALL JOBS” – HENRY FORD

SPECIFIC WATER CONSUMPTION:IT IS EXPRESSED IN M³/MW OR LITRE/KWH.IT RANGES FROM 1.7 – 8 M³/MW.IT DEPENDS ON SIZE, AGE AND TYPE OF PLANT, TYPE OF WATER CIRCULATION SYSTEM, ASH HANDLING AND WATER RECYCLING ETC..

BOKHARO THERMAL:1. It is situated on the banks of the river

Konar.2. It is the oldest thermal power plant in Asia

run by Damodar Valley Corporation. 3. It was started in 1952 in collaboration with

USA and West Germany by the then Prime Minister of the country Pandit Jawaharlal Nehru.

4. It has two power plants:BTPS 'A' was started in 1952 and closed down on 17 July 2000 for violating pollution norms.BTPS 'B' has three power generating units producing a total of 630 MW (3×210). The first unit was commissioned in 1986.

GMR POWER PLANT ( GAS):KADIAM MANDAL, EAST GODAVARIINSTALLED CAPACITY= 2* 383.77MW

INSTALLED CAPACITY IS THE MAX AMOUNT OF ELECTRICITY PRODUCED WHEN ALL THE RESOURCES ARE AVAILABLE

“IF U CANT MAKE IT GOOD, ATLEAST MAKE IT LOOK GOOD” – BILL GATES

EXAMPLE:HOW WE CONSUME?

THIS IS HOW WE PAY FOR OUR ELECTRICITY

For above example we pay : 50*2.6+(50*3.25)+(50*3.25)+…….+95*(7.38)=2182rs

“Earth provides enough to satisfy every man's needs, but not every man's greed.”

― Mahatma Gandhi