Existing and New (Revised) Emission Standards for coal based Thermal Power Plants in India

Existing and New (Revised) Emission Standards for coal based Thermal Power Plants(TPPs) in India

Existing Emission Standards:

Particulate Matter (PM) Emission

Parameter        Standard Limits, mg/Nm3

PM                    350 (for <210 MW TPPs)

PM                    150 (for 210 & above MW TPPs

New Emission Standards as per MoEF Notification dated 7.12.2015 :-

1) For new TPPs to be  installed after 1/1/2017. These units includes all those TPPs which have got EC and are under construction.

Parameter                   Standard Limits, mg/Nm3

PM                                         30

SO2                                       100

Oxides of Nitrogen(NOx)  100

Hg                                         0.03

2) For TPPs installed between 1/1/2003 to       31/12/2016, these units have to meet the limits   within two years from the date of MoEF Notification (7/12/2015)

Parameter             Standard Limits, mg/Nm3

PM                                       50

NOx                                    300

Hg                                       0.03

SO2     600 (for <500MW Power Plants)

SO2     200 (for Power Plants of 500MW & above)

3) For TPPs installed before 31/12/2003

Parameter       Standard Limits, mg/Nm3 

PM                         100

NOx                        600

Hg                          0.03

SO2     600 (for <500MW Power Plants)

SO2     200 (for Power Plants of 500MW & above)

Air pollutants Unit Conversion

The following is with reference to Air Pollutants,

(* means multiplication and,  / means division)

ppb :-   parts per billion by volume
ppm :-  parts per million by volume

Numbers

Million = 1,000,000

Billion = 1,000,000,000

Trillion = 1,000,000,000,000

1 ppm = 1000 ppb = 10^{3 ppb}
1 ppb = 0.001 ppm = 10^-3 ppm
1% = 10000 ppm
% = ppm * 10^{-4
% = (}10^{3 ppb *}10^{-4) = (ppb/10)}
 %= ppm * 10^-4 = ppb * 10<sup>-1

For concentrations  (of chemical contaminants or soil contaminants)  in water, in soil
the following holds true</sup>

1 ppm = (1 mg/Lit, like in water)= (1 mg/Kg, like for concentrations in soil) = (1gm/m³  like for concentration of chemicals in water)

same for ppb,

1 ppb = 1μg/Lit  = 1 μg/Kg = mg/m³ 

But for concentration of air pollutants in Air, following conversion formula is to be used,

mg/m³  is same as  mg/Nm^3
μg/m3  is same as  μg/Nm³

mg/Nm³ = (ppm * MW )/(0.08205 * °K)

where °K is Deg Kelvin and MW is 
molecular wt. of air pollutants

At 1 atm pressure and 25°C, the above equation becomes

mg/Nm³  = (ppm* MW)/24.45

or

μg/Nm³  = (ppb* MW)/24.45

Standard molar volume of an ideal gas at 1 atm pressure and 25°C temp = 24.45 m³/mol

and at 0°c this volume is 22.414 m³/mol

NAQI:- National Air Quality Index for India

NAQI
National Air Quality Index for India
There are Six (6) AQI categories like GOOD, SATISFACTORY, MODERATELY POLLUTED, POOR AIR QUALITY, VERY POOR AIR QUALITY, SEVERALLY POLLUTED. These AQI are integrated with AQI Sub-index (which is a range in real numbers). These six categories are decided based on Ambient concentration values of air pollutants & their likely health effects. The AQI sub index  and health impacts (health breakpoints) are evolved for eight (8) pollutants like PM10, PM2.5, NO2, SO2, CO, O3, NH3, Pb. 

NAQI standard are prescribed for these 8 pollutants for short term exposure (24hrs).  Sub-index is calculated based on ambient concentrations of these air pollutants. It is to be noted that AQI Sub-index is linear function of ambient concentrations of these 8 air pollutants.
The worst Sub-index determines Overall AQI.


AQI                         Possible Health impacts  
                        or health break point


Good -                    Minimum Impact
(0-50)

Satisfactory -        Minor Breathing
(51-100)                discomfort to
                               sensitive  persons

Moderately Polluted-  Breathing discomfort  
(101-200)                     to persons having Heart
                                      or Lung disease, to older
                                      ones & to children's

Poor -                     Breathing discomfort to
(201-300)              persons on prolonged
                               exposure 

Very Poor -            Respiratory illness to
(301-400)              people on prolonged
                               exposure 

Severe -               Respiratory effects even on
(>400)                  healthy people


One observation means one AQI calculated
for daily Ambient Air Quality data at
one Air Monitoring Station.



Air Pollutant      AQI Sub-index     Ambient        
                                                          concentration                                                                      of PM2.5

PM2.5                      100                  60 μg/m3
PM2.5                       75                   45 μg/m3
PM2.5                       50                   31μg/m3

Standards for Water Consumption in Thermal Power Plants in India

Standards for Water Consumption in Thermal Power Plants in India

1. All plants with Once Through Cooling (OTC) shall install cooling tower (CT) and achieve specific water consumption upto maximum of 3.5m3/MWh by 7/12/2017.

2. All existing Cooling Tower(CT) based plants reduce specific water consumption of 3.5m3/MWh by 7/12/2017.

3. New Plants to be installed after 1/1/2017 shall have to meet specific water consumption upto maximum of 2.5m3/MWh and achieve zero Wastewater discharge.

Guidelines for Discharge Point in Thermal Power Plants in India

Guidelines for Discharge Point in Thermal Power Plants in India

1. The discharge point shall preferably be located at the bottom of water bodies at mid-stream for proper dispersion of thermal discharge.
2. In case of discharge of  cooling water into sea, proper marine outfall shall be designed to achieve the prescribed standards. The point of discharge may be selected in consultation with the Concerned State Authorities.
3. No cooling water discharge shall be permitted in estuaries or near ecologically sensitive areas such as mangroves, coral reefs, spawning & breeding grounds of aquatic flora or fauna.

Temperature Limit for discharge of Condenser Cooling Water from Thermal Power Plant in India.

Temperature Limit for discharge of Condenser Cooling Water from Thermal Power Plant in India.

New Thermal Power Plants commissioned  after June 1, 1999 :-

New Thermal Power Plants, which will be using water from rivers, reservoir, lakes shall install cooling towers irrespective of location & capacity.

New Projects in Coastal areas using Sea water:

The Thermal Power Plants using Sea Water should adopt suitable system to reduce water temperature at the final discharge point so that the resultant temperature of receiving water does not rise.

Rise in temperature of Condenser Cooling Water from the inlet to the outlet of Condenser shall not be more than 10°C.

Standards for Discharge of Liquid Effluents from Coal based Thermal Power Plants in India

Environmental Regulations for Coal based Thermal Power Plants in India

Standards for discharge of Liquid Effluents

S.N	Source	Pollutants	Concentrations
1	Condenser Cooling Water (Once through Cooling System)	pH Temperature Free available Chlorine	6.5-8.5 More than 10°C than the intake water temperature 0.5mg/L
2	Boiler Blow-down	SS Oil & Grease Copper(total) Iron (total)	100mg/L 20mg/L 1mg/L 1mg/L
3	Cooling Tower Blow- down	Free available Chlorine Zinc Chromium Phosphate Other Corrosion inhibiting materials	0.5mg/L 1mg/L 0.2mg/L 5mg/L Limits to be established case by case basis
4	Ash Pond Effluent	pH SS Oil & Grease	6.5-8.5 100 mg/L 20mg/L