The coal cauldron

The Sahiwal power project, which will burn six million metric tonnes of coal each year – posing grave environmental risks to the soil, water and air of the region – needs to be brought under public scrutiny for compliance of pollution-control measures.
A Chinese company is building the project’s two power stations, each of 660-megawatt capacity (a total of 1320MW), at a cost of $1.5 billion. The Punjab Power Development Company Limited (PPDCL), set up by the Punjab government, owns the project. The power plant is scheduled to be completed in 2017.
Located in a populated area nearly 16 kilometres from Sahiwal city, the power project is spread over more than 639 acres of fertile agricultural land in whose vicinity passes River Ravi.
The civil society needs to keep a watch if the project’s proponent, PPDCL, follows the pollution-mitigation steps that the project’s feasibility report has promised and Nespak’s environmental impact assessment study recommended. Ten key pollution-mitigation measures include the following:
• The plant’s environmental impact assessment has been cleared on the premise that the power stations in Sahiwal will use imported coal that causes less pollution due to low-sulphur content – though it is expensive.
If the government starts using less expensive, local coal with high sulphur content, the pollution caused by the plant will be much higher and additional pollution-mitigation measures would be required.
The imported coal will be transported to Sahiwal through four to five railway locomotive trains every day – an operation which itself is fraught with environmental risks if the wagons carrying coal are not properly covered.
• The environment impact assessment study says that coal combustion and air emissions from the coal plants will include sulphur oxides, nitrogen oxides, carbon mono oxide, carbon dioxide, volatile organic compounds, particulate matter and mercury.
The plant will use Flue Gas Desulphurization (FGDs) for reducing sulphur oxides and Electrostatic Precipitators (ESPs) for particulate matter.
According to the environment impact study, the Sahiwal project has planned to use low-nitrogen oxides burners to control emissions of these gases though it should have a more efficient system of Selective Catalytic Reduction Converter for this purpose.
The environment study says that the use of burners will not be able to reduce the nitrogen oxides below the limits set by the national environmental quality standards (NEQS). According to the feasibility report, two SCR converters may be installed in future, but the impact study has recommended the converter’s installation before commissioning of the plant.
If this equipment is not installed, the air quality of the area will deteriorate causing several respiratory diseases among the local residents, especially children.
• Cooling is the largest use of water at a coal-fired power plant. The plant will require 4.5 cubic feet per second of fresh water to cool power stations; this water will be supplied from the nearby Lower Bari Doab Canal or tube-wells.
The Sahiwal project has adopted an indirect dry air-cooling system for steam, turbine condenser. However, this cooling method is less efficient than the recirculation water-cooling system which reduces gaseous emissions more than dry air-cooling. The environment impact study has suggested installing the latter system which should be incorporated in the plant design before it starts operating.
• One of the major forms of solid waste generated from the power plant’s operation will be the residual fly ash and bottom ash comprising mineral matter along with unreacted carbon and trace elements of mercury. The environment study has recommended installation of Flue Gas Mercury Control (FGMC) system to control and minimize the levels of mercury released, which at present is not part of the plant design.
• The leaching of ash from the plant may poison drinking water in the area. All coal ash stocks should be covered and fully protected. The storage areas need to be designated to control water run-off during rains and should be properly lined and contained to prevent leaks. Also, groundwater in the vicinity should be regularly monitored.
• The plant’s raw water reservoir must be also properly covered. The power stations will use an area of 21 acres as a raw water reservoir. Solid waste or sewage waste or presence of coal can contaminate the reservoir’s water. An open reservoir may cause diseases such as malaria, dengue etc.
• The wastewater from the plant will be discharged into open drain (nullah) passing through the site which will carry it to River Ravi. The wastewater will also seep into the sweet groundwater in the area. Thus, wastewater must be treated before disposal otherwise the canal water and the agricultural lands irrigated by its water will get contaminated with hazardous pollutants including mercury.
Similarly, improper handling and disposal of many chemical being used at the power plant can pollute surface water bodies such as nullahs. This risk needs to be taken care of by using drums and storage containers that are tight and do not leak. Wastewater containing chemical and oil spills should be channelled towards septic tanks and soaking pits before they flow into the open drain. If pollution-mitigation measures regarding wastewater are not fully taken, the contaminated water will harm crops and livestock in the area.
• More than 1200 trees have been cut and vegetation has been removed from 690 acres of fertile land for this project while it has been pledged that the same number of trees in addition to shrubs, grasses and ornamental plants will be grown under the environment management plant. Trees will also act as a barrier to noise from the power stations.
• A firefighting plan needs to be in place in case coal stocks catch fire. Further, a solid waste management plan to deal with collection and disposal of solid waste is needed as sanitary waste from the residential colony of 250 employees and solid waste in the form of coal ash may have an impact on human health.
• Noise and vibration will be produced from coal delivery and steam blowing and purging of boilers. It has been recommended that an ambient noise measurement programme is instituted to monitor the noise generated by the power stations and ensuring they are within the prescribed limits.
Email: adnanadilzaidi@gmail.com