In our last issue, we explored the detrimental effect of coal-fired power plants on the local aquatic and marine ecosystems1. We also delved into how the discharges from coal-fired power plants affect fish health and human livelihoods and health as well.
In this issue, we shall explore the various mitigation measures available to reduce or diminish the pernicious impact of coal-fired power plants on aquatic and marine ecosystems. The adage “Prevention is Better than Cure” is very apt when looking to mitigate the impacts of coal-fired power plants on fisheries.
According to Central Pollution Control Board (CPCB) standards2, the temperature of discharge water or effluent shall not exceed 5℃ above the ambient water temperature. It is known that a temperature difference of even 1℃ tends to have a harmful impact on the various life forms of the marine ecosystem, by altering their reproductivity and inducing heat stress. However, the issue is in the implementation of these guidelines and power plants have been found to release sea water which is 5 to 7℃ higher than the temperature of the inlet seawater temperature3. The environmental standards issued by CPCB should be adhered to on an urgent basis and heavy penalties should be levied on power plants defaulting on the temperature. The need is for CPCB to be more agile in bringing the defaulters to task by exercising their powers under Section 5 of the Environment (Protection) Act, 1986. Under this act, CPCB is empowered to issue directions for (a) the closure, prohibition or regulation of any industry, operation or process; or (b) stoppage or regulation of the supply of electricity or water or any other service4.
Compulsory installation of waterproof real-time temperature probes that can relay the data to a dashboard displayed on a giant screen at the plant boundary, where the local community can look at this data, should be brought in for power plants discharging water to a nearby waterbody. These temperature probes should be kept near the water outlet. This information can help the fish workers plan their fishing forays according to the temperature and also help CPCB levy penalty on regular defaulters. They should also be made to compensate the local fish workers who have to venture deep into the sea in search of fish. Power plants should also be asked to do a quarterly bio-assay test (90% survival of fish after 96 hours in 100% effluent). The current rule for annual testing is insufficient considering the nature and need of the fishing industry. Results of the bio-assay test can help fish workers plan their fishing expeditions better by informing them about the toxicity of the waters. Fish tend to move away from water containing pollutants or they carry the risk of death. All attempts by the industry towards non-adherence of the environmental standards should be met with stiff resistance from the affected community and members of the civil society.
For power plants depending on fresh water, a 2015 study by Centre for Science and Environment showed that coal-fired power plants are responsible for 70% of the total freshwater withdrawal by all industries and more than 80% of mercury emissions by the industrial sector in the country5. Coal-fired power plants in India are among the most wasteful consumers of water at an average of 4 m3 /h per MW compared to 1.34 m3 /h per MW in South Africa and 2.45 m3 /h per MW in China. As per Environment (Protection) Amendment Rules, 2015, notified by the Ministry of Environment Forest and Climate Change (MoEF&CC), all new plants installed after January 1, 2017, should not consume more than 3m3/h per MW. It is appalling to know that there have been cases when the government has been complicit with the power plants in violating the water usage guidelines. This is evident in the case of RTPS in Karnataka where the Consent to Operate (CTO) for the 5 year period 2016-2021 granted by the Karnataka State Pollution Control Board (SPCB) had water extraction limits in excess of the MoEF&CC 2015 notification6. There are power plants which regularly achieve 2 m3 /h per MW (like the CESC Budge Budge Power Plant, West Bengal, and JSW Vijayanagar Power Station, Karnataka) through improvements in fly ash management and internal water budgeting. Cycles of concentration (COC) of seven (CESC Budge Budge) and six (JSW Vijayanagar) in its cooling towers help these plants in lowering the water use. Both these plants follow dry handling of ash and boiler water is treated in an advanced system to allow reuse and reduce losses. CESC Budge Budge has a zero liquid discharge system (ZLD) which ensures water discharged from various uses is recycled back. It is also the only plant in India to have a dewatering system in place for bottom ash disposal7.
As discussed in part 1 of this series, residues in fly ash contain a cocktail of heavy metals and volatile organic compounds (VOCs) which contaminate our air, soil and water. These heavy metals and VOCs leach into the water and tend to accumulate in fish in a process known as bioaccumulation. Technological interventions like dewatering system for fly ash disposal ensure that the water is stripped off of most of the pollutants. This has the potential to reduce the chances of bioaccumulation of these pollutants in aquatic and marine life. Zero liquid discharge and efficient effluent and sewage treatment too would ensure the reduction in freshwater demand and stop pollutants from contaminating our water bodies
The onus is on MoEF&CC, CPCB and respective SPCBs to make sure the guidelines are implemented strictly. With the changes put in place in 2015 to the Environment (Protection) Rules (1986), India now has norms for discharge of effluents and spent water that matches global best practices. Limits to various parameters like colour, odour, suspended solids, particle size of suspended solids, pH, temperature, oil and grease, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), heavy metals, VOCs, bio-assay test and radioactive materials are in place on paper but we are severely handicapped when it comes to implementation and compliance. Coal-fired power plants should be asked to record the quantity of water used at each step of power generation and to actively strive to achieve zero discharge status. Detailed environmental and social impact assessment should be carried out covering all aspects of the established law and compliance adherence should be strictly enforced in letter and spirit. Currently, even plants which routinely flout norms almost always report compliance. This is exacerbated by the severely understaffed SPCBs in India. We need to wean away from the excuse of allowing the functioning of the most inefficient and polluting power plants under the garb of the need of power. This excuse is no longer valid with renewables available at competitive rates. The Environmental Management Cell of these power plants, required to be constituted as part of the plant’s Environmental Management Plan, should play an active role in ensuring adherence to prescribed norms.
CSE 2015, Heat on Power: Green Rating of Coal-Based Thermal Power Plants