pipe dreams treated sewage will not solve coal power’s water … · 2017. 6. 14. · pipe dreams:...

Pipe dreams Treated sewage will not solve coal power’s water problems

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Greenpeace India

Pipe dreams: Treated sewage will not solve coal power’s water problems

ASP Activated sludge process

BCM Billion Cubic metres or a 1000 MCM.

BOD Biological oxygen demand

CERC Central Electricity Regulatory Commission

CPCB Central Pollution Control Board

Crore 10 million

GW Gigawatt or 109 watt

JNNURM Jawaharlal Nehru National Urban Renewal Mission

KL kilo litre. Also equivalent to one cubic metre of water

MAHAGENCO Maharashtra State Power Generation Company

MCM Million cubic metres

MLD Million litres a day

MW Megawatt or 106 watt

NMC Nagpur Municipal Corporation

NTPC National Thermal Power Corporation

O&M Operations and maintenance

RBC Rotating biological contractors

RPO Renewable purchase obligations

STP Sewage treatment plant

TF Trickling Filters

TSS Total suspended solids

TWh Terawatt hour or 1012 watt hour. Also equivalent to billion units or billion Kwh.

UASB Up flow anaerobic sludge blanket

Abbreviations used in this report:

For more information contact:

Jai Krishna R Senior Research [email protected]

Anindita Datta Choudhury Senior Media OfficerGreenpeace [email protected]

Author: Jai Krishna R with contributions from Ashish Fernandes.

Reviewed by: Harri Lammi and Nandikesh Sivalingam (Greenpeace) and Shripad Dharmadhikary (Manthan Adhyayan Kendra)

Published by: Greenpeace India Society in June 2017

Acknowledgements: We thank Kelly D. Alley and https://sandrp.wordpress.com/for photo on page 11. Arun Ganesh/@planemad, OpenStreetMap India and Arvind Shivakumar, Greenpeace for help in GIS analysis.

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Executive Summary 5

Introduction 6

Sewage treatment in India 8

Feasibility analysis of treated water

supply for coal power plants in India 10

Case studies - existing examples of

treated sewage for coal power plants 14

Role of sewage in the water cycle 18

Conclusion 20

Appendices 21

Contents

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Executive summary

• About 87% or 200 GW of coal power plants would not be able to utilise treated sewage.

• Over 50 GW of the coal plants currently under construction would not be able to utilise any sewage for cooling. These represent over 90% of the plants under construction.

• Less than 11% of the total sewage treatment capacity can be utilised by coal power plants.

• Switching from freshwater to treated sewage water entails large investments in tertiary treatment technologies and the annual cost of water will increase by at least 300%.

• Utilising sewage as a source of water decreases the water availability in the region and has an impact similar to the use of freshwater. Switching to treated sewage water is not a solution to the water scarcity created by coal power plants and should be done after an impact assessment has been conducted.

In summary, switching from fresh water to sewage will not reduce the impact of coal power plants on water scarcity in the country

A more timely and cost-effective solution to the coal-water conflict could lie in a phase out of older, less efficient power plants, which also tend to consume the most water and emit the most air pollution and timely adoption of the water consumption target set for power plants by the Ministry of Environment, Forests and Climate Change (MOEFCC) in their notification of 7th December 2015.2 At the same time, all permits for new coal plants must be halted, as they are in any event not required at least till 2027, per the Central Electricity Authority’s draft National Electricity Plan.

Water shortages and regional droughts have become more pronounced in India. Following below par monsoons in 2015 and the subsequent country wide drought in early 2016, water shortages for coal power generation became acute and several plants were shut down for many months. In an attempt to address the growing conflict of coal power plants with farmers and urban communities, the Government of India proposed using treated sewage water as an alternative for fresh water in coal power plants through its power tariff policy announced in January 2016.

Coal power plants require large volumes of water - a 1000 MW coal power plant requires about 84 million litres of water each day, assuming that it’s operated at full capacity. Operating sewage treatment plants currently account for about 30% of the total sewage generated, and are mostly concentrated around metropolitan regions. The availability of treated sewage water within 50 km of a coal power plant therefore is dependent on the locations of coal power plants and sewage treatment plants. Besides, utilising sewage water for coal power plants also requires significant investments in tertiary treatment facilities and pipelines.

Key findings Less than 8% of coal power plants can switch to treated sewage water.

• Greenpeace analysis indicate that less than 8% of India’s coal power plants can completely switch from fresh water to treated sewage water. About 5% can partially meet their water requirements from treated sewage.1

Executive summary

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IntroductionPipe dreams: Treated sewage will not solve coal power’s water problems

(BCM) in 2010 to 130 BCM in 20505, a growth from 1% of the total demand to almost 9 % of the total demand. Coal power plants consume a bulk of this share with their intensive water needs for cooling. Some studies have put the consumptive water use of thermal power plants at 87% as compared to all other industrial sectors6.

In March last year, Greenpeace published the first ever global report measuring the future water requirements for coal - including mining and power generation7. The report uses data from government and industry sources, and projects that water consumption for coal power plants8 is expected to increase by 90% (from 19 BCM to 36 BCM) if the proposed coal power plants (1300 GW) are all commissioned. 44% of the existing coal power plants and 45% of the proposed coal power plants are be located in areas with high to extremely high levels of water stress. About a quarter of the existing and proposed power plants are located in areas that are suffering from over-withdrawal of water. All these results indicate a growing water risk factor for coal power plants.

Fresh water is vital for life, health and sanitation, agriculture as well as an important resource for industry – specifically in manufacturing and energy. As economies and GDP grow, water as a resource has become increasingly difficult to manage, leading to intersectoral conflicts in even moderately water stressed regions of the world. Water crises have been acknowledged by the World Economic Forum as one of the top three risks3 with high impact on a ten year horizon in 2015.

India with 2.5% of land mass, 4% of freshwater resources and 17% population of the world is a predominantly water stressed country. The per capita water availability is projected to drop from 1608 cubic metres per-capita in 2010 to 1140 cubic metres per capita in 2050.4

The nexus between water and energy has been receiving a lot of recognition in the past few years. Projections of water requirements for energy as compared to the domestic and agricultural sectors are expected to increase from 5 Billion Cubic Metres

Introduction

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IntroductionPipe dreams: Treated sewage will not solve coal power’s water problems

a measure to tackle increasing water shortages for thermal power plants. The Section 6.2.5 of the tariff policy makes the following new regulations:

• Thermal power plants which have a Sewage Treatment Plant (STP) of any municipality or a city within 50 km of their location should make arrangements for the water from the STP.

• If the thermal power plants are able to get treated water from the STP, the additional costs incurred can be allowed as a hike in their tariffs.

• They are also allowed to keep back up reserves from other freshwater sources in the event of any short supply- and costs for these should be included in the fixed costs of tariffs.

While the success of this policy is yet to be seen, we believe there needs to be some fundamental assessments that are required to find whether the policy can actually reduce water shortages for thermal power plants.

Questions that need to be answered: Q1: Are there enough sewage treatment plants in the country to feed the water needs for coal power plants?

Q2: What will be the cost for ensuring municipal sewage quality meets the quality standards needed for thermal power plants?

Q3: Does switching from fresh water to sewage water really mitigate the water risk factors for coal power plants? If yes, to what degree?

This report aims to answer these questions.

Drought of 2016 caused major loss of revenue for Indian coal power companies:In India, an average coal power plant consumes about 3.5 cubic metres of water per MW per hour. Older plants consume about 5 cubic metres/ MWh. New water efficiency regulations notified in December 2015 and to be effective from January 2017 stipulate a water rating of 2.5 Cubic metres per MWh of thermal power generation. The dependency of coal power sector on water was evident in the drought of 2015-16 which affected more than 266 districts in 11 states, reflecting a nation-wide calamity. Water shortages for cooling resulted in backing down of about 11 TWh of power generation and companies have lost potential revenues of over 560 million US$ from January till July 2016. NTPC and Adani power were the worst hit companies losing over 210 million USD of potential revenue during this period. With more than half of all the upcoming coal power plants located in medium to extremely high water stress areas of the country, the water risk for coal power generation in India should well be considered as a high impact operational risk.

New regulations require power plants within a 50 km range of a sewage treatment plant to to use treated sewage water:In January 2016, the government amended9 the 10 year old power tariff policy to bring in amendments in areas like land utilisation, surplus power sale, bringing in transmission projects under bidding route, increasing solar renewable purchase obligation (RPO) apart from

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Sewage treatment in India

50% of the total sewage generated in the country12 and account for almost 66% of the total installed capacity of sewage treatment plants (STP) in the country. Delhi and Mumbai which generate 17% of the total sewage of the country hold about 40% of the installed STP capacity.13

Sewage treatment capacity still far behind sewage generation:In 2009 when the volume of sewage generation was about 38,000 MLD, the treatment capacity was about 11,800 MLD. In six years, the sewage generation grew by compounded growth rate of 8.5 % to 62000 MLD while the treatment capacity grew at about 12.5% to 24000 MLD.

India generates about 62000 Million litres a day (MLD) of sewage as of 201510. It has an operational treatment capacity of around 19000 MLD11 or about 30% of the total sewage generated. Another 3130 MLD is being planned and is at various stages of development which will take that figure up to about 35%.

Sewage generation happens across the country but sewage treatment is mostly urban:Sewage treatment capacity and infrastructure is mostly concentrated in urban areas and metropolitan regions as large urban centres tend to invest more on water supply and sewerage infrastructure as compared to towns. The five states Maharashtra, Tamil Nadu, Uttar Pradesh, Delhi & Gujarat account for approximately


Table 1: Sewage generation Vs Sewage treatment capacity addition

Year Sewage generation (in a million litres a day)

Sewage treatment capacity (including operational, under construction and proposed capacities) in a million litres a day

2009

2015

Compounded growth rate

38,000

62,000

8.5 %

11,800

24,000

12.5 %

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Standards for sewage treatmentThe Ministry of Environment, Forest and Climate Change has issued a draft notification covering standards for effluents from sewage treatment plants in November 2015.16 While it's unclear whether this has been finalised, the draft version indicates that the new standards would be applicable for all new sewage treatment plants and the existing sewage treatment plants would be expected to comply with these standards within five years from the date of final notification. The older standards are based on the general standards issued in 1993 for discharge of environmental effluents into inland surface water- which covers effluents from sewage treatment plants.

While there are no specific standards for cooling tower makeup water for coal power plants by the government, NTPC the largest coal power generator in the country has specified standards17 for treated sewage water. Till the draft notification of 2015, there were no specific standards for STP effluent quality and therefore the parameters of these three notifications aren’t quite comparable. The only comparable parameters between these standards are Biochemical Oxygen Demand (BOD) and for Ammonia where the NTPC requirements are less than half of the 2015 draft standards. A comparison of the 1993 standards, 2015 standards and the NTPC requirements is listed in Appendix A.

ASP, the most widely used treatment technology in the country is woefully short of the treatment quality required by NTPC requirements and is best used a secondary treatment technology which forms the influent for a tertiary treatment plant.

The performance of existing STP’s are a cause of concern. A report18 by the central pollution control board (CPCB) in 2013 assessing the performance of STP's funded under the National river conservation programme found that 49 of the 152 STP's monitored did not even meet the older BOD standards of 30 mg/l.

Sewage treatment technologies in IndiaSewage treatment is usually classified into four phases, preliminary, primary, secondary and tertiary. Preliminary treatment involves removing of coarse solids and other large materials usually found in sewage. Primary treatment uses sedimentation and removes organic and inorganic solids and floating materials. Preliminary and primary treatment is often coupled with secondary treatment where residual organics and suspended solids are removed using aerobic and anaerobic biological processes (most cases).

Some common technologies used in secondary treatment are activated sludge process (ASP), trickling filters (TF), rotating biological contractors (RBC) and up-flow anaerobic sludge blanket (UASB). Combinations of these processes are sometimes used for treating industrial wastewater as well. Almost 60% of the secondary sewage treatment technologies used in India are based on ASP.14

Tertiary treatment is required to remove nitrogen, phosphorous, additional suspended and dissolved solids and heavy metals. Tertiary treatment is mostly employed when the treated water needs to be used for industrial processes or for human consumption. Based on the need, tertiary treatment utilises various stages like ultra filtration, reverse osmosis, ultraviolet treatment and demineralisation.

Costs of tertiary treatment are high The type of tertiary treatment usually depends on the end use of the treated water and is usually costly. The increased cost usually makes it less attractive for irrigation or drinking water and thus is mostly used for industrial uses which need a high degree of treatment. Typically, the cost of water per kilo litre (KL) after secondary treatment is about Rs. 34/ KL while tertiary treatment (ultra filtration + reverse osmosis) more than doubles costs up to Rs. 73/ KL.15

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Analysis of feasibility of treated water supply for coal power plants in India

Feasibility analysis of treated water supply for coal power plants in India

treatment facilities are usually located near large urban areas while coal power plants are mostly located near coal mines or in regions where land and water is available at lower costs which again are usually far away from urban regions.

A coal power plant of 1000 MW needs about 84 million litres a day while most of the sewage treatment plants in smaller towns usually have a treatment capacity of about 20 million litres a day. Additionally the cluster model of coal plant development for the last ten years has resulted in massive generation capacities located in close proximity. This means that even if a large sewage treatment capacity exists near a cluster of coal power plants there is a lesser chance that the total water demand of these clusters can be met by the sewage treatment plant.

The analysis was carried out using a combination of GIS (geographical information systems) software and using rule based best fit methodologies. The two primary data sets for coal power plants and for sewage treatment plants were acquired from Coal Swarm (July 2016) and from the CPCB inventory of sewage treatment plants, 2015.19 The problem statement for the analysis and the methodology used is available in Appendix B.

Summary of resultsThe results indicate that less than 15% of the total coal power plants dependent on freshwater needs actually have a sewage treatment plant within 50 Km of their location. This is because large sewage

Table 2

Coal power plants

Generation capacity in GW

Percentage with respect to total generation capacity

Water demand in million litres a day (3.5 cubic metres per MWh)

All coal power plants

Water needs fully satisfied

Water needs partially satisfied20

Water needs not satisfied

229

18

12

199

100%

7.9%

5.2%

86.9%

19276

1522

1003

16751

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Availability of treated sewage for coal power plants

Map for representational use only, boundaries depicted are not authenticated or verified

Sewage treatment capacity

0-60

3-18

All values in million litres a day (MLD).



Coal Power plant water demand not covered by treated sewage

3-2525-7272-121121-176176-252252-400

18-4545-7676-118118-166

60-200

200-480

480-930

930-1560

Coal power plant water demand covered by treated sewage

3 - 18

18 - 45

45 - 76

76 - 118

118 - 166

Coal power plant water demand not covered by treated sewage

3 - 25

25 - 72

72 - 121

121 - 176

176 - 252

252 - 400


0 - 60

60 - 200

200 - 480

480 - 930

930 - 1560

All values in million litres a day (MLD)

Availability of treated sewage water for coal power plants

All values in million litres a day (MLD)

Total sewage treatment capacity available: 23210 MLD

Utilisable sewage treatment capacity: 2525 MLD (10.9%)

Coal power capacity able to access treated sewage water : 30.1 GW

Coal power capacity not able to access treated sewage water : 199.4 GW

Map for representational use only, boundaries depicted are not authenticated or verified

Coal Power plant water demand covered by treated sewage

Sewage treatment capacityTotal sewage treatment capacity available: 23210 MLD

Utilised sewage treatment capacity: 2525 MLD (10.9%)

Coal power capacity able to access treated sewage water: 30.GW

Coal power capacity not able to access treated sewage water: 199.4 GW

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Table 3: Status of coal power plants

Table 4: Sewage treatment capacity that can be used by coal power plants

From the sewage treatment plant point of view- we have these results:

Coal power plants

Operational (in MW)

Under construction (in MW)


Water needs partially satisfied


Total number of sewage treatment plants

Volume of treated water available in these plants

Total volume of treated water that can be utilised by coal power plants.

Percentage of treated water that can be utilised by coal power plants

The analysis does not include proposed coal plants as the CEA in its draft National Electricity plan (2016) has indicated that no additional coal capacity is needed. Even if they are included it is likely that a similarly high percentage of them would be unable to use treated sewage.

Despite large volumes of treated sewage water available in the country, less than 11% of it can be utilised in coal power plants.

15369

10041

146788

322

23211 million litres a day

2525 million litres a day

10.88%

2750

1902

52632

This fact is further corroborated by the results which show that about 140 power plants with a generation capacity of 140 GW don’t have any sewage treatment plants within 50 Km of their location. About 42 power plants with a generation capacity of 50.3 GW have a sewage treatment plant within a 50 Km radius but cannot utilise the treated water either because their demands are large or because there are many coal power plants in close proximity competing for water at the same sewage treatment plant.

Chart 1: Coal power plants utilising treated sewage water

Water needs satisfied

7.9%

5.2%

86.9%


Water not satisfied

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not cause any long term damages to the power plant equipment. In addition to this, there are operation and maintenance (O&M) costs and an annual cost of water which can be at least three times21 more expensive than existing costs for freshwater.

The distance at which a sewage treatment plant is located from a coal power plant forms a sizeable part of the capital cost involved. The analysis gives an idea of the distances to which the pipelines have to be laid.

Costs of sewage water treatment for power plant uses is high The presence of a sewage treatment plant within 50 Km of a coal power plant is fundamental for coal power plants to switch from fresh water to treated water. As discussed in earlier chapters the quality of water available from these secondary sewage treatment facilities does not match the requirements for cooling tower make up water. Investment on tertiary treatment plants are necessary to ensure that treated water does

Table 5: Distance between sewage treatment facility and coal power plant

Category (generation capacity in percentage to total)

Coal power plants with water needs fully satisfied

Coal power plants with water needs partially satisfied

less than 10 Km

29.5% (5338 MW)

12.6% (1500 MW)

10-20 Km

26.4% (4789 MW)

35.2% (4212 MW)

20-30 Km

9.8% (1773 MW)

15.7% (1875 MW)

30-40 Km

29% (5267 MW)

20.5% (2449 MW)

40-50 Km

5.3% (952 MW)

16% (1907 MW)

Chart 1: Coal power plants utilising treated sewage water

© K

elly

D. A

lley

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Case Studies

There are four coal power plants that use treated sewage water for their make up water needs in the state- they are:

• MAHAGENCO’s Koradi power plant in Nagpur,

• RattanIndia Nashik power plant in Sinnar, Nashik,

• NTPC’s Solapur power plant in Solapur and

• NTPC Mauda power plant near Nagpur.

Other than the NTPC's Solapur power plant which is expected to be commissioned in July 201723, all three power plants are either partially or fully operational. Recently there are discussions24 about plans to link the Parli to sewage treatment plants in Nanded-Waghala municipal area, about 60 Km away from Parli power plant.

There have been very few examples of reuse of municipal sewage as cooling tower make-up water in coal power plants in the country and unsurprisingly all of these are in Maharashtra. Coal power plants in the state have faced extreme scarcities for water more often than other regions in the country. The 1,100 MW Parli power plant in Beed district is an infamous example. In the drought that lasted till July 2016, Parli had achieved a record of back-down time of almost 210 days and losing about 5 TWh of power generation. Despite allocating fresh water from irrigation projects and depriving farmers of their irrigation, the 81%22 share of coal in power generation has led the state government experiment with treated sewage water to ensure water security for its coal power plants in the last few years.

Case studies - existing examples of treated sewage for coal power plants:

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Case Studies

The tertiary treatment plant will utilise the secondary treated sewage from the municipal body’s STP and transfer the treated water to the power plant. As a royalty for the water, MAHAGENCO will pay ₹15 crores each year to NMC while the city corporation will share 50% of the cost of the new STP from a grant provided by the central government under the JNNURM26 programme. The cost of royalty will be increased at a rate of 10% every 3 years.

After the execution of the agreement between NMC and MAHAGENCO in 2008, some changes were made around 2010 regarding the allocation of land for building the secondary sewage treatment plant. It is likely the total cost of the project would have escalated due to delays and changes in the agreement.

The O&M of the secondary treatment plant would be covered by NMC and the O&M costs of the tertiary treatment plant and related infrastructure would be borne by MAHAGENCO.

Case study 1: MAHAGENCO’s Koradi power plant:The Koradi and Khaperkheda power plants are located about 15 Km north of Nagpur city. MAHAGENCO, or Maharashtra State Power Generation Company Limited, the state owned generator has planned an expansion of 1,980 MW in these plants. The koradi plant has an existing fresh water allocation of 75 Million cubic metres (MCM) from the Pench dam of the state water resource department. This allocation will be insufficient for the new expansions and an additional 38 MCM25 (about 104 MLD) would be required.

Since the additional requirement cannot be managed by the freshwater sources in the region, MAHAGENCO signed a memorandum of understanding in 2008 with the Nagpur Municipal corporation (NMC) to build a secondary sewage treatment plant of 130 MLD capacity at Bhandewadi, a tertiary treatment plant and the transmission network all at a cost of Rs 195 crores.

Nagpur city needs about 765 MLD for its water supply programmes. The city presently generates 345 MLD of sewage, after including losses. The municipal corporation has agreed to supply 110 MLD of wastewater which will match the additional requirement for MAHAGENCO’s Koradi power plant. The cost details of this deal is explained in Table 6.

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Case Studies

Infrastructure limited, at a cost of 260 Crores including capital and O&M costs for 30 years. The contractor also acquires rights to resell 175 MLD water to other users. If all the treated water is sold, then the contractor would reimburse the O&M cost of the expanded STP to the city corporation.29

NTPC has agreed to buy 150 MLD (55 MCM) of secondary treated water from the contractor and will pay for the tertiary treatment costs along with the cost of 35 km pipeline from the STP to the power plant, all of which costs 240 crores. This additional water available from municipal sewage will be sufficient to satisfy the water requirements of the stage 2 plant (1320 MW) while the stage 1 plant (1000 MW) still would need freshwater supplies from the water resource department. A summary of the costs are provided in Table 6.

Case study 2: NTPC Mauda power plantThe 2320 MW Mauda power plant is about 50 Km from Nagpur city. The stage 1 of the plant (1000 MW) was commissioned in 2014 and the stage 2 (1320 MW) is expected to be commissioned before March 2017. The plant was initially allocated 100 MCM (273 MLD) from the Gosikhurd dam to be picked up at a distance of 24 Km27 from the plant. However, in its tariff petition28 for the stage 2 plant submitted to the central electricity regulatory commission the company states that it intends to use the sewage generated from Nagpur city as its water source.

The water will be made available from the expansion project of the old Bhandewadi STP with an increased capacity of 200 MLD. This expansion project has been awarded by NMC to a private contractor, Vishvaraj

Table 6: NTPC Mauda Vs MAHAGENCO’s Koradi power plant: water cost comparison

Power plant Water requirement (in million cubic metres each year)

Cost per cubic metre

Total water cost each year (lakhs)

Capital cost (excluding O&M costs)

Using fresh water

NTPC Mauda- stage 1 (based on tariff petitions, for unit 1 of stage 1, 500 MW)

NTPC Mauda stage 2 (based on tariff petitions)

Using treated sewage

NTPC Mauda (stage 1 and 2) MAHAGENCO - Koradi and Khaperkheda

6.34330

42.048

54.75 (150 MLD)

40.15 (110 MLD)

3.84

3.2

9.75

3.70

243.9

1345

5338.1

1500

Not applicable

Not applicable

240 crores 195 crores

15

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Case Studies

Water costs are an important part of power tariffs for coal power plants. Rising water charges by state governments have often resulted in tariff revision petitions at CERC. In 2011 NTPC filed a petition to the central electricity regulatory commission (CERC) requesting an increase of tariff to match the rising water charges levied by state governments.

From the submissions to CERC, water charges for 12 coal power plants were increased by 94% to 700% in 2010, an year after the five year tariffs were fixed. The petition was dismissed by CERC in 2014. In its orders,33 CERC points that water charges are part of O&M costs and since O&M costs have a 5.72% yearly escalation, increased water charges cannot be accommodated after tariffs have been fixed. The new tariff policy of 2016 relaxes this norm and allows additional costs for utilising treated sewage water to be separately accounted and claimed for. This means the additional costs of using treated sewage water which could range from 300% to 700% will be reflected in the final tariffs decided by CERC.

Rising water costsFrom the case studies, we can observe the cost per unit of treated sewage water for NTPC’s Mauda plant is almost 300% as compared with freshwater charges with an additional capital cost of 240 crores. MAHAGENCO’s costs are lower and almost the same cost of fresh water31 although there is a large capital cost involved. The O&M costs for running the tertiary treatment plant is an additional cost for MAHAGENCO.

Recent reports32 assess the cost of tertiary treated water at minimum of Rs 15/ cubic metre up to Rs. 60/ cubic metre based on the quality of treatment. Assuming that a simple tertiary treatment like ultra/ micro filtration technology is used, the cost could rise up to Rs. 25 per cubic metre. Furthermore, these estimates are limited to the capital and operating cost of treatment while transportation of water by pipelines should be added to the overall cost. The additional costs incurred in utilising treated sewage water will have to reflect in the cost of power produced by these coal power plants.

RattanIndia’s Nashik coal power plant

The sewage treated water supply for RattanIndia’s Nashik coal power station in Maharashtra actually involves picking up the treated sewage water of Nashik city from the Godavari river 30 km downstream from the point where STP effluents are discharged into the river. This hardly serves as the best case of Municipal sewage reuse by coal power plants for two reasons:

• Poorly treated effluents from STP end up polluting the river rather than being directed towards a tertiary treatment facility.

• Water quality 30 km downstream from the point of STP discharge might be of a better quality due to dilution of treated sewage with freshwater from the river. It would be difficult to ascertain the need and cost of tertiary treatment without information from the company.

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Role of sewage in the water cycle

Sewage is a part of the water cycle. Sewage is 99%36 water and when discharged into the environment, it becomes a part of the larger water cycle. Sewage treatment plants are usually located in the banks of inland water bodies or close to the coast to facilitate easy discharge of the treated water. About 28% of the total treated sewage is discharged into the seas while the rest flows into the major and minor tributaries of our rivers forming a part of their catchment. Discharge of domestic sewage water from cities are part of the water availability assessments, accounted as return flow. Return flows from sewage is part of the freshwater that is needed for any downstream uses like domestic water supply, irrigation or industrial uses. The role of sewage in the natural water cycle is explained in the flowchart below.

India is rapidly urbanising. According to the 201134 census there are 53 urban agglomerations exceeding a population of 1 million and the growth of urban population has increased from 31.5 to 38%35 compared to the previous decade. With increased urbanisation comes the increasing need for water supply and sanitation. For the 22.6 billion cubic metres (BCM) of sewage generated each year in the country, sewage treatment capacities stand at about 37% or about 8 BCM. As a result, 14 billion cubic metres of untreated sewage water is discharged into our rivers and seas each year. Needless to say, the discharge of untreated municipal sewage along with industrial effluents are the major causes of water pollution in the country.


RainfallRivers

and water bodies

Sewage and natural water cycle

Resevoirs

Catchment of rivers,

discharge into sea

Downstream reservoirsEvapotranspiration

Domestic water supply

SewageNatural water cycle

Infiltration and run

off

80%

17

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Consumptive use of sewage water by coal plants:

Consumptive use of sewage as make-up water for cooling in coal power plants affects the sewage water cycle. This is because water allocated to coal power plants is mostly used for cooling which evaporates the water into atmosphere, making it unavailable for other uses.

Whether its fresh water from reservoirs or sewage water from cities, water consumption by coal power plants create the same impact on natural water cycles- by reducing the available water in the local environment. This is unlike other non-consumptive industrial processes where polluted water is returned back into the local environment which can then be treated before discharging into water bodies.

Thus, allocations of municipal sewage for consumptive uses in coal power plants should be seen similar to the allocation of fresh water from reservoirs and an assessment is necessary to understand the impacts of allocating sewage water to coal power plants.

Sewage as irrigationUse of sewage water for irrigation is not a new concept in India. There are many historical examples of this practice across the country. Bhavnagar and Ahmedabad municipalities in Gujarat had recognised and collected royalties37 for municipal sewage water from farmers cooperatives as early as 1940. Studies have shown that the high nutritive38 value of sewage has increased yields and reduced cost of external inputs in agriculture.

A 2013 study by the International Water Management Institute estimates that about 1 million hectares39can be irrigated with the sewage that is being produced in India. Present day examples40 of sewage irrigation are available from across the country- farmers utilise sewage water to grow vegetables in Delhi, fodder crops and paddy from the Musi river around Hyderabad, floriculture in Kanpur, wheat farming in Ahmedabad, aquaculture in Kolkata, horticulture and agroforestry in Hubli-Dharwad (Karnataka) and fodder crops in Solapur (Maharashtra)41 where the municipal corporation has recently decided to allocate its sewage to the NTPC power plant in the region.

While irrigation using untreated sewerage poses plenty of health and environmental risks, the irrigation potential and the nutritive value of sewage does provide an overall benefit for peri-urban agriculture.

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Conclusion

A more timely and cost-effective solution to the coal-water conflict lies in the phase out of older, inefficient power plants, which tend to consume the most water and emit the most air pollution and timely adoption of the water consumption target set for power plants in the MOEFCC notification of 7th December 2015. At the same time, all permits for new coal plants must be halted.

In 2015 India’s power generation achieved a surplus status. The CEA in its draft national electricity policy42 has projected that no new coal power plants need to be added till 2027 and all power requirements can be met through existing renewable energy targets and the approximately 50 GW of coal power plants which are in varying stages of construction.

Renewable technologies like wind or solar PV have multiple advantages over coal power plants. Their marginal environmental pollution and negligible water needs are in stark comparison with the polluting, water guzzling reality of coal power plants. With the government committed to add 175 GW of renewable energy to the grid by 2022 and further incremental additions beyond 2022, it's possible to transform India’s energy infrastructure towards a more modern, less polluting and water efficient future.

Coal power plants are water intensive. Large investments in the last decade have increased coal power capacity additions at a compounded growth rate of 11%. Most of these new coal plants are also located in clusters and their water demands compete with local water needs leading to water shortages to run the plants. The severe drought of 2016 affected water supplies to coal power plants and led to a generational loss of 11 TWh and potential revenue losses of over 560 million US$ (about INR 3600 crores). A possible solution proposed by the government to this conundrum is to promote the use of treated sewage water in coal power plants.

In our analysis the following results emerge:

• About 8% of the total coal power plants can completely switch to treated sewage water within 50 Km of their location.

• Less than 11% of the total sewage in the country treated can be utilised by coal power plants.

• Switching from freshwater to treated sewage water entails large investments in tertiary treatment technologies and the annual cost of water will increase by at least 300%.

• Utilising sewage as a source of water decreases the water availability in the region and has an impact similar to the use of freshwater. Switching to treated sewage water is not a solution to the water scarcity created by coal power plants and should be done after an impact assessment has been conducted.

• Therefore, utilising sewage water for coal power plants provides neither water saving nor a cost saving advantage.

Conclusion

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Appendices

Appendices

Appendix A: A comparison of the 1993 standards, 2015 standards and the NTPC requirements.

Parameters Older standards (1993)

Draft Notification for Sewage treatment plants. (2015)

NTPC requirements (2016)

pH

Biochemical Oxygen Demand (BOD)

Chemical Oxygen Demand Turbidity (in NTU)†

Total Suspended solids (TSS)

Ammonium (NH4-N)

Ammoniacal Nitrogen (NH3-N)

Ammonia (NH3)*

Total Nitrogen (as N)

Sulphide (as S)

Total Sulphur (as S)

Faecal Coliform (in MPN/100ml)

5.5 - 9.0

30

250

-

100

-

50

5

-

2.0

-

-

6.5-9.0

10

50

-

20

5

-

-

10

-

-

<100

-

<5

-

<10

-

-

-

<2

<10

-

<0.1

-

All Values in mg/litre except for pH, coliform and turbidity. †Turbidity and TSS measure a similar quality of water they are different in the methods of measurement. Particles like clay, bacteria, algae, sediment, silt can be identified by turbidity while settleable solids may not. * Ammonia (NH3) or Ammonium (NH4) presence depends on the pH of the waste water. If pH > 8, almost all Ammonium converts into Ammonia. Ammonia is one of the key ingredients for corrosion in metals and pipes and therefore lesser the ammonia, longer the life of equipments. Sulphur in water can form sulphates and sulphides which are also known to be extremely corrosive.

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Appendices

Data of sewage treatment plants: The list of sewage treatment plants as available from the CPCB includes the location, total treatment capacity for all the sub-units of sewage treatment facilities.

Sewage treatment facilities usually start with smaller capacities and larger plants were usually added later, based on the growing population of cities. In time, modern technologies and large units of 300 MLD and above became common for metropolitan regions and older units were sometimes replaced. Since the data had individual entries for all the units of the same plant, (for eg. Pirana Road STP in Ahmedabad had many stages- like Pirana -I and Pirana II) these STP’s were aggregated based on the proximity to each other. This was determined using the location coordinates.

In many large metropolitan regions, the STP’s are closely located in the peripheries of the regions. This could be a result of many factors like easy availability of land, existing sewerage networks etc. For this analysis, sewage treatment plants that are less than 13 Km apart to another plant were grouped together as a single plant and the total treatment capacities were added. The aggregated plant was renamed as a zone of the city (Delhi-central for example) and the midpoint of all the constituent plants is taken as the new location. Similarly, sewage treatment plants in relatively smaller cities (like Nagpur, Nashik, Mysore) were aggregated into one plant as well.

The aggregation of STP’s are necessary to simplify the analysis. Reducing the total number of sewage treatment plants while adding the treatment capacities helps to identify a single water source that is large enough to support a coal power plant. On the other hand, without aggregation a coal power plant would face a scenario of choosing two or three STP’s to match its water requirements.

The problem statement for this analysis can be stated as:

“To find out the one sewage treatment plant among the many sewage treatment plants located within 50 Km of a coal power plant that is closest to the coal power plant and completely satisfies the water requirement of the coal power plant.”

The usual methodology to solve this problem state involves iterative method to find a match between a coal power plant, the list of sewage treatment plants within 50 Km of the coal power plant and that which satisfies both the following conditions:

• The distance between the sewage treatment plant and the coal power plant is the shortest.

• Water available from the sewage treatment plant completely satisfies the water demand of the coal power plant.

This process was then repeated for every coal power plant and the list of sewage treatment plants within the 50 Km of the respective coal power plants. If a sewage treatment plant was found to be a match for two or more coal power plants, then the above conditions were to be applied again to find the best match among all the matches.

This analysis uses the iterative method, but also simplifies the data of sewage treatment plants and coal power plants.

Appendix B: Methodology of the analysis

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Appendices

Approximations used in the analysis: 1. All coal power plants are assumed to require 3.5

cubic metres per MWh of power generation and the water requirement for coal power plants are estimated for a plant load factor or 100%.

2. The maximum distance permitted between a coal power plant and a sewage treatment facility is 50 Km. However, while aggregating sewage treatment plants around large cities the mid point is being taken as new location- altering the actual distance between a sewage treatment plant and a coal power plant. This may alter the real distance by a few kilometres between the power plant and grouped sewage treatment plants. However the final results show that of the five large urban agglomerations that were aggregated three do not have any sewage facilities matching with any coal power plants. For the other two large cities, there variation in distance does not affect the best-fit results as there no other options nearby.

3. When analysing for best fits - a one to one relation is established between a coal power plant and a sewage treatment plant. If a group of coal power plants can establish a pooled interest in utilising all the treated sewage water within their respective 50 Km zones it can result in better utilisation of treated water available in the region along with a shared cost of tertiary treatment and laying pipelines.

The grouping of STP’s in metropolitan regions and smaller cities will change the actual distance of some STP’s with respect to the coal power plants in the region. in reality, this does not affect the analysis since very few coal power plants are located near cities.

For the purpose of the analysis, sub-classification of sewage treatment plants into operational, under construction or planned was not necessary as 80% of the sewage treatment plants are operational.

Data of coal power plants:The coal power plant data from Coalswarm includes all coal plants including the plants that use seawater for cooling or using air cooled condensers. Most43 of these plants were excluded from the analysis. Likewise, power projects that have been shelved or cancelled and those that have just been announced have been excluded from the analysis as well. The coal power plants were not classified into operational, under construction or proposed during the analysis and all these categories were given equal priority while looking for matches with sewage treatment plants.

The water requirement for the coal power plants were assigned based on the average water consumption of coal power plants at 3.5 m3 per MWh assuming a 100 percent plant load factor for the purpose of this analysis. Most of the new coal power plants in the country have an average water consumption of 3.5 m3 per MWh while many older plants have a significantly higher water consumption at around 5 m3 per MWh. The latest notifications on water efficiency by the Ministry of Environment and Forest (December 2015)44 stipulate the maximum water consumption of all existing coal power plants to be at 3.5 m3 per MWh while the new coal power plants are required to reduce it to 2.5 m3 per MWh. Considering that the 2.5m3 per MWh target is applicable only for the upcoming power plants, assigning an average of 3.5 m3 per MWh water requirement to all operational and proposed coal plants is a conservative assumption.

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Appendices

Best-fit analysis:

Using GIS based analysis, the number of sewage treatment plants within a 50 Km range of any coal power plant and the distance between the coal power plant and the sewage treatment plants within the range were derived.

The data was then used to find a best fit between a coal power plant and a sewage treatment plant based on the following rules:

A sewage treatment plant is a best fit for a coal power plant when:

1. The distance between the plants is the shortest.

2. Water available from the sewage treatment plant completely satisfies the water demand of the coal power plant.

For better interpretation of results and also to maximise the utilisation of treated sewage water, even the cases where the sewage treatment plant (within 50 km of a coal power plant) may not match the water requirements of a coal power plant were also categorised. Table 7 shows the categories of the results.

Table 7:

Categories Definitions




Coal power plant water demand is completely met by the sewage treatment plant. At least 25% of the coal plant water demand is met by the sewage treatment plant.

There are no sewage treatment plants within 50 Km of the coal power plant.orLess than 25% of the coal power plant water demand is met by the sewage treatment plant.

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Appendices

Appendix C: State wise results of the analysis

3,894.00

750

9,950.00

33,024.00

839

5,275.00

6,175.00

30

11,842.00

8,970.00

23,255.00

28,360.00

21,259.00

6,550.00

11,254.00

6,362.00

9,459.00

25,789.00

43

16,402.00

229,482.00

Total capacity in MW

327.1

63

835.8

2,774.00

70.5

443.1

518.7

2.5

994.7

753.5

1,953.40

2,382.20

1,785.80

550.2

945.3

534.4

794.6

2,166.30

3.6

1,377.80

19,276.50

Fresh water demand by coal power plants in MLD

454

0

0

0

839

1,620.00

195

30

1,250.00

0

130

2,356.00

912

3,650.00

330

592

62

4,010.00

43

1,646.00

18,119.00

Coal power plants with water needs fully satisfied in MW

1,205.60

0

0

0

0

0

2,318.50

0

0

773.8

0

3,565.50

457.1

0

1,057.10

1,520.80

0

1,043.80

0

0

11,942.30

Coal power plants with water needs partially satisfied in MW

2,234.40

750

9,950.00

33,024.00

0

3,655.00

3,661.50

0

10,592.00

8,196.20

23,125.00

22,438.50

19,889.90

2,900.00

9,866.90

4,249.20

9,397.00

20,735.20

0

14,756.00

199,420.70

Coal power plants with water needs not satisfied in MW

284.3

0.2

124.6

0

2,693.70

3,062.90

838.5

114.9

117.2

1,295.10

482.2

5,160.40

385.5

1,202.50

865.9

1,767.40

648.8

2,646.80

149.8

416.9

22,257.70

Sewage treatment capacity in MLD

139.4

0

0

0

70.5

136.1

211.1

2.5

105

65

10.9

497.4

115

306.6

116.5

177.5

5.2

424.5

3.6

138.3

2,525.10

Utilisable sewage water in MLD

Andhra Pradesh

Assam

Bihar

Chhattisgarh

Delhi

Gujarat

Haryana

Himachal Pradesh

Jharkhand

Karnataka

Madhya Pradesh

Maharashtra

Odisha

Punjab

Rajasthan

Tamil Nadu

Telangana

Uttar Pradesh

Uttarakhand

West Bengal

Total

State

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Appendices

Andhra Pradesh

Assam

Bihar

Chhattisgarh

Delhi

Gujarat

Haryana

Himachal Pradesh

Jharkhand

Karnataka

Madhya Pradesh

Maharashtra

Odisha

Punjab

Rajasthan

Tamil Nadu

Telangana

Uttar Pradesh

Uttarakhand

West Bengal

0 1000 2000 3000

In MILLIon LITreS a Day

4000 5000 6000

Sewage Treatment capacity compared to fresh water demand by coal power plants


Fresh water demand by coal power plants

Utilisable sewage water for coal power plants

25

Greenpeace India


Endnotes

16 Draft notification standards for Sewage treatment by MOEFCC. http://envfor.nic.in/sites/default/files/Draft%20notification%20of%20Sewage%20Treatment%20plan.PDF

17 Excerpted from invitation for expression of interest (EOI) by NTPC for treated sewage water scheme in NCPS Dadri.

18 http://www.cpcb.nic.in/upload/NewItems/NewItem_195_STP_REPORT.pdf

19 http://www.cpcb.nic.in/upload/NewItems/NewItem_210_Inventorization_of_Sewage-Treatment_Plant.pdf

20 In case of partially satisfied the generation capacity listed is not the absolute capacity of the coal power plant but the capacity that can be satisfied with available treated sewage water.

21 Refer Table 6: NTPC Mauda Vs MAHAGENCO’s Koradi power plant: water cost comparison

22 Economic survey of Maharashtra, 2015-16. https://mahades.maharashtra.gov.in/files/publication/ESM_1516_Eng.pdf

23 Central electricity authority, Broad status of thermal power plants, October 2016. http://cea.nic.in/reports/monthly/broadstatus/2016/broad_status-10.pdf

24 http://powermin.nic.in/sites/default/files/uploads/RS_25042016_Eng.pdf

25 City of Nagpur and MSPGCL Reuse Project, 2012, http://www.reclaimedwater.net/data/files/229.pdf

26 Jawaharlal Nehru National Urban Renewal Mission. http://jnnurm.nic.in/

27 EIA for NTPC Mauda stage -II, http://www.agaportal.de/pdf/nachhaltigkeit/eia/eia_kraftwerk_indien.pdf

28 Tariff petition for NTPC Mauda stage 2. http://www.ntpc.co.in/notices/6271/Mauda-stps-stage-ii-2x660-mw

29 Presentation by Mr. Shravan Hardikar, Commissioner, Nagpur municipal corporation. April 2016. https://swachhbharaturban.gov.in/writereaddata/Day%202%20-%20All%20PPTs.pdf

1 About 230 GW of coal power plants which are operational and under construction are included in this analysis. This data also excludes power plants which use sea water for cooling or use air cooled condensors to the extent of information publicly available.

2 http://www.moef.gov.in/sites/default/files/Thermal%20plant%20gazette%20scan.pdf

3 Global risks report 2016. http://www3.weforum.org/docs/GRR/WEF_GRR16.pdf

4 http://www.cwc.nic.in/main/downloads/Water%20and%20Related%20Statistics-2013.pdf -

5 Ministry of Water Resources, Government of India, 1999.

6 Centre for Science and Environment, 2004. http://www.cseindia.org/dte-supplement/industry20040215/misuse.htm

7 The Great Water Grab, How the Coal Industry is Deepening the Global Water Crisis. www.greenpeace.org/thegreatwatergrab/

8 As of 2015 December. The figures used for this study are of July 2016

9 http://powermin.nic.in/sites/default/files/webform/notices/Tariff_Policy-Resolution_Dated_28012016.pdf

10 Approximate conversion: 2740 Million litres a day is about 1 billion cubic metres/ year.

11 Inventory of sewage treatment plants, CPCB 2015. http://cpcb.nic.in/upload/NewItems/NewItem_210_Inventorization_of_Sewage-Treatment_Plant.pdf

12 CPCB July 2016 news letter, http://cpcb.nic.in/upload/Latest/Latest_123_SUMMARY_BOOK_FS.pdf

13 Urban Water Systems in India: A Way Forward. Mihir Shah http://icrier.org/pdf/Working_Paper_323.pdf

14 Ibid

15 Wastewater production, treatment and use in India, R.Kaur et al, 2012. http://www.ais.unwater.org/ais/pluginfile.php/356/mod_page/content/111/CountryReport_India.pdf

Endnotes

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26


30 Based on average estimates, stage 1 plant (1000 MW) will need about 31 MCM per year or 84 MLD for its operations. The information provided here is from the tariff petition submitted for the unit 1 of stage 1 (500 MW), available at: –http://ntpc.co.in/notices/476/mauda-stps-stage-%E2%80%93-i-2x500-mw-2014-19. There seems to be an anomaly here- NTPC seems to state that they need just 6.4 MCM of water to operate a 500 MW power plant.

31 Volumetric rates for bulk water tariff for Industry, Maharashtra government. http://www.mwrra.org/Volumetric%20BWT%20Order%20English.pdf

32 Closing the water loop: Reuse of treated waste water in urban India, PWC, https://www.pwc.in/assets/pdfs/publications/2016/pwc-closing-the-water-loop-reuse-of-treated-wastewater-in-urban-india.pdf

33 http://cercind.gov.in/2015/orders/SO121.pdf

34 http://pibmumbai.gov.in/scripts/detail.asp?releaseId=E2011IS3

35 http://censusindia.gov.in/2011-prov-results/paper2/data_files/india/Rural_Urban_2011.pdf

36 http://www.unwater.org/fileadmin/user_upload/unwater_new/docs/UN-Water_Analytical_Brief_Wastewater_Management.pdf

37 http://agris.fao.org/agris-search/search.do?recordID=QL2013000225

38 http://aquasec.org/wrpg/wp-content/uploads/2013/02/Amerasinghe_etal_2013_Wastewater_India_RR147_IWMI.pdf.

http://www.ais.unwater.org/ais/pluginfile.php/356/mod_page/content/111/CountryReport_India.pdf

39 http://aquasec.org/wrpg/wp-content/uploads/2013/02/Amerasinghe_etal_2013_Wastewater_India_RR147_IWMI.pdf.

40 http://www.iwmi.cgiar.org/Publications/Working_Papers/working/WOR128.pdf

41 https://thewire.in/41599/using-treated-sewage-in-thermal-power-plants-diverting-resources-from-agriculture-to-industry/

42 http://www.cea.nic.in/reports/committee/nep/nep_dec.pdf

43 Coal plants are removed in cases where information on cooling technology used is available from public sources.

44 http://egazette.nic.in/WriteReadData/2015/167141.pdf

Endnotes

Greenpeace is a global organisation that uses non-violent direct action to tackle the most crucial threats to our planet’s biodiversity and environment. Greenpeace is a non-profit organisation, present in 40 countries across Europe, The Americas, Asia and the Pacific.

It speaks for 2.8 million supporters worldwide, and inspires many millions more to take action every day. To maintain its independence, Greenpeace does not accept donations from governments or corporations but relies on contributions from individual supporters and foundation grants.

Greenpeace has been campaigning against environmental degradation since 1971 when a small boat of volunteers and journalists sailed into Amchitka, an area north of Alaska, where the US Government was conducting underground nuclear tests.This tradition of ‘bearing witness’ in a non-violent manner continues today, and ships are an important part of all its campaign work.

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pipe dreams treated sewage will not solve coal power’s water … · 2017. 6. 14. · pipe dreams:...

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