PFAS in Wells

 Andrea K. Tokranov et al, Prediction of Groundwater PFAS Occurrence at Drinking Water Supply Depths in the United States. Science 386, 748-755 (2024). DOI:10.1126/science.ado6638

In the research study cited above published at the end of October 2024, the U.S Geological Survey estimated that approximately 71 to95 million people in the Lower 48 states – more than 20% of the country’s population – may obtain their drinking water from groundwater that contains detectable concentrations of per- and polyfluoroalkyl substances, also known as PFAS, for their drinking water supplies. 

PFAS are a group of synthetic chemicals used in a wide variety of common applications, from the linings of fast-food boxes and non-stick cookware to fire-fighting foams and other purposes. This category of chemical has been widely used for over 80 years mainly for their ability to repel oil, grease, water, and heat. PFOS and PFOA found in Scotch Guard and an ingredient in Teflon and traditional Aqueous Film-Forming Foam (AFFF) - the Class B firefighting foam used to fight aviation and other chemical fires -were the first to become widely commercially successful.

PFAS are commonly called “forever chemicals” because many of them do not easily break down and can build up over time, making them a concern for drinking water quality. Exposure to certain PFAS may lead to adverse health risks in people, according to the U.S. Environmental Protection Agency.

Per- and Polyfluoroalkyl Substances (PFAS) do not occur in nature, they are an entirely synthetic substance. Yet, most people in the United States have been exposed to PFAS and have PFAS in their blood, especially perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).  Last year EPA release the final drinking water regulation for six PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS).

For this study, the USGS scientists built a predictive model of PFAS occurrence in groundwater at the depths of drinking water supplies across the continental United States, before any treatment. They trained the model on groundwater samples collected by the US Geological Survey (USGS) from 2019-2022 from three types of well networks: (i) public supply networks spanning principal aquifers,  (ii) observation networks targeting urban and agricultural land uses, and (iii) domestic supply well networks in principal aquifers. 

The team then conducted extensive PFAS source mapping, and the final model included 25 potential PFAS sources such as airports, metal coating facilities, plastics and resins facilities, printing facilities, fire training areas, chemical manufacturing facilities, and national defense sites, among many others. At least one PFAS out of the 24 individual PFAS analyzed was detected in 37% (n = 1238) of the groundwater samples analyzed for the model training dataset.  Observation wells had the highest detection frequency of any PFAS at 60% (n = 257), followed by production (public supply) wells (42%, n = 539); miscellaneous, other, and irrigation wells (29%, n = 59); and domestic wells (17%, n = 383). By individual compound, the highest detection frequencies were observed for perfluorobutane sulfonate (PFBS; 24.6%), PFOS (24.3%), PFOA (24.1%), and perfluorohexane sulfonate (PFHxS; 23.7%). All four compounds are included in the EPA’s PFAS National Primary Drinking Water Regulation rulemaking (6).  

“This study’s findings indicate widespread PFAS contamination in groundwater that is used for public and private drinking water supplies in the U.S.,” said Andrea Tokranov, USGS research hydrologist and lead author of this study. “This new predictive model can help prioritize areas for future sampling to help ensure people aren’t unknowingly drinking contaminated water. This is especially important for private well users, who may not have information on water quality in their region and may not have the same access to testing and treatment that public water suppliers do.”

My corner of Prince William County

Mankind Driving Global Methane Emissions

R B Jackson and M Saunois and A Martinez and J G Canadell and X Yu and M Li and B Poulter and P A Raymond and P Regnier and P Ciais and S J Davis and P K Patra, Human activities now fuel two-thirds of global methane emissions, Environmental Research Letters, September 2024, IOP Volume 19 , 10.1088/1748-9326/ad6463, https://dx.doi.org/10.1088/1748-9326/ad6463

A recent study (cited above) found that Mankind is responsible for two-thirds of global methane emissions. The research article cited above is from Rob Jackson and the Global Carbon Project. Rob Jackson is Stanford’s Michelle and Kevin Douglas Provostial Professor. Dr. Jackson and his lab examine the many ways people affect the Earth.  They're currently examining the effects of climate change and droughts on forest and grassland ecosystems. They are also working to measure and reduce greenhouse gas emissions through the Global Carbon Project (globalcarbonproject.org), which Dr. Jackson chairs. The Global Carbon Project also updates its Global Methane Budget (GMB) every few years. I have excerpted sections of the article.

Global average surface temperatures have reached another  all-time high in 2023 at 1.45 ± 0.12 °C above pre-industrial levels (WMO 2024). Worsened by climate change-induced drought, Canadian wildfires burned 18.5 million hectares, nearly three-times more land area than in any previous year on record (NRC 2023). Parts of the Amazon River reached their lowest levels in 120 years of data-keeping (Rodrigues 2023). The world has reached the threshold of a 1.5 °C increase in global average surface temperature and is only beginning to experience the full consequences.

The amount of methane (CH4) in Earth’s atmosphere continues to rise. Concentrations of methane are now about 2.5 times as much as was in the atmosphere in the 1850s. Methane is the second most important anthropogenic greenhouse gas after carbon dioxide ( CO2). Despite an increasing policy focus on methane as a potent greenhouse gas, methane emissions continue to rise (as do carbon emissions). Global anthropogenic methane emissions are now 15%–20% higher than they were 2000–2002. Global average methane concentrations reached 1.9 parts per million (ppm) in January of 2024 (Lan et al 2024). Annual increases in methane are also accelerating for reasons that are not fully understood and debated. 

Some gases are more effective than others at making the planet warmer and "thickening the Earth's atmospheric blanket." For each greenhouse gas, a Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, typically a 100-year time horizon, relative to the emissions of 1 ton of carbon dioxide (CO2). Gases with a higher GWP absorb more energy, per ton emitted, than gases with a lower GWP, and thus contribute more to warming Earth. Thus, though methane lasts much less than 100 years in the atmosphere, it is described in terms of the 100 years by it’s Global Warming Potential.

Methane’s lifetime in the atmosphere is much shorter than carbon dioxide (CO2), CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 is 28 times greater than CO2 over a 100-year period. Over a 20-year period, it is 80 times more potent at warming than carbon dioxide. Carbon dioxide concentrations in the atmosphere are currently 490 ppm 250 times higher than methane, so even at the higher Global Warming Potential it is still smaller than the impact from CO2. Since the signing of the Paris Climate Accord, global greenhouse gas emissions have continued to rise. We are further from net zero emissions than we were in 2015.

from EPA

Methane comes from both natural and anthropogenic sources. Total global methane sources, both natural and anthropogenic, both rose. The largest natural sources are wetlands and freshwater lakes, rivers, and ponds where methane-emitting bacteria thrive. Human activities that release methane include biofuel and fossil fuel burning, agriculture, and waste (landfills).

Dr. Jackson and his team performed both a bottom-up estimate and a top-down estimate using monitoring equipment (both satellite and ground-based) to identify the total and sources of methane. The methods proposed slightly different numbers. The absolute concentration of methane in the atmosphere was determined by the top-down method.

Dr. Jackson et al states that “Recent analyses suggest that methane mitigation may be cheaper than CO2 mitigation for a comparable climate benefit. Better quantification and attribution of methane sources are needed to support such mitigation efforts locally, regionally, and globally.” The study found that direct anthropogenic methane emissions were responsible for 65% of all methane released each year. It is even higher if land use changes are considered.

Natural sources of methane are likely to increase with increasing temperatures. Methane removal techniques is still in its infancy. So, we are left with mitigation for now. According to the last Global Methane Budget: Wetlands contributed 30% of global methane emissions, with oil, gas, and coal activities accounting for 20%. Agriculture, including enteric fermentation (cow belching), manure management, and rice cultivation, made up 24% of emissions, and landfill gas contributed 11%. Sixty-four percent of methane emissions came from the tropical regions of South America, Asia, and Africa, with temperate regions accounting for 32% and the Arctic contributing 4%.

Methane emissions rose most sharply in Africa and the Middle East; China; and South Asia and Oceania. Each of these three regions increased emissions by an estimated 10 to 15 million tons per year during the study period. The United States followed behind, increasing methane emissions by 4.5 million tons, mostly due to more natural gas drilling, distribution and consumption. Europe was the only region where methane emissions decreased over the study period, attributed to reductions chemical manufacturing and growing food more efficiently with better management of manure and landfills.

According to Dr. Jackson and his colleagues, curbing methane emissions will require reducing fossil fuel use and controlling fugitive emissions such as leaks from pipelines and wells, as well as changes to the way we feed cattle, grow rice and eat. “We’ll need to eat less meat and reduce emissions associated with cattle and rice farming,” Dr. Jackson said, “and replace oil and natural gas in our cars and homes.”

 

Virginia is Back in RGGI

Last week, Circuit Judge C. Randall Lowe ruled that governors and their agencies “may only do that which is permitted by statute. … As such, the only body with the authority to repeal the RGGI Regulation would be the General Assembly…Therefore, the court finds that the attempted repeal of the RGGI Regulation is unlawful, and thereby null and void.”

On July 10, 2020, Virginia formally adopted the CO2 Budget Trading Program (Part VII of 9VAC5-140) for the power sector to implement a carbon emissions trading and reduction program as authorized by the Clean Energy and Community Flood Preparedness Act (Article 4 of Chapter 1219 of the 2020 Acts of Assembly). The rule allowed for full participation in the Regional Greenhouse Gas Initiative (RGGI) to reduce carbon dioxide (CO2) emissions and make emissions allowances available for sale through an auction program that power producers use for compliance purposes. Proceeds from allowance sales are returned to Virginia to fund grants for climate mitigation and resilience programs in certain communities. 

RGGI is a carbon-trading/ cap program that is already in place in ten New England states. The RGGI reduces carbon emissions from fuel fired power plants by putting a price on carbon. At the time that then Governor Northam signed the bill into law his administration stated that “joining RGGI will create nearly $100 million in revenue each year.” This money does not appear out of thin air, the actual source of the RGGI revenue will be increased power rates since the cost of the carbon allowances is part of the rate base for electricity and will be passed onto consumers. 

With the growth of data center power use, the increase in fees and thus funding will probably be higher. Because of the captive nature of their ratepayers, the power-generators can and will fully pass on costs to consumers. Under the law signed by Governor Northam, RGGI proceeds go to grants programs for some communities and not to rebates to all rate payers.  RGGI fails to achieve its goal to reduce carbon emission as a carbon “cap-and-trade” system because it lacks any incentive for power-generators to actually reduce carbon emissions. Meanwhile demand for more and more electricity in Virginia is growing at an unprecedented rate due to data centers. 

Other states participating in the RGGI program designed their systems to provide rebates to their ratepayers, in Virginia the program operates as a hidden tax (and rather inefficient way to do it) on consumers and businesses in which the funds are disbursed through grant programs. Virginia consumers were originally told that the program would not increase their energy bills, but this is untrue. This is an inefficient method to tax and distribute funds for the benefit of some Virginians without achieving the intended greenhouse gas emission goal.

The compliance costs of RGGI program participation will be submitted by Dominion Energy and approved by the SCC, as they have in the past, and will impact electricity rates.  These costs will be directly related to the cost of allowances, along with other charges allowed under current law and regulations. Allowance prices have varied significantly in the past, and future prices will continue to vary.  Four other RGGI participating states provide electric bill assistance to customers using some of their auction proceeds which Virginia does not. The RGGI saves some Virginians money by ensuring  that all Virginians pay higher electric rates. 

Maybe the data centers should pay all of the RGGI fees since they are the reason Virginia cannot reduce it’s emissions. Buried in the Dominion Energy Integrated resource plan IRP is the fact that the carbon intensity of the Virginia electric grid increased 37% from 2023 to 2024. Though Dominion’s IRP attributes the increase in carbon intensity to the increase in use of natural gas, that is not completely true. The generation mix changed from 2023 to 2024 to halve the purchased power and triple the coal generation. That would do it.

This is from an appendix in Dominion 2024 IRP

COP 29 Ends

As I write this the 29th Conference of the Parties (COP29) in Azerbaijan has finally banged the closing gavel after running into overtime.  The annual two week United Nations climate talks were scheduled to end at 6 pm on Friday, but without an agreement in sight negotiations continued on until Sunday.

For 2 weeks, delegates from nations across the globe meet to discuss the next steps in the ongoing fight against climate change and pretend that it is still possible to keep global warming under 1.5 degrees Celsius. It’s not. Scientists think the earth may have already surpassed that briefly this year.  We are sitting on a melting ice cube. People (not only in the United States) are unwilling to do what it will take to solve the problem. So the crisis will grow. There will be drought, famine, flooding, death and wars. I believe mankind will survive, but it will not be pretty or nice.

The COP 29 meeting was saved from complete failure by a last minute agreement. Under the deal, “wealthy nations” pledged to fund $300 billion per year to be granted to the “developing nations”  by 2035, up from a current target of $100 billion. While a broader target of $1.3 trillion annually by 2035 was adopted, only $300 billion  annually was designated for grants and low-interest loans from developed nations to aid the developing world in transitioning to low-carbon economies and preparing for climate change effects. The rest will be loans.

In 1990’s when the Kyoto Treaty was signed by the European Union, Japan and Canada, the developed world including the United States represented 72% of global CO2 emissions from fuel, now they represent less than half of that and falling. Back then the United Nations defined the “developed nations”as the European Union, Australia, the United States, Britain, Japan, Norway, Canada, New Zealand and Switzerland. Notice that China now the largest generator of carbon emissions and India are not on that list.

from Carbon Brief

China’s historical emissions within its borders have now caused more global warming than the 27 member states of the EU combined, according to new analysis by Carbon Brief. That analysis shows that 94% of the global carbon budget, the total amount of carbon dioxide that can be emitted and still stay within 1.5 degrees C has now been used up. Cumulative emissions since 1850 have reached 2,607 billion tonnes of carbon dioxide (GtCO2). China’s historical emissions reached 312 GtCO2 in 2023, overtaking the EU’s 303 GtCO2. Their projections show that China is still way behind the 532 GtCO2 emitted by the US, however, according to the analysis they will surpass the United States mid-century.

The financing negotiations were complicated by the fact that the Paris Agreement though often referred to as a treaty is not one, at least not in the United States. None of the resolutions are binding. The U.S. Constitution requires that two-thirds of voting Senators agree for a treaty to be ratified. This was never done. The U.S. joined the Paris Accord under executive action by the Obama administration. President Obama did not even get the billion dollars he pledged approved in his budget. However, the Obama administration managed to spend $5.7 billion annually on international climate finance without specific budget authorization because most international assistance can count towards the goal. President Biden pledged to increase that to $11.4 billion a year by 2024.He fell far short of that number. Congress only approved $1 billion all other monies were "off the books" - the Biden administration specialty. 

Now with the election of Donald J. Trump there is unlikely to be additional funding. As  still the world’s largest economy, the United States is essential to meeting climate finance pledges. Yet we are running an unsustainable deficit. Mr. Trump is widely expected to renege on any non-binding commitments negotiated in Azerbaijan by the Biden administration and has said he will once more withdraw the United States from the Paris Agreement. None of these commitments have ever been binding. This is a matter that should be determined by congress.

We have a climate problem because of carbon dioxide emissions from the burning of fossil fuels. The reason we don’t stop using fossil fuels and use alternatives is because they cost more. They have a higher economic cost for land, transmission, power storage, and solar panels and wind turbines. When you have a higher economic cost you have fewer resources for other things (like health care, transfer payments, FEMA aid, highways, water systems, housing, cars, vacations- you get the idea) and lower you standard of living. It also means that things you make cost more and so you become uncompetitive against others using carbon fuel. It is one of the reasons China is flooding the world with low-cost products. They are made using coal. President-elect Trump should sell his proposed tariff on China as what it truly is- a tax on carbon emissions.

Further Comments on PW Water

On the Prince William Water website, you can find an information page on data centers. All their statements while true are incomplete and somewhat misleading in some instances.  This is part of a series discussing  more fully some of the issues they address. In the blog post below the bold face print is what Prince William Water posted the rest is my discussion.

Do data centers reduce available ground water for residents on private wells?

The drinking water provided by Prince William Water to serve new development in the western service area comes from public sources in the Potomac River and Lake Manassas, not from groundwater wells. Hence, public water supply does not affect ground water supply for private wells. 

True, the public water supply is drawn from the Potomac River for the western service area and the Occoquan Reservoir and Lake Manassas for the eastern service area. However, groundwater can be impacted by data centers (and development in general) in two ways. Directly and indirectly.

Directly. The water for data centers (cooling and landscape and miscellaneous indoor and outdoor use) comes from either public water supply (either potable water or reused water) or even potentially groundwater. There are no restrictions or permitting necessary for a data center to use a well for water supply in Prince William County. Watering lawns and landscaping at these large facilitiesthroughout the warm months uses a lot of water at these massive facilities also uses lots of water.

Data Centers are cooled using either air conditioning (electricity) or evaporative cooling (water). Evaporative cooling is more efficient and effective. Data centers that are water cooled use large amounts of water for cooling systems (even in closed loop systems), which ensure that the heat produced by these massive facilities is controlled. 

There are no restrictions or permitting necessary for groundwater use in Prince William County. The Virginia Water Withdrawal Reporting Regulation only requires the annual reporting of direct surface water and groundwater withdrawals each year of any entity withdrawing more than 300,000 gallons per month.

Reports made to DEQ for Prince William County indicate that 40,000,000-70,000,000 gallons of groundwater a year was being used for a pump and treatment system and 30,000,000-35,000,000 gallons of groundwater a year was being used by an industrial user (who I believe to be Amazon based on a conversation with DEQ). There are an unusual number of large capacity wells (100-750 gallons per minute) in the Manassas area that do not report to DEQ.  They could be pumping less than the reportable amount of water, or their owners simply unaware of their actual flow rate or the need to report use. Another way around the reporting requirements is to have several wells, none of which exceed the limit.

Ground water flow and storage is often viewed as static reservoirs that serve as the savings account for surface water flow. Through the hyporheic zone groundwater feeds streams between rain storms, but groundwater is dynamic and continually changing in response to human and climate stress [Alley et al., 2002; Gleeson et al., 2010]. Changes in precipitation patterns, the amount of precipitation, the , and the changes in land use impacts available groundwater and surface water.

Land use changes that increase impervious cover, add more suburban lawns, roadways, buildings, pavement and eliminate woodlands does two things. It reduces the open area for rain and snow to seep into the ground and percolate into the water table and groundwater and the impervious surfaces cause stormwater velocity to increase preventing water from having enough time to percolate into the earth, increasing storm flooding and preventing recharge of groundwater from occurring. Land use changes also potentially increase the use of groundwater by adding more homes and businesses that utilize groundwater.

Very slowly, changes in land use change the ecology of the watershed and can reduce the water supply over time. As groundwater continues to be used levels fall, perennial steams that feed the rivers become intermittent during dry periods like this past summer and the summer of 2023. This is what appears to be happening in the Bull Run Mountain Conservancy area where for the second summer in a row   perennial streams stopped flowing in the summer.

Changing land use and the changing climate that are bringing  new patterns of rain and drought and are impacting the Occoquan Reservoir.  As Prince William Water points out: “Once used by data centers in western Prince William County, the wastewater is treated at the Upper Occoquan Service Authority Water Reclamation Plant and released as reclaimed water to the Occoquan Reservoir. In this water cycle, water used from the Potomac is reclaimed and released into the Occoquan Reservoir, adding volume.” Higher wastewater effluent while the changing climate and land use reduce river flow can introduce higher relative concentrations of minerals and salts, pharmaceutical, personal care and cleaning chemicals into the drinking water supply, potentially requiring additional treatment lines at great expense for all customers of the Griffith plant.

As Prince William Water points out: “Additional purchased (water) capacity must be timed in coordination with required infrastructure improvements for both Prince William Water and Fairfax Water, since purchasing additional capacity and delivering more drinking water may require infrastructure improvements.” Infrastructure improvements like additional treatment lines, additional reservoirs to assure continued availability of water are very expensive. In the billions of dollar range. This is reflected in the price of water. 

We need more information before we damage or destroy our fragile Bull Run and Occoquan Watersheds. We are paving over the watershed with roads, data centers, parking lots houses and electrical infrastructure reducing the groundwater recharge, reducing our stream flow and increasing the water demand. Although hidden in the subsurface, groundwater is the most important freshwater component in the hydrological cycle. Groundwater exists below all land with varying distance to the surface, but only in 20-30% of the land area is groundwater close to the land surface to feed surface streams and provide ecological services.

Groundwater releases water to streams sustaining the base flow of streams and rivers (Hare et al., 2021). Groundwater is the primary source of springs and many wetlands  (Bertrand et al., 2011; Havril et al., 2018; Gleeson et al., 2020a). Finally, the groundwater saturated subsurface, the hyporheic, makes up the largest continental biome contributing to the health and purity of our water resource. The small changes that the Bull Run Conservancy has reported in the springs, seeps and streams is telling us that our watershed is changing, and not in a good way.

It appears that even with just the current level of development, the depth to groundwater is increasing enough to disconnect some streams from the groundwater during summer months. These are the first small signs that the watershed is beginning to die- streams become intermittent and eventually become ephemeral- flowing only during rainstorms. These streams flow into the Bull Run and the Occoquan River that provide the portion of our eastern service area drinking water supply that is not from recycled wastewater. Of course as Prince William Water points out, increasing numbers of data centers will increase the amount of wastewater available, but that may not be all good. During rainless periods the fraction of treated wastewater could exceed the amount of natural water very soon. 

Prince William County is beginning to see changes in the Bull Run watershed.  The groundwater is becoming disconnected from Little Bull Run and Catlett’s Creek in the area of the headwaters of those streams. Once the hydrology and ecological biome is destroyed by development, it cannot be easily restored, if at all. Protecting the Occoquan Reservoir requires protecting all the water resources in a region because all water in the watershed is connected.

 

Kumari Yadav S (2023) Land Cover Change and Its Impact on Groundwater Resources: Findings and Recommendations. Groundwater - New Advances and Challenges. IntechOpen. Available at: http://dx.doi.org/10.5772/intechopen.110311.

Anke Uhl, Hans Jürgen Hahn, Anne Jäger, Teresa Luftensteiner, Tobias Siemensmeyer, Petra Döll, Markus Noack, Klaus Schwenk, Sven Berkhoff, Markus Weiler, Clemens Karwautz, Christian Griebler, Making waves: Pulling the plug—Climate change effects will turn gaining into losing streams with detrimental effects on groundwater quality,
Water Research, Volume 220, 2022, 118649, ISSN 0043-1354,
https://doi.org/10.1016/j.watres.2022.118649

Julia Zill, Christian Siebert, Tino Rödiger, Axel Schmidt, Benjamin S. Gilfedder, Sven Frei, Michael Schubert, Markus Weitere, Ulf Mallast, A way to determine groundwater contributions to large river systems: The Elbe River during drought conditions, Journal of Hydrology: Regional Studies, Volume 50, 2023, 101595, ISSN 2214-5818,

https://doi.org/10.1016/j.ejrh.2023.101595. (https://www.sciencedirect.com/science/article/pii/S2214581823002823)

 

PW Water Comments Incomplete and Misleading

On the Prince William Water website, you can find an information page on data centers. The information while true is incomplete and somewhat misleading. Whether this is intentional, I do not know. I think it was intended to be comforting. Over the next couple blog posts I will more fully discuss the issues. In the blog post below the bold face print is what Prince William Water posted the rest is my discussion.

Do data centers use water for cooling?

Data center developers and operators use different cooling technology – water cooled or air cooled – based on several proprietary factors. The decision about which cooling technology is used is owner-determined and project-specific. 

Data centers generate heat. Servers and their related equipment generate a considerable amount of because every watt of power used by a server is dissipated into the air as heat. Feel the bottom of your own computer (this is why it is hard to keep the cat off the computer). The amount of heat output per server varies, depending on the type of chip and configuration. If the equipment gets too hot it will be destroyed. Data Centers are cooled using either air conditioning (electricity) or evaporative cooling (water). Evaporative cooling is more efficient and effective. In hot regions and with AI chips water cooling is preferred both for cost and heat removal ability.

In a water-cooled system, water-cooled chillers and cooling towers located on top of the data center roofs produce chilled water, which is delivered to computer room air conditioners for cooling the entire building. Some of this water can be recycled through the system more than once, recirculating the same water through their cooling systems multiple times while replenishing what evaporates.

According to Google, this practice saves up to 50% of water when compared with “once-through” cooling systems. However, eventually this reused water needs to be replaced with new water, due to mineral scale formation which could damage the cooling equipment or increase the conductivity of the water which could create static and damage the IT equipment.

The need for new water results from the build-up of calcium, magnesium, iron, silica, and salt which become concentrated by evaporative cooling cycles. The amount of water data centers consume also fluctuates based on seasonal weather conditions. Facilities typically use less water during the winter months and more during the summer months. We’ve seen this effect in water use data from Loudoun County.

Loudoun Water presentation to ICPRB showing seasonality of water use

Data centers are primarily located in the western areas of Prince William County. Western Prince William County drinking water is supplied by Fairfax Water’s Corbalis Water Treatment Plant, which draws from the Potomac River. Once used by data centers in western Prince William County, the wastewater is treated at the Upper Occoquan Service Authority Water Reclamation Plant and released as reclaimed water to the Occoquan Reservoir. In this water cycle, water used from the Potomac is reclaimed and released into the Occoquan Reservoir, adding volume.

The discharged cooling water that is too salty to continue reusing in the data centers is sent to UOSA wastewater treatment plant. This plant is not equipped to remove salt and minerals and so ultimately those excess minerals are mixed with all the other treated wastewater and released into the Occoquan River and flows right to the Occoquan Reservoir. During summer months and periods when there is no rain the treated wastewater is a significant and growing proportion of the water in the Occoquan Reservoir. For two generations UOSA has been a significant portion of the drinking water supply from the Griffith Plant which supplies eastern Prince William County through both American Water and Prince William Water.

The other sources of water to the Occoquan Reservoir are the streams (and groundwater-more on that Thursday) of the Bull Run water shed that flows into Bull Run and the streams (and groundwater) in the Occoquan Watershed that ultimately flow into the Occoquan River.

How much water do data centers use?

Data center water consumption depends on factors such as facility size, cooling type (water intensive or air cooled) and outdoor temperature. Prince William County had 34 data centers in 2023. Seasonal weather affects data center water use; facility water use is lower in winter and higher in summer. In 2023, data centers in Prince William County consumed approximately 1.4% of Prince William Water's average daily water demands and 6% of its maximum daily water demands.  

The industry treats water use (and everything else) it as a trade secret. However, Prince William Water 2023 financial report gives the water use for Prince William Water, 11,387,000,000 gallons for that year. The 34 data centers that existed in 2023 used in the neighborhood of 159,400,000 gallons of water (from Prince William Water- in addition a single data center user reported 35,000,000 gallons to DEQ from a well in Manassas).  Prince William Water also reports that 6% or 2,700,000 of the 44,400,000 peak use summer day was to data centers. It has been estimated that data center square footage will more than triple off of the 2023 number in the next 15 years.  

from PW Water 2023 Financial report

It should also be noted that the peak use day probably happened during the summer drought of 2023. The rainfall totals for May, June, July and August of 2023 were all below average in our area.  The reference year I used was from the  fiscal year 2023 which ended on June 30, 2023. The existing data centers in Prince William County and those coming on line in the next decade will continue to be supplied by the Corbalis Plant drawing its water from the Potomac River.  The Washington, DC, metropolitan area (WMA) is home to almost five million people, the federal government and commercial operations that support all of the people and government.

The regional water suppliers share the Potomac River as the sole major regional water resource. The waters of the Potomac are not infinite. Thirty-five years ago the regional water companies and came together to form the Interstate Commission on the Potomac River Basin (ICPRB) and a cooperative agreement (Co-Op) for planning and sharing the water resources available regionally.

 One of the most important functions of the ICPRB is that every five years they conduct a study to evaluate whether available water resources will meet forecasted water demands. The water resources of the Potomac River are limited. The most recent study accounted for both climate change and growth and  found that if droughts become much more severe as predicted in the climate forecast, even with the addition of the reservoirs in various stages of planning and construction: Vulcan Quarry, Milston Quarry, Travilah Quarry and Luck Stone Quarry B (adding over 13 billion gallons of water storage) and using water restrictions and demand management the Potomac River may be unable to meet combined water supply needs and the environmental flow-by at Little Falls during periods of drought. Even more water storage would be needed to ensure that during dry periods there is water for everyone.

Water demand from the Potomac River averaged 453 million gallons per day (MGD) for the for the last period reported in the study (2014-2018). The ICPRB projects that average annual water demand will increase to 501 MGD (10%) by 2040 and to 528 MGD (16%) by 2050. It is not clear how many data centers were included in the projections (if any), but the good news is that the ICPRB has a history of not adequately accounting for the adoption of low flow toilets and water efficient appliances so there may be some wiggle room in the forecast.

Nonetheless, the demand for water will increase. A wide range of evidence indicates that the earth has been warming over the past century and patterns of precipitation are changing.  These trends are likely to continue.  Likely changes in temperatures and precipitation will affect the availability, use, and management of water resources. The climate projections indicate that the mid-Atlantic states, on average, are becoming and will continue to get “wetter.” Climate scientists also warn, however, that floods and droughts will become more severe.  Our water infrastructure will have to include more water storage to meet a larger demand during longer droughts.

The summer of 2024 was a warm and dry. Though Hurricane Helene brought rain to us at the end of September, it was followed by the longest dry period on record -nearly 40 days. We are experiencing drought. Prince William Water and all regional water companies are attempting demand management because the flow of the Potomac River Water’s social media post featured November 7^th  read in part:

“Metropolitan Washington remains under a Drought Watch, following several months of low rainfall with dry conditions expected to continue throughout the fall and winter months. The Drought Watch was enacted in July by the Metropolitan Washington Council of Governments (COG). 

A "watch" is the second level of COG’s four-stage regional drought response plan, designed to monitor water levels and address drought conditions throughout the year. Despite the current conditions, regional officials emphasize that there is an adequate supply of water in the Potomac River and back-up reservoirs.

We encourage customers to practice wise water use for indoor activities—like washing clothes and dishes, showering, and brushing your teeth--and for outside uses like watering their lawns or washing their cars. Prince William Water has wise water use tips available below. If you are continuing to water your lawn, we recommend following the outdoor watering schedule below…” Prince William Water goes on to give an alternate day watering schedule and recommendations on how homeowners can reduce water usage.

Everything is fine, but please conserve water. Meanwhile, Prince William Water states that they can purchase additional water supply capacity from Fairfax Water.

from Prince William Water

Can Prince William Water support the water demands of proposed data centers and residential/commercial development included in the Prince William County Comprehensive Plan and recent land use policies?

Yes. Prince William Water can support development activity as envisioned in the Prince William County Comprehensive Plan, including the latest Comprehensive Plan update which included the Digital Gateway, with capacity currently owned by Prince William Water supplemented with the purchase of additional capacity when needed from Fairfax Water. 

 As specific land use applications are submitted with the related water requirements, Prince William Water will continuously monitor and assess the availability of existing water supply and, if necessary, the required timing to purchase additional capacity from Fairfax Water. Any additional capacity from Fairfax Water would be withdrawn from the Potomac River. 

Meanwhile the ICPRB and Fairfax Water are working to build enough water storge in the system to meet the expected demand. There is a limit to how much water can be captured by reservoirs- it is not infinite.  As more treatment and watr storage needs to be installed in the Fairfax Water system, the cost of the Between 2022 and 2023 the cost of the water purchased (and a little less was purchased in 2023 than 2022) increase by 20%.

Disinfect Your Well After the Flood

I read in the New Your Times this week that as the flood water in North Carolina has receded the U.S. EPA and the North Carolina Department of Health have been offering free water testing for the homes with private wells which are a third of North Carolina residents. Every well owner should test their well after flooding. The New York Times reports that so far the state and federal testing are finding that 40% of the wells are contaminated. This is not surprising, but there are actions that can be taken to restore the wells. If the mechanical components of the well were damaged by flowing debris the homeowner might be eligible for FEMA assistance. You can apply for FEMA assistance online or by calling 800-621-3362. The first thing is to repair any damaged equipment.

Severe flooding can cause septic waste and even chemicals from cars, stores and factories can enter groundwater making it unsafe to drink for days or even months depending on the extent of contamination and flow rate of groundwater. Essentially, anything that seeped into the groundwater will have to clear itself through natural attenuation (filtering by the soil and the contamination moving with the flow of the groundwater). A well may not be a safe source of water after the flood, but in all likelihood it will recover. Often all you need to do is flush the well then disinfect it.

Be aware that wastewater from malfunctioning septic tanks or chemicals seeping into the ground can contaminate the groundwater for several weeks if there was significant flooding.  The first thing you need to do is respond to any immediate problems and then test the water periodically to verify the continued safety of drinking water. Repeated disinfection and filtration can keep the water safe to drink until the problem is solved. If the well does not return to normal, a permanent water treatment system might be necessary if the grouting to the well casing has been damaged. A well professional can help you determine if a well needs to be replaced or repaired with treatment equipment installed. Years ago several neighbor’s wells were impacted by a flooded and failed septic system. It took several months for the contamination to clear, but it ultimately did.

Unless your well was submerged near a trucking depot, gas station, animal feed lot or other industrial or commercial source of chemicals it is likely that torrential rains or flood waters have infiltrated your well and you have “dirty or brownish” water from surface infiltration. This is especially true if you do not have a sanitary cap on your well or have a well pit. Historically, it was common practice to construct a large diameter pit around a small diameter well. The pit was intended to provide convenient access to underground water line connections below the frost line. Unfortunately, wells pits tend to be unsanitary because they literally invite drainage into the well creating a contamination hazard to the water well system. 

It is most likely if your yard was flooded or your well submerged that you have some surface infiltration of water including flood water from your septic system. In that case, chlorine shocking your well should disinfect your well and last at least 7-14 days you may have to do it more than once until everything is back to operating normally and any contamination in the groundwater has passed. Sadly, if you have a private well you are pretty much on your own. FEMA assistance might pay for well repairs or equipment, but you are going to have to take charge of the situation, and flush and clean your own well. After a flood, you are going to have to dry out your septic system and get it functioning again. If the flood waters were high enough to top the septic tank, have it pumped and go light on water use until the leach field dries out.

If your water is brown, the first thing you should do is run your hoses (away from your septic system and down slope from your well) to clear the well. Run it for an hour or so and see if it runs clear. If not let it rest for 8-12 hours and run the hoses again. Several cycles should clear the well. What we are doing is pumping out any infiltration in the well area and letting the groundwater carry any contamination away from your well. In all likelihood the well will clear of obvious discoloration. Then it is time to disinfect your well. This is an emergency procedure that will kill any bacteria for 7 to 14 days. It needs to be repeated until the source of the contamination is removed.

After 10 days you need to test your well for bacteria (and chlorine) to make sure that it is still safe. Testing the well for bacteria would determine if the water were safe to drink. A bacteria test checks for the presence of total coliform bacteria and fecal coliform bacteria. These bacteria are not normally present in deeper groundwater sources. They are associated with warm-blooded animals, so they are normally found in surface water and in shallow groundwater (less than 20-40 feet deep). Most bacteria (with the exception of fecal and e-coli) are not harmful to humans, but are used as indicators of the safety of the water. The chlorine test tells you if the lack of bacteria is due to the continued presence of chlorine. You need for both bacteria and chlorine to test negative to have successfully “fixed” your well.

To disinfect a well you will need common unscented household bleach.  For a typical 6 inch diameter well you need 2 cups of regular laundry bleach for each 100 foot of well depth to achieve about 200 parts per million chlorine concentration. You will also need rubber gloves, old clothes and protective glasses to protect you from the inevitable splashes, and don't forget a bucket to mix  bleach with water to wash the well cap.

• Put on the old clothes and safety glasses
• Run your hoses from the house to the well
• Fill bucket with half water and half chlorine. 
• Turn off power to the well
• Drain the hot water tank
• Remove well cap
• Clean well cap with chlorine and water solution and place in clean plastic bag
• Clean well casing top and well cap base using brush dipped in chlorine water
• Pull wires in the well aside if they are blocking the top of the well and clean them with a rag dipped in chlorine water mixture. Make sure there are no nicks or cuts in the wires. 
• Put the funnel in the well top and pour in the chlorine and water mixture
• Now pour in the rest of the chlorine SLOWLY to minimize splashing
• Go back to the basement and turn the power to the well back on
• Turn on the hose and put it in the well 
• Sit down and wait for about 45 minutes or an hour
• After 45 minutes test the well to make sure that the chlorine is well mixed
• Use the hose to wash down the inside of the well casing
• Turn off the hose
• Carefully bolt the well cap back in place
• Now go back into the house
• Fill your hot water heater with water, but do not turn it on to heat the water
• Draw water to every faucet in the house until it tests positive for chlorine then flush all your toilets. Turn off your ice maker. 
• Then do not use the water for 12-24 hours 
• Set up your hoses to run to a gravel area or non-sensitive drainage area. The chlorine will damage plants 

 

After 16 hours turn on the hoses leave them to run for the next 6-12 hours. The time is dependent on the depth of the well and the recharge rate. Deeper wells with a faster recharge rate take longer. If you cannot run your well dry and it recharges faster than the hoses use water you will need to keep diluting the chlorine. If you can run your well dry, you might have to let it recharge and run the water off again to clear the chlorine.

After about 8 hours of running the hoses begin testing the water coming out of the hose for chlorine. Keep running the hose and testing the chlorine until the chlorine tests below about 1 ppm.

• Drain the hot water heater again, open the valve to refill it and turn it back on
• Open each faucet in the house (one at a time) and let run it until the water tests free of chlorine. Be aware the hot water will sputter- big time- until all the air is out of the system. Flush all the toilets
• Change the refrigerator filter cartridge and dump all your ice and turn your ice maker back on. 

It is important not to drink, cook, bath or wash with this water during the time period it contains high amounts of chlorine whose by products are a carcinogen. Run the water until there is no longer a chlorine odor. Turn the water off. The system should now be disinfected, and you can now use the water for 7 to 14 days when the effects of the disinfection wear off. Hopefully, a single disinfection will be enough. 

Unlike public water systems, private systems are entirely unregulated; consequently, the well testing, and treatment are the voluntary responsibility of the homeowner. The local extension office (here in Virginia) or the local Department of Health can provide information and resource links for private well owners.   I am happy to answer emails or questions to the blog. Remember after you chlorinate a well the water typically runs brown until all the iron, iron bacteria and other minerals in the groundwater that you just oxidized are flushed out. Do not panic, it will clear.

I regularly chlorinate my well to knock back the iron bacteria and generally clean it out and refresh the water. For years I did this when my husband was out of town to avoid inconveniencing him for what I considered spring cleaning. During the pandemic when he was home during the chlorination, he was totally convinced that the continued sporadic reappearance of brown in the water was an indication that I had ruined the well. I had to tell him multiple times wait- it will clear. Finally, I just let the hose run for another 24 hours straight, and the brown was completely gone, and the test strips did not detect any chlorine. Usually, to be less water wasteful, I just get close enough and let time take care of it. (During this period I use bottled water or filtered water to make coffee and cook and then change the filter on the refrigerator when it clears completely.)  After a flood there are probably not water concerns so flush the well with abandon.