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Frequently Asked Questions

In summer 2010, Virginia American Water's Hopewell customers experienced an unpleasant taste and smell in their drinking water. The following "Frequently Asked Questions" provide background on the problem, its causes, and measures that Virginia American Water is taking to raise community awareness of the cause and possible solutions for the taste and odor issues in Hopewell's drinking water.

1. What caused the taste and odor episode in summer 2010?
2. What types of algae caused the problem?
3. What did Virginia American Water do to monitor the taste and odor-causing compounds?
4. How is Hopewell's drinking water treated?
5. What additional treatment measures did Virginia American Water take in summer 2010 to address the taste and odor problem?
6. What were the results after the additional treatment?
7. Was the water safe to drink during the summer, and is it safe to drink now?
8. Was any independent testing of the water quality conducted?
9. Will the taste and odor problem recur?
10. Will the expansion of the Hopewell water treatment plant help remedy the taste and odor issues that might reoccur?
11. What is Virginia American Water doing now to prepare for a possible recurrence?
12. How will the community be involved?
13. What is the role of the Stakeholder Advisory Group (SAG)?
14. Who are the SAG members?
15. Who are the Expert Panel members?
16. How can I learn more?
17. In June 2010, did Virginia American Water monitor the water for the taste and odor-causing compounds and for nutrients that contribute to algae blooms?
18. Have you checked with other jurisdictions that have had the same taste and odor problems in drinking water?
19. If the same unusually hot weather conditions occur this summer as we experienced in 2010, will the water have the same taste and smell?
20. Will the current expansion of the Virginia American Water treatment plant address the taste and odor issue?
21. Could you add more granulated activated carbon filters or change the filters more often to remove more MIB?
22. Could you back-flush the GAC filters to remove more MIB?
23. Has Virginia American Water considered algae-harvesting boats?
24. Have you considered extending the water intake pipe further into the channel of the river and/or deeper, or have you thought about using water from the James River, instead of the Appomattox?

1. What caused the taste and odor episode in summer 2010?
Algae growing in surface waters of the Appomattox River (the source of Hopewell's water supply) were the cause of the musty/earthy taste in Hopewell's drinking water. This algae bloom was a natural phenomenon related to the prolonged hot weather, a lack of rain and high levels of nutrients (phosphorus and nitrogen) in the watershed runoff. Algae blooms result from eutrophication, the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These nutrients typically promote excessive growth of algae. When the algae were removed during the water treatment process, they released non-toxic taste and odor-causing compounds that caused the water to have an unpleasant taste and odor.

2. What types of algae caused the problem?
Two algal species can cause taste and odor-causing compounds: MIB (Methyl Iso-Borneol) and geosmin. Hopewell's taste and odor episode was mainly related to MIB present at high concentrations in the Appomattox River (maximum >1,000 nanograms/liter); in comparison, geosmin levels remained very low (below 20 nanograms/liter). MIB can be detected by the average person when present in minute amounts, as low as 10 nanograms/liter. One nanogram/liter is equivalent to a single drop of water in 26 Olympic-size swimming pools.

3. What did Virginia American Water do to monitor the taste and odor-causing compounds?
Throughout the summer and into the fall, Virginia American Water monitored the compounds both before and after water treatment. While geosmin levels remained low, the concentrations of MIB in the Appomattox River rose during the summer, from 20 nanograms/liter in July, to 1,200 nanograms/liter at the end of August. By mid-September, the MIB levels declined to about 500 nanograms/liter. With the winter months, MIB levels are below 10 ng/L in the source water and the unpleasant taste and odor are now gone.

4. How is Hopewell's drinking water treated?
The Hopewell treatment plant conventionally treats water from the Appomattox River using the following four treatment steps: (1.) Pre-treatment in which various treatment chemicals are added to the river water. (2.) Settling removes dirt/mud particles from water. (3.) Filtration removes fine particles. Filtration in Hopewell is an elaborate process since it includes two separate filtration stages. The first stage involves anthracite filters (to remove particles), and the second stage includes granular activated carbon (GAC). During GAC filtration, water contaminants can be removed because they are retained by the activated carbon media. They can also be degraded by microorganisms colonizing the carbon media. (4.) Post-treatment involves the addition of various chemicals (disinfectant, fluoride) to refine water quality.

5. What additional treatment measures did Virginia American Water take in summer 2010 to address the taste and odor problem?
In response to the taste and odor issue, Virginia American Water implemented the following additional treatment measures to improve MIB removal. The total cost for this additional treatment was approximately $161,000.

(1.) A strong oxidant (sodium permanganate) was added at the beginning of the treatment train (pre-treatment) to oxidize various water constituents and break down some of the taste and odor substances. Permanganate residual was increased from 0.5 to 1.0 mg/L (applied dose of 8 ppm) when MIB levels increased in the river.

(2.) Powdered Activated Carbon (PAC) was added to the treated river water to remove additional MIB molecules. PAC is composed of fine activated carbon particles that are mixed with water before being added into river water as a treatment chemical. After reacting with water constituents and removing some MIB molecules, PAC particles are removed along with mud particles during the next process of settling. PAC feed rate was increased from 12-15 mg/L to 25 mg/L as river MIB levels increased.

Some PAC products (wood based, coconut) are better for removing MIB. A wood based PAC is being evaluated by conducting laboratory experiments.

(3.) An air diffuser (aeration step) was added to the treatment train to strip some of the MIB molecules prior to the filtration steps.

In addition, jar tests were run using alum supplemented with copper sulfate (concentrations of copper sulfate of 1, 2 and 3%). Adding copper sulfate did not lead to any MIB removal. Higher concentrations of copper sulfate (2% and 3%) were detrimental to coagulation.

6. What were the results after the additional treatment?
After the additional treatment measures were implemented, an average of 65% of the MIB was removed. However, due to extremely high levels of MIB in the Appomattox River, MIB levels did not drop below human detection levels after treatment.

7. Was the water safe to drink during the summer, and is it safe to drink now?
Yes and Yes. The compounds creating the taste and odor issue are not regulated by the Virginia Department of Health and did not pose a risk to human health. Hopewell's drinking water met and continues to meet all federal and Virginia of Department regulations.

8. Was any independent testing of the water quality conducted?
Yes. In late summer 2010, the City of Hopewell requested that a set of water samples be sent to an independent lab for testing. On September 13, water samples (plant effluent, distribution system samples) were collected and tested for various parameters (metals, minerals, ions, volatile organic compounds, taste and odor, and bacteriology) at the Fairfax Water Authority Central Laboratory. An environmental health specialist from the Virginia Department of Health (Hopewell) served as a witness during the sampling. Testing results showed a state value of 7 (earthy/musty) and a threshold odor number (TON) of 43. All other water quality results were normal and showed that the water met all the health standards, both federal and state. The testing data were sent to the Hopewell city manager, the local health department and the Virginia Department of Health Office of Drinking Water. In addition, a person from the Virginia Department of Health Office of Drinking Water inspected the Hopewell treatment facilities on August 19 and August 23, 2010.

9. Will the taste and odor problem recur?
We cannot guarantee that the taste and odor-causing compounds will not recur. The exceptionally hot and dry summer of 2010 and the presence of nutrients (phosphorous and nitrogen) in the watershed runoff were key factors in promoting the algae bloom, which led to extremely high levels of taste and odor-causing compounds. In addition, because there is no chemical treatment available for treating flowing river waters, such as the Appomattox, the algae cannot be controlled as it would be in water from a lake or reservoir. Algae blooms result from eutrophication, the process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These nutrients typically promote excessive growth of algae. Watershed protection is a long-term solution for improving surface water quality.

10. Will the expansion of the Hopewell water treatment plant help remedy the taste and odor issues that might reoccur?
The plant expansion will provide reliable and permanent feed equipment to add permanganate and powdered activated carbon (PAC). Additional GAC filters will also be added to the plant to improve treatment. However, MIB is very difficult to remove during conventional water treatment, and additional advanced treatment steps such as advanced oxidation will need to be considered to remove all of the MIB and resolve the taste and odor issue.

11. What is Virginia American Water doing now to prepare for a possible recurrence?
Virginia American Water is considering advanced treatment alternatives that involve advanced oxidation treatment (including ozone, ozone and hydrogen peroxide, and UV and peroxide) to oxidize MIB and geosmin. Virginia American Water plans to test one of these options during an advanced treatment plant trial during the summer months of 2011. However, the implementation of any of these options is costly, and it is important that the Hopewell community be aware of the financial implications of any solution. For this reason, Virginia American Water is inviting the community to learn more about the cause and possible solutions for the taste and odor issues in Hopewell's drinking water.

12. How will the community be involved?
Virginia American Water will organize two community information sessions. In addition, we are forming a Stakeholder Advisory Group (SAG), which will be involved in raising awareness about the cause and possible solutions for the taste and odor issues. A group of third party water quality and treatment experts (Expert Panel) will serve as resources for SAG members and be present at the community information sessions and SAG meetings.

The first community information session will be on January 27, 2011, 6:30 p.m. -8:00 p.m. More details will be posted in early January. The second community information session will occur in October 2011.

13. What is the role of the Stakeholder Advisory Group (SAG)?
Members of the SAG will participate in the two community meetings and four SAG meetings. During the SAG meetings, they will hear from the third party experts and have the opportunity to better understand the complex issues associated with addressing the taste and odor issue in Hopewell. After the advanced treatment plant trial during summer 2011, the SAG will meet in September to review the results of the plant trial and to participate in an evaluative process, which will assist Virginia American Water in making a decision about a solution to the taste and odor issue.

14. Who are the SAG members?
Members include elected and appointed officials in Hopewell, representatives of environmental groups, business leaders, planning officials, a representative from Fort Lee, and citizen representatives.

15. Who are the Expert Panel members?
Expert panel members water treatment, water quality experts and environmental experts from the Department of Environmental Quality, the Virginia Department of Health Office of Drinking Water, and Virginia Tech.

16. How can I learn more?
We will keep expanding information about Hopewell's water on the Virginia American Water website.

17. In June 2010, did Virginia American Water monitor the water for the taste and odor-causing compounds and for nutrients that contribute to algae blooms?
We are constantly monitoring and testing the water. Last June we conducted tests that confirmed that algae and MIB compounds were the causes of the taste and odor problem. We also monitored nutrients in the water (nitrogen and phosphorus), but the nutrient levels were not unusual.

18. Have you checked with other jurisdictions that have had the same taste and odor problems in drinking water?
Taste and odor in drinking water is a regional problem – and even a global problem. Each community's conditions are different and each year the water changes, so it is difficult to compare Hopewell's situation with that of others. Each community must evaluate the level of MIB compounds that it will treat. In Hopewell's case, a long-term solution relates to decisions about the health of the river from which we draw.

19. If the same unusually hot weather conditions occur this summer as we experienced in 2010, will the water have the same taste and smell?
This is a million dollar question! We can't say with any certainty whether the taste and odor will recur, but it is possible that with the right conditions, it could. Knowing that there could be a recurrence, we have not stopped working on the problem. We are exploring engineering solutions and working with the Stakeholder Advisory Group and a panel of experts to obtain community input.

20. Will the current expansion of the Virginia American Water treatment plant address the taste and odor issue?
With the plant expansion, we will add four additional granulated activated carbon (GAC) filters, which will remove more MIB than we were able to remove last summer. Because the plant expansion will slow the movement of the water through the treatment process, any water with the MIB compound will have more contact with the activated carbon in the filters, which should help reduce, but not completely eliminate, the taste and odor problem. In addition, the plant expansion will include a new powdered activated carbon (PAC) feed system to improve the reliability of feeding this treatment chemical.

21. Could you add more granulated activated carbon filters or change the filters more often to remove more MIB?
The GAC replacement program is site specific and depends on historical issues. The process takes two weeks per filter, and it is our practice to "reactivate" one filter at a time so that we can continue to filter through the other GAC contactors. Reactivating the GAC in one filter is expensive – about $60,000 per vessel. It is important that we balance cost with potential benefits.

22. Could you back-flush the GAC filters to remove more MIB?
No, back-flushing will not remove any more MIB.

23. Has Virginia American Water considered algae-harvesting boats?
We are open to exploring all feasible options to address the taste and odor issue and we welcome input from the Stakeholder Advisory Group, Expert Panel and Hopewell citizens. If a suggested solution will help reduce the taste and odor issue, we will then look into other factors, such as the cost and method to implement that solution. The goal is to find the most effective long-term solution (or solutions) that has the least impact on costs. We are planning to set up plant trials this summer to investigate possible solutions.

24. Have you considered extending the water intake pipe further into the channel of the river and/or deeper, or have you thought about using water from the James River, instead of the Appomattox?
Extending the intake pipe further into the channel is one of the many options we are investigating. We are installing some new water quality monitoring stations on the river, and we will need to gather data from further out in the channel to see if extending the pipe is a feasible solution. Access to both rivers would be useful because we could switch from one source to the other. The major issue in using the James River would be to extend the river water lines, and this construction project would be very expensive.