Granular Activated Carbon (GAC)
ALBEMARLE COUNTY SERVICE AUTHORITY AGENDA ITEM EXECUTIVE SUMMARY
AGENDA TITLE: Water Treatment (GAC) Presentation STAFF CONTACT(S)/PREPARER: Gary O’Connell, Executive Director
AGENDA DATE: November 21, 2013 INFORMATIONAL ATTACHMENTS: Yes
BACKGROUND: As we discussed at our Board meeting last month, the Rivanna Water and Sewer Authority (RWSA) is concluding the study phase to change the water treatment method to Granular Activated Carbon (GAC). This new process will allow us to meet the new E.P.A. regulations to control disinfection by-products (DBP’s) in drinking water. A number of GAC approaches were studied, and all the final alternatives meet the new E.P.A. standards in lowering DBP’s and improving water quality. The alternatives range in capital costs from $16.4 million to $19.5 million, and range in operational costs from $860,000 to $1.16 million. We provided a wealth of background information and reports last month, and that information is still available on our website. DISCUSSION: The RWSA will be discussing and taking action on the preferred GAC alternative at the November 26 RWSA board meeting. We have asked Mr. Mark Bishop, of the engineering firm Hazen and Sawyer, to make a presentation at our board meeting to outline the GAC options and respond to questions the Board may have about the water treatment process utilizing GAC. Attached is a memo from RWSA that outlines in more detail the options. The chart on page 2 is a quick view of the options and advantages of each. I should add here, as you evaluate the options, that we seasonally have a “taste and odor” issue in some parts of our system, and “manual” carbon treatment has been effective in removing it. The “full scale” option would be more effective, we believe, in addressing this issue. I remind you that the options to consider are for the Urban Water Treatment Plants ( No. Fork Rivanna WTP, So. Fork Rivanna WTP, and Observatory WTP). Scottsville WTP and Crozet will receive “full scale” GAC water treatment. BOARD ACTION REQUESTED: This is an informational item for Board discussion, and direction to the Executive Director. ATTACHMENTS: -RWSA Memo on GAC Options for Urban Water Treatment Plants
010101AgendaItemExecSumGACPresentation112113
695 MOORES CREEK LANE CHARLOTTESVILLE, VA 22902-9016 TEL: 434.977.2970 FAX: 434.293.8858 WWW.RIVANNA.ORG
MEMORANDUM TO:
THE HONORABLE MAYOR HUJA AND COUNCILORS ALBEMARLE COUNTY SERVICE AUTHORITY BOARD OF DIRECTORS
FROM:
THOMAS L. FREDERICK, EXECUTIVE DIRECTOR, RIVANNA WATER AND SEWER AUTHORITY
SUBJECT:
GRANULAR ACTIVATED CARBON FOR URBAN WATER TREATMENT PLANTS
DATE:
NOVEMBER 11, 2013
This memorandum is provided to summarize the current status of the Granular Activated Carbon (GAC) project for RWSA’s Urban Water Treatment Plants, which will be on the agenda for discussion by the Charlottesville City Council at its 7:00 p.m. meeting on Monday, November 18, 2013, and by the Albemarle County Service Authority Board of Directors at its 9:00 a.m. meeting on Thursday, November 21, 2013. As quick background on this issue, EPA requires all drinking water to be treated to very high standards, and also requires disinfection of all water to remove or inactivate viruses, bacteria, and microbial matter available in nature that could cause human illness. Water in nature also contains very fine traces of organic matter from the decay of plant material. It was discovered in the late 1970s that disinfectants can react with such matter, resulting in what are called “byproducts”, which in sufficient quantity can adversely affect human health. Recognizing these byproducts result from a process (disinfection) that is also essential to preventing disease, regulations have been implemented slowly in phases, as the technology to control byproducts without interfering with disinfection, has advanced. The latest phase, called Stage 2, goes into effect for the Urban System in October 2014 and will require RWSA to improve its water treatment process to the next level. As you may recall, the RWSA Board voted in favor of GAC technology as that next level and agreed to “take chloramines off the table” on July 25, 2012, after receiving unanimous support from the City Council, ACSA Board, and County Supervisors for this decision. At the time of the decision, it was known as public information that a qualified concept level engineering cost estimate for GAC in 2011 dollars was a sum total in excess of $18 million for all of the three Urban water plants.
16c T:\Board\Quarterly Updates to City and County\Activated Carbon Discussion Nov2013.docx
“Hybrid” vs. “Full Scale” GAC RWSA staff is proposing that the RWSA Board of Directors decide at its November 26, 2013 meeting whether to proceed with the Final Design of Granular Activated Carbon capital improvements based upon a “Hybrid” approach or a “Full Scale” approach. The differences between the two approaches are summarized below: “Hybrid” Definition of Option All drinking water retains existing treatment. Only a portion of the water receives GAC treatment, blended with water by-passing GAC but always reducing enough natural organic matter to meet EPA Stage 2 regulations. Defined GAC capacity South Fork WTP = 9 mgd constructed Observatory WTP = 3 mgd North Fork WTP = 2 mgd Estimated Capital Cost $17.3 million Hazen and Sawyer’s current $0.92 million projection of annual operating cost Advantages: Quantitative Sufficient to meet Stage 2 requirements consistently
Advantages: Qualitative
Lower capital and operating cost compared to “Full Scale” Very high quality water, but no advantages over “Full Scale” GAC treatment identified
“Full Scale” All drinking water receives both existing treatment and GAC treatment in order to consistently excel beyond EPA Stage 2 regulations.
South Fork WTP = 11 mgd Observatory WTP = 5 mgd North Fork WTP = 2 mgd $19.5 million $1.16 million
Very slight measureable improvement over “Hybrid” on the order of 5 to 10 parts per one billion of disinfection byproducts. Full availability for taste and odor control during summer algal blooms in reservoir Full reliability during emergency shutdown at one facility, or incident in a reservoir Increased flexibility in production between treatment plants during droughts
Regarding costs, we have further estimated the impact on an average household per month for the two options, based on a household of three using 53 gallons per person per day. For the “Hybrid” option, the average increased cost of water would be $3.29 per month. For “FullScale”, the increase would be $3.91 per month. We would note that these are averages for comparison purposes only, and do not take into account that there are differences between how the City and ACSA compute retail rates, meaning some may pay a little more, some a little less than the average. Also, households that use more than the average consumption will pay more. 2
Regarding the advantages, RWSA heard at its October 14 Open House that some citizens want the lowest risks possible and will support the “Full Scale” option on that basis. The presence of disinfection byproducts in drinking water are in extremely small quantities, making it very difficult to quantify the difference between “Hybrid” and “Full Scale”. Both will produce excellent water meeting all EPA Stage 2 requirements, but byproducts will be very slightly lower in “Full Scale” treated water. “Full Scale” treatment could offer some qualitative advantages, the most significant of which is the removal of taste and odor compounds from reservoir waters in the summer months caused by algal blooms (we presently use powered activated carbon or PAC for this purpose; Full-Scale GAC would eliminate the need to use PAC). Other advantages may occur in rare circumstances such as a severe drought or an emergency that requires a treatment plant to go off-line or potentially contaminates one of the reservoirs. It is possible to build the capital facilities for “Full Scale”, and also operate the treatment plant as a “Hybrid” during periods when source waters are high quality, thereby saving operating costs. The reverse (“Hybrid” capital facilities, “Full-Scale” operating) may not always be true, depending on overall Urban System demand, because the capacity of the GAC facilities is more limited. The RWSA Board would appreciate feedback regarding “Hybrid” vs. “Full-Scale” from other boards, or the public, prior to the November 26 meeting. Cost of GAC After the October 14 Open House, an e-mail from a local citizen raised questions about the magnitude of all cost estimates prepared by our engineering consultant, Hazen and Sawyer, in one statement suggesting the estimates were “falsely inflated costs” and another statement as “potentially inflated”. Two issues were raised: (1) an AWWA Journal article published in 2010; and (2) a cost estimate prepared by Integrated Resource Management, Inc. of California, a firm known as part of a national advocacy against chloramines. The e-mail also asks for “oversight” of the cost estimating process. Hazen and Sawyer has talked to the author of the AWWA Journal article, and the author’s estimates were based on EPA cost curves from 2003, escalated by inflation to 2009. The estimates in the article were based solely on the relative concept level costs for building various GAC capacities at a single water treatment plant. As there are many economies-of-scale issues associated with construction at one treatment plant as opposed to building GAC capacity at each of three Urban System water plants, the estimates are not comparable. After receiving the email, Hazen and Sawyer escalated the EPA cost curves to 2013 dollars, then applied the curve separately to each of our three water plants, then added the three numbers, and identified that this estimate was within the margin of contingency of Hazen and Sawyer’s current preliminary design estimate. As a result of now performing preliminary design, Hazen and Sawyer has also allowed for specific findings at our three water plants which are not accounted for in cost curve data, to include site layouts that anticipate future growth, and limitations on conditions of aging electrical supply at the facilities. Overall, the proper application of cost curve data actually confirms the Hazen and Sawyer cost estimates are reasonable. With respect to IRM’s July 2012 estimate, RWSA staff and Hazen and Sawyer reviewed the estimate, and found the estimate to be unreliable for RWSA’s planning purposes for several reasons summarized below and in Hazen and Sawyer’s 2012 response: 3
• •
•
•
By IRM’s own admission, no professional engineer worked on its cost estimate; No individual preparing IRM’s estimate ever visited any of the three water treatment plant sites, and “booster pump station and wet wells” (also known as “intermediate pump stations”) were removed from the estimate, apparently without recognizing fundamental engineering principles that require a survey of each site to confirm the site specific hydraulic profile to determine this need (a simpler way to say this is that water can’t run uphill against gravity without applied energy such as pumping); Building enclosures for the GAC contactors and ancillary above ground piping were removed from the estimate at all sites. Freezing temperatures occur in Virginia winters that could damage GAC equipment, and RWSA considers its obligation to reliable service too important to take this kind of risk; IRM called this a “package plant installation” and appears to dismiss as “compounded costs” items designed to integrate GAC equipment into an existing water treatment facility and control system, as if GAC works similar to “plug and play”. Unfortunately, GAC is not a package plant installation and the integration with the existing plant operations is necessary and vital to successful operation.
With respect to the question of “oversight”, this is a reasonable suggestion, but we would advise that the best way to achieve oversight is through having RWSA hire a panel of engineering experts to perform a value engineering analysis as the final design proceeds. These experts would provide an independent set of eyes looking for ways to amend design work to provide savings, where it can be achieved within the project objectives, or identify other design issues if appropriate before they become bigger problems. This type of panel was obtained for the Ragged Mountain Dam project and worked very well. The hiring of such a panel was discussed with the RWSA Board in October, and though no decision will be made before November 26, the idea was favorably received. Mr. Mark Bishop of Hazen and Sawyer will join me during the discussions by the City Council and the ACSA Board of Directors, and we are both happy to address any of your questions.
cc: RWSA Board of Directors
4
AGENDA TITLE: Water Treatment (GAC) Presentation STAFF CONTACT(S)/PREPARER: Gary O’Connell, Executive Director
AGENDA DATE: November 21, 2013 INFORMATIONAL ATTACHMENTS: Yes
BACKGROUND: As we discussed at our Board meeting last month, the Rivanna Water and Sewer Authority (RWSA) is concluding the study phase to change the water treatment method to Granular Activated Carbon (GAC). This new process will allow us to meet the new E.P.A. regulations to control disinfection by-products (DBP’s) in drinking water. A number of GAC approaches were studied, and all the final alternatives meet the new E.P.A. standards in lowering DBP’s and improving water quality. The alternatives range in capital costs from $16.4 million to $19.5 million, and range in operational costs from $860,000 to $1.16 million. We provided a wealth of background information and reports last month, and that information is still available on our website. DISCUSSION: The RWSA will be discussing and taking action on the preferred GAC alternative at the November 26 RWSA board meeting. We have asked Mr. Mark Bishop, of the engineering firm Hazen and Sawyer, to make a presentation at our board meeting to outline the GAC options and respond to questions the Board may have about the water treatment process utilizing GAC. Attached is a memo from RWSA that outlines in more detail the options. The chart on page 2 is a quick view of the options and advantages of each. I should add here, as you evaluate the options, that we seasonally have a “taste and odor” issue in some parts of our system, and “manual” carbon treatment has been effective in removing it. The “full scale” option would be more effective, we believe, in addressing this issue. I remind you that the options to consider are for the Urban Water Treatment Plants ( No. Fork Rivanna WTP, So. Fork Rivanna WTP, and Observatory WTP). Scottsville WTP and Crozet will receive “full scale” GAC water treatment. BOARD ACTION REQUESTED: This is an informational item for Board discussion, and direction to the Executive Director. ATTACHMENTS: -RWSA Memo on GAC Options for Urban Water Treatment Plants
010101AgendaItemExecSumGACPresentation112113
695 MOORES CREEK LANE CHARLOTTESVILLE, VA 22902-9016 TEL: 434.977.2970 FAX: 434.293.8858 WWW.RIVANNA.ORG
MEMORANDUM TO:
THE HONORABLE MAYOR HUJA AND COUNCILORS ALBEMARLE COUNTY SERVICE AUTHORITY BOARD OF DIRECTORS
FROM:
THOMAS L. FREDERICK, EXECUTIVE DIRECTOR, RIVANNA WATER AND SEWER AUTHORITY
SUBJECT:
GRANULAR ACTIVATED CARBON FOR URBAN WATER TREATMENT PLANTS
DATE:
NOVEMBER 11, 2013
This memorandum is provided to summarize the current status of the Granular Activated Carbon (GAC) project for RWSA’s Urban Water Treatment Plants, which will be on the agenda for discussion by the Charlottesville City Council at its 7:00 p.m. meeting on Monday, November 18, 2013, and by the Albemarle County Service Authority Board of Directors at its 9:00 a.m. meeting on Thursday, November 21, 2013. As quick background on this issue, EPA requires all drinking water to be treated to very high standards, and also requires disinfection of all water to remove or inactivate viruses, bacteria, and microbial matter available in nature that could cause human illness. Water in nature also contains very fine traces of organic matter from the decay of plant material. It was discovered in the late 1970s that disinfectants can react with such matter, resulting in what are called “byproducts”, which in sufficient quantity can adversely affect human health. Recognizing these byproducts result from a process (disinfection) that is also essential to preventing disease, regulations have been implemented slowly in phases, as the technology to control byproducts without interfering with disinfection, has advanced. The latest phase, called Stage 2, goes into effect for the Urban System in October 2014 and will require RWSA to improve its water treatment process to the next level. As you may recall, the RWSA Board voted in favor of GAC technology as that next level and agreed to “take chloramines off the table” on July 25, 2012, after receiving unanimous support from the City Council, ACSA Board, and County Supervisors for this decision. At the time of the decision, it was known as public information that a qualified concept level engineering cost estimate for GAC in 2011 dollars was a sum total in excess of $18 million for all of the three Urban water plants.
16c T:\Board\Quarterly Updates to City and County\Activated Carbon Discussion Nov2013.docx
“Hybrid” vs. “Full Scale” GAC RWSA staff is proposing that the RWSA Board of Directors decide at its November 26, 2013 meeting whether to proceed with the Final Design of Granular Activated Carbon capital improvements based upon a “Hybrid” approach or a “Full Scale” approach. The differences between the two approaches are summarized below: “Hybrid” Definition of Option All drinking water retains existing treatment. Only a portion of the water receives GAC treatment, blended with water by-passing GAC but always reducing enough natural organic matter to meet EPA Stage 2 regulations. Defined GAC capacity South Fork WTP = 9 mgd constructed Observatory WTP = 3 mgd North Fork WTP = 2 mgd Estimated Capital Cost $17.3 million Hazen and Sawyer’s current $0.92 million projection of annual operating cost Advantages: Quantitative Sufficient to meet Stage 2 requirements consistently
Advantages: Qualitative
Lower capital and operating cost compared to “Full Scale” Very high quality water, but no advantages over “Full Scale” GAC treatment identified
“Full Scale” All drinking water receives both existing treatment and GAC treatment in order to consistently excel beyond EPA Stage 2 regulations.
South Fork WTP = 11 mgd Observatory WTP = 5 mgd North Fork WTP = 2 mgd $19.5 million $1.16 million
Very slight measureable improvement over “Hybrid” on the order of 5 to 10 parts per one billion of disinfection byproducts. Full availability for taste and odor control during summer algal blooms in reservoir Full reliability during emergency shutdown at one facility, or incident in a reservoir Increased flexibility in production between treatment plants during droughts
Regarding costs, we have further estimated the impact on an average household per month for the two options, based on a household of three using 53 gallons per person per day. For the “Hybrid” option, the average increased cost of water would be $3.29 per month. For “FullScale”, the increase would be $3.91 per month. We would note that these are averages for comparison purposes only, and do not take into account that there are differences between how the City and ACSA compute retail rates, meaning some may pay a little more, some a little less than the average. Also, households that use more than the average consumption will pay more. 2
Regarding the advantages, RWSA heard at its October 14 Open House that some citizens want the lowest risks possible and will support the “Full Scale” option on that basis. The presence of disinfection byproducts in drinking water are in extremely small quantities, making it very difficult to quantify the difference between “Hybrid” and “Full Scale”. Both will produce excellent water meeting all EPA Stage 2 requirements, but byproducts will be very slightly lower in “Full Scale” treated water. “Full Scale” treatment could offer some qualitative advantages, the most significant of which is the removal of taste and odor compounds from reservoir waters in the summer months caused by algal blooms (we presently use powered activated carbon or PAC for this purpose; Full-Scale GAC would eliminate the need to use PAC). Other advantages may occur in rare circumstances such as a severe drought or an emergency that requires a treatment plant to go off-line or potentially contaminates one of the reservoirs. It is possible to build the capital facilities for “Full Scale”, and also operate the treatment plant as a “Hybrid” during periods when source waters are high quality, thereby saving operating costs. The reverse (“Hybrid” capital facilities, “Full-Scale” operating) may not always be true, depending on overall Urban System demand, because the capacity of the GAC facilities is more limited. The RWSA Board would appreciate feedback regarding “Hybrid” vs. “Full-Scale” from other boards, or the public, prior to the November 26 meeting. Cost of GAC After the October 14 Open House, an e-mail from a local citizen raised questions about the magnitude of all cost estimates prepared by our engineering consultant, Hazen and Sawyer, in one statement suggesting the estimates were “falsely inflated costs” and another statement as “potentially inflated”. Two issues were raised: (1) an AWWA Journal article published in 2010; and (2) a cost estimate prepared by Integrated Resource Management, Inc. of California, a firm known as part of a national advocacy against chloramines. The e-mail also asks for “oversight” of the cost estimating process. Hazen and Sawyer has talked to the author of the AWWA Journal article, and the author’s estimates were based on EPA cost curves from 2003, escalated by inflation to 2009. The estimates in the article were based solely on the relative concept level costs for building various GAC capacities at a single water treatment plant. As there are many economies-of-scale issues associated with construction at one treatment plant as opposed to building GAC capacity at each of three Urban System water plants, the estimates are not comparable. After receiving the email, Hazen and Sawyer escalated the EPA cost curves to 2013 dollars, then applied the curve separately to each of our three water plants, then added the three numbers, and identified that this estimate was within the margin of contingency of Hazen and Sawyer’s current preliminary design estimate. As a result of now performing preliminary design, Hazen and Sawyer has also allowed for specific findings at our three water plants which are not accounted for in cost curve data, to include site layouts that anticipate future growth, and limitations on conditions of aging electrical supply at the facilities. Overall, the proper application of cost curve data actually confirms the Hazen and Sawyer cost estimates are reasonable. With respect to IRM’s July 2012 estimate, RWSA staff and Hazen and Sawyer reviewed the estimate, and found the estimate to be unreliable for RWSA’s planning purposes for several reasons summarized below and in Hazen and Sawyer’s 2012 response: 3
• •
•
•
By IRM’s own admission, no professional engineer worked on its cost estimate; No individual preparing IRM’s estimate ever visited any of the three water treatment plant sites, and “booster pump station and wet wells” (also known as “intermediate pump stations”) were removed from the estimate, apparently without recognizing fundamental engineering principles that require a survey of each site to confirm the site specific hydraulic profile to determine this need (a simpler way to say this is that water can’t run uphill against gravity without applied energy such as pumping); Building enclosures for the GAC contactors and ancillary above ground piping were removed from the estimate at all sites. Freezing temperatures occur in Virginia winters that could damage GAC equipment, and RWSA considers its obligation to reliable service too important to take this kind of risk; IRM called this a “package plant installation” and appears to dismiss as “compounded costs” items designed to integrate GAC equipment into an existing water treatment facility and control system, as if GAC works similar to “plug and play”. Unfortunately, GAC is not a package plant installation and the integration with the existing plant operations is necessary and vital to successful operation.
With respect to the question of “oversight”, this is a reasonable suggestion, but we would advise that the best way to achieve oversight is through having RWSA hire a panel of engineering experts to perform a value engineering analysis as the final design proceeds. These experts would provide an independent set of eyes looking for ways to amend design work to provide savings, where it can be achieved within the project objectives, or identify other design issues if appropriate before they become bigger problems. This type of panel was obtained for the Ragged Mountain Dam project and worked very well. The hiring of such a panel was discussed with the RWSA Board in October, and though no decision will be made before November 26, the idea was favorably received. Mr. Mark Bishop of Hazen and Sawyer will join me during the discussions by the City Council and the ACSA Board of Directors, and we are both happy to address any of your questions.
cc: RWSA Board of Directors
4
