Memorandum
City of Lawrence
Utilities Department
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TO: |
David L. Corliss, City Manager Cynthia Wagner - Assistant City Manager Diane Stoddard - Assistant City Manager |
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FROM: |
Philip Ciesielski, Assistant Director of Utilities |
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CC: |
Dave Wagner, Director of Utilities Mike Lawless, Deputy Director of Utilities Aurora Shields, Water Quality Manager Beth Krishtalka, Assistant to Director Mark Hegeman, Utilities Operations Superintendent |
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Date: |
May 13, 2014 |
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RE: |
May 20, 2014 Agenda Item – Authorize Staff to Negotiate a Supplemental Agreement with Burns & McDonnell for Engineering Services for Phase 1 Process Improvements for Project UT1209 – Taste and Odor, and Algal Toxin Water Treatment Process Evaluation |
Background
The generation of taste and odor compounds and algal toxins in the City of Lawrence, KS raw water sources has occurred periodically. These sources are surface water from the Clinton Reservoir and Kansas River. There is small contribution of Kansas River alluvial well water. At present the sources are separate and treated at plants dedicated to each. Clinton Reservoir water is treated at the Clinton Water Treatment Plant, and Kansas River surface and well water is treated at the Kaw River Water Treatment Plant. Both plants generally employ presedimentation, powder activated carbon addition, lime softening, disinfection by sodium hypochlorite and dual media filtration.
The current treatment plant processes provide sufficient reduction of geosmin for most events of record to produce finished water below the taste sensitivity of most humans. The most recent event at Clinton Lake, which persisted for about ten days during June 2012, had raw water geosmin levels that exceeded any previous event of record by nearly four times. The inability of the current treatment process to remove these high levels of geosmin resulted in customer calls regarding the taste and odor of the drinking water.
Presently, algal bloom events related to the generation of geosmin, MIB and/or algal toxins are not well understood. The City of Lawrence is currently working with United States Geological Survey, the US Army Corps of Engineers and other area utilities in several scientific studies to understand these events and attempt to predict their future frequency and severity.
The purpose of the project was to evaluate drinking water treatment processes that will enhance the removal of taste and odor compounds, microtoxins and viruses at the Clinton and Kaw water treatment plants. The scope of the work included water testing and analysis; evaluation of existing plant processes; evaluation of additional treatment processes, and existing process modifications; estimated capital, and operational and maintenance costs of proposed options; and the present worth value of the proposed options. Treatment options evaluated included advanced oxidation, filtration, and adsorption technologies.
Project History
On August 21, 2012 the City Commission authorized staff to advertise an RFP for Engineering Services for Project UT1209 – Taste and Odor, and Algal Toxin Water Treatment Process Evaluation.
On December 3, 2102 the City Commission authorized staff to negotiate an Engineering Services Agreement with Burns & McDonnell for the project.
On March 12, 2013 the City Commission authorized the execution of an Engineering Services Agreement with Burns & McDonnell in the amount of $137,128.00 for Project UT1209 – Taste and Odor, and Algal Toxin Water Treatment Process Evaluation.
Project Status
Burns & McDonnell has submitted the Final Report for Project UT1209 – Taste and Odor, and Algal Toxin Water Treatment Process Evaluation as summarized below.
Burns & McDonnell performed two main tasks: (1) an evaluation of the current processes at both treatment plants, including an evaluation of chemical feeds and doses, and (2) an evaluation of advanced treatment options for T&O removal. Capital and O&M costs were provided for these options.
The Kaw WTP processes were evaluated as part of the Integrated 2012 Water Utilities Plan. The only process improvement currently proposed at the Kaw WTP is the replacement of the lime slakers. The existing equipment has significant maintenance issues and is less efficient than current technologies. This process improvement is not expected to impact the removal of T&O compounds.
The report recommends process optimization improvements at the Clinton WTP to address T&O compounds including retrofitting the existing presedimentation and primary basins with tube settlers to increase sedimentation efficiency; the addition of carbon dioxide, liquid lime, and ferric chemical feed systems, and rapid mix chambers to enhance the coagulation process.
The optimization of the current Clinton WTP treatment processes as recommended above, in conjunction with the Department’s proactive source water monitoring, are expected to effectively treat historical levels of T&O compounds. Burns & McDonnell noted in the report that if T&O compound levels continue to increase, or become more persistent in the source waters, additional treatment using advanced oxidation processes will be necessary to provide effective treatment. To that end Burns & McDonnell evaluated the potential addition of advanced oxidation treatment via ozone, hydrogen peroxide, and UV treatment at each facility by pilot testing raw water samples and reviewing the plant site layouts. Based on the pilot testing of the source waters, and due to physical space limitations, the only feasible alternative for the Kaw WTP is combined ozone oxidation. At the Clinton WTP, UV with hydrogen peroxide is the recommended advanced oxidation treatment technology.
Staff Recommendation
Staff recommends proceeding with the Phase 1 process optimization improvements for both the Kaw and Clinton WTPs outlined below at a total estimated project cost of $5,880,000.00.
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Kaw WTP |
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Lime Slakers |
$1,420,000.00 |
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Clinton WTP |
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CO2 System |
$1,310,000.00 |
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Liquid Lime System |
$780,000.00 |
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Ferric Chloride System |
$400,000.00 |
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Tube Settlers Presed |
$970,000.00 |
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Tube Settlers Primary |
$650,000.00 |
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Rapid Mixers |
$350,000.00 |
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Estimated Total |
$5,880,000.00 |
Future Phase 2 enhanced taste and odor treatment utilizing Ozonation at the Kaw WTP and UV/Hydrogen Peroxide at the Clinton WTP as estimated in 2013 is $11,680,000.00.
Project Funding
The 2014 CIP includes funding for a portion of the Phase I improvements with the remainder of the improvements included in the Department of Utilities recommended 2015 CIP and Rate Plan.
Action
Authorize Staff to Negotiate a Supplemental Agreement with Burns & McDonnell for Engineering Services for Phase 1 Process Improvements for Project UT1209 – Taste and Odor, and Algal Toxin Water Treatment Process Evaluation.