City of Lawrence

Department of Utilities

MEMORANDUM

TO: David L. Corliss, City Manager

Cynthia Boecker, Assistant City Manager

Diane Stoddard, Assistant City Manager

FROM: Philip E. Ciesielski, Assistant Director of Utilities

CC: Dave Wagner, Director of Utilities

Mike Lawless, Assistant Director of Utilities

Beth Frailey Krishtalka, Management Analyst

Mark Hegeman, Utilities Operations Superintendent

Dave King, Utilities Maintenance Superintendent

DATE: July 14, 2010

RE: July 20, 2010 Agenda Item – Execute Supplemental Agreement No.1 to the Engineering Services Agreement with Black & Veatch for Project WW0601 Anaerobic Digester Improvements at the Lawrence Wastewater Treatment Plant

Please include the following item on the City Commission agenda for consideration at the July 20, 2010 meeting.

Authorize the City Manager to execute Supplemental Agreement No.1 to the existing Design Phase Engineering Services Agreement with Black & Veatch increasing the scope of services from the addition of a heat dryer to the rehabilitation of Digester No.3, with no change to the existing fee, for services in conjunction with project WW0601 improvements to the Anaerobic Digester Process at the City of Lawrence Wastewater Treatment Plant.

Project Description:

This Capital Improvement Plan (CIP) project was recommended as part of the 2003 Wastewater Master Plan. The project is required to increase the capacity of the wastewater plant’s solids processing stream to match the plant’s liquid processing capacity and provide treatment for a community of 100,000 persons.

Project History:

In April 2006 the Department of Utilities contracted with Black & Veatch for an evaluation and testing of the existing digester system, and the delivery of a Pre-design Report outlining design options and a recommended scope of improvements to satisfy the CIP project requirements. In December 2006 Black & Veatch submitted a Pre-design Report, including costs, outlining options for improvements to the digester process, solids drying and digester gas utilization. The recommended improvements included the design of a dewatering and thermal dryer process, odor control, associated modifications to the existing biosolids dewatering building to accommodate the dryer installation, modifications to existing piping and valves in the solids and gas control buildings, installation of insulation on the concrete roof of Digester No.1, modifications to the gas control building/equipment to allow processing of additional digester gas and an evaluation of energy recovery from the digester gas system.

Upon receipt of the Pre-design Report staff paused the project while an evaluation of options for solids handling at the proposed Wakarusa Water Reclamation Facility (WWRF), and its integration into existing processes, was completed as part of WWRF Basis of Design Report. Based on the information and recommendations in these reports in September 2008 Staff recommended continuing project WW0601 Anaerobic Digester Improvements to expand the solids handling capacity at the existing wastewater treatment plant.

In April 2009 the Department of Utilities entered into an Engineering Services Agreement with Black & Veatch for design engineering services related to the recommended improvements in the 2006 Pre-Design Report. In July 2009, as part of the design process, one of the proposed sludge dryer equipment suppliers, Fenton Environmental Technologies, performed pilot testing to dewater and thermally dry samples of undigested sludge from the wastewater plant process stream. While the undigested sludge proved to be satisfactorily dewatered and dried the resulting thermally dried product exhibited unacceptable odor properties in both the dried and rewetted state. The resulting odors make the thermally dried product unacceptable for use in the biosolids beneficial reuse program. The only acceptable disposition for the product would be a sanitary landfill.

Based on the results of the above pilot testing Black & Veatch was directed to provide an updated summary of anaerobic digester capacity improvement options, including construction and operational costs, that meet the goal of the original CIP project of increasing the solids processing capacity and provide treatment for a community of 100,000 persons.

It is recommended that existing Digester No. 3 structure be rehabilitated and put back into service along with the required improvements and expansion of the sludge heating system and the gas compressor system. Additional improvements to the digester gas handling and cleaning system to improve the quality of the gas and increase the amount available for reuse in fueling the sludge heating system are also included.

Black & Veatch has provided a project estimate of $6.2 million for the design and construction of the above improvements. This estimate represents the upper bound for the project and at the current level of detail contains percentage estimate for various associated improvements including electrical and instrumentation systems, site work and project contingency. Staff and Black & Veatch feel this estimate will be reduced through the detailed design process and the shift of some of the project, the instrumentation and control for example, to Department of Utilities staff.

The Departments list of future Capital Improvement Projects includes $500,000.00 in proposed projects that are related to the replacement of equipment in the digester process. This equipment has been included for replacement in the Capital Improvement Plan because it is nearing the end of its useful service life. The equipment included in the future Capital Improvements Plan will also be replaced as part of the currently proposed scope to rehabilitate Digester No. 3.

While the design scope related to the rehab of Digester No.3 and the related gas compressor, sludge heating and solids pumping improvements is more extensive and complex than the scope of the originally contracted project for the thermal dryer Staff and Black & Veatch have worked to draft the current Supplemental Agreement No.1 to execute the design phase of the project within the remaining funds encumbered on the current Engineering Services Agreement.

Staff anticipate bringing a future Supplemental Agreement for Construction Phase Engineering Services for City Commission consideration at the time the project is scheduled to bid.

Project Funding:

The original project construction scope was included in the Department of Utilities proposed Capital Improvement Projects and 2009 Rate Plan and Bond Issuance at an estimated cost of $5,000,000.00. An additional $500,000.00 was included in the 2009 budget for design from reallocated 2007 bond funds for an existing total project budget of $5,500,000.00. $388,990.00 of these funds was originally encumbered with Black & Veatch for design. To date $38,060.25 have been paid for engineering services. Based on the recommended scope and project estimates staff are currently requesting the reallocation of $700,000.00 of existing Bond Funds to the Anaerobic Digester Project budget for a project total of $6,200,000.00.

Action Request: