Memorandum

City of Lawrence

Utilities Department

 

TO:

David L. Corliss – City Manager

Cynthia Wagner - Assistant City Manager

Diane Stoddard - Assistant City Manager

FROM:

Philip Ciesielski – Assistant Director of Utilities

CC:

Dave Wagner – Director of Utilities

Mike Lawless – Assistant Director of Utilities

Beth Frailey Krishtalka – Assistant to Director

Mark Hegeman – Utilities Operations Superintendent

Dave King – Utilities Maintenance Superintendent

Date:

Septmber 28, 2011

RE:

Agenda Item – Advertise RFPs R1110 and R1111 for Engineering Services for Projects UT1201 - 2012 Electrical Improvements Program and UT1202 - 2012 Mechanical Improvements Program

 

Please include the following item on the City Commission Agenda for consideration at the October 4, 2011 meeting:

Authorize Staff to advertise Request for Proposals R1110 and R1111 for Engineering Services for Projects UT1201 - 2012 Electrical Improvements Program and UT1202 - 2012 Mechanical Improvements Program.

Project Description 

The Requests for Proposals cover several projects as described below.

 

Department of Utilities 2012 Rate Plan and Capital Improvement Program

Variable Frequency Drive Replacement Program (Electrical)

The majority of the large horsepower electric motors operated by the Utility Department are powered through Variable Frequency Drives. Variable Frequency Drives allow the motor speed to vary in response to load or need. Variable Frequency Drives are more efficient, provide more control and create less wear and tear on motors and pumps than traditional constant speed motor controls and starters. Several of these drives have been in service for over a decade and need to be replaced to maintain the reliability of the equipment.

 

This scope of this project includes the replacement of four (4) each drives located at the Clinton Water Treatment Plant Intake, the Wastewater Treatment Plant blower building, the excess flow pumping facility and the influent pumping station. This project is the initiation of a phased program targeted at replacing the variable frequency drives as they reach the end of their service life.

 

Pump Efficiency and Control Program (Electrical)

Wastewater Pump Station PS5 is one of the larger wastewater pump stations in the collection system. Currently when the water level at this station reaches the upper set point a pump is started at 100% speed and when the water level is pumped down to the lower set point, the pump is turned off. This requires several start and stops per hour (depending on flow). The installation of variable frequency drives will allow the pumps to run more consistently at a lower speed to match the required flow. This operation is more efficient electrically and eliminates the wear on the electric motors due the frequent starts. Utilities Department staff will program, build and install the required PLC controls for the modified pump operations based on flow and level control.

 

Kaw Water Treatment Plant Carbon and Ammonia Facilities Backup Generator (Electrical)

The project involves the removal of the 1975 incoming power substation and switchgear. This equipment has exceeded its useful life and the switchgear has failed. The equipment will be replaced with a diesel powered backup generator sized to power the carbon, ammonia and sodium hypochlorite feed systems and other accessory areas not served by the existing generator. The installation of this generator will provide the Kaw WTP with redundant power to all process systems via the two generators. The Kaw WTP’s primary electrical feed will remain through the second Westar substation, transformer and switchgear which were upgraded in 2002.

 

Kaw Sand Screen Replacement (Mechanical)

The Kaw Sand Screen is part of the raw water intake and pumping system at the Kaw WTP. The screen is installed in Low Service Pump Station No.2 to intercept debris ahead of the raw water pumps. The screen was installed in 1988 and due to the hostile service environment has reached the end of its reliable service life. The equipment was out of service on multiple occasions this summer due to drive system failures. During the process of repairs it was found that a number of direct replacement parts for the motor and gearbox system are no longer available.

 

Sanitary Sewer Pump Station 4 & 5 Improvements (Mechanical)

The project includes the installation of flow meters and emergency bypass pumping connections at each pump station. Pump Stations 4 & 5 deliver significant volumes of flow directly to the Wastewater Treatment Plant. These stations are the only two that pump directly to the wastewater treatment plant that have not yet been equipped with flow meters. The addition of these flow meters will result in plant operations staff being unable to readily monitor and quantify flows as they are pumped toward the plant.

 

The project also includes the addition of an emergency bypass pumping connection at each station. In the event of loss of electrical service, or damage to the pumps and/or station electrical systems these connections allow flows to be pumped using a trailer mounted diesel powered pump. These connections are a standard design feature of Department pump stations constructed during the last seven years.

 

Clinton Water Treatment Plant 42” Filter Influent Pipe and Coupling Repair, and Master Backwash Valve Replacement (Mechanical)

During the expansion of the Clinton Water Treatment Plant the interior of the 42” diameter filter influent pipe from the south basin train was found to be severely deteriorated at a chlorine feed point. Deterioration was also found at several downstream pipe joints. The corrective work was originally scheduled to be completed during the expansion however; water production needs required the plant to be put back in service prior to completing the work.

 

The Clinton WTP master backwash valve controls the flow of backwash water used to clean the filters. The valve modulates flow rate to ensure a complete backwash without upset of the filter media layers. The valves operation has become erratic and it often does not completely shut off flow. Maintenance staff have the valve and operator on hand and the project will provide for installation and startup of the valve and operator.

 

Reallocated 2007 and 2008 Revenue Bonds

Clinton Water Treatment Plant Motor Control Center Replacement (Electrical)

The Motor Control Centers, (MCC) located at the Clinton Water Treatment Plant, are over thirty years old and replacement parts for the MCC’s are no longer available.  The Motor Control Center is essential, as it receives the incoming electrical feed and distributes 480 Volt AC power to the major components in the plant including Pumping and Chemical Feeds. The inability to obtain repair and replacement parts results in any failure of the MCC leaving a portion of the facility inoperable.

 

Project Funding: The projects are included in the Department of Utilities 2012 Rate Plan and Capital Improvement Program; and reallocated 2007 and 2008 Revenue Bonds.

Action Request: Authorize Staff to advertise Request for Proposals R1110 and R1111 for Engineering Services for Projects UT1201 - 2012 Electrical Improvements Program and UT1202 - 2012 Mechanical Improvements Program.

Thank you for your assistance. Please advise if you have any questions.