Memorandum

City of Lawrence

Utilities Department

TO:	David L. Corliss – City Manager Cynthia Boecker - Assistant City Manager Diane Stoddard - Assistant City Manager
FROM:	Mike Lawless – Asst. Director of Utilities
CC:	Dave Wagner – Director of Utilities Alan Landis – Purchasing Specialist
Date:	March 16, 2010
RE:	Emergency Replacement of Water Heater at the WWTP

Please include the following item on the City Commission Agenda for consideration at the March 23, 2010 meeting:

Approval of the emergency replacement of the water heater in the Biosolids Building at the Wastewater Treatment Plant by Chaney Incorporated in an amount of $19,639.00.

Project Description

This will be the third water heater since the original one failed. The previous two water heater replacements failed after one year, are out of warranty, and were about $5,000 each. Staff has been researching the original water heater and other alternatives to restore heated water to the biosolids polymer process that would last longer than one year. The original water heater failed after 8 years has an in-kind replacement cost of $27,856. Staff has researched the use and environment that the water heater will be in and have found an alternative to the original at a cost of $19,639.

The original water heater has a 150 gallon, nickel lined tank with a recovery rate of 750 gallons per hour at an 80 degree temperature rise and a 20 year tank warranty. The alternative has a 130 gallon glass lined tank with a recovery rate of 720 gallons per hour at an 80 degree temperature rise and a five year tank warranty. With the longer tank warranties, it is likely the heating elements will fail (generally between eight to ten years) before the tank. The original and alternative water heaters have features that are designed to help prevent failures similar to the lower cost replacements.

Cold water requires almost double the amount of polymer to be used in the biosolids dewatering process.  This additional polymer is then returned to the head of the plant in the filtrate. While staff was researching the options for the water heater replacement, the high level of polymer being returned to the head of the plant is interfering with the treatment process. It is causing additional scum and foam to be present at the primary clarifiers disrupting concentration of the settled solids. This means more gallons of sludge are being pumped to the digesters which require additional energy to heat and process. Currently, the cost of the higher polymer use is about $2,000 per month.

Because of the treatment process disruption, staff, with approval of the City Manager, has proceeded with the emergency replacement of the water heater.

Project Funding: 

This project will be funded out of the Department of Utilities Operations and Maintenance budget for wastewater treatment.

Action Request:  Utilities staff requests approval of the emergency replacement of the water heater in the Biosolids Building at the Wastewater Treatment Plant by Chaney Incorporated in an amount of $19,639.00.

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