In April 2018, Delta Diablo Sanitation District (DDSD) contracted with W. M. Lyles Co. to perform the Primary Clarifier Area Improvements Project at the DDSD Wastewater Treatment Plant in Antioch. This Design-Bid-Build Project involved repairs to some aging infrastructure at the facility, as described below:

• Replacement of the sludge and scum pumps and associated piping at the four primary clarifiers.
• Structural demolition and rebuilding of the pump station floor in order to replace the existing corroded underdrain   system with a new floor trench drain system.
• Concrete waterproofing repairs to the clarifier launder walls which had experienced significant corrosion over the past 40 years of service.
• Replacement of the exposed electrical feeds to the clarifier drive mechanisms and pump systems.

Through our extensive experience in existing plant rehabilitation and building projects in the Design-Build market, we recognized a value engineering opportunity to provide a better finished product for the new floor trench drain system that resulted in a net savings to DDSD and at the same time eliminated the highest risk to be experienced on the Project. Instead of completely demolishing portions of the existing slab which is 10 feet below the groundwater table and replacing it with a new trench drain, we proposed installing a completely new slab with the new trench drain on top of the existing slab. This process involved several focus meetings with DDSD to address all of the design considerations and keep plant operations staff abreast of all the changes and decisions to be made.