MWH Constructors
Bachman WTP Project
What makes it interesting?
In the Secondary Treatment Basins, MWH is removing the old chain-and-flight sludge collectors and replacing them with a new system called the Zickert Sludge Removal System in all three trains at the Bachman WTP. It is more commonly used in European countries and relatively new in the United States.
How HCSS Software assisted with this project
HeavyJob allows us to have our foremen do time in the field on their iPads. They also can take pictures and tag them to location. Supervisors do separate daily reports but combine to one single report. HeavyJob tracks our production on the fly while updating quantities. Project manager and project superintendent use the projection report to track individual codes (labor, material, equipment and GC’s) and overall job cost. We use “true up” to update HeavyJob for the material and equipment cost for the project from our accounting software.
Project Description:
The Bachman WTP Project is modifying the water treatment plant to change the treatment process, including enhanced coagulation and biological filtration, for improved water quality and disinfection stability. These changes are needed to be in compliance with the new requirements of the EPA’s Safe Water Drinking Act and Enhanced Surface Water Treatment Rule.
Bachman WTP is a very constrained site. There is work going on at all 3 DWU WTPs in north Texas, so construction schedule and sequencing of shutdowns is critical and has many milestones with LD’s associated with them.
MWH is removing the old chain-and-flight sludge collectors and replacing them with a new system called the Zickert Sludge Removal System. The Zickert Sludge System is a bottom sludge scraper constructed for a continuous sludge transport. The scraper consists of a hydraulic power pack, cylinder unit, link rod system and a number of wedge-formed profiles. The profiles are welded together in a framework of flat bars, which together function as a moving floor in the tank. The moving floor is sliding on gliding strips, which are attached to the tank floor.
In train 3, MWH had to demo the existing flocculation equipment and interior concrete walls. Currently they are constructing the sludge valve vault for the new sludge suction lines and constructing new walls, deck and thickening the existing slab to accommodate the new Zickert system. MWH will start this train up and will complete the Milestone #4 (210 days from draining the basin)/ The other two trains that they install the Zickert Systems in the secondary basins are Milestone #5 (165 days from draining the basin) and #6 (165 Days from draining the basin).
The project also includes demo of the existing clear well and constructing a new one in the same location. MWH had to isolate the existing lines to the clear well during several total plant shut downs in the early mornings during low water demand periods. The shoring and demolition of the clear well is complete. MWH is drilling piers and pouring the slab sections of the new clear well. The completion of the clear well is Milestone #9 (550 after NTP)
