Things Aren't Always as They Seem... Water Wednesday is Back!
Category: Water Treatment
Written By: Keith Rutherford, PE
Date: May 17, 2022
Working in old treatment plants is a fact of life for the Treatment Practice these days. The 1980s was a hotbed for new treatment plant construction using EPA funding and now those plants are in need of serious rehabilitation.
The record drawings provide a good start for finding out what is existing, but sometimes that isn't enough. The Treatment Practice provided a design for a bulkhead system that would allow parts of the Bustamante Treatment Plant in El Paso to be isolated for rehabilitation.
The bulkheads were fabricated using record drawings and field measurements that were made above the waterline, but in the end, the bulkheads could not be inserted all the way to the bottom of the channel for various reasons. Debris, brackets mounted to the side of the wall, items dropped in the channel over the years and 20-foot tall concrete walls that aren't 100% plumb... whatever the reason, the solution wasn't going to be solved from the surface.
CALL IN THE DIVERS
Believe it or not, there are people who get excited by jumping into a channel filled with wastewater. The dive team took turns entering the different areas of the channel and collecting measurements with a gaging rod at various points up and down the channel. While they were in the channel, they removed several items that had been dropped including a section of safety grating and some concrete blocks. They also cleaned some settled sludge from the channel to allow their measuring frame to be set flat on the floor of the channel.
Some of the measurements showed areas of the channel that were as much as 3.5 inches narrower than that shown on the record drawings and measured above the surface.
We are now in the process of determining the best way to modify the bulkheads to fit within the dimensions taken by the divers. In hindsight, calling in the divers before designing the job would have been very helpful. Making the divers a part of the installation team will also be considered so that they can clear any areas where the modified bulkheads may bind on the channel walls.