Wastewater Treatment Plant construction costs continue to rise



Regular change orders since the Liberty Hill City Council decided in April to switch vendors for the equipment and technology being used in the new wastewater treatment plant expansion have caused the project budget to grow well beyond its original $9.68 million.

On the Council agenda Monday was an additional change order, to the tune of $1.55 million, but details of that change were not included in the packet and the item was postponed to be brought back for future consideration.

If the additional cost is tacked on, it will mark the fourth time since changing direction in April that the Council will have signed off on a cost increase, and will bring the project total up over $13 million.

“This is part of the change order for changing from Microdyn to Suez and there was still some clarification in the bid cost and we had a meeting with the contractor today (Monday) and he’s supposed to get us some answers back because there was some clarification we needed before I was good to present that to Council,” said Mayor Rick Hall of the postponement on the change order vote.

The original change approved in April was for the City to use equipment from Suez Environment, rather than from Microdyn MBR which supplied the equipment for the most recent expansion. The wastewater plant opened in 2018 using Microdyn equipment and technology, and the extension was also going to use the same equipment and technology.

The equipment, which was set to cost the City $2.2 million through Microdyn, will cost $2.6 million from Suez, the new supplier, adding on $400,000 to the project cost at that time. The equipment cost is separate from the bid award approved for Cunningham Constructors & Associates, Inc., of Georgetown to build the plant.

Then in May, the change was with the construction company building the expansion, in the amount of $1.35 million. That brought the construction contract to where it now stands at $11.35 million.

In August, a number of smaller change orders, adding $18,346 to the cost, were passed by the Council.

After the May change order, Hall said he did not believe there would be significant changes to the project going forward.

“There may be a couple of minor changes as we get into it, but I don’t really see a lot,” Hall said at the time. “One of the reasons we’ve made such drastic changes in this is just since the Microdyn plant has been operational we spent almost $800,000 over what was budgeted or explained to us we would need to spend the first year. We’re on track to be close to that amount this time. Adding these automated processes would help us reduce that cost.”

Hall attributed the decision to switch companies to past issues with the Microdyn equipment.

“We just had a lot of concerns with that plant and its day-to-day operations,” Hall said of the plant, which opened in 2018. “It’s cost the city a lot more money in operating expense over what was anticipated, I would say something in the neighborhood of three quarters of a million dollars more annually than what was budgeted.”

In March 2019, Liberty Hill spent $270,000 to replace the 18 Microdyn membrane bioreactor modules at the wastewater treatment plant after they were damaged due to a failed screen intended to keep larger items out of the plant.

Due to the nature of the damage to the modules, they were not covered under warranty.

The screen failure allowed items through the system that clogged and damaged the membranes. In repairing the screen, gravel, some wire and even a piece of PVC pipe was found in the screen.