By BECKY KISER
Hays Post
The renovation of the Hays wastewater treatment plant, built in 1953, will use the process of a 5-stage oxidation ditch with final clarifiers and denitrification filters. City commissioners voted 4-0 Thursday night to accept the recommendation by Project Manager Stan Christopher of HDR Engineering, and city staff.
City commissioner Shaun Musil was absent from the meeting.
Three processes were reviewed over the past two months and each includes biological nutrient removal to meet treatment requirements.
The selection of the oxidation ditch with denitrification filters (Option 2) was made based on factors including ease of operation, lowest present value, and its ability to meet current and anticipated future effluent federal limits. The option will also improve effluent
quality for continued irrigation and indirect recharge reuse.
CDM Smith (CDM Constructors, Inc.) has the contract for Phase 1, 90% Design and GMP Development, for the rebuilding of the WWTP. Christopher told commissioners that CDM believes they may be able to change the 5-stage operation process to 3-stages, which would save about $500,000 in capital costs.
“They offered up some innovative ideas which may result in this being converted to a 3-stage process,” Christopher said. “If that proves out to be the case and allows us to meet today’s (effluent) limits and those in the future, it would bring the capital cost of the biological process down about $500,000.”
“This was a very involved process,” said Hays City Manager Toby Dougherty.
“We had the kickoff meeting in early January and the first task was to identify the (treatment) process. CDM, with HDR, has been busy. At that first meeting we had at least four process engineers there, structural engineers, electrical engineers, people representing the construction side. There were a lot of opinions thrown around, a lot of heated discussion, but that’s how we get to a good decision.
“I feel we reached a good recommendation for you commissioners. We’re very happy with the way this process is working,” Dougherty concluded.
This is the city’s most expensive project to date–estimated at $30 million–and the first major work to use the Owner-Representative/Design-Build process.
The renovation must be completed by 2018 to adhere to stricter federal and state effluent requirements.
The city was fined $18,000 last year by the Environmental Protection Agency for excessive ammonia levels in 2012.