TREASURE ISLAND — Sewer manhole covers in the 115th Avenue roadway will probably never become a location for a photo opportunity spot, but the town’s specially designed sewer hatches could get into the public works record books for their distinctive specifications.
During their Jan. 6 meeting, city commissioners authorized Public Works staff to hire TLC Diversified Inc. to install a specially designed, watertight sewer access wet-well hatch and valve vault replacement for Lift Station #7 “in the amount not to exceed $145,374.”
Public Works Director Michael Helfrich said staff believes the actual “not to exceed price” of the project will be less than the requested amount due to design modifications.
There are currently two hatches in the 115th Avenue roadway; one is a watertight wet well hatch, while the other is a valve vault hatch that will be redesigned and replaced; it is being relocated to reduce noise created when cars and trucks traverse over it due to its angle in the roadway.
Helfrich said after relocation the valve vault hatch will make “a lot less noise.” The valve vault will be reinstalled closer to the edge of the avenue to match the angle of the road and minimize the sound of vehicles moving across the access hatch.
Helfrich told commissioners the project was initiated “to reduce inflow at the city’s wastewater lift stations. Public Works identified the need for water-tight access hatches approximately four years ago. However, most of Treasure Island’s wet wells are located within a roadway, so a watertight hatch would also be subject to direct traffic vehicle loads.”
Last year, on July 24, the city commissioners unanimously authorized a contract with TLC Diversified Inc. for utility rehabilitation and construction services.
It took eight months to get the watertight hatch design completed, because “to our understanding (a hatch) has never been built that would hold the weight of a truck; not only is it water tight, it will also hold a truck, so it can roll over the top of it,” Helfrich explained.
In trying to secure a hatch the city found “many hatch manufacturers can provide a hatch meeting the city’s water tightness or vehicle loading requirements, but not both,” he said.
With the assistance of its continuing engineering consultant, the city came across Bradenton-based SAK Enterprises, which specializes in the custom fabrication of flood-proofing products and has manufactured access hatches.
The project was delayed due to some safety factors and additional engineering, Helfrich said.
The hatches were expected to be delivered to the contractor around Jan. 15. After hatches are installed, milling and paving of the roadway will be completed.