Underground Construction - October 2020 - 26

2020 CAPABILITIES GUIDE
SPECIAL ADVERTISING SECTION

Cambria Lift Station: Rehabilitation of
a steel wet well
The Village of Lombard, Illinois was evaluating the maintenance and
operational costs of their Cambria Lift Station, which was experiencing service
issues due to poor operation of the check valves and inefficient pumps.
Installed in 1989, the steel can lift station had exceeded its service life. During
heavy rain events, the wet well would become filled with solids due to excess
inflow and infiltration which were eventually pumped back to the lift station.
Public Works staff estimated its maintenance at a yearly cost of $30,000 to
$40,000. Rehabilitating the facility was the obvious solution for a reliable
sewer collection system.
Located within gravity wastewater pipelines, a lift station moves wastewater
from a lower elevation to a higher elevation. Within these lift stations is a
storage container called a wet well. When the sewage meets a predetermined
level within the well, a pump or series of pumps discharges the sewage into a
force main which transports it to a higher elevation in the collection system.
Phase 2 of the Cambria Lift Station Rehabilitation was performed under
two contracts with Christopher B. Burke Engineering, Ltd. of Rosemont, IL as
the design consultant.
The first contract addressed a manhole modification, sewer televising and
the installation of a permanent bypass line. The second contract consisted of
the replacement of pumps, piping, control panel, flow meter, and air vacuum
manholes, rehabilitation of the existing steel wet well, and site restoration.

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OCTOBER 2020 | UCONonline.com

Only technologies that allowed minimal reduction of I.D. (inner
diameter) of the wet well were considered in order to allow sufficient
maintenance and operational space for the three new pumps; therefore,
coatings and spray-on linings were initially specified.
The Village of Lombard project manager began to research other potential
rehabilitation technologies. Hobas centrifugally cast, fiberglass reinforced,
polymer mortar (CCFRPM) pipe soon presented itself as an alternate option
that would provide a long-term corrosion-free solution well within budget.
"The Village sought an alternate coating/lining process that would
eliminate the need for cathodic protection and thus reduce maintenance
costs. Through research related to linings/liners that stood up to H2SO4,
CCFRPM came up as a potential fit. By using the Hobas liner, Public Works
would have two benefits, the elimination of cathodic protection and a
long-term service life structural liner," said Ray Schwab, Civil Engineer II,
the engineering project manager for the Village of Lombard.
Cathodic protection is a technique of preventing corrosion of a metal
surface by converting anodic properties of metal to cathodic (a passive
state) through electrical DC currents. A cathodic protection system will
transfer corrosion forming properties from the protected surface to a linked
anode with more active properties, thus corrosion activity is limited to the
anode rather than the protected surface.
Due to its prevalent use to rehab sewers, Hobas was added as an
alternate per an addendum. The Village allotted the Hobas pipe alternative
a $30,000 deduction against the anticipated life cycle cost for cathodic
protection, which would have been necessary for the two spray coating
alternatives (Epoxy/Polyurethane and Structural Engineered Polyurethane).
However, the deduction did not come into play, as the Hobas alternative
was the low bid even without the deduction. John Neri Construction of
Addison, IL was the low bidder utilizing the Hobas option. Construction
began in April of 2019 and was completed in June of the same year.
"John Neri Construction has worked with the Village of Lombard on
numerous successful projects over several years. The rehabilitation of the
Cambria Lift Station was the first time JNC has worked with Hobas as well as
their fiberglass liner product. The depth of the lift station required 33 feet of
110-inch inside diameter (I.D.) pipe to be inserted into the existing 120-inch
I.D. steel wet well. Being that the outside diameter (O.D.) of the Hobas pipe
was 114 inches, it was a very tight installation," said Nicholas Neri, assistant
manager/estimator, John Neri Construction. "Once installed, JNC was
able to core the Hobas pipe to accept the influent and effluent piping.
We were very pleased with the integrity and quality of the Hobas material,
as its assembly and installation couldn't have gone more smoothly."
"The station is performing great since the improvements. Pump failures
due to clogs and faulty check valves have all been eliminated by the
improvements at the station," said Lukas Sharp, water/sewer pumping
supervisor, Village of Lombard.
Since 2010, Hobas has been providing pipe material for the rehabilitation
of wet wells. Rehabilitation of these wet wells via sliplining is ideal due to
lower labor cost, longer life than linings and the elimination of cathodic
protection. *
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Underground Construction - October 2020

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