ROPEC – Emergency Temporary Pumping System


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ADDITIONAL PHOTOS:

Project Type: Heavy Civil - Waste/Water

Project Stats:

  • Emergency work while facility still functioning

Project Information:

Contract type: General Contracting
Completion: March 2014
Owner: City of Ottawa
Mech/Elec: JL Richards



The construction management of the Emergency Temporary Pumping System at the ROPEC Raw Sewage Pump Station.  This emergency project was completed in an existing facility while the facility remained in operation.  All areas of work had to be well isolated and marked/identified whether indoors or outdoors, to delineate construction zones. Phase one included the removal of the existing corroded pipe flares from the effluent chamber. The roof components of the effluent chamber had to be cut and removed in order to gain access to the chamber, and the existing pipes were cut to remove the pipe flares. Once the roof components were removed, the odours of the effluent chamber were open to the atmosphere and a grating had to be fabricated as workers required a platform to work from. This grating not only supplied a movable platform for the workers, it allowed the steam created from the warm effluent mixing with the frigid winter air to vent and allow workers to work within the chamber. At the end of each work day, a steel plate was installed over the grating which minimized odour escape during non-working hours. As the discharge pipes into the effluent chambers are normally in use, coordination and safety lock-out protocols had to be created to shut down the appropriate discharge piping and ensure worker safety.

The second phase involved the installation of four 600mm bypass pipe lines with four temporary pumps. This installation included two 335HP and two 240HP pumps with starters in weatherproof enclosures, connection of electrical and control wiring to starter/VFDs, completion of on-site locates for all existing utilities and infrastructure, installation of temporary piping, valves, air release, couplings/joints etc. from final pump locations to the existing sewage flume channel, connection of pumps to the new temporary electrical system, installation of permanent power along with testing, startup and commissioning of pumps and transformer. Four 600mm discharge lines were installed to discharge from the pumps within the raw Sewage Pump Station wet wells to an exterior existing sewage flume channel 300m from the building. The interior portion of the 600mm bypass lines were installed in a very restricted area in the lower levels of a Raw Sewage Pump Station that required routing around existing columns, pipes, mechanical screens, and heaters. An access opening needed to be cut into the foundation of the building in order to get the pipe lengths into the building. The interior pipe was carbon steel that was prefabricated in the mechanical contractors shop and delivered to site and welded in place. Because there was only one gantry crane within the Raw Sewage Pump Station, as much work as possible was fabricated in the shop to keep costs down and to minimize the bottleneck of the site crane. All of the interior pipe work within the basement level was restricted access, and the installation of the pumps, bases, electrical cable, and vertical piping within the lower level wet wells was confined space. A site specific health and safety plan was created, and daily health and safety talks were held with the site superintendents and sub trades to review all operations and conditions on site. There were no health and safety incidents on site. The exterior portion of the 600mm bypass lines were installed in winter conditions and had limited ground cover. The discharge lines ran in parallel and created a 12 foot wide channel which had to navigate existing gas lines, water lines, abandoned tunnels and foundations, and existing services, while maintaining .5% slope to drain back to the wet well when the pumps are not in use. Because of the draining requirement, the pipe run could not simply route over obstructions as this would create sumps within the pipe, so routing was very critical. Locates and test pits were used to verify obstructions and plan in the routing of the pipe. Both the interior and exterior piping was completed in parallel and connected seamlessly at the designated entry point of the building.

The third phase of the work included the removal, transport, refurbishing, testing, re-installation, and commissioning of an existing 900 hp motor. This motor work was removed early on within the program and the refurbishing was completed while all of the other contract work was being completed.

The emergency project commenced on January 27, 2014 and received Substantial Completion on March 28, 2014 in advance of the spring melt. The project was on time and under budget.