Water. desalination + reuse

PROJECTS | 24 | Desalination & Water Reuse | February-March 2014 needed to be installed and commissioned. This also meant extensive overall installation time, increased man power to perform start-up checks, consideration for more commissioning spare parts, and a higher number of overall part failures upon start-up. The modular blocks of electrical equipment were prefabricated, installed in containers and shipped to the site in Trinidad. Inside the electrical containers, cables were installed and wiring complete and terminated as much as possible. Longer project cycles resulted in larger electrical and mechanical equipment blocks being designed for the Randolph E Harley and Estate Richmond Power Plant SWRO facilities. These relatively larger pieces of equipment, however, meant fewer pieces were needed to install and commission. Both the modular design and the larger equipment posed installation challenges. When the modular units were prefabricated and installed in containers, the weight of the containers with the installed equipment still required large-sized cranes and forklifts, as did the installation of the larger block electrical and mechanical equipment. At the Point Fortin site, onsite space constraints made the installation of the containers and equipment difficult. However, the overhead access allowed equipment and containers to be lifted and lowered in to place. The challenge at the Randolph E Harley and the Estate Richmond Power Plant facilities was to place the larger- sized equipment inside the building, with no overhead access to lift and lower the equipment into place. The equipment was moved into the building and placed using trolleys, large forklifts and short- boom cranes, where possible. PREfabRiCaTing and PRETESTing PRiOR TO SiTE A practice that is commonly employed is to skid, prefabricate and pretest a piece of equipment or system when possible. This reduces onsite construction, installation and commissioning time and resources. Using this design practice was particularly advantageous at the Point Fortin and St Croix sites. At Point Fortin, the prefabrication of the skidded and smaller module equipment blocks resulted in easier installation. The number of cable pulls, wiring terminations, pipe runs, pipe joints, FRP field wraps and leaks was minimized. In addition, the amount of time required to troubleshoot issues onsite was reduced by pretesting equipment prior to deployment. The same efficiency was seen at the Estate Richmond Power SWRO facility on St Croix. Prefabrication and pretesting of all the MMF vessels, pipe racks, and controls proved successful. As soon as the equipment was placed, secured, and media loaded, the equipment was ready for operation. In contrast, the MMF pretreatment system equipment was not pretested or set up at the Richmond E Harley Power Plant SWRO on St Thomas, and it required more effort and resources onsite. inTakES Seven Seas Water was required to construct a new intake pump-house for the SWRO facility in Trinidad. It was built 450 m offshore with a jetty walkway out to it and an attached electrical room. Construction of the intake pump house was particularly challenging, as it required an offshore barge to complete the work. Harsh sea and weather conditions played Overview of the SWRO plant at the Petrotrin Marine Terminal Facility in Trinidad

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