Installation of stainless steel spot liners and grouting into a deep ocean wastewater treatment plant outfall
After an international solicitation could not produce an acceptable means of repairing leaks in a deep ocean outfall, ASI was contracted to repair three deepwater leaks in the Ponce Regional Wastewater Treatment Plant Deep Ocean Outfall, located at Ponce, Puerto Rico. These repairs were conducted using an ROV to place spot repair liners inside the outfall pipe to cover the joints that were indicated to be leaking.
The purpose of the spot repair liners is to seal the pipeline at those locations to prevent leakage of treated effluent at those joints; not to structurally enhance the pipeline or stabilize the joints. Spot repair liners and repair methodology was based on the worst case presented in documents, which indicated a vertical joint deflection of 10.9 degrees. ASI designed and fabricated an alternate version of the spot repair liner that could articulate between 0 and 12 degrees to accommodate any deflection up to that amount.
Trials were conducted at ASI’s indoor ROV testing tank to verify equipment and methodology by the same technicians who would complete the installation in Puerto Rico. ASI’s thorough review of the project and verification of equipment and procedures were completed to ensure a successful installation of the spot repair liners and sealing of the leaks.
The spot repair liners were installed using an ROV, over two of the three joints. Due to an undocumented piping offset, the spot repair methodology was not applicable for one of the leak sites. Alternatively, an external repair cannot be done and deep diving (saturation) technology cannot be utilized to perform an internal repair. ASI was further contracted to repair this joint internally using ROV deployed technology with a grout injection methodology specially designed to accommodate the conditions at the joint.
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