Resolving Oil Pollution Abatement Problems in the U.S. Fleet
Wavelengths: An Employee's Digest of Events and Issues (NAVSEA Carderock)
By Leslie Spaulding
PHILADELPHIA-For the past five years, high capacity oil/water separators (OWS) have been installed on the Fleet's larger platform ships, such as LHAs, LHDs, and CV/CVNs. These systems were integrated with pre-existing oil pollution abatement (OPA) systems using guidelines from previously installed surface combatant OPA installations. However, tank and piping configurations onboard large hull classes can differ significantly and present unique integration problems.
Numerous design, integration, operational, reliability, and maintenance issues associated with this higher capacity OWS have been identified and documented by the Environmental Quality Systems In-Service Engineering Branch (631). These systems, known as the C-50 and C50/RF01 OWS, have also shown that many OPA system and subsystem designs that appear viable on paper actually become problematic when installed and operated on ships.
Complicating the situation was the Navy acquisition of a commercial-off-the-shelf oil content monitor (OCM), that was being installed on large platform ships at the same time of the OWS installations. This monitor also presented very significant reliability problems.
"The Navy was using an oil content monitor and an oil water separator that were essentially commercial-off-the-shelf equipment with little at-sea time," said Code 631 branch head, Rick Ruediger. "The ships started to immediately have significant certification problems, and ultimately operational reliability problems. The separator had a number of components that didn't hold up in the marine environment."
Ruediger continued, "While we continued to go onboard the ships to certify the installations to ensure the ship could operate the systems within the NAVSEA certification requirements, we continued to discover problems associated not only with the separators and the monitors but with the integration of those equipments with the rest of the system, including oily waste holding tanks (OWHTs) and tank level indicators, receivers, and switches. The alteration put the equipment on the ship and piped it up to those systems. It didn't really integrate it with the rest of the system."
Complicating the matter further was the fact that these separators use vacuum- pumps that draw the fluid through the separator. The plates in the separators also require cleaning approximately every six months, which poses a problem for the Fleet Sailor. Once the cleaning process was complete, the Sailor would have to reseal the separators properly for the vacuum to work. In many cases, the OWS system gaskets were failing before the OWS was ever taken down for routine maintenance.
The aircraft carrier community (COMNAVAIRLANT/PAC) nominated the system for top management attention/top management issues (TMA/TMI). This brought significantly more attention to the problem and enabled resources to be made available to address the problems more rapidly. In response to the Fleet problems, SEA 05M4 direction and the TMA/TMI working group, Code 63 proposed changes to the system to make it much more reliable without impacting the overall performance of the system. Although the changes to the systems in the Fleet were originally programmed for installation in POM 04, NAVSEA requested Code 631 to build a test site to prove the changes would work. Planned installations of these modifications would not be formally programmed until successful demonstrations of these changes were completed.
"We were tasked to build a test site and conduct tests in the laboratory to determine if our proposals would work," said Ruediger. "Additionally, SEA 05M4 and 05MR tasked Code 63 to execute three shipboard demonstrations on the LHD 1, CG 47, and DDG 51 Classes." These shipboard demonstrations will follow the land-based laboratory T&E of the system improvements in FY 03.
Oil Pollution Abatement Test Site
The Oil Pollution Abatement Test Site, located in Bldg. 1000, was designed as an integrated oil pollution abatement system rather than simply an oil/water separator installation. It integrates the oil/water separator and the oil content monitor, all the control valves, and the self-cleaning strainer-all designed to reduce overall system maintenance and interface from the Fleet Sailor to reduce the manning requirement. It also incorporates alternative tank level switch technology. The entire system is being controlled by a programmable logic controller (PLC). The PLC will essentially handle the full operation of not only the separator, but the flows from the oily waste holding tanks to the separator, direct transfer of bulk oil from the oily waste holding tank to the waste oil tank and all associated valves and even the OCM to a certain degree.
"We have also designed in a bypass, so we no longer process bulk oil through the separator," said Ruediger. "There's no reason to process oil that's already separated. This has never been done before. Usually everything just flows through the system."
Ruediger explained the separation process: "Essentially, the separator is a series of parallel plates typically with 1/4-inch gaps between them. In water, the oil droplet only has to rise a fraction of an inch for it to be separated out. In normal operation, we process from the oily waste holding tank, which has fluid that is being generated across the ship in bilge pockets and transferred by pumps to the oily waste holding tank. In the oily waste holding tank, you get some natural separation. An oil level is on top, and an emulsion layer is in the middle. At the bottom is a water layer with small oil droplets in it. This is the layer we want to try and process through this technology."
The test site is versatile. "The beauty of the test site is that we can take this oil/water separator out and replace it with any other one," said Ruediger. "The site really enables us to do the same kind of evaluation with any primary treatment technology that we want to employ."
The test site was designed by Mary Lee, Karen Shull, Kevin Neaves, John Maloney, T.J. Nesbitt, and project engineers Stephen Hopko and Steve Lehman, who deserve a lot of credit, (all Code 631). Code 63's contractor, GeoCenters, particularly Brian Trees, provided significant help in developing installation drawings and assisting in the C-50 test site design. GeoCenters also assisted in the development of the PLC, which has been turned over to the PLC designer/programmer, Bob Morsa (9556). The C-50 test site was built by Code 914 shop members: Irving Lamb, Walter Reed, Andrew Law, Michael Mallory, Gerard O'Keefe, Edward Berchik, Paul Jones, Richard Amaral, Craig Ercolani, Michael Sweeney (supervisor), William Citino (planner/ estimator), David Freshcoln (supervisor) Nazzarenvo Tomasetti (electrical engineer) and Larry Simons (631). Special thanks go to Ben Pigg (914), who participated throughout the construction evolution. "The shop got us through heavy mission readiness panel requirements," said Ruediger. "They deserve a lot of credit. It was a tight schedule. Robert Schepis (631) and the Philadelphia Public Works Center (PWC) were also key in getting the site through the mission readiness panel."
Under the guidance of team leader Tony Morales (631), Hopko, Maloney, and Lehman began testing at the Oil Pollution Abatement Test Site in May, shortly after passing the mission readiness panel. During the month of July, Code 631 engineers tested three pumps in a total of four configurations for their ability to transfer fluids from the OWHT to the OWS under variable tank and flow rate conditions (variable flow rate is a beneficial new design feature for these OWS systems). This testing was part of the pump selection phase of the overall system testing. Additionally, as part of the pump selection test phase, they quantified the impact of using a particular pump upstream of the OWS by measuring and comparing the OWS performance response (OWS effluent quality or oil content) when injecting different oil concentrations and oil droplet size distributions upstream of the pump. Based on these tests, Code 631 determined that the OWS could definitely be made into a pressurized system, eliminating the need for a vacuum and the maintenance problems associated with it.
During August, a Division-developed in-situ cleaning process is being tested. This method, developed by Codes 632, injects air and a bioaugmentation product, allowing the Sailor to clean the unit without taking it apart. Key to installing this process in the C-50 units are Steve Verosto and Mario DiValentin (both in 632), under the guidance of Mary Jo Bieberich (632), and Larry Murphy and Toby Cole (both in 634), under the guidance of Peter McGraw (634).
"We hope to extend the life of the unit substantially through this cleaning method," said Ruediger. "This cleaning method requires that we modify the internals of the separator slightly. We're testing that design this month, and hopefully we will be able to integrate it in future system designs. That will be a major reduction in maintenance costs."
In September, Code 631 will be conducting PLC testing, as well as all the interface testing with various tank level indicator technology. The tests will include proofing-in the controller design and programming-all the "what if" scenarios. Once the PLC portion of the testing is complete, Code 631 will be operating all the other components to do the reliability and meantime between failure testing, cycling for thousands of cycles to ensure that the meantime between failure exceeds a typical deployment schedule.
Finally, an installation on USS Wasp (LHD 1) is currently planned for November. Following her availability, she will deploy, and the system will get its first true at-sea test.
"During the availability, we'll be assisting the Norfolk Naval Shipyard in the design and installation of the system," said Ruediger. "Before she leaves, we'll do a final debugging of the PLC-any kind of interface problems we have with signals on the ship that might not have been detected in the lab."
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