The Rota Power Plant Site is an active diesel-powered electrical plant where contaminated soil and groundwater are present.  The contaminants of concern at the Site are polychlorinated biphenyls (PCBs) in soil and petroleum hydrocarbons in groundwater.  The Site is located in Songsong Village on the island of Rota in the Commonwealth of the Northern Mariana Islands (CNMI). The power plant sits approximately 100 feet from the shoreline of the Philippine Sea. EPA is addressing the PCB contamination by excavating the contaminated soil and shipping it off-island for disposal.  The estimated clean-up volume is 200 cubic yards.

Operations at the site include the generation of power for the island of Rota, storage of new and used oil, and oil/water separation. The Rota Power Plant site contains four primary aboveground storage tanks (ASTs) as well as day tanks and drum and transformer storage areas. There are two oil/water separator (OWS) systems are located at the Rota Power Plant site. One rudimentary OWS consists of drums from which oil is manually skimmed. The system is located inside the main Power Plant building and drains to the north of the building into a pit. A second in-ground OWS is piped from the secondary containment areas of the ASTs and the drum storage berm located in the western portion of the property. This OWS can hold 2,500 gallons of oil and water and discharges separated water directly to a pit dug in the ground.
 

In addition, there are several current and former transformer storage areas where PCB-laden transformer oil may have leaked onto the soil.

MONDAY June 2, 2014:  Personnel on-site: EPA – 2, START – 1, ERRS – 8, SEARCH – 1:  Work on the trench segment #1 continued, excavation to depth was achieved.  A welder was brought on site to cut the 1” trench plate so that it was easier to manage in the trench.  The crew set up a new area with silt fence for the trench rock backfill, which was awaiting delivery.  ERRS began excavation of trench segment #2, without the shoring box system, and the archeologist identified some pottery and a small piece of human bone.  Excavation work was halted and the crew wrapped up with other tasks while the archeologist began documentation and further investigation of the area in question. A small group stayed with the archeologist to assist while she continued exploration and documentation. The archeologist and OSC Rogow informed HPO about the discovery, and awaited response on the data collection proposal.  One strand of sorbent boom was moved to around the contaminated soil pile.

TUESDAY June 3, 2014:  Personnel on-site: EPA – 2, START – 1, ERRS – 8, SEARCH – 1, USCG - 1:  The archeologist requested additional time in the morning to continue investigation work, so a smaller group was brought in to work with her.  The OSC and archeologist coordinated with HPO, both on Rota and Saipan.  Archeological investigation continued until mid afternoon, with assistance from Rota HPO.  ERRS installed silt fence in preparation for the rock arriving.  The RM continued to coordinate with the quarry regarding the washed rock and they were still working on repair of the washer.  Unwashed rock was delivered to the site, and ERRS began washing operations.  In the afternoon, excavation of trench segment #2 was able to continue. 

WEDNESDAY June 4, 2014:  Personnel on-site: EPA – 2, USCG – 1, START – 1, ERRS – 8, SEARCH – 1, RT&T - 3:    ERRS continued working to remove the coral substrate in trench segment #2.  The seal on the hammer was displacing and the crew worked on that at the beginning of the day.  The RM worked with Hawthorne Equipment (the heavy equipment subcontractor) to determine a solution for the hammer.  OSC Musante and the RM went to the quarry to check out the washed rock and approved of it for use on the site.  The quarry began washing operations, but no washed rock was delivered to the site by the end of the day.  A subcontractor was brought on site to help assist with rock washing.  START began sampling of the groundwater wells, with the assistance of USCG and ERRS.  By the end of the day, 3 wells were sampled.  Trench shoring box #2 was set by ERRS. 

THURSDAY June 5, 2014:  Personnel on-site: EPA – 2, USCG – 1, START – 1, ERRS – 8, SEARCH – 1, RT&T - 3:    START continued and completed groundwater sampling and prepared samples for shipment.  ERRS dug out slough from the two trench boxes and set end plates.  It was determined that another one of the steel plates needed to be cut, so arrangements were made for a local welder to provide that service.  Available washed rock was placed in the trench segment #1, and it was not enough.  The quarry was supposed to deliver washed rock in the morning, but 2 truckloads of washed rock came towards the end of the day.  The trench box #1 was lined and filled with rock.  Laborers on site continued to hand wash rock for the trench.  OSC Musante and the RM went to the quarry to see if there was any way that we could assist in more efficient rock washing operations.  The first set of TPH data came back on the overburden stockpile samples.  All TPH data was below action levels and suitable for reuse as backfill.   

FRIDAY June 6, 2014:  Personnel on-site: EPA – 2, USCG – 1, START – 1, ERRS – 8, SEARCH – 1, RT&T - 3:   START sent out water samples.  ERRS continued work on trench segment #1, placing rock and removing part of the trench box #1.  They cleaned out trench segment #2 and began work on removal of overburden and then coral substrate in trench segment #3.  Local labor assisted with rock washing and cutting of steel plate.  No washed rock was delivered today, but washing operations continue at the quarry.  Archeological monitoring continued. 

SATURDAY June 7, 2014:  Personnel on-site: EPA – 2, USCG – 1, START – 1, ERRS – 8, SEARCH – 1, RT&T - 3:   ERRS completed the excavation of coral substrate in trench segment #3 and set trench shoring box #3 in place.  They also installed geotextile and plastic liners in trench segment #2 and set a sump riser pipe, stabilizing it with rock backfill.  Local labor assisted with rock washing and two truckloads of washed rock from the quarry were delivered.  Archeological monitoring continued.  START set up the water treatment system and completed treatment of water from monitoring well sampling operations.  OSC Rogow coordinated with Archeologist regarding identified items.

SUNDAY June 8, 2014:  DAY OFF