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 addressed the PCB contamination by excavating the contaminated soil and shipping it off-island for disposal in 2013.  The CERCLA (PCB) portion of the site was completed in July 2013.  This POLREP addresses the OPA portions of the response action, aimed at addressing oil seeping into the ocean.   

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.
  

MONDAY June 30, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 0, ERRS – 7, APEC - 1, SEARCH - 1.

OSC Reiner demobilized.  ERRS Coury and Howe demobilized, ERRS Malin (APEC) arrived on site from Guam.  USCG Knight demobilized. Five shipping containers of contaminated soil for shipment to the US Mainland were transferred off site.  ERRS continued excavation of recovery trench segment 1 and removed overburden and set up shoring for excavation segment 2.  Coral was extremely hard and no oil observed in trench segment 1. ERRS started removal of overburden in interceptor trench segments 13 and 14, but overburden removal was halted due to discovery a concrete pillar. The archeologist discovered and processed a human femur (thigh bone) recovered from the overburden of recovery trench segment 2. Hawthorne’s mechanic was on site and repaired the forklift and the loader. A subcontractor delivered three loads of washed coral to the site for trench pack.

TUESDAY July 1, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 1,  ERRS – 7, APEC - 1, SEARCH - 1.

START Schwennesen arrived on site.  SEARCH archeologist departed site at 9:00 AM today. ERRS completed excavation of recovery trench segment 1 and started on segment 2.  Coral was soft in segment 2 and oil started to appear in trench.  ERRS started to prepare for concrete pads around manway and built, placed and leveled wooden forms. SEARCH archeologist investigated the concrete pillar and in the process discovered a second and a building floor in between the pillars which were determined to be remnants of a Japanese building. SEARCH archeologist and the EPA will work to resolve issues with the building remnant to determine if the interceptor trench excavation can be installed to its full extent or whether it has to be truncated. In addition, a subcontractor delivered three loads of washed coral to the site for trench pack.

WEDNESDAY July 2, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 1,  ERRS – 7, APEC - 1, SEARCH - 0.

SEARCH archeologist off site. ERRS backfilled recovery trench segment 1 with crushed, washed coral to above the water table, installed a sump within the segment and covered crushed coral with filter fabric.  ERRS completed excavation of recovery trench segment 2 and removed overburden from recovery trench segment 3. Note that overnight, very little oil accumulated in segment 2 prior to the initiation of trenching in the morning.  START collected three stockpile samples (SP-26, -27, and -28).  Five ~30-gallon drums and/or clumps of a black, tar-like substance were removed from the recovery trench Box 3 overburden, and were set aside pending determination of disposition.

THURSDAY July 3, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 1, ERRS – 7, APEC - 1, SEARCH - 1.

SEARCH archeologist return on site (approximately 2:30 PM). START received analytical results for waste materials for interceptor trench segments 8 and 9 which showed that TPH levels are below site action levels. ERRS started work at 8:30 AM due to delayed arrival of analytical results.  ERRS set up shoring, and initiated and completed rock breaking and excavating in recovery trench segment 3. One to two feet of soft coral was encountered, beneath that a coarse sandy matrix with cobble and gravel fragments for the entire trench segment. In fact, the sand in segment 3 heaved at the bottom of the trench precluding achieving the target depth of 16 ft, therefore a depth of 14 ft was achieved. Oil started accumulating in the trench and diesel odor was much stronger than that observed in previous segments. During the rock breaking of recovery trench segment 3, oil sheens were observed on the water proximal to diesel-impacted beach front.  START shipped 3 stockpile samples.

 FRIDAY July 4, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 1, ERRS – 7, APEC - 1, SEARCH - 1.

Overnight a significant amount of brown-colored diesel had accumulated into recovery trench segment 3. ERRS over-excavated recovery trench segment 3 for ten feet and determined that we still in the sandy zone, at which point it was decided to prepare for the install of segment 4.  Removed overburden and set shoring. ERRS also removed the sump from recovery trench segment 2, then backfilled and compacted trench segment 2 with overburden to above the water table--effectively abandoning recovery trench segments 1 and 2 for oil recovery purposes due to low oil recovery potential. Additionally, ERRS backfilled recovery trench segment 3 with crushed, washed coral to above the water table, installed a sump within the segment and covered coral with filter fabric.

SATURDAY July 5, 2014:  Personnel on-site: EPA – 1, USCG – 1, START – 1, ERRS – 7, APEC - 1, SEARCH - 1.

ERRS completed excavation of recovery trench segment 4. The coarse sandy zone ended approximately half way into this segment as the material graded from soft to moderately hard coral at depth towards the north. Segment 4 did not have as much oil inflow as segment 3, nor was the diesel odor as strong. ERRS backfilled recovery trench segment 4 with crushed, washed coral to above the water table. ERRS also placed excavated, clean coral and overburden on top of the filter fabric in recovery trench segments 1& 2 and compacted and completed to grade. In addition, ERRS, on the advice of the SEARCH archeologist, placed two feet of overburden on the building floor south of the interceptor trench and resumed excavation of interceptor trench segment 13. There was a film of oil in the trench, and the fluids had the distinct diesel odor.  A tropical storm impacted the island causing high winds, high surf and ocean levels. This broke the boom and washed it ashore; the boom will be replaced when conditions return to normal.

SUNDAY July 6, 2014:  DAY OFF