Newport Terrace Landfill (Continuous Gas Monitoring System) Cal/EPA Integrated Waste Management Board Newport Terrace Landfill (Continuous Gas Monitoring System) Abel Martinez-Centeno May 13, 2005 CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Content Introduction Site Location Background Site Conditions Fill Areas Gas Migration Concerns/Gas Assessment Continuous Gas Monitoring System System Installation/Areas Covered Reports/Results Questions CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Introduction Newport Terrace LF/Newport City Dump # 1 (1953 – 1967) Orange County LEA Requested Investigation Assistance CIWMB Performed Gas Investigation (Jul/01 – Dec/02) Field Results/System Instrumental Gas Migration Status (Structures) Determine Compliance of Facility Structures 20919.5(a)(1) The Newport Terrace Landfill (aka Newport City Dump # 1) was owned and operated by the City of Newport Beach between 1953-1967. The Orange County LEA requested the assistance of the Board to assess the potential of gas migrating to buildings on-site, among others issues. CIWMB performed a gas investigation of structures on-site using a 10-channel continuous gas monitoring system, which operated on a 24x7 basis for 18 months. The field results obtained through the use of the continuous monitoring system were instrumental on the assessment and determination of: Gas migration status and impact of on-site structures, as well as to; Determine compliance of facility structures Section 20931(a), states that monitoring of on-site structures includes but is not limited to buildings, subsurface vaults, utilities or any other areas where gas build up would be of concern. CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Site Location 19th Street & Balboa Blvd. Newport Beach, CA Site is located in the northeast of the intersection of West 19th Street and Balboa Blvd., in Newport Beach. 2. Huntington Beach is located to the east 3. Costa Mesa to the North 4. And faces the Pacific Ocean on the South. CIA SCALE 1:100,000 CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Site Location COSTA MESA NEWPORT BEACH 41-ACRE Site total an area of 41 acres The site is actually located on the City of Newport Beach, for strange that this may appear. The 41-acre site was acquired by the City of NPB in 1953 from the City of Costa Mesa and subsequently mined and land filled. CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Background 1953-1965 Site Utilized for Extraction Aggregate (Asphalt) (Excavations Below WT) 1960-1967 Subsequently Utilized as Refuse Disposal (Refuse Fill & Rubble Fill Areas) 1968-1972 Site Geology & Soil Investigations 1972-1975 Site Developed into Condominium Complex Sand Vent Barrier (1972) Gas Extraction System in Place (1975) The Sully Miller Company under contract with the City of NPB, utilized portions of the site for extraction of materials used in the production of asphalt. Site subsequently utilized as refuse disposal area. In preparation for the site to be developed, several site geology and soils investigations were conducted at the site to determine the earth and foundations work needed prior to development. Ruble fill are will required engineer fill to support structures Refuse fill area will not adequately support residential structures due to material decomposition. Site was developed into a condominium complex in 1972 and was completed in 1975. Engineering controls established at the site include a 15 feet-deep sand vent trench. And a gas extraction and collection system completed in 1975. CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Site Conditions N REFUSE FILL AREA Upon termination of mining operations, excavations at the site were filled inert solid materials, drill cuttings, paper, plastics, glass and metals and grass clippings. Two are predominate at the site, the rubble fill area composed mainly of inerts and drill cuttings, and the refuse fill area where all the other materials went. RUBBLE FILL AREA CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Site Conditions N Engineering controls established at the site included a 15 feet-deep sand vent trench. The gas barrier acted to stop gas moving into the condominiums locate east and west of the refuse area. A gas extraction and collection system was completed in 1975. The gas collection system was installed to extract gas in both areas (rubble and refuse). CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Site Conditions N Site conditions that trigger the LEA’s and Board intervention include: Several gas monitoring probes were exceeding the gas rule at the perimeter boundary, specifically those in the east and south boundaries. However, the use and application of the continuous gas monitoring system was determined necessary due to the presence of “Hot Spot” areas localized among residential structures on the west side of the development. It was originally anticipated that some of this gas may have to be migrating from the Refuse Fill Area, which was lately discarded due to the fact that in the rubble fill area underneath these structures material with the potential to release gas was encountered. AREA OF CONCERN CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Concerns Gas Probe Sand Barrier Refuse Fill Rubble Fill Inert + Drill Cuttings Given that some of the deep monitoring probes and extraction wells near the residences in the west side, showed high concentrations of methane, the use of a continuous monitoring system was deemed necessary to assess structure safety with respect to levels of methane. It was originally assumed that the gas may have been migrating across from the refuse fill area underneath the gas barrier. However, during investigation it was discovered that drill cuttings and other materials with the potential to release methane gases were disposed of in this area. CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Gas Assessment Structures Safety and Compliance w/Methane Gas Rule Assessment – Simulate Worse Case Scenario Statistically Valid Data = Continuous Monitoring System The assessment to be implemented had to be specific and target 3 main issues. Determine Structure Safety with respect to concentrations of methane gas and compliance with SMS. The assessment should be able to simulate the worse case scenario, for example, the gas migration through preferential pathways originated by breaks through the cover and slab-on-grade foundation by utilities, cracks, tree-roots, etc. The data collected should be representative and statistically valid to be able to make a confident determination of the gas occurrences at the site, hence a continuous monitoring system was granted. CIA CIWMB/CIA

Continuous Monitoring System Newport Terrace Newport Terrace/Gas Investigation CIWMB Continuous Monitoring System Data-Logger System Controller The system utilized was a 10-channel continuous monitoring system with hardwire connections Remote sensor (catalytic combustible gas detector), explosion proof with a detection range from 0ppm to 50,000ppm (LEL) in 45 secs. 10-channel controller operated at 120 volts with capability for audio alarms. Data-logger is a battery and 120 volts operated logging system left at site to collect data at any rate specified by user. The collected data is then transferred to a PC that can be connected remotely via modem for display and analysis. Remote Sensor CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB System Installation 1. Assess Structure Safety 3ft bgs Installation of the sensors was done specifically to simulate the case scenario. Gas migration through preferential pathways originated by breaks through the cover and slab-on-grade foundation by utilities, cracks, tree-roots was simulated. A subsurface area that simulates an enclosed space was created by penetrating the first couple of feet of soil and installing a perforated probe. Then, the sensor was hardwired to the controller and logging system for data acquisition. CH4 from Landfill? CH4 from Drill Cuttings? 2. Simulate Worst Case CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Sensor Installation SELECT LOCATION MARK LOCATION TRENCHING BOREHOLE CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Sensor Installation INSTALL PROBE CABLE LAYOUT SYSTEM SET UP SENSOR INSTALLATION SENSOR CALIBRATION CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB System Layout 10 Methane Sensors Installed N Area of Concern 2-acre 24x7 Monitoring Capability This is the general picture of the system utilized at the Newport Terrace Condominiums in NPB: 10-Methane sensors were installed and operated on the west side of facility to assess on-site residential structures The total area covered equals 2-acres and was targeted on the locations with the “Hot Spots” System was operated on a 24x7 basis and during the 18 months of operation, methane was not detected on the areas of study. No CH4 Detected (18 Months) CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Areas Covered CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB System Reports Some of the features that the software is capable of providing include: System set up and configuration Data download (compatible w/excel spreadsheets) Mathematical and statistical analysis of data CIA CIWMB/CIA

Conclusions/Determination Newport Terrace Newport Terrace/Gas Investigation CIWMB Conclusions/Determination Over 1,400 Data Points Collected Daily/Sensor – Reliable Statistical Analysis. No Gas Detected Above SMS – 18 Month Period System Reliable - Site Determined Safe with Respect to Gas Occurrences (2001) Determined that Engineered Fill underneath Condos - Stopping Gas Migrating into Surface (Structures) System Used as Assessment Tool –Dismantled and Made Available for Futures Projects (2002) Some of the high notes about this assessment are: System showed to be very reliable for this application once the system ups and downs were mastered and proper calibration and maintenance was provided. The amount of data collected is definitely very valuable and inexpensive when compared to manual labor of doing monitoring with portable instruments. One of the pluses of this system is the convenience of remotely accessing it to download data and to change its programming. This feature could also be used to alarm or page someone to inform of a high gas level or simple to inform when a sensor got out of whack and needed calibration. CIA CIWMB/CIA

Newport Terrace/Gas Investigation CIWMB Questions ? ? Questions? CIA CIWMB/CIA