ES Projects

Los Reales Landfill

  • Objectives
    To ensure the safety of the public and the environment by monitoring, managing, and controlling landfill gas, deep soil vapor and groundwater quality for the unlined portion of the landfill.
  • Location
    5300 E. Los Reales Rd.
  • Waste Acreage
    283.5 (lined and unlined portions of the landfill)
  • Operation Dates
    1967-present
  • Status
    Active Clean-up Site
  • Type
    Groundwater Protection Project
  • Annual Budget
    Approximately $260,000
  • Contact
    City of Tucson - Environmental Services 520-791-3175
  • Description
    Los Reales Landfill is an active municipal solid waste landfill located near I-10 and Craycroft Rd. The site is regulated by the Arizona Department of Environmental Quality’s (ADEQ) under the Solid Waste Unit, the Water Quality Assurance Revolving Fund (WQARF) program and the Voluntary Remediation Program (VRP). Groundwater contamination of tetrachloroethene (PCE) and trichloroethene (TCE) above regulatory standards has been detected along with other volatile organic compounds (VOCs) at concentrations below regulatory standards from the older, unlined portion of the landfill. The City is operating a groundwater pump and treat system to contain and cleanup the contaminated groundwater. Treated water is used for dust control and is also re-injected into the groundwater. The City is required to report the amount of groundwater extracted annually to the Arizona Department of Water Resources (ADWR). The City entered the VRP program for the remediation and closure of the Southwest Disposal Area (SWDA), an area of the landfill which accepted industrial waste from 1977 to 1980. The City briefly operated a deep soil vapor extraction system at the SWDA to remove VOCs to prevent vapors from contaminating groundwater. Methane extracted from the landfill gas system is sent to Tucson Electric Power Company and used to provide electricity to the community.
  • Additional Info
    Although groundwater contamination has been detected above regulatory standards, there are no Tucson Water drinking water wells nearby. The City monitors three downgradient private drinking water and irrigation wells during routine monitoring events for landfill impact.
  • Activities
    Groundwater Monitoring, Landfill Gas Control System, Landfill Gas Remediation (soil vapor extraction), Groundwater Remediation
  • Last Update
    Wednesday Jun 8, 2022
View this project on the Environmental Management Projects Map

Project Details

Status Updates

  • January & July
    The City collects samples from approximately forty-two groundwater extraction wells, monitoring wells and private production wells semi-annually during these months. Samples are collected monthly from the groundwater treatment system. Semi-annual monitoring reports are prepared to document the results.
  • February 2015
    The City submitted the semi-annual groundwater monitoring and treatment system progress report for July-December 2014 to ADEQ and ADWR. Since 2000, the groundwater pump and treat system has removed 25.66 pounds of PCE and 9.5 pounds of TCE. The results are documented in the annual report, which is provided in the report/attachment section of this website.
  • July 2012
    The City submitted request to modify the remedial action plan to ADEQ for approval. The modification would allow the City to cease groundwater extraction in areas with limited off-site plume movement but continue to extract and treat groundwater in areas with significant off-site plume movement. ADEQ approval is pending.
  • February 2012
    The City installed a new groundwater extraction well to replace a well that failed. The City connected an existing monitoring well to the extraction system to help provide additional containment.
  • March 2008-July 2010
    The City installed four groundwater extraction wells to replace older wells that have failed and no longer contain the plume. In addition, the City installed three new wells and associated infrastructure to connect to the groundwater pump and treat system to prevent off-site migration of the plume.
  • June-October 2007
    The City installed infrastructure to connect seven additional groundwater extraction wells to the groundwater pump and treat system to control and reduce off-site migration of the plume.
  • May 2003-October 2007
    The City intermittently operated a soil vapor extraction system (SVE) at the SWDA to remove deep soil vapor VOCs contaminating groundwater. The system is no longer operating; however the City monitors the vapor wells peroidically and will return the SVE system to operation if needed. As of 2009, the SVE system has removed approximately 465 pounds of VOCs.
  • March 1999-Present
    Operation of the groundwater treatment system. As of December 2010, the system has treated approximately 254 million gallons of groundwater and removed 15.4 lbs of PCE and 5.38 lbs of TCE.
  • April 1999
    Los Reales Landfill was placed on the WQARF Registry, designating the area as a State Superfund Site.
  • June 1995-March 1999
    The City constructed wells, piping, electric and other infrastructure for the groundwater pump and treat system.
  • 1995-1998
    The City installed shallow landfill gas monitor probes to monitor methane concentrations between the landfill and nearby businesses and began routine monitoring.
  • April 1995
    ADEQ WQARF approved the groundwater pump and treat system to clean the groundwater.
  • September 1994
    The City completed two studies to evaluate the best strategy to clean up and contain the groundwater contamination. The best strategy identified was a groundwater pump and treat system.
  • October 1991
    The City completed the site investigation which fully defined the plume of VOC impacted groundwater extending northwest approximately a quarter of mile from the northwest corner of the landfill.
  • August 1988-December 1990
    Additional groundwater monitor wells were installed and sampled to define the extent of the VOC plume.
  • August 1988
    VOCs were detected in the groundwater monitor wells along Los Reales Rd.

Pictures

Soil vapor extraction system at the Southwest Disposal Area. The system removes VOCs from the deep soil sub-surface air to prevent the vapors from contaminating groundwater.

Inside the groundwater pump and treat building. Water is pumped from groundwater wells to this compound where it is air stripped to remove the Volatile Organic Compounds (VOCs). The VOCs in the air is then scrubbed by activated carbon.

View of the energy to gas project compound at the Los Reales Landfill. Gases are extracted from the waste and brought to this compound prior to being piped to Tucson Electric Power.

Drilling new groundwater extraction well. Picture of drilling rig.

Picture of city hydrogeologist logging soil samples collected from drilling new groundwater extraction well.

This is one of types of groundwater extraction well vaults at Los Reales Landfill. Groundwater is extracted from one of these type of wells and pumped to the treatment compound where Volatile Organic Compounds (VOCs) are removed.

Attachments

  • Evaluation of Remedial Strategies Part II

    The City of Tucson Environmental Services retained consultants Montgomery and Associates to evaluate groundwater remediation strategies and provide recommendations for future operations. This document is a revised report to clarify items as requested by ADEQ in a letter dated December 28, 2012. The text, figures, and Appendix E to the report are available at this link. For the full document contact, Environmental Services office at 520-791-3175.

  • Evaluation of Remedial Strategies

    The City of Tucson Environmental Services retained consultants Engineering and Environmental Consultants, Inc and Montgomery and Associates to evaluate groundwater remediation strategies and provide recommendations for future operations. This document presents the results of this evaluation.

  • 2018 Annual Report

    This report summarizes groundwater monitoring, groundwater treatment system progress and performance, and soil vapor extraction performance for 2018. The text, figures, and tables to the report are available at this link. For the full document contact Environmental & General Services at (520) 791-3175.

  • 2019 Annual Report

    This report summarizes groundwater monitoring, groundwater treatment system progress and performance, and soil vapor extraction performance for 2019. The text, figures, and tables to the report are available at this link. For the full document contact Environmental & General Services at (520) 791-3175.