Challenge

The City of Phoenix owns several active and closed landfills that require continuous services, including engineering services, environmental protection services, and groundwater monitoring.

Solutions

GLA was awarded with three contracts in 2019 to help with solid waste support on-call services for engineering, environmental protection, and groundwater monitoring. Our team has provided a wide range of services since 2019, ranging from development of future solid waste stations, services for active stations, and post-closure support.

First, we provided development services for four potential locations for the future 27th Avenue solid waste transfer station. Our team began by undertaking due diligence investigations of four potential sites, including site overview, site history, review of zoning and land use restrictions, and records review. Investigations also included fatal flaw analyses. These investigations culminated in due diligence reports laying out conclusions and recommendations, with specific feasibility criteria providing guidance on engineering, operation, and transportation conditions. Our team also produced conceptual site layout drawings showing details of infrastructure location and traffic patterns  for the two sites that scored the highest during evaluation.

Second, GLA has provided services for active sites, including modernization services, gas line, leachate sump, and erosion repairs, and various design services. In particular, our team assisted with the modernization of the 27th Avenue material recovery facility by providing siting, design, and construction of new facilities. Our team began this project by evaluating different options for modernization through site visits and equipment evaluations. Our team produced conceptual design layouts and a feasibility analysis. We recommended three options for modernization: to design and construction a new facility, to refurbish and expand the existing facility, or to build a new recovery area within a pre-existing building at the facility. The City ultimately chose to modify and upgrade the existing equipment based on our evaluation.

Our team has also provided ongoing services at the SR85 Landfill. In addition to landfill erosion repairs and production well assessments, our team has provided design services for Cell 1 and Cell 2, a 19-acre and 22-acre cell construction project, respectively. Our team provided cell design, construction plans, technical specifications, and quality assurance for both of these cell-construction projects. We also attained permitting for two significant modifications to the existing Solid Waste Facility Plan for a vertical height increase and a new landfill fill sequence plan. Lastly, our team implemented a pilot study at the landfill that uses on-site phytoremediation as a sustainable solution to dispose of leachate and condensate.

Lastly, we have provided post-closure support for a variety of sites. Our team has provided detailed budged and liability modeling for the City’s active and closed landfills, addressing annual and future infrastructure, gas, amortization, capping, post-closure, and equipment costs. We have worked on updating Stormwater Pollution Prevent Plans for the City’s closed landfills, and provided landfill gas monitoring and maintenance services.

Results

Our services have ensured the City’s various solid waste facilities remain technically and environmentally feasible while also ensuring that the facilities are upgraded with innovative and durable equipment. We have ensured that the facilities, both active and inactive, can accommodate future growth, buyer contamination expectations, and operational effectiveness and meet all regulatory requirements.

We are proud of our ability to provide on-going services in a variety of areas, demonstrating our company’s wide-range of talents.

— Doug Junk, Project Manager