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Expert Interviews

Christine Mejia Arbogast Discusses Meeting the Needs of the Solid Waste Industry

Headshot of Christine Mejia Arbogast

Christine Mejia Arbogast has more than 35 years of solid waste planning, permitting, and engineering experience. She has directed long-term solid waste strategic planning studies for major metropolitan and small public solid waste management agencies. 

She has assisted solid waste system owners and operators through the process of facility development, from initial planning and permitting to design and construction support, facility closure, post-closure maintenance, and redevelopment. She also manages large, multi-discipline, on-call solid waste contracts that include a wide range of services in support of traditional solid waste facility development, as well as evaluation and design of next generation solid waste facilities.  

Christine is Tetra Tech’s Unit President for Solid Waste West and coleads our Solid Waste Solutions Growth Initiative. Her recent work has focused on helping solid waste system managers meet new requirements for diversion of organic waste from landfills and the assessment of financially and environmentally sustainable solid waste management practices. Her work has included evaluation of landfill capacity optimization options, waste diversion and organics management programs, renewable energy and conversion technologies, and food waste recycling and prevention programs. Ms. Arbogast also managed an award-winning landfill redevelopment project in Mountain View, California, and supported an outside consultant on an award-winning solid waste management plan for the County of El Dorado, California. She holds a bachelor’s degree in Civil Engineering from California State Polytechnic University, Pomona and is a California Registered Civil Engineer.


How has solid waste management evolved in the last 20 years?

Twenty years ago, our clients were primarily focused on safely disposing of waste in landfills, building liner and cover systems, and establishing programs and infrastructure to protect the environment from potential impacts from landfilling. While this is still an essential function of solid waste system operators, new regulations are encouraging highest and best use of material resources and the incorporation of renewable and conversion technologies into solid waste systems. Mandates to divert waste from landfills and to more effectively control landfill gas emissions have resulted in the solid waste industry moving from a simple linear model of waste collection and landfill disposal to a more circular approach that incorporates waste reduction, reuse, recycling, and waste conversion to renewable products. This progression to a sustainable solid waste management model takes time, as local governments must reconcile the high cost of new diversion practices and innovations with the low cost of traditional landfilling.


What drivers and factors are affecting the way solid waste is managed in the United States?

Like many industries, regulations and economics are driving change. With recent climate change legislation focusing on reducing greenhouse gas (GHG) emissions, control of methane gas—a potent GHG—in landfills has been a huge driver for organics diversion.

Another major development is China’s tightening of standards for contamination levels in imported recyclables. Historically, most recyclable materials collected in the United States have been shipped to China for recycling. This policy requires improved collection programs, including greater public outreach and education. There also will be a need for material recovery facilities that further reduce contamination, and we will need more local markets for recyclables.

On the economic side, solid waste management continues to be a highly competitive industry.  Landfill disposal costs remain low in many parts of the United States, and establishing competitively priced waste diversion programs and associated infrastructure is challenging without new regulatory drivers or mandates. Siting and permitting landfill expansions or new landfills is difficult and costly. This results in solid waste system operators preserving their landfill capacity by diverting waste and exploring alternative waste management technologies. As waste flows decrease with more diversion, solid waste managers are considering other revenue-generating opportunities at their landfills—for example, solar projects on closed landfills and landfill gas to fuel and electricity.


What innovations do you see in the industry to address changes in solid waste management?

For years now, landfill diversion programs in the United States have focused on traditional recycling of glass, metal, and paper. With the diversion of organic waste now becoming more of a focus, solid waste system operators are challenged by the lack of infrastructure and markets for recycling or repurposing of organics, particularly food waste. To meet new diversion goals, our clients need innovative programs and infrastructure to process and repurpose diverted waste.

Our clients are looking at composting facilities that convert organic waste to soil amendments to be used in agriculture, nurseries, road construction and maintenance, and urban landscapes. They are considering anaerobic digestion facilities, which use microorganisms to break down organics into compost and generate biogas that can be used as a renewable energy source. Co-digestion at wastewater treatment plants is a lower-cost anaerobic digestion option that features conversion of source-separated food waste into a slurry that is added to a wastewater treatment plant digester, resulting in higher quality gas production. A wide range of emerging conversion technologies for solid waste—chemical and thermal—also are being considered that produce heat, steam, electricity, and fuels. These emerging technologies are not yet proven on a commercial scale in the United States, but they are used in Asia and Europe where regulatory mandates result in cleaner feedstock and landfill tip fees are significantly higher than in the United States. Canada also is at the forefront of waste diversion and alternative technologies, as landfill tip fees in Canada are typically much higher than in the United States.


How is Tetra Tech responding to these changes and clients’ needs?

Choosing the right solid waste management solution for a community is unique to each situation and related operational, economic, environmental, and social challenges. Tetra Tech’s outstanding international team of solid waste planners and engineers have helped clients walk through these complex and rapidly evolving challenges to arrive at solutions that meet their unique needs. We have prepared feasibility studies; developed long-term strategic plans or roadmaps for system development; and designed and supported the construction of composting, anaerobic digestion, and landfill gas beneficial use projects—converting landfill gas to fuel or electricity—for some of the largest municipalities in North America as well as the private sector. We also have supported remote, rural communities in addressing their distinct set of waste management challenges.

Our strength is the diversity of our project portfolio and the depth of our in-house talent. Our staff includes specialists who have worked for system developers, operators, and regulators. As a result, we have a great perspective on what is practical, what has worked, and what has been a challenge. We bring to bear best practices and lessons learned in a rapidly evolving solid waste industry.


What is on the horizon for how we manage our solid waste?

With climate change and GHG emission reduction goals driving legislation throughout North America and on a national level, a focus on diverting organics from landfills will continue. Much like the early 1990s, when recycling mandates drove change in the solid waste industry in the United States, organics legislation will drive our clients’ future needs. This includes expansion of curbside collection programs for diverting green and food waste and expansion of infrastructure to process organics. Landfill tip fees are still low compared to alternatives. Economics as well as social and permitting challenges will, therefore, be factors in how long it takes for programs, infrastructure, and markets to evolve. Landfill disposal will continue to be a significant component of a solid waste system, since there will always be residuals to be disposed, even with the most efficient of alternative practices and technologies. Tetra Tech’s wide-ranging expertise in the full life cycle of solid waste management positions us to meet our clients’ needs in a fast-evolving industry.

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