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The Green Dream: For Waste, Zero is the Magic Number

Seventy percent of DIA's deicing fluids is collected and a good portion is recycled and reused into other products.

DIA covers about 34,000 acres of land.

Denver Zoo's goal is to become a zero waste facility by 2025.

The zoo's waste-to-energy system is in the zoo's new Toyota Elephant Passage exhibit.

You could say at the Denver Zoo and Denver International Airport, waste is not garbage. After all, both organizations are working toward goals of zero waste to landfills. But as with many initiatives, it's about the journey, not just the destination.
Zero waste sounds like it's simply an environmentalist's dream. Think about it for a second. Zero waste, which means absolutely no waste to landfill. 
The technical definition of zero waste comes from the Zero Waste International Alliance, which states: 
"Zero Waste is a goal that is ethical, economical, efficient and visionary, to guide people in changing their lifestyles and practices to emulate sustainable natural cycles, where all discarded materials are designed to become resources for others to use. Zero Waste means designing and managing products and processes to systematically avoid and eliminate the volume and toxicity of waste and materials, conserve and recover all resources, and not burn or bury them. Implementing Zero Waste will eliminate all discharges to land, water or air that are a threat to planetary, human, animal or plant health."
In our consumption-driven society, it seems like that's just impossible, right? Apparently not in Colorado. Our friendly corporate brewery to the west, MillerCoors recently announced that its Golden brewery is now landfill-free. MillerCoors claims that for the brewing industry, the accomplishment is significant: no other breweries, including small craft or large national, have managed to achieve landfill-free status.
Over at the University of Denver (DU), the Reduce, Reuse, Recycle committee began a zero-waste initiative at hockey games this season. The program places volunteers throughout the concourse to help hockey fans recycle or compost. This season the committee focused on the concourse and successfully diverted 47 percent of waste away from landfills, according to the school. The committee hopes to extend this zero-waste mindset to basketball games as well.
In addition, both the Denver Zoo and Denver International Airport are also participating in the fight against trash and are making real, tangible moves toward zero waste.
The greenest zoo of them all? Denver Zoo's goal is to become a zero waste facility by 2025.
One of the main points to consider about zero waste is that there's no pressure to pursue it. Sure, everyone would like to see less trash go to landfill, but as of now, there isn't a government mandate to adopt a zero waste philosophy. 
But in Jennifer Hale's opinion, the Denver Zoo had no other choice.
"For us, at the Denver Zoo, our mission is to secure a better world for animals," says Hale, Director of Safety and Sustainability for Denver Zoo. "To do that, we better be walking the talk and so it would not be a good practice for us to be wasteful and impact the environment. We want to the do the right thing." 
To help achieve its environmental goals, the Denver Zoo created a Sustainable Management System (SMS). This system allows the zoo to identify, evaluate, manage and improve the zoo's sustainability performance. 
Part of the SMS project is to become a zero waste facility by 2025.
The zoo is working toward the goal by establishing an extensive recycling program and a "green" purchasing policy. However, one of the biggest moves, arguably, is its innovative waste-to-energy system. 
This system will be housed in the zoo's new Toyota Elephant Passage exhibit that will chemically convert zoo waste in a high temperature, low oxygen process into a usable combustible gas, called syngas. The zoo will convert 90 percent of zoo's waste stream into energy, resulting in a diversion of diverting approximately 1.5 million pounds annually from the landfill, saving the zoo as much as $150,000 a year in energy and waste-hauling costs. This system will produce one byproduct: ash, which can be used as a soil amendment.
Operating at high temperatures will also produce waste heat that will be used to heat the 18,000-square-foot elephant center and 11,000-square-foot rhino/tapir holding facility, through radiant heat systems. 
Zoo employees designed the gasification technology, with help from the National Renewable Energy Lab in Golden. Hale says the zoo is pursuing patents for the technology.  
Right now, the zoo is in the process of getting a permit for the system and Hale says they hope to have it up and running later this year. 
"What is unique is that, while various forms of gasification technology has been around for years, our process was developed by our own staff," she says. "It's pretty innovative for a zoo to do this. This can be used elsewhere on college campuses, small communities -- it's a big opportunity." 
DIA covers about 34,000 acres of land. Taking sustainability to new heights
Craig Schillinger, environment public health manager for DIA, acknowledges the airport takes up a lot of space. With about 34,000 acres (or 53 square miles), it is the largest airport in the U.S. in terms of total area. The current facility can accommodate 50 million passengers a year. DIA has a population of 30,000 workers, 900 of which are city employees.
In a sense, DIA is its own city, which guarantees one thing: lots of waste. 
DIA is the only U.S. international airport that has designed and implemented an ISO 14001-Environment Management System (EMS) that encompasses the entire airport. DIA's EMS provides a framework for the airport to identify, prioritize and manage the environmental aspects of its operations. One key item on the agenda is to become a zero waste facility by 2020.  
"We have an environment management system and we are proud of it," Schillinger says. "Just this morning, I looked over the draft of the sustainable management plan and it's several hundred pages long. It has at least 12 different initiatives, and financial pieces as well. It's a big deal. We want to make sure what we are doing makes sense."  
DIA defines zero waste as recycling, repurposing, and composting, or otherwise diverting from the landfill everything that they are able to within current technology. DIA waste audits revealed that 60 to 70 percent of the municipal solid waste trash sent to the landfill is recyclable, reusable or compostable. The airport has a recycling program that includes: metals, paper, plastics, construction wastes, electronics and deicing fluids.
Take for instance, about 70 percent of deicing fluids is collected and a good portion is recycled and reused into other products, Schillinger says. 
DIA continually works with concessions, tenants and business partners establish and refine specific collection activities for each waste stream where recycling alternatives exist. For example, DIA received a state grant to purchase a plastic film baler to enable the airport to capture and recycle a commodity that used to simply be thrown away. addition, DIA has a nascent composting program in the terminal and public restrooms.
Recycling collection areas are also a key emphasis and are within reach of all aircraft. Southwest Airlines has constructed a waste center with a compactor dedicated to recyclables coming off their airlines, and the airline diverts more than 20 percent of their waste from the landfill.
The recycled materials are delivered into the commodity markets by the airport's solid waste contractor, Waste Management, Inc. DIA receives rebates on its recyclables based on market prices for these commodities and these rebates help to offset the costs of recycling, says.
Organic material, such as compost and wood, is hauled by Waste Management to A1 Organics, which operates a composting farm in Keenesburg, Colorado. The material is processed into compost and mulch for residential and agricultural purposes.
While DIA will eventually like to serve as a model for other airports, Schillinger says there's still plenty of work to be done before they get to that point. 
"We at DIA feel we still have some ground to cover before we are able to stake that claim with regards to zero waste," he says. "We have multiple programs in place and in discussion that, if developed and implemented, will be industry-leading for airports."

Read more articles by Heather Caliendo.

Heather is a Denver-based journalist and Confluence contributor. 
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