Dallas Embraces Recycling and Bioreactor Technology

Michael Fickes

Texans are known for liking things big: Big hats, big trucks and big ranches. As the old saying goes, “Everything is big in Texas.”

But for Dallas solid waste officials, bigger isn’t necessarily better. In “the Big D,” the Sanitation Services Department is focused on reduction. Specifically, the city is aiming to reduce the amount of trash that it sends to its landfill through recycling while also reducing the airspace consumed by waste that is placed in the disposal site by recirculating leachate. In the process, the sanitation department is hoping to not only extend the life of the city’s landfill, but to bring in valuable revenue as well.

Ramping Up Recycling

When it comes to recycling, Dallas historically has been something of a laggard. In 2003, a task force report prepared for then-Mayor Laura Miller found the city’s landfill diversion rate for fiscal year 2001-2002 was a measly 2 percent. By contrast, San Francisco, currently the nation’s recycling champ with a 75 percent diversion rate, had a 46 percent diversion rate at the time. Additionally, the report found that only 25 percent of Dallas households were participating in the city’s recycling program.

After the task force report, the city set out to more than quadruple its recycling tonnage from 10,000 tons in 2003 to 43,600 tons in 2011 and to double the household participation rate to 50 percent by the same year. To reach the goals, Dallas waste officials determined that they had to change the method of collecting recyclables and increase community outreach, says Ron Smith, assistant director with the Dallas Sanitation Services Department.

Having decided that the previous recyclables collection program — which required residents to separate recyclables into blue plastic bags — was too cumbersome, the department opted to implement a single-stream program that allows residents to put all of their recyclable materials into one, 95-gallon cart. Furthermore, in 2007, the department began phasing in an initiative called OneDAY Dallas. The initiative replaced the previous collection schedule, which called for two trash pickups and one recycling pickup per week for each single-family household, with a schedule in which each residence has its trash and recycling picked up once a week, on the same day. The initiative now has been implemented across the entire city.

To further spread the recycling gospel, Sherlyn McAnally, the city’s waste diversion specialist, is conducting a host of outreach programs to boost recycling in facilities that traditionally have proven resistant to it: multifamily buildings, mixed-use developments and hotels.

To generate interest among apartment and condominium residents in downtown Dallas, McAnally meets regularly with homeowner associations, apartment complex managers and residents. “We have 13 to 15 properties in pilot projects that have been operating for one to three years,” she says.

McAnally also works with the Dallas Downtown Improvement District to service downtown multifamily buildings. “We put rolling carts into the buildings near the trash chutes, usually two per floor,” she says. “On a specified day, the Improvement District maintenance people move the carts to a central location. The city will pick up carts on [its] recycling routes. In other cases, the Improvement District workers will dump the carts into recycling containers on routes picked up by private contractors.”

As part of its recycling promotional efforts, the city has taken advantage of grant programs run by the North Central Texas Council of Governments. McAnally recently obtained a $68,000 grant to develop recycling programs for Dallas hotels and a $77,901 grant to promote sustainable management practices, including recycling, to multi-use developments, in which commercial and residential properties are located on the same site.

Finally, McAnally manages programs designed to teach students and residents of elder care homes about recycling. She also oversees a course that teaches homeowners about backyard composting as well as two special recycling “roundups” a year.

All in all, the city’s various recycling strategies are paying off. By the end of 2007, recycling tonnages had tripled to about 30,000 tons. Last year, Dallas exceeded its goals a year ahead of schedule by collecting 44,444 tons of recyclables and having a household participation rate of 60 percent.

“For 2011, we are projecting 53,000 tons of recycling collections,” Smith says. That would represent about 10 percent of the municipal solid waste generated by the city.

With the framework set by the OneDAY Dallas program and special programs directed at hard-to-reach recycling audiences, Smith and McAnally believe the city is positioned to continue diverting more and more materials from its landfill.

All Wet

Four years ago, the Dallas McCommas Bluff Landfill became the first landfill in Texas to receive permits to construct an enhanced leachate recirculation (ELR) system, also known as a bioreactor. The facility immediately installed an ELR in the current landfill cell.

A conventional landfill uses pipes to collect gas. At the bottom of the landfill, a piping system collects leachate and pumps it out of the landfill for disposal. In an ELR system, leachate drains to the bottom of the cell, as usual, but the leachate collection system re-introduces the leachate into the cell through a perforated piping system.

The ELR system speeds the decay of landfilled materials. As materials decay, they shrink in size, creating more space for disposal. “The landfill currently has 45 years of life left,” Smith says. “We estimate that the ELR technology will [increase that length by] 20 to 30 percent.”

That’s not all. The trash isn’t just getting smaller — it’s producing methane at an accelerated rate, about 4.5 million cubic feet of methane per day. The landfill’s gas collection system sends the gas to a facility built and operated by a third-party contractor, which cleans and processes it to the quality of pipeline-ready natural gas.

The contractor then ships the gas via pipeline to California, where it is sold as a green, renewable fuel. California is a ready market because state law requires utilities to generate a percentage of their electricity from renewable sources.

It Pays To Be Green

Dallas’ recycling and leachate recirculation operations are not only conserving valuable airspace at the McCommas Bluff Landfill: they also are generating revenues for the city.

The city delivers its collected recyclables “to a processor that pays [us] a percentage from its sales to manufacturers,” Smith says. The city’s revenue from the sale of recyclables is expected to reach $2.5 million this year, Smith adds. That number should increase — with allowances of course for the ups and downs of the recycling commodities markets — as the city’s recycling rate continues to grow.

The contractor that receives the gas collected by McCommas Bluff’s ELR system pays Dallas at a rate of 12.5 percent of the gross sales price it receives from California utilities. This year, Smith estimates, the city will receive about $1.3 million in revenues from sales of the gas, up from about $1 million in 2010. Dallas officials also expect that number to rise as more methane is produced in the coming years, Smith adds.

The revenues help fund the Sanitation Services Department’s annual $80 million operating budget. The department must pay for itself. It is, according to Smith, a full cost recovery operation. “When we provide recycling, garbage, bulk and green-waste collections, we figure out what it costs to do the work and invoice our customers — residents,” he says. By creating recycling and landfill gas programs that generate revenues, the city can help restrain rising costs for residents in the future.

Michael Fickes is a Westminster, Md.-based writer.

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Sidebar: Dallas Department Profile

The Dallas Sanitation Services Department collects trash and recycling from 230,000 single-family households and about 2,100 commercial customers — mostly multifamily buildings in the city’s central business district. “Most of the commercial solid waste in the city is handled privately,” says Ron Smith, the department’s assistant director.

To ensure that the trash and recycling trucks run their routes as efficiently as possible, the city is automating its collection fleet. Currently, just more than half of the 155-truck collection fleet consists of automated side loaders. The rear loaders are equipped with tippers. “The side loaders can’t get to the cans in some parts of the city,” Smith notes. “So we’re still using rear loaders in some areas, at least for the time being.”

The department also uses route optimization software as well as onboard route management and onboard global positioning system (GPS) technologies. “Technology is a big help,” acknowledges Smith. “You can find out where the routes are inefficient, when we need to talk to a driver, and when we can defend drivers against accusations of not making a pick up or reckless driving.” — MF