Summer in Laramie is a time to venture out of the UWYO bubble, so I want to focus this first post on a question that affects the entire community. Those of you who dump green waste in Laramie, or fertilize your gardens, or run your toilets and sinks into the wastewater stream, might be interested.
Last month, the City of Laramie held two free compost days, inviting residents to the landfill to load buckets, trucks, and trailers with nutrients for their soils. The Solid Waste Division has been composting since 2009, when it began mixing green waste with biosolids from the Wastewater Treatment Plant (Compost Program Information). If the word “biosolids” means nothing to you, know that it is an innocuous way of saying sewage sludge – the stuff separated from the city’s wastewater during treatment.
I’ve had a handful of conversations about the town’s compost, and every one of them went one of three ways. One,some people had never heard about the sewage connection, and they were disgusted and worried when they finally did. Or two, they were conspiratorial – in-the-know and extremely suspicious about what the town was selling. Three, there were a few waste nerds who supported the idea: a microbiologist who deals in tiny, icky things, and a couple of local gardeners who have their own composting toilets. Before you seal your own opinion, I have a few reasons to give the city’s compost program a chance.
Without a doubt, people have a variety of concerns that would lead them to skip free compost day. I am willing to bet, though, that poop is a big one. Their resistance boils down to common knowledge, and the wisdom, “Don’t shit where you eat.” Our whole sanitation system is designed to prevent this from happening. Throughout history, containing germs and diverting waste were the steps that allowed people to survive childhood and mothers to survive childbirth. That is why it is important to know that composting biosolids does not violate these goals. Rather than dumping its pipes into the Laramie River, the town runs wastewater through a process that removes heavy metals, and then uses microorganisms to break down nutrient pollutants like ammonia, a form of nitrogen useful to plants (Water and Wastewater). The organisms and the chemicals they have digested make up the sewage sludge separated from water before it is zapped with UV light and released into nature (Water and Wastewater).
Municipalities have three legal options for what to do with sludge: incinerate it, add it to the landfill, or use it as fertilizer. Not only is composting biosolids an alternative to releasing greenhouse gases or bulking up the dump; it is a system that captures nutrients with the potential to pollute and lends them to plants. In this context, Laramie’s use of sewage sludge seems like a win for human and ecological safety. And the method is far from unique.
According to Solid Waste Division (SWD) Manager Brooks Webb, “a lot of the products [people] buy at home improvement stores contain biosolids”. Some of the compost on the market is made up of precisely the same materials as Laramie’s city compost. Around the country, 50% of biosolids are used as a soil additive, and their application is regulated by the Environmental Protection Agency (Biosolids). I can see how the fact that something is used and regulated might not be enough to assure people that it is safe. To get a picture of those regulations in practice, I am going to walk you through what I have learned about the city’s recipe for compost.
Throughout Laramie’s warm-ish season, residents drop tree trimmings, grass clippings, and dead leaves into green waste bins around town. The SWD empties these bins weekly, building a heap of green scraps on a ridge outside the landfill. Green waste, like biosolids, can either be burned, landfilled, or shredded and composted. Sanitation workers build ten-foot tall windrows to cook thousands of tons of shredded plant material and biosolids into compost, seven parts green to three parts “black”. In order to meet standards, the piles have to maintain a temperature above 130 degrees for fourteen days straight. The windrows undergo testing for nutrient quality, pH, salmonella, and heavy metals, and the tests are published on the City’s website (City of Laramie). If the compost fails tests, or there is too much leftover, the SWD uses the material as cover for the landfill before they leave at night. According to Webb, the trash has to be covered at the end of every day, “to prevent odors, fires, and keep animals and flies away.” During the winter, warm compost is a useful stand-in for frozen soil.
“Last year no piles failed tests,” Webb said, “The year before we had two windrows out of 32 fail the salmonella test and one that would not maintain temperature.” All three of these piles were used as landfill cover, and not as fertilizer. The EPA rules for the use of biosolids (40 CFR Part 503) are explained here: The standard Laramie uses is Exceptional Quality, or EQ, and works so that once compost passes testing, it can be distributed “as freely as any other fertilizer or soil amendment to any type of land” (Land Application of Biosolids). One limit to Laramie’s program is that the compost cannot be spread on reclamation sites, although biosolids are used for this purpose elsewhere (Biosolids, Webb).
I understand that even with all this in mind, people may still have reasons to look elsewhere for their compost. In every year’s tests, samples showed the presence of lead and other metals, which might alarm some residents. Compared to the EPA’s standards (link:http://www.cityoflaramie.com/DocumentCenter/View/3680), however, these numbers are miniscule. We have standards, and not zero-tolerance policies, because exposure to metals is a guarantee of life on Earth.
A few people I spoke with were hesitant about the quality of the city’s compost, which they thought would have less nutrients per pound than the composts they make with their own food waste. Home compost is an effective way to tighten a family’s cycle of waste, and it is free every day. I have spoken with two gardeners in Laramie who even produce their own “Humanure”, and swear by its soil-enhancing properties. They are reassured that the pathogens and pharmaceuticals in the fertilizer they are using is their own, and not a slurry from every person and industry in town. Still, we surrender our sewage and our garbage for mass processing; the only way to close our collective loop is to find solutions that work on a large scale. Municipal compost slows the growth of the landfill and recycles nutrients that would either be buried or leached away.
If you are still shopping for a soil additive, and you were initially turned off by the idea of biosolids, I hope that you will give the city’s compost a second look. Even after the free giveaway, it is cheaper than most commercial products, and it could help the SWD continue their program. If you make your own compost, I propose an experiment; try both and see if you notice a difference. Apparently, the greatest challenge with composting green waste in Laramie is finding demand. People are eager to clean up their yards, trees, and gardens, and our huge pile of plant scraps leads to a heaping supply of compost. Now and then, the SWD hears from local companies or ranches willing to buy in bulk, but demand is unpredictable. As we organize and sanitize our lives, we are constantly producing leftovers. Waste accumulates whether or not we are paying attention. By re-envisioning waste and nutrients, we can help promote safety and sustainability on a municipal level. If the most recent free compost day is any indication, a significant number of Laramie residents are willing to do so. Webb told me that 479 people showed up on May 21st to take away over two million pounds (1007 tons) of compost.
“Biosolids”. United States Environmental Protection Agency. US EPA, 28 Jan. 2016. Web. Accessed 30 May 2016. https://www.epa.gov/biosolids
“Compost Program Information”. Laramie, Wyoming. City of Laramie. Web. Accessed 30 May 2016. https://www.cityoflaramie.org/index.aspx?nid=290
“Land Application of Biosolids”. EPA Guide to Part 503 Rule. Available from:https://www.cityoflaramie.org/DocumentCenter/View/3680. Accessed 30 May 2016.
“Water and Wastewater”. Laramie, Wyoming. City of Laramie. Web. Accessed 30 May 2016. https://www.cityoflaramie.org/index.aspx?nid=283
Webb, Brooks. E-mail interview. 31 June 2016.
Webb, Brooks. Personal interview. 5 May 2016.