According to the state Department of Public Health and Environment, 3,650 tons (7.3 million pounds) of marijuana plant waste was produced by the state's pot industry in 2019, and that number would be increased to 7,300 tons by a requirement that unused plant matter and product be mixed with waste such as sawdust, mature compost, bleach, coffee grounds, sand, glass or shredded paper — as long as the marijuana-to-waste ratio is 50/50.
Although the state Marijuana Enforcement Division didn't remove or alter the 50/50 requirement, as had been discussed at previous meetings, the MED did open up several paths around it in the department's latest round of extensive rule updates, adding new exemptions for biomass recycling and composting methods. According to CDPHE marijuana environmental impact researcher and small-business consultant Kaitlin Urso, the new waste removal rules will take effect at the start of 2021.
"This is something the cultivators asked for, something they wanted," she says. "Growers want to make these sustainable decisions and send plants to compost."
Under the new MED rules, marijuana cultivators can send their leftover stalks, leaves and unusable plant matter to facilities for anaerobic digestion, a process of accelerated compositing that captures the emitting gases.
"It captures the gasses to use them as a commodity," Urso explains. "When you're just composting, you're recovering the nutrient value from the plant material, but you're still releasing the gases into the atmosphere."
Other options include biocharring, or burning plant material into a nutrient-dense charcoal that can be used as a cultivation additive, as well as biomass gasification, a thermochemical conversion of plant matter into usable gases. The new exemptions will also make it cheaper to remove waste more sustainably, Urso adds, as most commercial composting companies charge by the pound for pick-up. Under the previous 50/50 rules, that would have doubled the cost.
Additions to the industry retail code allow for more consumer recycling, as well. While marijuana-package recycling rules were already in place in Colorado, they didn't address sanitization and structural integrity to maintain childproof stability. Those details have since been ironed out, and dispensaries are now allowed to offer package receptacles in their lobbies. Previously, the receptacles had to be placed in the pot shop's retail areas, spaces that generally aren't very big and are coveted by vendors. The new rules also allow for customers to recycle marijuana packages purchased from different stores.
The MED will soon begin reaching out to marijuana business owners to inform stakeholders of the new waste-removal options.
The new rules represent "the low-hanging fruit" of Colorado waste-removal issues this year to Urso, who hopes the MED addresses future environmental impacts next year. She is currently finishing writing up a state study that measured the carbon impact of terpenes — plant compounds responsible for marijuana's smells and flavors — in urban marijuana cultivations. The CDPHE expects to publish that before the end of the year.
The state's new waste removal and packaging were implemented as part of a wide array of MED updates to the state's retail marijuana code. Another notable addition includes a new marijuana business accelerator program for low-income entrepreneurs.