Davis staff report solid-waste progress, warn state rules on biosolids could cut diversion rate

Jennifer Gilbert, the city conservation coordinator, told the Davis Natural Resources Commission on April 7 that Davis residents and businesses are meeting many new state recycling and organics requirements but that a state policy change treating wastewater biosolids as disposal (not diversion) will add about 3,000 tons to the city landfill totals in 2025 and materially lower the reported diversion rate.

Why it matters: the city reports it sent about 34,000 tons of material to landfill in the last reporting year and has been holding steady near a roughly 62percent diversion rate; adding 3,000 tons of biosolids as disposal will reduce the city diversion percentage even while local sorting and collection programs perform well and compliance with SB 1383 is strong.

Gilbert opened the commission briefing by explaining how Davis solid-waste service is structured and where responsibilities sit: Recology Davis is the contractor that collects trash, recycling and organics under a city franchise; the city oversees reporting, outreach and compliance. "So we're gonna talk trash tonight," Gilbert said as she began the presentation.

Key figures and program notes from the presentation: - Annual landfill tonnage reported by the city is about 34,000 tons; the city sent roughly 3,000 tons of biosolids to the nearby Yolo County landfill each year, Gilbert said. Those biosolids have been used by the landfill for daily cover but, under a new state interpretation effective in 2025, those tons will be counted as disposal rather than diversion. - The city reports a per-person disposal rate of roughly 2.9 pounds per person per day, compared with a 3.6-pound benchmark the state uses as the 50percent diversion threshold; Davis is tracking near a 62percent diversion figure and aims for 75percent. - The city has about 17,000 organics carts in service since the 2016 organics roll-out; Recology recently began accepting cartons at drop-off sites only (cartons are not yet accepted in curbside carts). - In a record single week in December the city recorded about 1,500 tons of yard waste, driven by unusually heavy winter growth and rains. - Recology reports residual contamination of 5to7percent in Davis recyclables, lower than many curbside systems, which Gilbert attributed to Davis dual-stream collection and 50 years of local recycling practice. - Contamination monitoring done under SB 1383 showed about 81percent of residential bins received a "good job" tag during the most recent monitoring cycle; Recology will perform route monitoring and will supply new tags. - Procurement and end-market obligations under SB 1383 remain a significant problem: the state requires jurisdictions to procure a set amount of compost product (Davis' target is 8,000 cubic yards annually); the city met about 0.49percent of that target last year and has been trying multiple approaches (parks mulch/compost purchases, giveaways), but available, safe end-markets remain limited and some recent loads contained metal shards that make them unsafe for park use. - Food recovery work is underway: Gilbert reported nine Tier-1 grocery generators and two Tier-2 restaurants enrolled in edible-food recovery arrangements, many reporting positive results to the city.

Gilbert also described the city's approach to implementing SB 1383 (state law requiring organic waste recovery), which includes color-coded carts (recycling blue, organics green), consultant-led contamination monitoring with notice tags ("good job" and corrective "let's sort it out" tags), multilingual outreach, and free technical support for businesses (audits, free bins, labels and training resources). She said the city is focusing enforcement on ensuring infrastructure and labeling are in place before escalating to notices of violation.

On cartons, Gilbert said: the city had previously accepted some cartons in organics programs based on earlier composting facility guidance, but a new composting contractor reported cartons were not breaking down. "We have a contract with the landfill; technically, under contract, they have to take our cartons because it's in the acceptable list for the composting facility. So, technically, they have to take it, but we know that they don't want it. So we don't want to keep sending it," she told commissioners.

On biosolids, Gilbert summarized challenges and the immediate impact: the wastewater treatment plant's dried biosolids have been used by the neighboring Yolo County landfill for daily cover; the state now treats those landfill-used biosolids as disposal, which will add about 3,000 tons to the city's disposal totals for 2025 and reduce the reported diversion rate even if local collection improves. "It doesn't mean our programs are failing," she said; "it's biosolids."

Commissioners and attendees asked clarifying questions about whether UC Davis hauling is included in the city's totals (Gilbert said city numbers cover only City of Davis accounts; most university accounts report separately), about the mechanics of contamination monitoring and business audits, and about where recyclables go (Gilbert said Recology has committed to traceability for bales it ships and tries not to export low-grade plastics unless markets are certified).

Gilbert listed upcoming outreach and operational items: the annual bulky-waste voucher mailing, two Recology shred events, expanded senior outreach for hazardous-waste pickup appointments, and a solid-waste cost-of-service study to examine future rate adjustments.

The commission did not take formal action on the substance of Gilbert's report; the presentation produced clarifying questions, discussion of program capacity and procurement challenges, and requests for follow-up information on procurement and biosolids alternatives.

Ending: Gilbert closed by directing commissioners to the city's Greener Davis resources for ongoing updates and offering to answer follow-up questions by email to the public works address; commissioners applauded the city's recycling milestones and asked staff to return with further detail on procurement options and biosolids alternatives.