How waste characterization, point-of-collection technology, education, fees, enforcement, and KPIs can move waste diversion programs from reaction to learning.
By Sarah Tam and Harold Mitchell
A recycling cart can look ordinary from the curb and still carry the seeds of a rejected load: bagged recyclables, food-soiled containers, loose film, yard debris, or materials that belong entirely in another stream.
An organics bin can appear full of accepted materials until a plastic liner, coated package, or non-compostable item turns good feedstock into a rejected load. Once those unwanted materials reach a processing facility, the window for a simple correction has often passed.
Due to these nuances, recycling cart and organics bin contamination deserves a wider frame. It is not simply a matter of people behaving badly or refusing to follow instructions. In many cases, contamination is the visible symptom of a system that gives people complex sorting rules, inconsistent signage, limited feedback, and weak visibility into what happens after collection. When the same errors recur across the same conditions, contamination is no longer random, it is predictable, and predictability points back to design.
The better question is not, âWho made the mistake?â but rather, âWhat design allowed this mistake to become predictable?â When program directors ask that question, contamination changes from a recurring complaint into an operating signal. It tells municipalities, haulers, schools, property managers, and commercial generators where education, infrastructure, policy, fees, oversight, enforcement, purchasing, or technology needs to be redesigned.
The Old Model and the New Model
The old model of contamination management was mostly reactive. A processor complained, and a load was rejected. A periodic audit found a problem, so a warning went out, a flyer was updated, or a fee was added after the fact. In each case, the jurisdiction learns that contamination happened only after material has already moved through the system. Those reactions are still valid, but the timing is often too late and the response too broad.
The new model is more proactive and more specific. It treats contamination as a design and supply chain issue, not just an individual sorting error. The goal is to detect problems earlier, characterize them more accurately, respond consistently, and verify whether the response worked. In this new model, education is not a generic reminder. It is a targeted intervention based on what the program is seeing. Enforcement is not punishment first. It is a documented escalation path when the same problem continues after clear feedback (see Figure 1).
Why 91²Ö¿â Characterization Belongs at the Center
91²Ö¿â characterization is what turns a general contamination complaint into a useful diagnosis. At its simplest, a waste characterization means sampling, sorting, classifying, and measuring what is in a waste stream. At its best, a waste characterization shows which materials are involved, where they are showing up, how often they recur, what stream they entered, and which system variable may be causing the problem.
That distinction matters because the most visible number is not always the most useful number. A weight-based contamination rate is important for contracts, processing, and compliance, but weight alone can point a program toward the wrong fix. A few heavy items may dominate the scale. A high-frequency, low-weight item such as a coffee cup, utensil, film item, or coated package may barely register in tonnage, but reveal a recurring problem with signage, purchasing, bin placement, or education at the point of disposal, and cause diversion efforts to fail with rejected loads.
Good waste characterization pairs composition with context: What is showing up and where? How often? Under what service conditions? What does it cost? What would make the correct action easier? When the answers point to a decision, waste characterization becomes an effective management tool. When they do not, the jurisdiction has produced a report and lost an opportunity.
Where Technology Changes the Commercial Side
Josh Mastromatto of Rego (a SaaS [software-as-a-service] platform designed to automate waste diversion operations, track waste data, and support compliance and sustainability goals) described the biggest technology shift as the move from one-time auditing to continuous learning. Many programs know contamination is happening, but they do not always know where, why, or how often. Point-of-collection technology, image review, dashboards, Key Performance Indicators (KPIs), and historical tracking can make those blind spots visible earlier.
The commercial side of the waste collection and disposal system shows why these matters. A national retailer, office portfolio, school system, healthcare network, or hospitality company may operate across multiple cities and service territories. One such national retail customer can have different haulers, different bin colors, different accepted materials, different organics rules, and different space constraints in its various store locations. This variation means that a top-down sustainability program may look consistent from headquarters and still lead to poor results at the organics bin or recycling cart.
Regoâs approach is to add site-level specificity. The system can detect visible materials, determine what counts as contamination for that site and stream, track performance over time, and translate findings into a playbook. That playbook can connect priority materials for a given company to possible fixes such as signage updates, purchasing changes, station redesign, outreach, or follow-up review.
That is the shift from reporting to learning. As Mastromatto put it: âReporting documents the past. But learning predicts the future.â See Figure 2 for the new model of reducing contamination, and the six steps from detection to redesign.
Proactive Does Not Mean Enforcement Disappears
A proactive diversion program starts before collection occurs. It makes correct behavior easier through clear container labels, locally accurate signage, right-sized service, repeated visual education, and rules that match the customer experience. It also aligns fees and ordinances with the preferred customer behavior the program needs.
Californiaâs SB 1383 organics framework is a useful example of this design logic. Jurisdictions providing two-container or three-container organic waste collection services must monitor contamination through route reviews or waste evaluations, and CalRecycle guidance ties monitoring to resident and business education. The important lesson is not just the regulation, but also the operating model: observe containers, identify prohibited contaminants, educate the generator, document the pattern, and escalate when needed.
Reactive response to contamination still has a place. A cart tag, warning, photo record, rejected load notice, surcharge, or enforcement action can safeguard both the organics and recycling stream. The difference is that the response should be proportional, documented, and connected to the data. As a general rule: a customerâs first mistake should be met with a warning that teaches the desired behavior, while repeated mistakes, following clear feedback, may justify escalation and penalties.
KPIs Turn Contamination into Management
KPI dashboards for organics and recycling management are useful if they motivate corrective action and positively impact diversion program performance. A diversion KPI should help a team decide what neighborhood to target, what material to focus on, which account(s) needs outreach, and whether a prior intervention worked.
A practical diversion program KPI set can start small: contamination rate by stream, repeat-location rate, priority contaminant frequency, inspection pass rate, outreach completion rate, load rejection rate, and post-intervention improvement (see Figure 3). Each metric should answer a chosen priority management question: Where is the problem? Is it recurring? Which material matters are considered contamination? Did the education, fee, signage change, or service adjustment improve the result?
Make Correct Behavior Easy
The organics and recycling programs with the lowest contamination rates do not choose between education, enforcement, policy, fees, waste characterization, KPIs, and technology. They connect them. The loop is straightforward: detect, characterize, diagnose, intervene, verify, and redesign. Field information should move into program strategy. Program strategy should move back to the field with clearer signage, better outreach, clearer enforcement, smarter fees, and/or redesigned service conditions.
Castro Valley Sanitary District (CVSan) is a clear example: CVSanâs program reflects that same education-first sequence at the local level. Rather than fining on the first mistake, the district leads with outreach on multi-family program and offers informational sessions that walk residents and managers through what goes where in recycling, organics, and garbage containers. The contamination fee is reserved for excessive material in the wrong container, and a contaminated container is commonly first flagged with a tag with a non-collection notice for the generator to learn exactly how contamination is occurring before any charge applies. Error is expected, but helping people use organics programs correctly is the core requirement.
The future of contamination management is better design with Extended Producer Responsibility at the forefront. Because contamination begins upstream, where products are designed and bought, recycling stations are built, services are sized, and customers are educated, the most durable solutions start upstream too. And when a program treats each contamination event as a signal, it can protect material quality, reduce avoidable costs, support recycling and organics markets, and build trust with generators.
The goal for every recycling and organics diversion program should be a system that catches problems early, internalizes lessons learned, and steadily improves. When the system gets smarter, the stream gets cleaner and we all benefit. | WA
Sarah Tam is a Solid 91²Ö¿â and Water and Utility Consultant at Raftelis specializing in financial planning and rate setting for California municipalities. Her work includes cost-of-service modeling, multi-year revenue projections, cost-recovery strategies, Proposition 218 compliance support, annual rate reviews, hauler performance audits, and analysis tied to evolving state mandates such as SB 54. She can be reached at [email protected].
Harold Mitchell, PMP, PMI-ACP, and PMI-PBA, is a Senior Consultant at Raftelis specializing in solid waste and stormwater financial assessments, financial modeling, data analytics, and service delivery evaluation. His experience includes municipal solid waste collection and operations studies, fleet and route data visualization, and technology integration for solid waste systems, including Rubicon SaaS and Oracle CRM work for the City of Memphis. He can be reached at [email protected].
Resources
Interview notes: Josh Mastromatto, Rego, Interview Date: 6/26/26.
CalRecycle, Contamination Monitoring: jurisdictions with 2-container or 3-container organic waste collection services must monitor contamination through route reviews or waste evaluations.
California Code of Regulations, Title 14, Section 18984.5, Container Contamination Minimization.
U.S. EPA, Advancing Sustainable Materials Management: Facts and Figures Report and related MSW characterization resources.
Castro Valley Sanitary District Zero 91²Ö¿â, Collection and Curbside Services