How IoT technology could solve San Francisco’s waste problem

By Anne Poirot

Three years — that’s how much time the city of San Francisco has left to reach its zero waste goal that was set in 2003. From the beginning, the goal was ambitious — but far from impossible. Now, the city faces a final challenge, and closing its waste gap on deadline will require out-of-the-box thinking.

San Francisco established its zero waste program with a target of recycling and composting 100% of the waste generated in the city. So far, San Francisco has been able to divert as much as 80% of its waste from landfills by implementing a vast political, economic, and educational program. In addition, a public-private partnership was created with the San Francisco-based waste management company Recology, which is in charge of recycling, composting, and landfill management. Recology has worked hand-in-hand with the city to help it to reach its goal by integrating new waste-sorting technologies and improving city-wide collection services.

The current lifecycle for that waste can be seen in the chart below.

State-of-the-art waste sorting

In 2016, Recology spent $11.6 million to update its recycling facility. Recent advancements and innovations in the field of robotics made it possible to implement better, more targeted sorting techniques. First, the presort line, where recyclable items are separated manually from non recyclables one, was extended, making it the longest in the United States. Mechanical sorting of glass, cardboard, paper, and metal was updated using spinning disk screens that carry lighter paper to the top while heavier cans and bottles fall back down. Metal and cans are then separated using magnets. To sort plastic, two optical sorters were installed using a beam of light to recognize different types of plastic and separate them with puffs of air. Lastly, the outdated glass cleaning system was given a modern upgrade, enabling it to separate glass from similarly sized paper, metal, and plastic.

The improvements allowed Recology to increase its daily waste processing by 170 tons per day and adapt to new types of recyclables, such as cardboard boxes from online shopping and light plastic containers for beverages and food, which are widely used in San Francisco.

While these changes did provide significant benefits, Recology still wants to implement new modifications to its services to manage the growing volume of compostable and recyclable materials. To do so, Recology wants to optimize routes for collection trucks to dedicate more capacity to recyclables, offer higher capacity recycling bins and lower capacity waste bins as the default service for residential customers, and build an organic transfer facility at its existing transfer station. In addition, the company wants to start a pilot program to test new methods for sorting the contents from black trash bins so that recyclable and compostable materials can be recovered.

The awareness barrier to zero waste

Despite improvements in sorting technology, achieving zero waste by 2020 seems harder than initially expected as San Franciscans continue to send nearly 600,000 tons of waste to landfills every year. To push this number closer to zero, the city must act on the consumer part of the waste stream to increase recycling and composting participation. Education and outreach are key, and consumer behavior studies show that resident’s behavior can be influenced by the level of knowledge they have. Helping citizens to be aware of the relationship between waste generation and environmental impact, as well as procedural information about waste-sorting processes can improve the likelihood that someone will recycle or compost. These behavioral changes are necessary in tandem with technology upgrades.

Improved sorting technology at Recology has provided a good start, but those improvements alone were not enough. To reach zero waste, San Francisco needs to innovate its educational outreach strategy using new technologies to raise awareness. Specifically, data measurements and analytics technologies could help increase awareness and enhance the program’s impact on San Franciscans’ behavior. Consumers tend to underestimate how much they personally waste and how little they recycle or compost. This phenomenon was studied on a national scale with food waste in a survey conducted for the Johns Hopkins Center for a Livable Future. In the study, researchers found that although 45% of respondents declared food waste was an important issue, 56% indicated that they only discarded small amounts of purchased food. This shows a clear gap between respondent perception and reality, as 40% of food is wasted across the U.S.

IoT: An Internet of Trash

San Francisco needs to empower residents and businesses with concrete data to close its waste gap. Measuring waste generation along with recycling and composting performance will allow residents and businesses to have better insights into their waste habits and encourage them to take action. Residents could see a positive return by optimizing their grocery shopping and reducing waste generation, allowing them to save money. Businesses, meanwhile, would be able to leverage data analysis to improve recycling and composting, increasing diversion discounts and reducing trash collection costs.

To record and analyze this data, Internet of Things sensors could be implemented at various points in the waste stream to monitor waste generation, recycling, and composting. Trash containers, for example, could be equipped with sensors. This technology is already being developed by the San Francisco-based startup Compology. Compology’s sensors take high-resolution pictures of the inside of waste containers numerous times a day and send those images to the cloud. This allows waste haulers to monitor container fullness and optimize truck routes or schedules to only pick up trash at containers when needed. This image-based technology could also be used to analyze containers’ contamination by estimating the proportion of non recyclable items in the trash. Computer vision and machine learning will be necessary to create a hardware-software device capable of recognizing which type of trash is being thrown out. With this newly available information, San Francisco would be able to successfully implement educational programs that target households or businesses with high contamination rates.

Photo credit: Compology

These types of technologies could also be applied to restaurants and have a meaningful impact on food waste reduction. Hardware equipped with scales and computer vision sensors can analyze and categorize the types of food being wasted, allowing restaurants to manage inventory and reduce costs. For example, a hotel offering a breakfast buffet could be able to estimate how much fruit salad goes to waste every day for not being eaten and therefore reduce the amount of fruit salad prepared and fruit bought. Mintscraps, a San Francisco-based startup, is developing this kind of technology. Currently, the company offers software allowing restaurants to weigh waste and categorize it, but the ultimate goal is to use hardware sensors capable of categorizing waste autonomously using computer recognition.

Regardless of how San Francisco chooses to divert its last 20% of waste from landfills, the city will need to innovate. The types of technologies referenced above may provide one piece of the puzzle, helping to uncover the data buried in the city’s landfill and empower residents and businesses to take action. Ultimately, their participation will determine the success or failure of the zero waste program as it approaches its 2020 deadline.

Follow Orange Silicon Valley’s Sustainable Food Systems publication on Medium for more looks at the food we eat, how waste gets managed, and how technology can play important roles.

Disclaimer: The views and opinions expressed in this article belong to the author and do not necessarily reflect the position or views of Orange or Orange Silicon Valley.