Mushrooms are decomposers—they break down dead organic matter and return nutrients to the soil for new growth.  

Our inventiveness and design skills have led us to an unsustainable linear system of cradle-to-grave consumption. These skills will also be essential in transforming our current system to one that considers our quality of life and that of all other species. This change will require us to broaden our outlook and deepen our understanding of the system.

The first in-depth attempt to understand the system of human consumption patterns in a world of finite resources was Limits to Growth. One of the book’s authors, Donella H. Meadows, was so discouraged by the lack of action in response to their findings, she spent the rest of her career exploring how to change systems. Such change requires what Meadows calls “dancing with systems,” an approach that involves observing at the big-picture level and the detailed level, staying humble and a learner, expanding time and thought horizons and attending to what is important, not just what is quantifiable. One of the most effective leverage points she identified was to change the goals of the system. ←  Donella Meadows et al., Limits to Growth: A Report for the Club of Rome’s Project on the Predicament of Mankind (New York: Universe Books, 1972); Donella Meadows, “The Dance,” Donella Meadows Archives (undated), linkDonalla Meadows, “Leverage Points: Places to Intervene in the System,” The Sustainability Institute (1999), link.

Designing for Material Flows

The goal of zero waste has been inspired by nature, whose materials are recycled in circular loops, in elegant and intricate designs that optimize resources. Many man-made materials such as aluminum, glass and gypsum wallboard can be recycled in perpetual loops too, but only if we design our materials, products and processes to allow for this. If our buildings and cities are designed so we can easily separate our cans and food scraps, then our landfills won’t emit methane and we won’t need to mine them later when there’s no aluminum left. An industrial system based on circular material loops and maximizing of assets, reuse and recycling is known as the circular economy, and leads to economic, environmental and social benefits. ←  Ellen Macarthur Foundation, “What Is a Circular Economy?” link.

Technical and biological (organic) materials are separated into two loops. The inner transformation loops—sharing, maintaining and reusing—use less energy and resources than the outer loops of refurbishing or recycling. These priorities align with those of the ‘waste hierarchy’. ←  Waste hierarchy, in order: prevention, minimization, reuse, recycle, energy recovery and disposal.

Visualizing architecture’s role in promoting circular material loops within a system can be done with a stock and flow diagram. In the center is the stock—for example, the amount of organic materials in the trash of a residential building. The goal is to decrease this stock, which can be done by reducing the flow of organic waste being discarded (left-hand side of the diagram) or by increasing the flow of organic waste to places other than the landfill (right-hand side). Factors that influence these material flows are added to the diagram, and those that an architect can influence are outlined in red. System diagrams can expand considerations, and other causal loop diagrams can identify factors with greater potential for system change. Two factors we determined were very important are the ease of transport through the building (how to manage material flows (see Planning for Waste as a Material Flow) and feedback loops that influence behavior. (See BPS 2.11)

Circular Economy diagram

Designing a method to move discarded materials through a building requires knowledge of the materials’ quantity and composition. Most architects have no means of calculating this. How can one design for an unknown quantity of materials that need to be separated, stored and moved to the curb every day? These guidelines include a calculator that will give architects the ability to estimate the quantity of recycling, organics, textiles and trash they can expect in their building—and options for reducing the volume and transporting it—so that they can design for material flows.


Engineers specify the conduits and pipes that transport gas, electricity, and potable and waste water in and out of buildings, independent of human labor. Materials, however, are not uniform and are largely moved by hand. Decisions must be made every step of the way: Do I want this anymore? Which bin does it belong in? Where should I set out this bag? The materials are handled many times by different people before reaching the final processing or disposal location. The decisions are made in response to many factors and in many locations, not just in a waste room. We need to broaden the view of what designing for zero waste means, beyond a trash chute or a bin enclosure, to the whole building and even the neighborhood.

Architects need to consider not only occupants but also building staff and collection personnel, as the management of a building’s materials is interwoven with the management of flows within the city. The design of waste setout in an isolated building has a powerful effect on the quality of life on the street, and the design of the street and sidewalk influence how waste is managed in a building. So designing a city for material flows requires an integrated approach, with architects, planners, developers, communities, waste haulers, reuse organizations and government agencies working together.

Learning from Ecosystem Change

By comparing the attributes that develop in nature as ecosystems mature into diverse, resilient systems with circular resources flows, we can gain insight into ways human systems can be designed to do the same.

Many species develop long-term mutually beneficial relationships, in which services are swapped for resources. For example, squirrels collect acorns, clean them, leaving their scent on them, before burying them in hundreds of locations, scatter hoarding them for the winter months. When the squirrels don’t find all the acorns, those that remain buried are well positioned to germinate, dispersing the oak trees’ seed to new areas.

Lichen is an example of a mutually beneficial relationship between alga and a fungus.

DSNY’s partnership with Housing Works, called refashionNYC, is also a service-resource mutualism. The agency benefits because it is able to use fewer resources for refuse collection and disposal. Housing Works is able to collect more textiles for resale in its stores, and the profits fund housing and healthcare for HIV-positive people. Such win-win relationships help propel the waste system in the direction of circular material flows while reaping benefits for the city. More broadly, the rise of collaborative consumption—explained by Rachel Botsman as “an economic model based on sharing, swapping, trading or renting products and services, enabling access over ownership”—slows down material flows through the efficient use of assets, resulting in less waste. ←  Rachel Bostman, “The Sharing Economy Lacks a Shared Definition,” in Fast Company (11/21/13), link.

Niche specialization, or adaptation to fill a narrow role, is another characteristic that increases as ecosystems develop. BKRot, a composting group in the Bushwick neighborhood of Brooklyn is a specialist in NYC’s waste and social systems. The group finds vacant plots of land and employs local youth to collect food waste by bike, from restaurants and households. Waste is composted as the lots are transformed into community gardens and finished compost is sold in local stores and to neighbors and other gardens. Many successful companies participating in the collaborative economy are niche specialists, such as those that offer freelancers space to work in restaurants that are closed during the day.

BKRot’s composting operation

Informational feedback loops become more prevalent as an ecosystem develops and act to balance the system. In NYC, electricity usage is always metered and is frequently submetered for individual units. Financial incentives and informational feedback have both been shown to change behavior, reducing energy usage.36 Our waste system is woefully short on information and feedback loops, and developing these within our buildings could help balance our material flows. ←  Raanan Gerberer, “Submetering Your Building’s Electricity: Paying for What You Use,” in The New York Cooperator (9/2011). link.

Increasing opportunities for feedback loops, collaboration, social interaction and niche specialists can help transform NYC’s system. Designing waste solutions at a community level, which capitalize on a neighborhood’s unique characteristics, opens opportunities for collaboration that are otherwise unavailable at the city or individual building level (see Punt Verd and Clichy-Batignolles case studies).

The design of a city reflects and guides its citizens’ aspirations. Transforming the city to reflect the goals of OneNYC will inspire New Yorkers to live in a way that helps reach them. If we design for pedestrians and cyclists, people will walk and bike. If we design for material flows, people will reduce their waste.

In her “Manifesto for Maintenance Art, 1969!” DSNY artist in residence Mierle Laderman Ukeles distinguishes between development—which she associates with separation and individuality; and maintenance—which she associates with unification and perpetuation of a family, city and the earth. Ukeles merges art and maintenance in a collaborative, creative and cohesive process—one we need to bring into architecture as well. If we consider material flows as well as other natural resources, our buildings can weave together human and natural systems to ensure the future of our city. ←  Mierle Laderman Ukeles, Manifesto for Maintenance Art 1969! link.

Next Section: Residential Building Context →