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Dissecting ISO 37120: The long road to zero waste cities

Submitted by scc staff on October 3, 2014

By George Karayannis, LEED AP

We continue our series on the new ISO 37120 Smart City standard with a look at the 12th of 17 themes defined in the standard – solid wasteImage removed. indicators.  As previously described, ISO 37120 includes 46 ‘Core’ (must report) and 54 ‘Supporting’ (should report) indicators.  The solid waste theme has three Core and seven Supporting indicators.

The solid waste theme is unique within ISO 37120 in that its 10 indicators are the most of any theme, perhaps underscoring the need for more effective management of resources globally.  This indicator has cities reporting on the generation and recycling of both hazardous waste and municipal solid waste (MSW) – more commonly known as trash. 

Image removed.MSW consists of everyday items we use and throw away, including packaging, yard waste, furniture, clothing, food scraps, newspapers, appliances, paint and batteries. Every yearan estimated 11.2B tonnes of solid waste  are collected worldwide, and decay of the organic portion of solid waste is contributing to about 5% of global greenhouse gas (GHG) emissions. Of all the waste streams, waste from electrical and electronic equipment containing new and complex hazardous substances presents the fastest-growing challenge in both developed and developing countries.  Waste disposal is also a big business, estimated at $57 billion in the US and $410 billion globally.

Americans waste.  A lot.  The U.S. produces 25% of the world’s waste from less than 5% of the world’s population.  In general, Americans generate 4.4 pounds of individual waste per person per day (over 1,600 pounds annually, each), and recycle 1.5 pounds per day or about 35%.  In Europe, Denmark generates the most MSW per person  (1,500 pounds), and Estonia the least (600 pounds).  Several cities worldwide are leading the ''zero waste'' effort, including San Francisco and Capannori, Italy, both of which achieve 80% or higher recycling rates.

''We’re proud of the 80% diversion rate, the highest in the country, certainly of any city in North America,'' San Francisco Mayor Ed Lee told PBS. ''And we’re not going to be satisfied with that. We want 100% zero waste. This is where we’re going.''

Many Third World countries fail to collect the totality of municipal waste generated, leading to significant health hazards from water, land and air pollution.  In low income countries, for example, collection rates are lower than 70%, with more than 50% of the collected waste disposed through uncontrolled landfilling and about 15% processed through unsafe and informal recycling.  The commonly accepted waste stream strategy is shown in the following waste management hierarchy, which essentially reinforces the concept of the ‘3 Rs’ – reduce, reuse and recycle. 

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Core Indicators

1.     Percentage of city population with regular solid waste collection (residential).

This indicator only reflects the extent to which the city population has access to solid waste collection and does not address the quality of the service or the city’s ability to properly dispose of its waste.  While the metric is fairly straightforward to calculate (number of households served by waste collection divided by city population), the standard is currently vague on how to handle slum populations which frequently do not enjoy routine city services such as waste collection.

2.     Total collected municipal solid waste per capita.

Wealthier nations consume more and, therefore, generate more waste. By reporting this indicator per capita, cities can more readily educate citizens on their individual impact on the waste stream. I was appalled when I learned during my research that, as an American, I generate 4.4 pounds of waste on average every day.

3.     Percentage of a city’s solid waste that is recycled.

Recycled waste includes materials diverted from the waste stream that are recovered and processed into new products following local government regulations.  Hazardous waste recycling shall be reported separately. The benefits of recycling are plenty and fairly well known to anyone not philosophically opposed to the concept. For example, for every tonne of paper recycled, 17 trees and 50% of the water can be saved. Leading cities worldwide are aggressively pursuing zero waste strategies that would push this number to nearly 100%.

Supporting Indicators

1.     Percentage of the city’s solid waste that is disposed of in a sanitary landfill.

Sanitary landfills are fairly rare throughout the world, and are defined as having a carefully designed structure that uses a clay or synthetic liner on the bottom and a daily covering of soil.  About 55% of the waste generated in the U.S. goes to landfills while around 90% of waste created in the United Kingdom is disposed in this manner.

2.     Percentage of the city’s solid waste that is disposed of in an incinerator.

In highly industrialized European countries, waste incineration plants have been used increasingly over the last 50 years, mainly because it has been more difficult to find new sites for landfills in densely populated areas. The public concern for the environmental impact from MSW incineration has, however, increased significantly over the last 20 years. That's forced manufacturers to develop, and the plants to install and operate, expensive air pollution controls.  Incineration of MSW reduces waste weight approximately 75% and volume 90%.  Waste incineration is particularly popular in countries such as Japan where land is scarce. Denmark and Sweden have been leaders in using the energy generated from incineration for more than a century, in local combined heat and power facilities supporting district heating systems. In 2005, waste incineration produced 4.8% of the electricity consumption and 13.7% of the total domestic heat consumption in Denmark However, there is significant debate about the merits of waste incineration. 

3.     Percentage of the city’s solid waste that is burned openly.

Openly burning MSW is typically a Third World problem, and it contributes to health problems, air and water pollution and GHG emissions.  In Kigali, the capital of Rwanda, a staggering 84% of solid waste is burned openly.

4.     Percentage of the city’s solid waste that is disposed in an open dump.

Open dumping of solid waste generates various environmental and health hazards.  The decomposition of organic materials produces methane, which can cause fires and explosions. In the Mexican city of Tampico  a fire burned for over six months at the local open dump.

5.     Percentage of the city’s solid waste that is disposed of by other means.

I don’t really have anything to add to this indicator as the other indicators seem fairly inclusive.

6.     Hazardous waste generation per capita.

While the definition of hazardous waste differs globally, ISO 37120 maintains an expansive view of hazardous waste as ''any substance which can be harmful to people, plants, animals or the environment,'' and which exhibits ''toxicity, flammability, corrosivity or reactivity.''   The U.S. definition of hazardous waste, determined by Congress, excludes dangerous materials such as radioactive waste, toxic household waste, oil and gas drilling waste, and many other obviously hazardous materials.  As a result, U.S. hazardous waste laws do not regulate 95% of the country’s hazardous waste.  The EPA estimates that the U.S. generates 40M tons of hazardous waste annually.

7.     Percentage of city’s hazardous waste that is recycled.

ISO 37120 does not currently draw a distinction between hazardous waste and e-waste -- the computers, mobile phones and electronic devices increasingly present in our lives.  An estimated 50 million tons of e-waste  are produced each year, in part from the 30 million computers discarded each year in the U.S. and the 100 million phones disposed of in Europe annually. The EPA estimates that only 15-20% of e-waste is recycled.


George Karayannis  has over 25 years of emerging technology and complex solutions sales, business development and marketing experience. He is currently Director Utility Sales, Trimble Energy and has held leadership positions at Schneider Electric, Lockheed Martin Energy Solutions, AT&T and wireless sensor startups.  He has also served as a city councilman and is restoring a 100-year old opera house to LEED Gold status. @gkarayannis

Next in the series: –Telecommunications and innovation indicators for smart cities

Previously in our Dissecting ISO 37120 series: