That’s Some Serious Shit

Closing the gaps for a circular economy

Cities provide great opportunities for connectivity, jobs, and culture. The proximity of everything allows for increased efficiency and maximized profits. However, one issue has always haunted urban areas – the issue of waste. With so many people concentrated in one relatively small area, waste can become a serious environmental hazard and health threat. Human excrement can carry pathogens, cause eutrophication and degrade the natural environment. Furthermore, depending on the conditions at which the waste is disposed, it can release harmful gasses such as hydrogen sulfide, nitrous oxide, and methane. To make matters worse, modern sewage contains increased levels of chemicals previously foreign to any water body, such as drugs, micro-plastics, hydrocarbons, and high quantities of detergents.

Ancient Roman sewage canal

Historically, cities have been densely polluted areas with poor water and air quality. The main way that we have, and often still do attempt, to minimize the problems is by physically removing our waste to a satisfactory distance. In some cases this meant throwing it out of the window and in more civilized times, we developed sub-terrenial canals that brought human excrement out of the city and into local water bodies. The latter provided a temporary solution to human health concerns but nothing in terms of environmental protection. This has resulted in large ecological footprints related to urbanization. Since then many cities have become more advanced in their methods of disposing of not only excrement but also other forms of waste. However, for most this historical attitude and fear of waste has unfortunately made waste into something that has to be gotten rid of, not as a potential opportunity.  

Newtown Creek wastewater treatment facility

Some cities have begun to realize the potential of sewage as biogas and even fertilizer for crops. Utilizing biogas and fertilizer potential has both economic incentive as well as reduces dependence on fossil fuels. Take the Newtown Creek wastewater treatment plant in Brooklyn, New York for example. It is the largest of 14 wastewater treatment plants in New York City. It is a state of the art facility that mixes both art and tech, with massive egg-shaped bio-digesters that decorate the skyline and generate natural gas, fertilizer, and water. Everyday this plant produces 1,200 tons of biosolids for fertilizer…. that’s a lot of shite, but can it make a difference? How much CO2 emissions could that mitigate? Assuming we use 7.35 tons of biosolids per ha of farmland in place of synthetic fertilizer, with a savings rate of 0.77 tons of CO2 per ha (when transport is considered), that would save us 45,885.7 tons of CO2 per year! The natural gas produced is injected into the grid and heats roughly 2500 homes, reducing the annual CO2 emissions by about 16,000 tons annually. This is the equivalent of removing about 3,000 cars off the road! So all in all we are talking about a reduction of about 61,885 tons of CO2 emissions for 1,000,000 people. If that doesn’t sound like a great opportunity to close the loop between waste and resources I don’t know what does.

Newtown Creek wastewater treatment facility

Another Fantastic example of a city attempting to close the holes in their economy is San Francisco. However, San Francisco has focused mainly, not on what goes down the drain but on what goes in the can. San Francisco already diverts 80% of its waste from landfills into composting or recycling programs and by 2020 it aims to be a zero waste city. Despite dealing with a similar problem, San Francisco chose a very different approach than New York. While NYC employed an infrastructural and technological approach, San Francisco took a more interdisciplinary approach that involved law, economics, and education. SF was the first city to pass a mandatory composting laws and ban a variety of environmentally unfriendly items such as styrofoam and plastic bags. They simultaneously used economic incentives such as higher collection rates for non recyclable non-compostable items. Furthermore, unlike in NYC where there are countless decentralized private companies managing trash, there is one waste collection company (Recology) in SF, allowing for smooth implementation and realization of goals. Finally, they had effective educational campaigns that promoted these programs and gained widespread public support.  The cherry on top is that this program is run fully on collection fees and does not have any substantial difference in cost to neighboring programs! Sounds like a win-win situation.

These two cities are an inspiring example of how the traditional pitfalls of cities can be flipped into collective benefits.  I think it is also a sign that it is about time that we change our perspectives about waste to an arguably more simplistic one. Let’s put it back into our economy and not let it destroy the environment. Let’s design products and infrastructure that accommodates the reality that our waste has to go somewhere. It doesn’t just disappear. Or in other words lets try to remember the old saying “One man’s trash is another man’s treasure”.

Sources

Brigham K. July 14 2018. How San Francisco sends less trash to the landfill than any other U.S city. CNBC. [Internet] [cited 2019 March 30]. Available from: https://www.cnbc.com/2018/07/13/how-san-francisco-became-a-global-leader-in-waste-management.html

Brown S, Leonard P. 2004. BIOSOLIDS AND GLOBAL WARMING : MANAGEMENT IMPACTS.

Chahbazpour D. 2017. EPA Renewable Natural Gas Technology Transfer Workshop National Grid ’ s Journey.

NYC DEP (New York City Department of Environmental Protection). 2019. Wastewater. March 30.

4 thoughts on “That’s Some Serious Shit

  1. This is a super cool idea! Though, as you mentioned in the beginning – it is not only the human waste that goes into the sewage, but also detergents, drugs, and other nasties… Do you know how well do they can be cleaned/treated out of the system?

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  2. I agree with VoiceforWords. We can certainly treat human waste and generate useful products out of it, but some pollutants are more tricky. I think what we really need to do is combine technological solutions with better education and legal enforcement.

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  3. I agree that these two cities are certainly great examples of how to deal with city waste, but I’m missing a bit of context in which those solutions came into being. Why in these two cities? Did the local governments initiate these ideas, or where they demanded by the citizens? Do you think it is likely that other large cities will also adopt these ideas?

    Personally, I feel like the image you’re describing is a bit too simplistic. I think we should also look at barriers that are stopping other cities from adopting these kinds of ideas, which I’m sure there are. If we also focus on how we can overcome them, the solutions adopted by New York and San Francisco become way more promising.

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  4. @voiceforwords considering the volumes of waste entering treatment plants, the proportions of certain pollutants are negligible – especially after being digested anaerobically. However, for more common issues, like detergents, I believe some level of processing before anaerobic digestion would be wise. @penguincampaigner I agree and think that especially law enforcement and education could significantly help change the types of waste that can reach the waste processing facilities.
    @manonauc local governments chose to implement these measures to please a desire for reduced environmental impact and reduce costs (in the case of NYC). As far as barrier in place, it really isn’t too complicated, existing infrastructure becomes more expensive to maintain over time and policy makers will eventually need to update their waste management systems. The biggest issues are the initial investment, lack of public awareness/support, and a lack of urgency. Most of the world has a very unsustainable way of managing all types of waste (ie dumping it in the ocean or rivers), if people considered waste and environmental issues more cities with the means would certainly implement similar methods. Things must be proven to work before they can be implemented as a common practice.

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