Circularity & Waste Management via Water Treatment

Starting Circularity in Developing Regions

We’ve always had trash. As long as we’ve been a tool-making species, we’ve been leaving our discards behind us like a particularly unglamorous trail of breadcrumbs — from rubbish piles left by prehistoric hunter-gatherers, to the refuse pits outside Athens and Rome. But how, one must ask, did we get from the occasional pit outside the city gates to literal mountains of trash looming over every major metropolis like some sort of malodorous monument to human ingenuity? The answer, as it so often is, involves a combination of clever men in suits and a spectacular failure to think things through.

Yes, there are obviously far more people now than there were in pre-industrial times. But we are also generating vastly more trash per person, and the trash we are making is far less capable of breaking down and returning to the earth. The industrial revolution greatly increased our production abilities, which was genuinely marvelous. Then came the idea of increasing sales by making things disposable, which was rather less so.

How We Got Here

Starting in the mid-1920s with the Phoebus Cartel — a delightful arrangement among lightbulb manufacturers to ensure their products burned out faster than they needed to — and continuing through the 1930s, 40s, and 50s, the rise of planned obsolescence ensured that people would be buying more and more and more, simply discarding their old things regardless of whether they still worked perfectly well. As products were expected to last a shorter amount of time, they were made more cheaply, which meant they lasted even less time, which meant they were made even more cheaply, and so on in a downward spiral that someone really ought to have noticed sooner. All throughout the twentieth century, new methods and strategies were constantly being invented to sell more stuff, and the environmental cost was something that almost no one considered at all. Consuming more was simply assumed to be the same thing as living better, a proposition that has aged about as gracefully as a mayonnaise sandwich left in the sun.

I listen to old radio shows, and I distinctly remember hearing advertisements from the 1970s for beer featuring a “special new packaging feature” — bottles that you didn’t have to pay a deposit on, because you could simply throw them away rather than return them. The announcer delivered this news with the breathless excitement of a man describing the moon landing. Such incredible progress.

The result of all this ingenuity is the linear economy we live in today: resources are extracted from the earth, made into things, those things are used briefly or not at all, and then discarded. The loop is never closed. The resources are never returned. They simply accumulate, in landfills and oceans and the digestive systems of seabirds, as a kind of permanent receipt for our transactions.

The Proposal

What follows is a description of one practical, implementable strategy for beginning to change this — not all at once, which would be both impossible and exhausting, but incrementally, starting with the largest and most tractable piece of the problem.

The approach centers on organic waste: food scraps, yard waste, and other biodegradable materials that make up somewhere between thirty and sixty percent of what most cities throw away, with the higher end of that range appearing most often in developing regions where food makes up a larger share of household expenditure and manufactured goods a smaller one. The figure varies considerably depending on the city, the country, and precisely how organic waste is defined and measured, so treat any single number with appropriate skepticism.

The proposal is to divert this organic fraction away from landfills and into anaerobic digestion facilities, where it can be broken down by microorganisms in the absence of oxygen. The outputs of this process are biogas, which can be used to generate electricity or heat, and digestate, a nutrient-rich material that functions as an effective agricultural amendment. In other words, what was previously a waste management problem becomes, with the right infrastructure, a modest power station and a fertilizer factory. It is, as such things go, a rather elegant trick.

Why This, and Why Now

The case for starting with organic waste rather than some other fraction of the waste stream is straightforward enough to state and genuinely compelling once you think it through.

Organic waste is the largest single component of the municipal waste stream in most cities, which means it represents the largest single opportunity for diversion. It is also, when it ends up in a landfill, one of the more problematic components: decomposing organic material produces methane, a greenhouse gas considerably more potent than carbon dioxide over short time horizons, and leachate, which has a tiresome habit of finding its way into groundwater. Getting organic waste out of landfills is therefore beneficial simply as a matter of reducing harm, before one even considers what useful things might be done with it instead.

There is also a subtler but important point about what removing the organic fraction does for the rest of the waste stream. Organic material is not merely the largest component of municipal waste; it is also the component that makes everything else harder to deal with. Decomposing food waste contaminates the materials around it, makes sorting more difficult and unpleasant, and reduces the value and usability of materials that might otherwise be recyclable. Once the organic fraction has been removed and routed to its own processing pathway, what remains — metals, plastics, glass, paper — is a smaller, cleaner, more manageable volume of material that is considerably easier to sort and route to appropriate facilities. Pulling out the organic fraction first is not just solving one problem; it is making every subsequent problem more tractable.

The Benefits

The benefits of a well-implemented organic diversion program are worth enumerating, because they are more numerous than one might initially expect.

Methane capture and energy generation. Anaerobic digestion produces biogas that can be used to generate electricity or heat. A facility processing the organic waste of a mid-sized city can generate meaningful amounts of energy — enough to power the facility itself and potentially contribute to the local grid. The alternative, which is allowing organic waste to decompose in a landfill and releasing methane into the atmosphere uncontrolled, is straightforwardly worse by any measure one cares to apply.

Reduced landfill burden. Diverting thirty to sixty percent of the waste stream from landfills significantly extends the operational life of existing facilities and reduces the need to site and build new ones, which is an undertaking that tends to be expensive, contentious, and productive of very few friends.

Agricultural soil amendment. The digestate produced by anaerobic digestion is a genuine agricultural resource. It improves soil structure, water retention, and biological activity in ways that synthetic fertilizers, whatever their other virtues, simply do not. Farmers who have access to quality digestate tend to find it worth using, which creates a demand-side pull that helps sustain the economics of the whole system.

Phosphorus recovery. This one deserves particular attention, because it connects a local waste management decision to a global strategic problem that most people have not yet heard of but probably should have.

Phosphorus is essential to all living things. It is a critical component of DNA, of cell membranes, of the molecules that transfer energy within cells. For agriculture, it is simply irreplaceable — there is no substitute, no workaround, no clever alternative. And unlike nitrogen, which can be fixed from the atmosphere by industrial processes, phosphorus must be mined from phosphate rock deposits, which are finite, geographically concentrated, and being depleted at a rate that has serious people genuinely concerned about long-term supply.

Meanwhile, we are burying phosphorus in landfills. Every ton of food waste that goes into the ground takes its phosphorus content with it, locking it away in a form that is not available to agriculture and that no one is going to go back and retrieve. We are, in effect, mining phosphorus from one hole in the ground and throwing it into another one, which is the sort of thing that sounds obviously foolish once you say it out loud.

Anaerobic digestion recovers the phosphorus in organic waste and concentrates it in the digestate, where it is available for agricultural use. A city that routes its organic waste through digestion rather than landfill is closing a nutrient loop that industrial agriculture has left gaping open. The phosphorus that grew food in the surrounding region can, in this way, return to the surrounding region’s soil — not all of it, and not perfectly efficiently, but substantially better than burying it permanently in a hole. Given the long-term supply picture for phosphate rock, this strikes most reasonable people as preferable.

A cleaner, more manageable remaining waste stream. With the organic fraction removed, what remains is considerably easier to work with. Separate collection streams for plastics, metals, glass, and paper become more practical to implement and more economically viable, because the materials being collected are cleaner and less contaminated. The organic diversion program does not just solve the organic waste problem; it simplifies every waste management challenge that comes after it.

Why Developing Regions Are the Right Place to Start

The argument for focusing initial implementation efforts on developing regions is not a condescending one — it is not that developing regions need more help, or that they are more desperate, or that they make a convenient testing ground. It is simply that developing regions represent the moment in the process where intervention is most likely to be effective.

Cities in developing regions are, in many cases, still building their waste management infrastructure. They do not yet have fifty-year-old landfill contracts, or municipal collection systems designed around assumptions that no longer serve them well, or entrenched institutional arrangements that would need to be dismantled before anything new could be built. They have the thing that developed-region cities mostly lack, which is the freedom to build something right from the beginning rather than retrofit something right after the fact. Retrofitting, as anyone who has tried to update an old house knows, is always more expensive, more complicated, and more productive of unpleasant surprises than simply building correctly in the first place.

There is also a compounding benefit specific to developing regions that goes beyond the organic waste problem itself. When a city builds organic waste collection routes from scratch, it is not only building the physical infrastructure for collecting organic waste. It is establishing collection routes that exist and function, a workforce that knows how to operate them, institutions that have learned to manage them, and — perhaps most importantly — a public that has begun to think of its waste as something separable rather than an undifferentiated mass to be handed off and forgotten.

That last point is not trivial. The habit of separating waste at the source, once established, is the foundation on which everything else is built. A city whose residents have learned to put their food scraps in one bin has done the hard cultural work that makes it possible to later ask them to put their plastics in another bin, and their metals in another, and their paper in another. Each additional material stream becomes easier to add because the conceptual and behavioral groundwork has already been laid.

In a developing-region city that is building its waste infrastructure from the ground up, the organic collection system does not just solve an organic waste problem. It becomes the first layer of what could, over time, become a genuinely circular material economy — one in which the various streams of what was formerly called waste are each routed to appropriate processing, and from there back into productive use. The organic stream was always the logical place to start, because it is the largest, the most immediately tractable, and the one whose removal makes everything else more manageable. But in a city that is still deciding what its systems will look like, starting there also means starting a process rather than merely solving a problem.

The Question of Scale

One reasonable concern about any proposal of this kind is the question of scale: does this actually work at the scale of real cities, with real populations, and the genuine complexity that entails?

The answer, based on existing implementations, is yes — with the important caveat that the specifics of implementation matter considerably and that no two cities will face exactly the same challenges. Anaerobic digestion of municipal organic waste is not a theoretical proposition. It has been implemented in various forms in cities across Europe, North America, and parts of Asia, and the basic processes are well understood. The technology is not experimental. The questions that remain are primarily logistical and economic rather than technical.

This is actually an argument in favor of starting in cities of modest size rather than immediately attempting implementation in megacities. A city of a few hundred thousand people is large enough to make the economics work and generate meaningful data, but small enough to be manageable — to identify what works and what doesn’t, to work through the challenges before the stakes get larger, and to build institutional capacity before it is needed at maximum scale.

Then move to a city of a million people and address the challenges of scale. Then perhaps a city of five million. If the system works across that range — from a few hundred thousand to five million — it can very likely work anywhere. The fundamental processes do not change with scale; only the logistics and the magnitudes do.

A Beginning

The transformation of a linear economy into a circular one is not something that happens in a single bold stroke. It happens through the accumulation of practical, fundable, implementable changes that each make things a little better and that together, over time, add up to something genuinely different.

Diverting organic waste from landfills to anaerobic digestion facilities is not the whole of circularity. It is, however, a real and achievable start — one that improves public health, supports agriculture, generates energy, returns irreplaceable nutrients to the soil, and begins to change the fundamental relationship between a city and its waste. It gets organic material back into productive cycles rather than burying it in the ground. And by removing the largest and most disruptive fraction of the waste stream first, it clears the way for everything that comes after.

The phosphorus buried in landfills today is phosphorus that cannot grow food tomorrow. The collection routes not built today are institutional capacity not available tomorrow. The habits not established today are habits that will be considerably harder to establish once a different and less tractable system has had time to entrench itself.

We have been conducting this accounting badly for a very long time, and the ledger is not balancing in our favor. Starting to close that loop — here, now, in the cities that are still deciding what their infrastructure will look like — seems like exactly the sort of obvious good idea that we will one day be astonished we took so long to pursue.

Though perhaps not too astonished. We did, after all, once celebrate the invention of the throwaway bottle.

by Eric Sparks, 2025