Posts Tagged ‘compost

14
Dec
08

subtlety and sweetness: bioreactor landfill

Andries Vierlingh, a 16th-century Dutch dike master, specialized in small interventions—subtle alterations in the natural environment that would bend the forces of nature to his purpose. He studied tides and currents to understand how to encourage the waters to deposit silt where he needed a dike, how to set the tides to scour a channel where he was looking for better drainage. “With subtlety and sweetness,” he wrote, “you may do much at low cost.”   He recommended patience, gentleness, and cleverness. His minimalist approach was mostly inspired by necessity. He had dirt, and he had labor in ample supply, as well as spades to bring the two in fruitful alliance. He had primitive, wind-driven pumps but often unobliging weather. Very little wood, except profusions of willow shoots with which to weave mats. No stone, except prohibitively expensive imports. Small wonder that he looked to subtlety.

In the U.S. today, true want of resources is an unaccustomed circumstance. Vierlingh’s spirit of patient minimalism is rarely practiced, I suspect in part because greater glory lies in bigger budgets and more fantastic equipment. So it is something of a surprise to find an experiment in such minimalism at Yolo County Central Landfill, in the middle of the grasslands just west of Sacramento, California.

The experiment in question is an effort to render our trash into a geologic formation, cheaply and expeditiously. That is the description of the project offered by Don Augenstein of the Institute of Environmental Management in Palo Alto. Don is a somewhat other-worldly presence, a fount of information on garbage, renewable energy, and climate change, and one of the movers behind the Yolo County outdoor garbage lab. He invited me along on a tour of the dump on the dreary Wednesday before Thanksgiving, together with a gaggle of junior college students who didn’t look wildly enthusiastic about their field trip.

yolo, trash arriving

yolo, trash arriving

Since this was a regular working day, the landfill was as busy above ground as below.  Trucks drove in large loads and small, coming in thick and fast enough to cause a backup at the gate.  Heavy equipment trundled over the mounds, compacting and molding and pushing around the fresh leavings. Piles of stuff that can be snatched from the abyss were being moved from one place to another. Concrete was being mauled into its constituent parts. A sorry pile of bathroom porcelain, sat pale and forlorn in the middle of this bustle, the still center in a vortex of industrial activity. Flocks of gulls, inevitably, wheeled above the scene, screaming as they always do.

bioreactor cell

bioreactor cell

Much of what is to be seen at Yolo is just conventional landfill and its attendant recycling activities. The proceedings remind me of a landfill in Amersfoort, in the Netherlands. But several “cells”—the lined landfill compartments in which our trash is stored until we can think of a better thing to do with it—have been rigged at Yolo as bioreactors. Leachate is judiciously circulated through these cells, which have been constructed very much like the usual layer cake of trash and daily cover, but with a subtle difference.  The daily cover itself is permeable so as to facilitate the even movement of moisture. The whole thing is topped with a layer of shred tire and then wrapped in plastic, which in turn is held in place by whole tires and wheelhubs and other  paper weights that sanitary engineers typically have ready to hand. The shred tire layer on top is to encourage the desired flow of methane gas through the dump, for more efficient extraction. The plastic wrapper prevents its escape into the atmosphere. The whole sandwich is built and monitored under the watchful eye of Ramin Yazdani, whose business card lists him as senior civil engineer at the Yolo Planning and Public Works Department.

methane to electricity

methane to electricity

The purpose of the bioreactor is to more effectively collar methane, a significant part of which goes on the lam at conventional “dry tomb” landfill despite methane capture systems. Methane doesn’t directly harm humans (as many of the other landfill effluents have the potential to do), but it is a potent greenhouse gas. “Fugitive” landfill emissions contribute significantly to global warming. However, when captured, methane is an effective fuel, and the idea behind the bioreactor is to get the trash to give up all the gas in a short, sharp burst. In this way, the trash becomes less of an environmental menace and at the same time a more economical source of fuel—a double whammy in favor of the planet.

Experiments to do the same thing are being conducted in Spain, France, Belgium and elsewhere, but in vessels specially built for the purpose. These “digesters” are expensive and require significant energy inputs. They can’t handle all the waste in the waste stream, even after recyclables are removed. And they extract far less methane from the “feed stock” than the landfill bioreactor at Yolo—which has an extraction rate of more than 95% over the course of a year.

This excellent result is achieved at low cost, both in terms of funding and energy inputs. The most remarkable “energy in” lies in the dedication and inexhaustible inventiveness of the human motors behind the experiment—Augenstein’s genius with numbers and Yazdani’s wizardry in building things that work almost out of nothing. Vierlingh would be very pleased to find out that throwing more resources at the problem delivers a less effective solution than an attentive eye and subtle adjustments in the way a landfill is put together.

ramin yazdani, monitoring underground activity

ramin yazdani, with monitoring equipment

In the meantime, the garbage at Yolo is monitored as carefully as a patient in the ICU. Continuous measurements of moisture, temperature, and pressure inside the stewing trash heap are taken, while the composition of gases that arise from it is analyzed. Workers collect leachate samples that go off to a different lab for analysis.

Regulators have yet to be persuaded that simple and subtle solutions may be more sound than big-muscle engineering, and so the collection and analysis of data proceeds patiently as does the effort to present results. I hope they succeed, because their solution seems important in a world where landfill still is the most common trash management approach. What’s more, their spirit of inspired minimalism seems to be the right recipe for a hot and nearly exhausted planet.

06
Aug
08

On Fire

In late July, a huge compost pile caught fire at the Palo Alto dump. Gigantic billows of smoke drifted off to the neighboring communities, creating considerable alarm among the residents, most of whom (understandably) don’t like to be intimate with landfill and its various effluents. Fire engines and helicopters were dispatched to extinguish the smoldering ruin, after which a crew sifted through the entire pile in search of hot spots.

Compost Pile in 2006

Compost Pile in 2006

Barbara Cimino, a spokeswoman for the fire department, sought to calm the fears of residents in the path of the smoke, explaining it was all very harmless and quickly brought under control. The Huffington post fueled the flames by adding “toxic” to its headline, although that’s unlikely, considering it was the compost pile that was laid waste, so to speak. It won’t have been more unhealthy than smoke is, generally, I should think and to be avoided, but “toxic smoke” suggests something else to me.

Cimino noted that the fire department was investigating whether a truck had brought in combustible material. That’s what caught my ear, as definitely newspeak. Compost is by definition combustible. Moreover, the process of biodegradation generates heat and smoldering fires in landfills are common, as they used to be in haystacks, where moist hay can spur biodegradation and result in spontaneous combustion). Compost can’t be any different. So however it happened, in all likelihood, it was just in the nature of things.

A couple of years ago, I got a tour of the Palo Alto landfill from the manager, who showed me the active face, the recycling operations on top of the fill, the vast closed area which holds nothing but pipes and grass on top of the fill, and the area converted to park. He drove me around and explained what was what and how things worked, grudgingly at first and much more enthusiastically when he discovered I was nothing but ears.

He’d worked at the landfill since the early 1980s and told me stories about people stealthily trying to dump motor oil when the workers weren’t looking. About a lady bringing huge loads of new cabbage patch dolls just before Christmas, which the workers rescued and gave to a not-for-profit. About another lady dragging a worker under her car as he was helping her get unstuck from a muddy spot. About yachtsmen abandoning their craft as the marina silted up. leaving the landfill crew to deal with the remains.

Sunrise over the Palo Alto Dump

Sunrise over the Palo Alto Dump

And he explained that the landfill was smoldering under the surface pretty much all the time. Usually, the workers coould tell where the hot spots were when their PVC methane collection pipes melted. There wasn’t much they could do about it except lay more pipe for methane collection.

He told me he didn’t know what he would do when the landfill closed, not too far in the future now. He didn’t have much education, being an outdoors kind of guy, but operating the heavy machinery on the landfill all those years had caused a lot of damage to his body. It left him quite a few years away from retirement but not very many options.

It was an education, as I gradually realized that landfill workers get squeezed between government organizations that demand less trash, residents who want to dump whatever they want to get rid off, regardless of regulations, and the trash itself, which is wayward, nasty, and toxic.

Many people like the park that has been created out of the part of the landfill that was closed years ago, but the landfill manager, my tourguide, would just as soon hang himself as walk around there. “It’s filthy,” he said. “and there are nasty creatures all over it–black widows, rats, and all sorts of other vermin.” We’ll have to give it to him. he knew what he was talking about.

31
Mar
08

Entente

Some time ago I wrote about the arrival of worms in my life, a moment of unanticipated but therefore not less rueful buyer’s remorse on my part. We were off to a rocky start, those worms and I, with me on the cusp of an intense and unhappy ambivalence and the worms presumably shell-shocked out of their usual complacency by unaccustomed travel. (Check out Dilemma for the original story.)

I can now happily report that we’ve worked out some form of peaceful coexistence. I add some scraps to the bin and watch the lid go down slowly, at which point I add some more scraps. Other than that, nothing happens. Whether the worms are happy or disgusted, they haven’t chosen to let me know. They are very discreet, silently chomping away at the goodies. They accept the edges of the bin as the far reaches of the universe and haven’t given any evidence of a desire to explore the world, light out for the territories, or otherwise emancipate themselves from the family circle. So the whole thing, it seems, works out on both sides.

“Seems” because I confess that I have not performed a census of the population, either by counting or weighing my critters, to see how they stack up now against the original pound. I’m heedful of Annie Dillard, who, in Pilgrim at Tinker’s Creek, creeped herself out by looking too closely at the writhing, swirling, pullulating abomination of hatching insect eggs. Not to follow her example, I have avoided too careful an examination and all I know for certain is that my wrigglers are in their bin and that they do in my leftovers, very, very slowly.

My worms are modest eaters, which is a good thing as well as a disappointment. The literature suggested that a pound of worms make short shrift with half a pound of scraps a day. Either this is a sales pitch or the population took a serious hit during the transition into my household. Anyhow, their modest appetite means I can leave them for a fortnight without a minder. It also means they aren’t making much of a dent in the overall volume of my trash. It also means that, until now at least, they aren’t really worth the effort.

25
Feb
08

The Highest Point in Drenthe

The Netherlands started out in its career in modern history as a combination of morass and hard-scrabble country. Pliny reports that the morass dwellers looked like shipwrecked sailors: “They try to warm their frozen bowels by burning mud, dug with their hands out of the earth and dried to some extent in the wind more than the sun, which one hardly ever sees.” The more stable uplands in the back country could only with the greatest effort be made to yield a meagre subsistence to small huddles of peasants. Not exactly the land of milk and honey.

The soggy lowlands were eventually improved, but the hard-scrabble uplands pretty much stayed that way into the 20th century, when the Dutch government hatched a scheme to transport garbage from the western cities, which had become overwhelmed by their own trash, to poor Drenthe, for use as soil amendments. A nice instance of what I like to think of as social metabolism, the exchange of food and ordure between urban and agricultural areas to keep the whole thing in more or less in balance.

I was born in one such trash-embarrassed city, Hilversum, which started exporting its leftovers to Drenthe in the early 1960s and lived for a while in Amersfoort, which started participating some time in the 1950s I believe. I hereby publicly take responsibility for having done my best for Drenthe.

Garbage Boil

Anyhow, what started out as a large-scale composting venture eventually got derailed by cheap chemical fertilizers. And all of that is why Drenthe has a gigantic garbage dump, repository of noncompostable trash from its early days and from trash not suitable for incineration more recently, all of it cemented together by the ashes produced by the ovens next door. More than 20 million cubic meters of unpleasantness quietly simmers below the surface of the neatly landscaped hills, like a boil in the skin of the earth.

A View of Drenthe, from Atop the Trash

In fact, the thing is still growing, as the waste stream from the west has diminished but not dried up. At more than 40 meters above sea level, it is the highest point in the entire province of Drenthe. Ironically, it is the best vantage point from which to admire the local landscape.

The dump is now also a park, very lovely if you don’t pay too much attention to the plastic bags that escape from the active face and blow about here and there before being snagged by the orange-vested workers patrolling the trails. A little visitor center at the summit maintains a guest book, in which I found the following roughly-translated entry, probably written by a high school student on a field trip: “I think it is incredibly beautiful here, but it’s a pity there’s so much trash lying around. If you guys just pick it up, it would be really nice.”

Oude Diep

At the foot of the slopes runs the peaceful little river Oude Diep, recently restored, where a father and his son are angling for fish. Putting the catch on the dinner table might would require quite a bit of optimism, it seems to me. More than I think I could muster.

19
Feb
08

Geology of Trash

My brother arranged for a tour of the local dump in Amersfoort, where I lived from 1972 to 1977 or so. I still visit occasionally because my parents are there. The tour is an outside chance, a singular piece of good luck. A regular citizen doesn’t have ready access to garbage once it’s passed into the hands of the people who make away with it. I’ve eyed the mountain from the motorway to Amsterdam, wondering how I could get close enough for a good picture.

The Outward Face

I’ve admired especially the herd of deer that maintains the grass at the appropriate height free of charge, although I’ve also seen a flock of sheep wandering like dirty clouds across the brow of the garbage tumulus. The animals are undoubtedly there to inspire warm fuzzy thoughts in the passing motorists.

Definitely, the mountain puts its best face forward, grassy slopes with cute animals turned out. But there’s no denying that, if all goes according to plan, the mountain will be the highest point in Amersfoort in some 15 to 20 years. And on top, the whole thing looks distinctly menacing, hosting a variety of recycling operations as well as ongoing dumping of materials that are too dangerous to burn.

Compost in the making




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