Crap Happens
Three hundred million Americans head to the restroom multiple times a day. The amount of sludge produced staggers the mine—7 million dry tons per year and counting. And it’s not even just crap—it contains residues from everything else we put down the drain, from the detergent in your dishwasher to the chemicals used at the industrial plant down the street.
Can the United States continue to flush all that waste down the drain? Can Western-style sanitary practices be replicated throughout the developing world without breaking the natural water and nutrient cycles? And what if the answer is that each one of us needs to start taking more responsibility for where our crap winds up? It ain’t easy being green as it is, but even the most diehard enviros may not be ready to live under the same roof with a composting toilet.
Journalist Catherine Price, a contributing editor at Popular Science and a 2008 Middlebury Fellow in Environmental Reporting, gives a crap about crap. Over the course of three days, she’ll take Grist readers on a guided tour through the bowels of sewage. So grab some extra toilet paper and get ready for some straight poop on poop.
Sludge, farmer’s friend or toxic slime?
Should what we put down our sewers ultimately wind up back on our plates? Marc Samsom via Flickr
Urine, feces, menstrual blood, hair, fingernails, vomit, dead skin cells. Industrial chemicals, pharmaceuticals, soaps, shampoos, solvents, pesticides, household cleansers, hospital waste.
Sewage sludge, the viscous brown gunk left over when wastewater is treated, is more than just poop: it’s an odiferous smoothie of everything we pour down the drain. There are pathogens; there are heavy metals. PCBs, dioxins, DDT, asbestos, polio, parasitic worms, radioactive material—all have been found in sludge. Despite pretreatment programs that prevent some of the most noxious stuff from entering the public sewers, sludge can include so many toxins that the Clean Water Act lists it as a “pollutant.”
So it’s a little surprising where it ends up: Today more than half of America’s sewage sludge is spread on land as fertilizer.
Granted, this isn’t a new idea. For most of human history, our crap has ended up back on land—and it wasn’t until the past century, which brought flush toilets and public sewers to mainstream America, that using excrement as fertilizer started sounding at all strange. Sure, this system was driven partially by convenience, but it also made ecological sense: our urine and feces contain the same nutrients that plants need. Spreading it on land closes the nutrient loop; it avoids the need for chemical fertilizers. Eat, shit, fertilize, and eat again. For thousands of years, this arrangement worked just fine.
Or, rather, almost fine. As human populations grew and concentrated, health problems like cholera outbreaks inspired a push for flush toilets and public sewer systems. This led to huge improvements in public health, but resulted in a new problem: sewers mixed domestic sewage with industrial waste and spewed it untreated into rivers and lakes. The next step was sewage treatment plants, which separated liquids from solids, but in solving one issue they created yet another: the cleaner they made the water, the dirtier the leftover sludge. Adding to the challenge, as the population of the United States grew, so did the amount of sludge: we’re currently generating more than 7 million dry tons a year and counting—and we have no intention of cutting back.
Meanwhile, as a mycelium of sewer pipes spreads underneath our cities to whisk our waste away from us, Americans became increasingly squeamish about dealing with excrement. We’re now a nation of “fecaphobes,” obsessed with toilet humor but unaware and uninterested in what happens to our actual crap. We don’t want to think about it; we don’t want to deal with it. We want to flush the toilet and forget.
Sludge from Los Angeles is dumped at Green Acres, a Los Angeles-owned farm in Kern County, California.Courtesy Bakersfield Californian. The Office of Water doesn’t have the privilege of forgetting about sludge—it’s the Environmental Protection Agency department responsible for dealing with America’s sewage. In the 1990s its job got even harder: sewers and wastewater treatment facilities mandated by the 1972 Clean Water Act more than doubled the amount of sludge America produced each year, and the 1988 Ocean Dumping Act eliminated the option of getting rid of it at sea. The OW had been encouraging land application on a limited scale since the 1970s. Now, faced with limited options and a never-ending supply, it evaluated its remaining possibilities—landfilling, incineration, or land application—and settled on the cheapest option available: promoting sludge as fertilizer.
To make this palatable to the American people—or, at least, to prevent them from thinking about it too hard—the word “sludge” had to go. So the sewage industry’s main trade and lobbying organization, the Water Environment Federation, stepped in. (WEF and OW often work closely together.) It organized a “Name Change Taskforce” and sponsored a contest to come up with a different term for sludge. Rebranding was an area in which WEF had experience—originally founded in 1928 as the brown-sounding “Federation of Sewage Works Associations,” it had recently gone through its fourth name change, and had begun referring to its members, who included sewage plant operators and waste management corporations, as “water quality professionals.”
The renaming contest received over 250 entries, many of which suggested that even water quality professionals still enjoy a good poop joke. Submissions included “bioslurp,” “black gold,” “sca-doo,” “hu-doo,” “geoslime,” and “the end product”; one person proposed rebranding sludge as “R.O.S.E.” (“Recycling Of Solids Environmentally”). Critics asked whether a rose by any other name would still smell as bad, and in 1991 WEF settled on “biosolids,” a term that Sheldon Rampton, co-author of Toxic Sludge Is Good For You, suggests “must have been chosen precisely because it evokes absolutely nothing in the minds of people who hear it.”
Of course, from the wastewater treatment industry’s perspective, that was the point: they didn’t want any visuals. Armed with an empty word, their next goal was to make “biosolid” suggest something positive. So in 1992, OW and WEF joined in a “cooperative agreement” called the Biosolids National Public Acceptance Campaign and hired a public relations and lobbying firm called Powell Tate to produce a report on how to improve the public image of sludge.
The resulting campaign—“Biosolids 2000”—didn’t answer important questions, like why people living near biosolids application sites complained of health problems, or why current federal legislation still permits every business, institution and industry in the country to dump 15 kilograms (33 pounds) of untreated hazardous waste into the sewer system each month, no reporting required. It also failed to prevent 2000 and 2002 reports from EPA’s own Office of Inspector General from stating that “EPA cannot assure the public that current land application practices are protective of human health and the environment.”
And yet partially because of OW and WEF’s PR efforts, partially because of our willful ignorance, the effort to rebrand sludge as biosolids has largely been successful. Although some is still incinerated or buried in landfills, today more than 50 percent of America’s sewage sludge is spread on land.
Biosolid digesters at the Hyperion Treatment Plant in Los Angeles.Courtesy Brian RaimondiDiane Gilbert, a spokesperson for biosolids at the Hyperion Wastewater Treatment Plant in Los Angeles, is a water quality professional of the sort endorsed by the Powell Tate report. Her enthusiasm seems genuine, but like other biosolids spokespeople I interviewed, she is also a master at following the guidelines articulated in biosolids media training guides. [Sample tip: “If the reporter asks rapid fire (multiple questions), choose the easiest.”]
Enthusiastic and bubbly, Gilbert grew up in Louisiana and has been at Hyperion since 1987. But Gilbert’s involvement with sewage sludge started even earlier; with a father who worked at a wastewater treatment plant and used sludge to fertilize the family’s garden, she considers herself a poster child for land application. “I’ve been eating food fertilized with biosolids for as long as I can remember,” she told me, after I’d returned from a tour of the plant. (Tip: “Encourage the reporter to meet you at a working location.”) “So if anyone should be affected by biosolids, it should clearly be me.”
I’d come to Hyperion because I wanted to learn more about this mysterious brown substance—how it was made, how it was monitored, and how worried we should be. Eager to dispel my concerns about land application, Gilbert had originally wanted to take me to Green Acres, the 5,000-acre city-owned farm just outside of Bakersfield, where Los Angeles ships most of its treated sludge to grow various grass crops to be fed to dairy cows. (Tip: “Location visuals help enhance and give credibility to your message.”)
Unfortunately, lawyers got in the way. Green Acres is in Kern County, and residents there don’t like the idea of being the recipients of Los Angeles’ crap. So, like an increasing number of communities across America, Kern County passed a ban on the land application of sewage sludge. Los Angeles responded by suing the county, and since the lawsuit is still pending, lawyers have gotten cagey about letting reporters visit the farm.
Instead Gilbert and I grabbed sandwiches and headed for a darkened conference room at Hyperion, where Gilbert popped in a promotional movie about Green Acres. With a synthesized soundtrack reminiscent of the theme song for Doogie Howser, M.D., the movie opened with a picture of a field of wheat, its title superimposed in yellow bubbly script.
“Imagine turning arid soil that can only grow tumbleweeds and sage brush into nutrient-rich soil that can grow crops for livestock,” said a male narrator, blessed with the voice of a 1950s public service announcer. “Imagine doing this without saturating the soil with
chemicals.”
He continued, smoothly substituting euphemisms for That Which Must Not Be Named: “Now imagine tons of treated primarily organic material from wastewater treatment plants being used to change the soil through its own nitrogen, phosphate, phosphorous and other natural ingredients.”
The movie was titled, appropriately enough, “Imagine.” But instead of being a paean for peace, it invited me to imagine a world in which all of our “beneficial,” “nutrient-rich” biosolids were put to use as fertilizer—and followed a script that could have come directly from the Powell Tate report. I took a bite of my sandwich as the narrator dispelled concerns about using sewage sludge as a soil amendment. “There will always be skeptics who question the use of biosolids,” he announced, “just like there were skeptics who didn’t believe that people could fly—until the Wright Brothers proved them wrong.”
Among many others, these skeptics include two unrelated Georgia dairy farmers, Andy McElmurray and Bill Boyce. Starting in 1979 and 1986 respectively, both began using free sludge as fertilizer on their farms, a practice the city of Augusta assured them was safe. But starting in the 1990s, problems arose: hundreds of the men’s cows died, McElmurray discovered his land was contaminated with aluminum, which he attributed to the sludge, and a 1999 test found that milk from some of Boyce’s surviving cows contained thallium an element once used as rat poison—at 120 times the concentration EPA allows in drinking water.
Both farmers filed lawsuits against the city and in March 2008, U.S. District Judge Anthony Alaimo issued a 45-page ruling on one of McElmurray’s lawsuits that found that “senior EPA officials took extraordinary steps to quash scientific dissent, and any questioning of the EPA’s biosolids program.”
And that’s just the cows. Today, 16 years after the official federal sludge rules came into effect in 1993, EPA still doesn’t have a system in place to monitor or investigate sludge-related health complaints. But in 2002, a team of researchers produced the first peer- reviewed article (whose findings were recently backed up in a separate study) to both document health complaints from people who’d been exposed to sludge and explain how this exposure might have made them sick.
The long list of health problems reported by the study’s 48 participants includes asthma, fevers, nausea, vomiting, skin rashes, coughs, burning eyes and throats, sinusitis, and diarrhea. Two subjects died from Staphylococcus aureus infections acquired shortly after being exposed to freshly applied biosolids. (Interestingly, while EPA’s Office of Water—the department responsible for writing the sludge rules denies that these deaths were at all connected to biosolids exposure, EPA’s office of Research and Development approved the paper for publication and supported its conclusions.) When the researchers compared their subjects’ rate of staph infections to that of hospital patients, considered “a recognized risk group for S. Aureus,” the infection rate of the study’s subjects was approximately 25 times higher.
According to EPA paperwork, the lead author of this study, David Lewis, Ph.D., resigned from EPA in 2003. Lewis, however, says he was essentially fired for speaking out on sludge—and his former lab director backs him up. She wrote in a 2008 statement that Lewis’s termination was “involuntary” and that Lewis “was an excellent researcher and an asset to EPA science.”
Motivated by stories like these, several passionate groups—like Citizens for Sludge-Free Land, Sludge Victims and Riles (Resource Institute for Low Entropy Systems)—have dedicated themselves to fighting the land application of sludge. They run websites; they lobby politicians to try to change the rules. But as for the rest of Americans, the subject of sludge is still not something we dwell on.
Unfortunately, as arguments and lawsuits against land application pile up—not to mention the sludge itself—our days of blissful ignorance might be limited. I’d come to Hyperion not just because it had occurred to me that we should be thinking about what happens to our sewage, but because I could see a day in the not-so-distant future when we’d be forced to.
Given the inconsistency and toxicity of the ingredients in sludge, the loopholes in its regulations and the mounting criticisms against its use, I kept reaching the same conclusion: despite the Office of Water’s insistence on the safety of spreading sludge on land, we should be looking for alternatives. The United States will never stop producing shit. But there must be a better way to deal with it.
Regulating biosolids
Biosolids are regulated under what’s known colloquially (to those who speak colloquially about sewage) as the 503 Sludge Rule, which came into effect in 1993. Technically titled “40 CFR 503—Standards for the Use and Disposal of Sewage Sludge,” it’s complicated enough that EPA came out with a “Plain English” guide to help make sense of the rule’s requirements and details.
It’s not light reading, so here are the basics: The most recent version of the 503 rule regulates seven heavy metals in sludge. It also divides biosolids into two categories for land application, Class A and Class B, based on the number of detectable pathogens that they’re allowed to contain.
For biosolids to qualify as Class A, they have to be treated with a method that’s been shown to “persistently reduce pathogens in biosolids,” according to USDA agronomist Rufus Chaney, like composting or heat drying. The resulting material must contain non- detectable levels of fecal coliform or salmonella, enteric viruses and helminth ova (i.e. parasitic worms) according to EPA-specified testing methods.
Class B biosolids must also be treated to reduce pathogens, but the only pathogen reduction requirement is for fecal coliform.
To prove they qualify as Class A or Class B, biosolids can either be tested directly for pathogens, or the sewage plants can demonstrate that they’ve used a treatment process which has been proven to achieve the required level of reduction.
Class A biosolids—which can be created through methods like heat drying and composting—can be used on most land without any restrictions (hence Milorganite); Class B biosolids have regulations about where and how they can be used, including waiting periods before crops can be harvested for human consumption.
EPA doesn’t have any testing requirements for other potential contaminants like synthetic chemicals, antibiotics, hormones, pharmaceuticals, pathogens or metals not listed in the 503 guidelines, or radioactive material (which can be excreted in the urine and feces of people going through radiation therapy).
Chaney, a senior researcher at the Agricultural Research Service who is supportive of land application, claims that there’s no need to test for additional substances because “biosolids have not been found to contain levels of these materials which cause risk to humans or the environment.” He also commented in a separate message that “there has been no evidence of infection from Class B biosolids used according to EPA regulations, and certainly none from Class A biosolids products”—a statement that anti- sludge advocates criticize. As Caroline Snyder, founder of Citizens for Sludge Free Land, put it to me in an email, “Since EPA and Chaney and the rest have bent over backwards NOT to document adverse effects, have worked to COVER up adverse effects, [and] used fraudulent data in these cover-ups, it is not surprising that there is little documented evidence.”
Businesses struggle to profit from sewage sludge 0
Part 2 of Grist’s special series on poop.
“We’re trying to get the pieces bigger—ideally the size of pencil erasers,” said John “Rus” Miller, handing me a plastic packet of a brown, dry, crumbly material with the texture of couscous and the odor of manure. That’s because it was manure—in the form of dried sewage sludge. To me, it looked and smelled like shit. But when Miller looked at the pellets, he saw coal.
I was visiting a company named Enertech‘s plant in Rialto, California, because I was searching for alternatives for what we currently do with sludge—the dark brown, complex material that’s left over after wastewater is treated. Referred to as “biosolids” by the sewage industry, more than half of America’s sludge is applied to land as a soil amendment or fertilizer. However, since sludge also contains thousands of chemicals, pharmaceuticals residues, and other toxic materials that get dumped into our sewers, many call this more of a problem than a solution.
But what if we could use sludge as energy? In addition to undigested food, it contains woody material from toilet paper and billions of microorganisms from our digestive tracts and the plants where sludge is treated, all of which contain carbon. Sewage treatment plants have captured methane from their sludge for years, which can either be sold or used to run the plant—but those systems only partially reduce the volume of the sludge that’s left over. So far there’s no widespread method to create energy and get rid of the sludge at the same time.
You’d think this wouldn’t be the case. Back in 1873, before most American cities had sewer systems to begin with, Scientific American commented that “(i)t is no exaggeration that the problem of the conversion of the excremental waste of towns and people and the refuse of factories into useful materials is now engaging as much of the attention of intelligent minds throughout the world as any social question.”
Other social questions trumped sewage, though, and it’s only been recently that the cost and controversy of our current methods has inspired a new generation of intelligent minds to look for alternative solutions. Some of these, while exciting, are still embryonic, like fuel cells that use sewage-eating microbes to produce electricity, closed-loop incinerators that run off of sludge and waste oils, biofuel made from sewage-fed algae, or methods that gasify sludge into liquid fuel. But a handful of promising alternatives are already in use. One of them is SlurryCarbTM.
Enertech’s plant in Rialto, California, is producing a biofuel from processed sludge.Courtesy EnertechThe theory behind SlurryCarb is not particulary complicated: take sludge, dry it into pellets, then burn it as a carbon-neutral replacement for coal. And in fact, when I first saw Enertech’s Rialto Plant, I wasn’t particularly impressed. Flanked by a sewage treatment facility and a cement manufacturer, it blends in perfectly with its industrial surroundings. Large silos of sludge feed into an outdoor network of metal pipes; eventually, the sludge goes through a centrifuge and heat dryer and comes out as pellets on the other end.
But while the idea of burning sludge is simple, there’s a big problem: when it arrives from the wastewater treatment plant, sludge is really, really wet. Treated sludge looks like clumpy dirt but it’s actually 70 to 85 percent water, much of which has to be removed before the sludge will burn. Adding to the challenge, a lot of the liquid in sludge is locked within its cell walls. Releasing that trapped liquid takes so much energy that although plants have been pelletizing sludge for years (usually to use as fertilizer), there’s a net energy loss.
That’s where Enertech is different. Unlike a traditional heat-drying plant that uses evaporation to get rid of water—which requires a lot of energy—Enertech pressurizes its sludge so that it never boils. Then it uses controlled heat to break down the sludge’s cell walls and force them to release their water. Enertech’s overall process uses less than half as much natural gas as a traditional drying plant and produces what the company claims is a net energy gain of approximately 95 percent. Granted, that gain doesn’t take into account the energy the wastewater treatment plant used to dewater the sludge before it got to Enertech. But the system works well for Enertech’s balance sheets: not only do the treatment plants take care of some of the drying beforehand, but they have to pay Enertech a tipping fee for every ton of sludge that it accepts.
At full capacity, Enertech hopes that its Rialto plant will produce 200 dry tons of SlurryCarb per day, which prompts the obvious question of what they’re going to do with it—in most markets, dried shit doesn’t go for much. Luckily for Enertech, the answer is right next door: cement plants. Making cement produces a lot of carbon dioxide, and most cement plants run on coal—and ever tightening regulations make cement plants eager to find substitutes for the coal in their kilns. SlurryCarb, which is cheaper and has about half of the BTUs of bituminous coal, is exactly that. (It’s also a hell of a lot easier to extract.) Even better, sludge’s leftover ash contains silica, another ingredient in cement, and can be incorporated directly into the cement mixture. Cement plants therefore don’t just reduce the volume of the sludge by burning SlurryCarb—they make it disappear.
So far, Enertech has contracts with two cement companies in Southern California, and is in talks with five more. Its technique has also attracted foreign attention: the Masdar Clean Tech Fund is considering hiring Enertech to handle the biosolids produced by Masdar, a planned development in Abu Dhabi for 50,000 people that aims to be the world’s first carbon-neutral city. Back home, Miller says he’s spoken with sewage agencies in most of America’s major cities, who are watching the Rialto plant with interest. If it’s a success, Enertech hopes the SlurryCarb process might become a common way for sewage treatment plants to dispose of sludge.
“But what if you eventually produce so much that the SlurryCarb gets used in places besides cement plants?” I asked Miller when he explained that SlurryCarb could be used in other industries as a substitute for low-grade coal. “What would you do with all the ash?”
“That,” he said, “would require some pretty creative thinking.”
Which brings me to a different plastic bag. This one’s black, tucked into a shelf in my living room, and contains a collection of sewage related products that I’ve picked up in the course of my reporting. Most can be clearly traced back to sludge—a sample of SlurryCarb-like pellets from a different plant, for example, or a pouch of compost made from sludge and wood chips in an enormous building that used to be an Ikea warehouse. But one of my sewage souvenirs looks like it doesn’t belong: a jar, about the size of a pill bottle, containing tiny black chips the size and shape of a crumbled Oreo cookie. They don’t look or smell like they came from sludge—in fact, they don’t have a smell at all. The chips are glass aggregate, the sparkly material commonly seen on roofing shingles.
Minergy subjects sludge to extremely high temperatures to produce a glass aggregate used in a variety of construction materials.Barb ScheiberThe glass came from a company named Minergy, whose technology is currently being used in a plant at the North Shore Sanitary District in Illinois that won a 2008 Global Grand Project Innovation Award from the International Water Association. Instead of selling dried sludge as fuel, Minergy’s technology uses it as energy for its own process: it combusts pre-dried sludge to create temperatures so high—roughly 2400 to 2700 degrees Fahrenheit—that the minerals that would usually be left over as ash melt into molten glass. When this hot liquid is put into cold water, it shatters, creating the tiny black chips in my jar. It’s as if the sludge consumed itself, avoiding the problem of residual ash by never making it to begin with. The resulting aggregate can be used in shingles, asphalt, concrete, ceramic tiles, sandblasting grit, and a variety of other construction materials.
It’s exciting stuff, but the North Shore Sanitary District has run into a very mundane problem: human hair. Flushed down shower drains, incorporated into sludge, hair (and other similarly stringy objects) clogged NSSD’s machinery, which has been temporarily shut down as its operators work on a solution.
That’s the thing about sludge, though—it has tremendous potential for reuse, but a lot of dirty details. To find out how the various technologies stack up, I called James Smith, a senior environmental engineer who’s been at EPA for more than 40 years and has played an important role in shaping biosolids regulations. He said that the “world is watching the outcome of the SlurryCarb start-up,” and he was especially positive about a technology called the Cannibal process, which can reduce the volume of sludge produced by up to 80 percent, partially by getting different types of microbes in the sludge to eat each other. But as for the bigger question of the future of sludge?
“It depends on whose Ouija board you have,” Smith said. “I think what we’re all hoping for is [a process that leaves] very few residuals to deal with, and for whatever we do have to deal with to be the highest quality possible.”
Unfortunately, regardless of which processes emerge, all these alchemies are likely to come with a catch. The solids in wastewater are so diluted that they need to be dried before their energy is recovered, which requires a lot of energy itself. Even worse, while these technologies might prevent toxic chemicals from seeping into farmland, they also prevent nutrients from returning to the soil—a deficit that brings increased use of synthetic fertilizers and their accompanying host of problems. An ideal solution would do one without the other, nourishing the dirt without contaminating it. But until we figure out how to better segregate our waste streams, even the best new techniques will still suffer from this critical, unavoidable flaw.
Catherine Price is a contributing editor at Popular Science whose work has appeared in the New York Times, The Best American Science Writing and Slate, among many other publications. The research for this article was funded through a Middlebury Fellowship in Environmental Reporting.
