Patrick J. McNamara

Tertiary-treated municipal wastewater is a significant point source of antibiotic resistance genes into Duluth-Superior Harbor.

In this study, the impact of tertiary-treated municipal wastewater on the quantity of several antibiotic resistance determinants in Duluth-Superior Harbor was investigated by collecting surface water and sediment samples from 13 locations in Duluth-Superior Harbor, the St. Louis River, and Lake Superior. Quantitative PCR (qPCR) was used to target three different genes encoding resistance to tetracycline (tet(A), tet(X), and tet(W)), the gene encoding the integrase of class 1 integrons (intI1), and total bacterial abundance (16S rRNA genes) as well as total and human fecal contamination levels (16S rRNA genes specific to the genus Bacteroides ). The quantities of tet(A), tet(X), tet(W), intI1, total Bacteroides , and human-specific Bacteroides were typically 20-fold higher in the tertiary-treated wastewater than in nearby surface water samples. In contrast, the quantities of these genes in the St. Louis River and Lake Superior were typically below detection. Analysis of sequences of tet(W) gene fragments from four different samples collected throughout the study site supported the conclusion that tertiary-treated municipal wastewater is a point source of resistance genes into Duluth-Superior Harbor. This study demonstrates that the discharge of exceptionally treated municipal wastewater can have a statistically significant effect on the quantities of antibiotic resistance genes in otherwise pristine surface waters.

The impacts of triclosan on anaerobic community structures, function, and antimicrobial resistance.

Triclosan is a widespread antimicrobial agent that accumulates in anaerobic digesters used to treat the residual solids generated at municipal wastewater treatment plants; there is very little information, however, about how triclosan impacts microbial communities in anaerobic digesters. We investigated how triclosan impacts the community structure, function and antimicrobial resistance genes in lab-scale anaerobic digesters. Previously exposed (to triclosan) communities were amended with 5, 50, and 500 mg/kg of triclosan, corresponding to the median, 95th percentile, and 4-fold higher than maximum triclosan concentration that has been detected in U.S. biosolids. Triclosan amendment caused all of the Bacteria and Archaea communities to structurally diverge from that of the control cultures (based on ARISA). At the end of the experiment, all triclosan-amended Archaea communities had diverged from the control communities, regardless of the triclosan concentration added. In contrast, over time the Bacteria communities that were amended with lower concentrations of triclosan (5 mg/kg and 50 mg/kg) initially diverged and then reconverged with the control community structure. Methane production at 500 mg/kg was nearly half the methane production in control cultures. At 50 mg/kg, a large variability in methane production was observed, suggesting that 50 mg/kg may be a tipping point where function begins to fail in some communities. When previously unexposed communities were exposed to 500 mg triclosan/kg, function was maintained, but the abundance of a gene encoding for triclosan resistance (mexB) increased. This research suggests that triclosan could inhibit methane production in anaerobic digesters if concentrations were to increase and may also select for resistant Bacteria. In both cases, microbial community composition and exposure history alter the influence of triclosan.

The effect of thermal hydrolysis pretreatment on the anaerobic degradation of nonylphenol and short-chain nonylphenol ethoxylates in digested biosolids

The presence of micropollutants can be a concern for land application of biosolids. Of particular interest are nonylphenol diethoxylate (NP(2)EO), nonylphenol monoethoxylate (NP(1)EO), and nonylphenol (NP), collectively referred to as NPE, which accumulate in anaerobically digested biosolids and are subject to regulation based on the environmental risks associated with them. Because biosolids are a valuable nutrient resource, it is essential that we understand how various treatment processes impact the fate of NPE in biosolids. Thermal hydrolysis (TH) coupled with mesophilic anaerobic digestion (MAD) is an advanced digestion process that destroys pathogens in biosolids and increases methane yields and volatile solids destruction. We investigated the impact of thermal hydrolysis pretreatment on the subsequent biodegradation of NPE in digested biosolids. Biosolids were treated with TH, anaerobic digestion, and aerobic digestion in laboratory-scale reactors, and NPE were analyzed in the influent and effluent of the digesters. NP(2)EO and NP(1)EO have been observed to degrade to the more estrogenic NP under anaerobic conditions; therefore, changes in the ratio of NP:NPE were of interest. The increase in NP:NPE following MAD was 56%; the average increase of this ratio in four sets of TH-MAD samples, however, was only 24.6 ± 3.1%. In addition, TH experiments performed in pure water verified that, during TH, the high temperature and pressure alone did not directly destroy NPE; TH experiments with NP added to sludge also showed that NP was not destroyed by the high temperature and pressure of TH when in a more complex sludge matrix. The post-aerobic digestion phases removed NPE, regardless of whether TH pretreatment occurred. This research indicates that changes in biosolids processing can have impacts beyond just gas production and solids destruction.

Autocatalytic Pyrolysis of Wastewater Biosolids for Product Upgrading

The main goals for sustainable water resource recovery include maximizing energy generation, minimizing adverse environmental impacts, and recovering beneficial resources. Wastewater biosolids pyrolysis is a promising technology that could help facilities reach these goals because it produces biochar that is a valuable soil amendment as well as bio-oil and pyrolysis gas (py-gas) that can be used for energy. The raw bio-oil, however, is corrosive; therefore, employing it as fuel is challenging using standard equipment. A novel pyrolysis process using wastewater biosolids-derived biochar (WB-biochar) as a catalyst was investigated to decrease bio-oil and increase py-gas yield for easier energy recovery. WB-biochar catalyst increased the py-gas yield nearly 2-fold, while decreasing bio-oil production. The catalyzed bio-oil also contained fewer constituents based on GC-MS and GC-FID analyses. The energy shifted from bio-oil to py-gas, indicating the potential for easier on-site energy recovery using the relatively clean py-gas. The metals contained in wastewater biosolids played an important role in upgrading pyrolysis products. The Ca and Fe in WB-biochar reduced bio-oil yield and increased py-gas yield. The py-gas energy increase may be especially useful at water resource recovery facilities that already combust anaerobic digester biogas for energy since it may be possible to blend biogas and py-gas for combined use.

Can Autocatalytic Pyrolysis of Wastewater Biosolids be Energy Neutral and Generate Value-Added Products?

Over eight million metric dry tons of wastewater biosolids are produced annually from water resource recovery facilities (WRRFs) in the United States. WRRFs are facing multiple challenges including energy generation, nutrient recovery, and pollutant removal requirements. Autocatalytic pyrolysis of wastewater biosolids is a promising process to improve energy generation and product recovery while removing pollutants. In particular, it can generate biochar (a valuable soil amendment) as well as high-yield pyrolysis gas, which is a renewable clean energy to complement the energy requirement at WRRFs. An energy analysis of autocatalytic pyrolysis was conducted with the assumption of 10% heat loss and using the highest catalyst loading. The results showed that the autocatalytic pyrolysis at 600°C was slightly exothermic but was endothermic at 700°C and 800°C. Therefore, some py-gas was used to supply the heat for 700°C and 800°C operation. However, the remaining fraction of py-gas still reduced the energy for biosolids drying by approximately 70%. At pyrolysis temperatures of 600°C, the remaining py-gas could cover 40% of the energy for biosolids drying. In summary, autocatalytic pyrolysis of wastewater biosolids can be energy neutral and generate the value-added product, biochar.

Introductory Editorial: Water Microbiology

Microbiology Insights aims to provide researchers working in this complex, quickly developing field with online, open access to highly relevant scholarly articles by leading international researchers. In a field where the literature is ever-expanding, researchers increasingly need access to up-to-date, high quality papers on areas of specific contemporary interest. Thus, this supplement will allow readers to distinguish the signal from the noise. The editor in chief hopes that through this effort, practitioners and researchers will be aided in finding answers to some of the most complex and pressing issues of our time.

My Zapotec Museum: Violence, Capitalism, and Memory in Oaxaca, Mexico

This article offers a close reading of two sites of memory in Oaxaca’s Sierra Zapoteca: a community museum about mining in the region and the ruins of a giant textile factory. While the factory ruins are difficult to find and effectively hidden by the Zapotec peasants using the land for farming, the museum at Natividad is open to the public and celebrates the role of Zapotec miners in this industrial sector. Together, both of these sites reveal a Zapotec people’s history of industrialization and the complicated nature of capitalism and ethnic identity. In addition to dealing with each site, the essay proposes that “sites of memory” require for their meaning interactions with people through bodily experiences based on movement, sight, and touch— a sensory experience that activates memory formation. Finally, the essay reflects the author’s attempt to consider the violence of capitalism that remains largely hidden within each site. Deadly violence— that is, armed violence— seems to be a distant memory in the Sierra Zapoteca of Oaxaca, Mexico. From 1855 to 1920, Zapotec men and women from this region fought in a series of civil wars against foreign interveners, rival political opponents, and the revolutionary army of the Constitutionalists that eventually took power. They even turned against each other in a bloody regional war that forever shifted the balance of power from one town to another. I wrote about that history of violence and sacrifice among Zapotec communities using the framework of nationstate formation to explain how the memories of those struggles animated political culture for at least two generations.1 That was relatively easy, since I could use documents found in municipal, state, and national archives. More difficult to explain is another kind of violence, one that remains hidden and seemingly unacknowledged by the people of the Sierra Zapoteca. That is Ethnohistory Published by Duke University Press 672 Patrick J. McNamara the violent history of industrial capitalism that changed the lives of workers during the nineteenth and twentieth centuries and that continues to pose a threat to the people of this region today. Archival documents provide some information for the stories I want to think about in this essay, but more important are two sites of memory in the region: a small mining museum in the town of Natividad and the ruins of a giant textile factory in the Xía Valley. Although I am calling these two places “sites of memory,” I want to clarify that I am departing in important ways from Pierre Nora’s use of the term. Nora overdraws the distinction between history and memory, arguing that places themselves have filled the void in a world without history.2 I prefer Keith Basso’s emphasis on the interactions between people and places. The Apache about whom Basso writes rely on the landscape as a guidebook from the past that helps them make sense of the present. Sites of memory in this context become a stage on which the past is brought to life by people who know the language of the landscape, the code of meanings embedded in trees, rocks, streams, and mountains.3 The importance of people moving within and around particular places fits with my own understanding of how memory works as a cognitive process within the brain. I think of memory formation as an active, physiological event that transforms experience into brain wave patterns that are organized, stored, and recalled through the activation of chemical neurotransmitters.4 The factory ruins and mining museum have meaning through the bodily interaction with these places. These sites have no inherent meaning without the person; the meaning or code is activated through human contact in which meaning or memory is assigned. We need to walk through these places, touch the objects, and experience the sensation of imagining going into the earth or working within the walls of a factory. Memory formation is an active, bodily practice, a performance of consciousness that changes in the very act of recalling the past to the present. Thus sites of memory are those places outside the body that initiate memory formation.5 In this essay, I offer a brief overview of the mining museum and the factory ruins. Both of these sites reveal a Zapotec people’s history of industrialization and the complicated interaction between ethnicity and wage labor. At the heart of my inquiry lies an exploratory reflection on my own interaction with the people of the Sierra Zapoteca and these two sites. In that sense, this essay is inspired by Michael Taussig’s My Cocaine Musuem.6 I begin with the mining museum, then turn to the factory ruins, and conclude with reflections about my own Zapotec museum. Ethnohistory Published by Duke University Press Violence, Capitalism, and Memory in Oaxaca, Mexico 673 The Mining Museum at Natividad I came to the mining town of Natividad to work in a local archive and to take photos of the exterior buildings of the gold mine. There was no real archive, but the photos were easy enough to take if I did not mind people looking at me suspiciously, asking with their glances, “What is that güero [white guy] doing taking photos of our mine?” I met a local regidor, an elected official on the town council, either by chance or because someone notified him of a stranger in town. Arrón Cruz was friendly and helpful and eventually gave me a private tour of a new mining museum the community had opened the year before. The museum was quite impressive, and Cruz proved an excellent guide, along with a young woman in charge for that day. At first they said I could not take any pictures, but after I started talking about the history of the mine, about the owners and incidents that had happened at the mine, Cruz told me that I could take all the photos I wanted. The museum showed the depth of the mine and the dugout tree trunks used as ladders that miners climbed to move from one level to the next. One of the most impressive displays explained how people processed their own clumps of ore, using a round grinding stone called la rastra. The mannequin in this display bore an incongruous smile, I thought, since his unprotected hands would have been soaking in a chemical bath made up mostly of mercury. The museum boasted many old photographs, hard hats, old lamps, maps, documents, pieces of machinery, information about the miner’s union, and even a walkthrough model of the mineshaft itself. The museum is officially called Museo Comunitaria Minerero de Natividad. I learned that the miners discovered an especially rich vein in 1929 and tripled production over the next four years of operation. Around this time, the mine operated at its highest capacity, employing nearly 1,000 workers from throughout the region. Employment rates have fallen since then by more than 90 percent. Another display showed an old air compressor used to exchange bad air from the mine with oxygen from outside. The museum employee explained how it all worked, but Cruz frequently interrupted and explained things further. He had helped organize the museum, and the guide was clearly deferential to his interventions. The tour ended very nicely. With a nod from Cruz, the young woman extracted a bottle of mescal from a desk drawer and poured two glasses. Cruz and I toasted each other and our shared appreciation of this moment that brought us together. Later, Cruz and I went down a small lane and entered what looked like someone’s private residence. They had a table in a back room and we had more mescal divided between a few beers. It did Ethnohistory Published by Duke University Press 674 Patrick J. McNamara not matter that it was ten o’clock in the morning or that I had to drive my rental car back along narrow mountain roads. I was engaged in fieldwork and I had to be a good researcher. The mining museum sits near the actual mine, which is something of a relic itself. While machinery has been updated over the years, the exterior structures largely look as if they were built in the early twentieth century. The museum represents an effort by the workers and the community to tell their own story of industrial labor. It celebrates the workers of the community, the risks they took, the tools they used to work, and the equipment that kept them safe if it functioned properly. It is an objectcentered museum, with just a few letters and documents recording the series of owners and the quantity of gold extracted from the mine. In this regard, the mining museum provides the context— or rather, the metarepresentational code— people need to situate themselves as members of the community or as outsiders walking through a place intended to invoke memory formation. But the museum avoids any history of conflict that took place at the mine. No mention of the concern residents had that mining engineers had polluted the local river with cyanide. No account of the workers’ confrontation with mine owners over the right to extract a piece of ore for home processing. No story about the months of tension in the region when the owners installed an electrical fence around the property to keep people from taking their own chunks of ore. And no version of the night the workers burned down the company store after the company turned off the electricity to the fence. The administration of this museum has joined with an international organization called Musesos Comunitarios. More conflicts are likely, as an international mining company has plans to extend mining in the region. In fact, Zapotecs have already started organizing against this dangerous expansion of mining that promises limited benefits for people of the region. The Factory Ruins at Xía In stark contrast to the mining museum, the factory ruins of a giant textile mill in the Xía Valley provide no guide to interpretation, no clues to how we should think about this place. In fact, many Zapotecs of the region do not know about the factory or the ruins, and those who do know are oft

Zapotec Women: Gender, Class, and Ethnicity in Globalized Oaxaca (review)

Breton worked closely with José-León Coloch for five years in the preparation of this translation. Coloch possessed a written copy of the text and, like his father-inlaw before him, acted in the drama during public performances and knew large portions of the text by heart. This close collaboration between Breton and Coloch is, I believe, the greatest strength of the present work. A proper understanding of the text requires not only language skills, but a firm understanding of the drama’s cultural context. Breton is among the finest ethnographers working in the field of highland Maya studies today and his extensive work in Rabinal and close relationship with Coloch and others familiar with the Rabinal Achi make him uniquely prepared to not only understand the words of the text, but their underlying meaning.In this extensively revised and updated second edition of her classic ethnography, Lynn Stephen explores the intersection of gender, class, and indigenous ethnicity in southern Mexico. She provides a detailed study of how the lives of women weavers and merchants in the Zapotec-speaking town of Teotitlan del Valle, Oaxaca, have changed in response to the international demand for Oaxacan textiles. Based on Stephen’s research in Teotitlan during the mid-1980s, in 1990, and between 2001 and 2004, this volume provides a unique view of a Zapotec community balancing a rapidly advancing future in export production with an entrenched past anchored in indigenous culture. Stephen presents new information about the weaving cooperatives women have formed over the last two decades in an attempt to gain political and cultural rights within their community and standing as independent artisans within the global market. She also addresses the place of Zapotec weaving within Mexican folk art and the significance of increased migration out of Teotitlan. The women weavers and merchants collaborated with Stephen on the research for this book, and their perspectives are key to her analysis of how gender relations have changed within rituals, weaving production and marketing, local politics, and family life. Drawing on the experiences of women in Teotitlan, Stephen considers the prospects for the political, economic, and cultural participation of other indigenous women in Mexico under the policies of economic neoliberalism which have prevailed since the 1990s.