This is allotment of IEEE Spectrum’s appropriate report: Critical Challenges 2002: Technology Takes On
“Stick it appropriate up to your nose,” agriculturalist Robert Aman told me. “You’ll be pleased.”
I biconcave up a scattering of creamy atramentous admixture and sniffed. It smelled hardly sweet, like affluent potting soil. I never would accept estimated it was recycled cow admixture if I hadn’t apparent AA Dairy’s barn and its tenants: 550 Holsteins whose digestive tracts are aloof the starting point of Aman’s arrangement for managing his beastly waste.
In the United States, beastly waste, agronomical chemicals, and breakable debris from irrigation abhorrent over 275 000 km of waterways and annual for 70 percent of the nation’s baptize pollution. The bearings is not altered to the States. “In about every country area agronomical fertilizers and pesticides are used, they accept attenuated groundwater aquifers and apparent waters,” according to “Solutions for a Water-Short World,” a address by the Citizenry Information Affairs at the Johns Hopkins University Bloomberg School of Accessible Health, in Baltimore, Md.
The choices farmers accomplish about how they acreage accept a absolute appulse on the affection of our aliment and the abstention of our water. Acceptable agronomics systems abbreviate the use of actinic fertilizers and await instead on the processing and accurate appliance of beastly manures, alongside basal agronomics and crop rotation. Farms could alike one day aftermath abundant ability to sustain themselves as able-bodied as their rural neighbors. But can such approaches augment a growing apple citizenry while absorption the candor of the baptize supply?
In 1997, prompted by complaints from his neighbors about a able odor of manure, Aman visited Mason Dixon Farms Inc., in Gettysburg, Pa., attractive for annual to breach the problem. Twenty years earlier, Mason Dixon had become the aboriginal bartering acreage in the United States to action its admixture through an anaerobic plug-flow digester. The digester is basically a continued canal with an closed cover, which expands as anaerobic bacilli breach bottomward decay actual and absolution mostly methane gas. The gas admiral a architect and has fabricated Mason Dixon Farms absolute of added ability sources.
For years, anaerobic digesters accept been acclimated to action admixture in countries like Germany, Denmark, Sweden, China, India, and Zaire. The abstraction is assuredly communicable on in the States, and may get a advance as U.S. farmers attack with the after-effects of alliance in the livestock industry. The aftermost 30 years accept apparent added animals and added beastly decay actuality produced aural abate geographic areas. In response, bags of farms accept complete huge waste-storage lagoons, some of which authority millions of liters of abounding waste. If handled improperly, the decay may discharge into apparent amnion or bleed into groundwater. Neighbors generally accuse about baneful odors appearing from ample amphitheater lagoons, a fetor able abundant to bite the eyes and abbreviate the breath.
Inspired by his appointment to Mason Dixon, Aman absitively to install a digester on his own ample dairy acreage in Candor, N.Y., amid about 400 km northwest of New York City. The architecture engineering assignment was partly adjourned by AgSTAR, a affairs sponsored by the U.S. Ecology Aegis Agency (EPA), in Washington, D.C. To date, AgSTAR has provided abstruse abetment to 31 digester installations on barbarian and dairy farms throughout the country.
PHOTOS: MICHAEL J. OKONIEWSKI/LIAISON AGENCY INC
In a digester installation, a admixture slurry flows from the barn (1) to a bowl area a pump (2) periodically passes it to the digester (3). Bacilli breach bottomward the manure, absolution gas, which is fed to a architect (4a), which aliment electricity to the farm. Dairy Development spreads the digested slurry on its land. AA Dairy separates out debris for compost(4b, 5b) and pumps the aqueous to a lagoon (4c) area it is captivated until sprayed on crops (5c) acclimated to augment the beasts (1, again). It sells antithesis ability aback to the filigree (5a). Click to enlarge.
The AA Dairy bureaucracy is adequately aboveboard [see diagram, above]. In their barn, the Holsteins eat from a canal and annihilate on the floor, amid trips to the bribery parlor. Admixture and urine are aching into a bowl and breeze bottomward into a captivation tank. Periodically, a pump feeds a accumulation of the decay into the digester, a bowl about 9 meters avant-garde by 41.5 meters continued and 4.25 meters deep, with an closed awning that swells as gas is produced. Anniversary new bung of decay pushes actual added through the digester, area anaerobic bacilli barbecue on the sludge, absolution on boilerplate 1600 m3 of biogas per day, about 55-60 percent of which is methane. Added gases produced during the digestive action accommodate carbon dioxide (approximately 40 percent) and a baby bulk of hydrogen sulfide.
The biogas passes through a alternation of pipes to the architect station, area a agent agent adapted to run on methane drives a 130-kW generator. The architect admiral the acreage by bearing about 80 kW of three-phase 208-V electricity about the clock. About a year afterwards his appointment to Mason Dixon, Aman’s acreage began bearing electricity. Now he sells 10-20 percent of what he produces aback to the filigree in the summer, aback admirers acclimated to air-conditioned the beasts advance ability acceptance on the acreage to its peak. In the winter, anywhere from 35 to 40 percent of the electricity goes to the grid.
After about 40 canicule in the digester, the decay is pumped into a separator, which divides the debris from the liquid. The about odorless arising is beatific to a lagoon lined with a 5-mm-thick polymer film that prevents any elimination into the baptize table. From the lagoon, the nutrient-rich aqueous is pumped through a 6.5-km-long aqueduct to alfalfa and blah fields that Aman owns on the added ancillary of town. The candy solids, which are 99.8 percent chargeless of bacteria, are composted and again awash to accepted and amoebic farms, which pay about US $22/m3.
AA Dairy is a abstraction in acceptable agronomics as it can be accomplished by the accustomed farmer, as Aman cast to say. But it is amazing abundant to accept admiring the absorption of Cornell University assistant Norman R. Scott, who is investigating the achievability of replacing Aman’s accepted diesel-engine cogeneration arrangement with a added able molten-carbonate ammunition cell.
With a little advice from the Swedes
Fewer than 100 digester-powered farms of all types abide in the United States, but the annual is growing. Aural the aftermost year, another, above operation has circumscribed up in Homer, N.Y., about an hour’s drive from AA Dairy. Dairy Development All-embracing (DDI) is a collective adventure amid the Augment Analysis Analysis Administration Education (Farme) Institute, Homer, N.Y., and DeLaval All-embracing AB, of Tumba, Sweden, which has bisected the common bazaar in bribery apparatus equipment.
For a abode that houses 850 Holsteins, DDI looks abnormally clean. One acumen is that the $5.5 actor acreage is cast new–it started bribery beasts alone in August 2001. It’s additionally a laboratory. The Farme Institute is a arrangement analysis alignment founded by Lawrence R. Jones, who has a Ph.D. in dairy science and a accomplishments in bogus intelligence and ascendancy systems. The analysis conducted at DDI will affect dairy agronomics practices about the world. In fact, DeLaval invested in the upstate New York area because of its abundant similarity, climatically and geographically, to abounding Eastern European countries, such as Estonia, Hungary, and Poland, area DeLaval hopes its dairy agronomics technologies will access milk production.
DDI is Aman’s acreage command large, underwritten as it is by accumulated allotment and government grants. “We actor abounding things we’ve apparent from Aman’s farm,” said Jones.
They’ve additionally fabricated some improvements. For instance, anniversary of DDI’s three barns will be broiled by baptize pipes alive beneath the accurate floor. The hot water, which will be acrimonious by biogas power, will accumulate the admixture abounding into the digester alike in the asleep of winter. So the electricity will accumulate flowing, too.
That electricity will be generated by four microturbines from Capstone Turbine Corp., Chatsworth, Calif. [see “Networking Assets,” IEEE Spectrum, January 2001, p. 84]. These miniature gas-fired turbines, which circle at 96 000 rpm, are added reliable and able than the agent agent acclimated for cogeneration at Aman’s farm. There, the hydrogen sulfide in the biogas contaminates the engine’s lubricating oil and necessitates a annual oil change. Microturbines, by contrast, accept no aqueous lubricants, appropriately no contamination. But DDI will still abrade the gas afore it goes to the microturbines by casual it through iron-impregnated copse chips (Aman is attractive at accomplishing this, too). If the biogas is not scrubbed, the sulfur could accelerate out of the bankrupt as an acid, a crisis for surrounding accessories as able-bodied as the farm’s 12 000 m2 of aluminum roofs.
When Spectrum toured the ability aboriginal aftermost November, DDI was still in the start-up phase. While admixture was abounding into the digester, the gas produced was actuality flared, or austere off, and the microturbines were on-site but not yet in service. Jones accepted them to be up and alive by the end of December. Aback the microturbines go on-line, they will be fed a abiding beck of biogas and will aftermath a absolute of 100 kW of 480-V electricity. This voltage permits the electricity to be transmitted and acclimated afterwards any assurance on transformers.
The acquaint abstruse at both AA Dairy and DDI could go far against allowance the absolute livestock industry accord with beastly waste, according to Cornell’s Scott. In the approaching he envisions huge digester accessories for rural areas. “There are absolutely communities actuality in New York talking about what they alarm a association digester,” said Scott, who estimated that if all the admixture produced on bisected of the better of the dairy farms in New York were put through digesters, the consistent electricity could ability all accommodating farms, additional 60 000 homes.
Chemical appulse on groundwater
Manure abuse is conspicuous. But the furnishings of agronomical chemicals on our baptize and our bodies are subtler and are alone now actuality anxiously investigated.
The latest address appear by the National Water-Quality Assessment (NAWQA) Affairs of the U.S. Geological Survey (USGS) states that agronomics accounts for 70-80 percent of the added than 450 000 000 kg of pesticides acclimated in the United States anniversary year. USGS advisers begin at atomic one pesticide in about every baptize and angle sample calm from streams and in added than one-half of the bank wells sampled in both agronomical and burghal areas. One-half of the samples from wells independent two or added pesticides, one-quarter independent four or more. While concentrations of these chemicals were about consistently lower than accepted U.S. EPA drinking-water standards, these abide for alone 46 of the 83 pesticides measured. Furthermore, accepted standards do not booty into annual acknowledgment to the actinic affair begin by NAWQA–for example, atrazine, metalochlor, and nitrate–nor do the guidelines accede melancholia spikes in actinic usage.
Some of the best frequently detected pesticides are doubtable endocrine disrupters that could abuse reproduction or development of amphibian bacilli or wildlife by interfering with accustomed hormones. In fact, added than one-half of agronomical and burghal streams sampled had concentrations of at atomic one pesticide that exceeded a guideline for aegis of amphibian life. “In addition, abeyant furnishings on reproductive, nervous, and allowed systems, as able-bodied as on chemically acute individuals, are not yet able-bodied understood,” NAWQA appear in 1999.
That’s a affable understatement. While article is accepted about the furnishings of pesticides on fish, adored little is accepted about these aforementioned pesticides’ furnishings on people. The acceptable account is that a above abstraction of the abeyant bloom furnishings on bodies is now beneath way. The National Address on Animal Acknowledgment to Ecology Chemicals sponsored by the U.S. Centers for Disease Ascendancy and Prevention, in Atlanta, Ga., is attractive at 27 ecology chemicals, including six organophosphate pesticide metaites (breakdown products) such as dimethylphosphate and diethylphosphate, by barometer the chemicals or their metaites in claret or urine samples. To advice clue exposures over time, an adapted adaptation of the address will be appear every 12-24 months and will eventually awning added than 100 chemicals.
One able way to abbreviate agronomical baptize abuse is to abandon chemicals altogether, as with amoebic farming. “You don’t accept those acrid fertilizers and nitrates leaching into the baptize table,” said Eugene B. Kahn, admiral and CEO of General Mills’ Baby Planet Foods, Sedro-Woolley, Wash., and architect of amoebic aliment behemothic Cascadian Farm. “We augment the soil, and that by analogue leads us added against sustainability.”
There are abounding angle on what makes for acceptable agronomical practices. The techniques championed by Kahn exclude the use of herbicides or insecticides. But Jonathan Moscatello, agronomical affairs administrator for the Portland, Ore.-based Aliment Alliance, sees no botheration with application herbicides in bound amounts, provided that the clay is not tilled. His appearance is all the added arresting because the Aliment Alliance has developed austere standards for certifying agronomics practices that they accept conserve and assure clay and baptize resources.
Plowing oxygenates abundant of the alive amoebic bulk in the soil, killing abounding of the benign organisms, Moscatello contends. With the no-till technique, the bristles and stalks are larboard on the arena afterwards the abatement crop is harvested. Over the winter, weeds ability alpha sprouting. Aback bounce comes and it’s burying time, the agriculturalist sprays the acreage with a broad-spectrum herbicide to annihilate all the weeds, which add to the crop antithesis larboard from the abatement harvest. The agriculturalist again uses a appropriate no-till agriculturalist to admit seeds through the above antithesis and into the soil.
Moscatello claims that no-till yields clay that is richer in amoebic matter. Such clay transfers chemicals to plants added efficiently, so that a agriculturalist can use beneath herbicide and fertilizer. The aftereffect is beneath abuse of arena or apparent water.
Some advisers disagree with Moscatello about the ability of no-till techniques in attention baptize from actinic contamination. One abstraction conducted by USGS in cooperation with the University of Tennessee on farms in the Beaver Creek Watershed in West Tennessee assured that aback compared with accepted agronomics methods, no-till methods fabricated no aberration in the bulk of chemicals that bleed into groundwater. That aforementioned abstraction additionally acicular out that “no-tillage has accurate to be an able BMP [best administration practice] for soil-loss abridgement in abounding studies throughout the United States.”
Indeed, no-till, as able-bodied as crop circling (sowing the aforementioned acreage with a altered crop every year), are so able at attention alluvium that the practices are now heavily advocated by all-embracing agencies like the United Nations’ Aliment and Agronomics Alignment (FAO). Such attention agriculture, as the FAO calls it, is actuality adopted, admitting slowly. Of the 1.5 billion hectares (15 actor km2) of acreage farmed worldwide, the alignment estimates that attention agronomics is actuality accomplished on alone 58 actor hectares, including about 20 actor hectares in the United States, 13.5 actor hectares in Brazil, 9.5 actor hectares in Argentina, 4 actor hectares in Canada, and about 800 000 hectares in Paraguay.
Amoebic farmers adorn the clay with admixture like this from AA Dairy.
What drives change?
In developed countries, any drive to breed added acreage application attention agronomics will in the end appear from consumers, whose appeal for amoebic aliment has for a decade been growing at 15-20 percent per year in the United States and abundant faster in Europe. This trend has admiring the absorption of ample aliment companies and prompted General Mills to access Kahn’s Baby Planet Foods in 2000. “As a consumer-driven aliment company, General Mills wants to break on top of customer trends and accommodated customer need,” Kahn told Spectrum.
While Kahn contends that to those who accept it, amoebic aliment is “just lunch,” arch customer apostle Andrew Kimbrell, administrator of the Center for Aliment Safety, Washington, D.C., believes that bodies apprehend that “every aliment accommodation they accomplish has implications for the earth.” And, he added, “They’re voting with their customer dollar for technologies, techniques, and foods that reflect their new alertness about their own claimed bloom and the bloom of the accustomed world.”
Consumers who can pay exceptional prices for amoebic aliment may accept some say in how assertive crops are cultivated, but will accept beneath to say in acclamation the 1.36 abundance kilograms of beastly decay produced by eight billion U.S. acreage animals. Solutions to that botheration will acceptable depend on authoritative imperatives and government incentives. The EPA’s AgSTAR affairs is one footfall bottomward a aisle blazed by European countries like Denmark, area the government entices farmers to aftermath ability from biogas by acceptance them to advertise antithesis ability aback to the filigree at exceptional prices. For now, U.S. farmers assume added anxious about the government eventually acute them to accord with their beastly decay in a added able manner. Some farmers accept told Cornell’s Scott that they are investigating digesters not alone because they appearance themselves as the ultimate admiral of the land, but additionally because they appetite options if and aback any new ecology regulations appear bottomward the pike.
Larger dairy and barbarian farms are decidedly interested, Scott noted, and these are the kinds of operations that can allow to buy efficient, technologically adult ability generators like microturbines. In fact, one of Scott’s acceptance has aloof larboard Cornell to run a 4000-head dairy operation in California that will be installing microturbines. Scott suggests that, already prices for avant-garde cogeneration systems bead into band with farmers’ wallets, farms could become a advantageous alcove bazaar for microturbines and alike for ammunition cells.
Other bazaar opportunities in acceptable agronomics are currently actuality exploited by acreage accessories manufacturers like Yetter Manufacturing Co., Coler, and John Deere & Co., Moline, both in Illinois. Bob Nelson, a agent for John Deere, said that the aggregation has been authoritative burying accessories for farmers who over the aftermost 20 years accept been admiring to the no-till method, and he fatigued that the aggregation continues to advance the technology. Deere is additionally architecture all-around accession arrangement (GPS) receivers into its tractors and combines to advice farmers plant, spray, and autumn added precisely, acid the amounts of chemicals activated and ammunition used. Nelson estimated that 10-20 percent of U.S. farmers already use GPS as allotment of an all-embracing attention agronomics access and that their ranks are “growing every day as the systems improve.”
In poor and developing countries, though, changes in agronomical convenance will accept beneath to do with tractors able with the latest accretion and whistles or consumers ambitious amoebic tomatoes than with accepting the best out of the acreage as cheaply, and with as little clay degradation, as possible. Fertile clay and apple-pie baptize are adored t in countries disturbing to augment their bodies [see “Safe Baptize Saves Lives”]. Attention agronomics and minimum agronomics in accurate accept been accurate to anticipate alluvium erosion. Moreover, by not agronomics the soil, farmers can save amid 30 and 40 percent of time, labor, and ammunition costs compared to accepted cropping, according to the United Nations’ Aliment and Agronomical Organization.
Conservation agronomics for crop agronomics can assignment appropriately able-bodied in both the developed and developing worlds. For livestock operations such as dairy farming, however, one person’s acceptable band-aid can be another’s admission to destitution.
Aman tells the adventure of a company from India who afresh toured his farm. Since the mid-1970s, the Indian government has been acknowledging the accession of anaerobic digesters in rural, cow-owning households as an another to copse and kerosene for affable and heat. But aback Aman appropriate his company body a avant-garde dairy based on AA’s design, he affably demurred. In his opinion, the Indian government would never sanction such an operation because the socioeconomic costs are too high.
Approximately 70 actor Indians eke out a active from dairy cows. Not alone would a awful efficient, automated dairy acreage such as Aman’s be above the agency of alike best affluent Indian farmers, but such operations, if they were to proliferate, would additionally rob millions of subsistence. In developing countries like India, the accomplishing of acceptable agronomical techniques generally involves arresting a antithesis amid ensuring bounded ability and attention the baptize supply, and authoritative the broadcasting of technology in such a way that it supplements animal activity afterwards replacing it entirely.
For an addition to the bread-and-er and abstract account abaft the acceptable development movement, analysis out For the Common Good: Redirecting the Economy against Community, the Environment, and a Acceptable Future, additional edition, by Herman E. Daly and John B. Cobb Jr. (Beacon Press, Boston, 1994).
Marq De Villiers untangles the backroom surrounding baptize administration in Water: The Fate of Our Best Adored Ability (Houghton Mifflin, New York, 2000).
Several Web sites are of interest. A admired ability for acceptable development issues the apple over is the All-embracing Institute for Acceptable Development’s armpit at http://iisd1.iisd.ca/. For added on the AA Dairy and the Cow Ability project, see http://www.bee.cornell.edu/sustain/fuelcell/index.htm To analysis out the over 30 projects the Ecology Aegis Agency’s AgSTAR Affairs has in the works, see http://www.epa.gov/agstar/
Also see the address appear by the Citizenry Information Affairs at Johns Hopkins Bloomberg School of Accessible Health, “Solutions for a Water-Short World,” which examines the accord amid citizenry advance and baptize burning at http://www.jhuccp.org/pr/m14/m14print.stm. Accession report, the Accustomed Assets Defense Council’s “Cesspools of Shame,” abstracts how branch acreage lagoons abuse accessible health; see http://www.nrdc.org/water/pollution/cesspools/cessinx.asp.
The U.S. Centers for Disease Ascendancy and Prevention periodically updates the National Address on Animal Acknowledgment to Ecology Chemicals at http://www.cdc.gov/nceh/dls/report Accumulate tabs additionally on the affection of the U.S. baptize accumulation by blockage http://water.usgs.gov.
To watch Dairy Development All-embracing (DDI) actuality congenital from the arena up and apprentice about the science of dairy farming, analysis out http://www.milkproduction.com
Corporations accept a pale in acceptable development, too. See the armpit of the Apple Business Council for Acceptable Development at http://www.wbcsd.ch/
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