331 14 Treat ment of Antibiotics in Swine Wastewater Craig D. Adams 14.1 INTRODUCTION The formation and occurrence of antibiotic-resistant bacteria (especially pathogens) intheenvironmentareofsignicantconcerntosociety,andarethespecicfocusof thescienticandregulatorycommunities.InanimalagricultureintheUnitedStates andelsewhere,antibioticsareprovidedtoswinefortherapeuticreasons,aswellasfor growthpromotion.Manyantibioticsthatarefedtoorinjectedintoswinemaypass throughtheswineunmetabolizedand,therefore,endupintheswinemanurethatis passed into the treatment system. Accordingly, it is of considerable interest that an economicalandeffectivemeansoftreatingtheseantibioticspreventorminimize theirintroductionintotheenvironmentduringtheireldapplication(Figure 14.1). Contents 14.1 Introduction 331 14.2 Typical Manure Handling Systems for Swine 332 14.2.1 Interior Storage 332 14.2.2 Exterior Storage and Treatment 333 14.2.3 Multicell Lagoon Systems 334 14.2.4 Anaerobic Digestion 334 14.3 Sorption of Antibiotics in Swine Lagoons 336 14.4 Hydrolysis of A ntibiotics in Lagoons 337 14.5 Biological Treatment of Antibiotics in Conventional Swine Treatment Systems 337 14.5.1 Anaerobic Biodegradation 338 14.5.2 Aerobic Biodegradation 339 14.5.3 Inhibition of Anaerobic Biodegradation by Antibiotics in Swine Lagoons 339 14.6 Chlorine Treatment for Antibiotics in Swine Wastewater 340 14.6.1 Antibiotic Removal 340 14.6.2 Simultaneous Disinfection 342 14.6.3 Comparison of Selected Classes of Antibiotics 345 14.7 Other Treatment Approaches 345 14.8 Concluding Remarks 346 References 347 © 2008 by Taylor & Francis Group, LLC 332 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 14.2 TYPICAL MANURE HANDLING SYSTEMS FOR SWINE Swinemanureisamixtureofurineandfeces,whichoftencontainssignicantcon- centrations of antibiotics and hormones. Swine manure may typically contain only 10to20%solidsand,therefore,isgenerallyinslurryform.Thus,swinemanuregen - er ally cannot be handled using solids handling equipment. Lagoon slurry is usually dischargedthroughdirectlandapplicationtocroplands.Whiletheslurryhassig - ni cant nutrient value, it may also contain antibiotics, hormones, antibiotic-resistant organisms, as well as excessive phosphorus and other problematic contaminants. Land application of liquid slurry from anaerobic lagoons or storage basins, and anaerobic digesters, is typically achieved by using irrigation-type equipment. These systems include stationary spray guns, sprinkler systems, and controlled ooding. 14.2.1 INTERIOR STORAGE Swinemanurefromconnedproductionfacilitiesisoftenstoredineitherinterior (underoor) or exterior (lagoon) storage basins (Miner et al., 2000). The underoor basin or pit is located directly beneath the slatted oor of the building housing the swine ( Figure 14.2). The swine manure, along with excess food and other solids, fallsorisperiodicallyrinseddownintotheunderoorpit.Maximumstoragetime inatypicalunderoorpitmayrangefrom5to12months(Mineretal.,2000).Ven - ti lation of the underoor pits is critical to remove noxious gases such as hydrogen suldeandammonia,aswellascarbondioxideandmethane,fromtheconnement building.Priortoremovalfromthepit,themanuremustbeagitatedtohomogenize itsothatallofitcanbecompletelyremovedfromthepit,andtoensurethatthe FIGURE 14.1 Sludgepumpusedtotransferlagoonslurryfromlagoontoadjacentelds. © 2008 by Taylor & Francis Group, LLC Treatment of Antibiotics in Swine Wastewater 333 removed manure has uniform nutrient characteristics. Agitation is usually achieved usingpumpsplacedinmultiplelocationsalongthepitwall(Mineretal.,2000).The dischargefromunderoorstorageisgenerallyappliedtosurroundingeldsasafer - tilizer, although it is usually nonoptimal relative to nutrient p:n ratios. 14.2.2 EXTERIOR STORAGE AND TREATMENT Analternativetoanunderoorstoragebasinistheexteriorstoragebasin,commonly referredtoasa“lagoon.”Occasionally,exteriorstorageofmanureisinsteadaccom- pl ishedbyusingatanklocatedoutsidethebuilding;thisisfarlesscommon,how- ev er,thantheuseofalagoon.Generally,swinemanureiscollectedusingaslatted oordesign,andthenperiodically(e.g.,twiceperday)ushedwithwatertomoveit from the building. Inthesimplestdesign,themanureowstoasingle-ortwo-stagelagoonforstor - age and treatment, followed by periodic land application. A variation of this system rstprovidesforliquid-solidseparation,afterwhichthesolidsmaybecomposted andtheliquidpassedtoalagoonforstorageandtreatment,priortolandapplication (Miner et al., 2000). Inamoresophisticatedsystem,thewastefromthebarnismixedandpumped into an anaerobic digester. Methane generated in the process provides for energy recovery.Theefuentfromtheanaerobicdigesterisoftenpumpedintoananaerobic lagoon for storage and treatment, followed by land application (Miner et al., 2000). Avarietyoflagoonsystemsareusedforswinewastewatertreatment.Alagoon system may be a single cell, or may contain multiple cells in series. Generally, lagoons are not aerated and are, therefore, anaerobic. In some cases an aerated cell isusedforenhancingammoniaremoval. FIGURE 14.2 Insideaswinebarnatatypicalconcentratedanimalfeedoperation. © 2008 by Taylor & Francis Group, LLC 334 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems Inastandardanaerobiclagoon,swinemanureisstoreduntilthetimeofyearthat is amenable for eld application, that is, when the nutrients are needed and the ground isnotfrozen.Additionally,sometreatmentofthemanureisachievedinthelagoon andthequalityoftheslurrychangeswithtime.Ingeneral,solidsaredecreased,which makestheslurrymuchmoreamenabletoeldapplication(Mineretal.,2000).Key differences between an anaerobic digester and an anaerobic lagoon for swine waste treatment are that lagoons have no temperature control and cannot capture methane for energy recovery (unless appropriately covered). Depending on the region, in the colder winter months, anaerobic activity in a lagoon may be very low relative to that inthewarmersummermonths.Astemperaturesincreaseduringthetransitionfrom winter to summer, the excess stored organic matter may cause enhanced anaerobic activity until stored organic loads are reduced (Miner et al., 2000). 14.2.3 MULTICELL LAGOON SYSTEMS Two-andthree-celledlagoonsystems,inseries,arealsousedatsomefacilities. Typically,therstcellisoperatedasinasingle-cellsystem.Mostsolidsareretained intherstcell,whichprovidesforadditionalsolidsdecomposition.Inthenalcell, algaeoftenmaythrive,allowingbetterslurrytreatment(Mineretal.,2000).Addi - tionally, aeration is sometimes added to the nal cell to improve efuent quality. Multicelledsystemsaremorecommonwhenthelagoonwateristobeusedasthe ushingwaterforthebarns. Asanexampleoftypicaltreatmentparameters,characteristicsofswinebarn wastewaterintwodifferentlagoonsystemsstudiedbyQiangetal.(2006)arepre - s e nted in Table 14.1. For L agoonSystemA,comparisonoftheinuent(A-INF)and efuent (A-EFF) from the rst of two anaerobic cells showed a signicant reduction insolublechemicaloxygendemand(SCOD)anddissolvedorganiccarbon(DOC), while ammonia, alkalinity, pH, and UV adsorption all in creased(Table14.1).C om- parisonoftheinuentintothesecond(overow)cellanditsbulkconcentration(A- OV)(whichisperiodicallylandapplied),showedafurtherreductionofSCODand COD,aswellasammonia(Table14 .1). As econdtwo-celllagoonsystemwasalsostudied(LagoonB)thatwassimilarto Lagoon System A, except that the rst cell of the lagoon was aerated. Similar treat - me nt was achieved for SCOD and DOC. However, a much lower ammonia concen- tr ationwasachievedintheefuentoftherst(aerated)cell(B-EFF),whichhelped achieve a very low nal ammonia concentration (B-OV) in the second (nonaerated) cell. The slurry from this second cell is periodically land applied. 14.2.4 ANAEROBIC DIGESTION Swine manure is also amenable to treatment in an anaerobic digester. An anaerobic digester is enclosed so as to capture product gases (e.g., hydrogen sulde, ammonia, methane,andcarbondioxide)andtoallowefcienttreatmentoftheswinewaste. However,becausethislevelofefcientwastetreatmentisnotrequiredintheUnited States for CAFO wastes, the perceived cost associated with anaerobic digesters haslimitedtheiruseforswinemanuretreatmentintheUnitedStates.Theuseof © 2008 by Taylor & Francis Group, LLC Treatment of Antibiotics in Swine Wastewater 335 TABLE 14.1 Mean Physical-Chemical Properties of Wastewaters from Two Swine Lagoons Properties Lagoon A Raw Waste from Barn (AINF) Lagoon A Bulk Slurry from 1st (Anaerobic) Cell (A-EFF) Lagoon A Bulk Slurry from 2nd (Anaerobic) Cell (A-OV) Lagoon B Raw Waste from Barn (BINF) Lagoon B Bulk Slurry from 1st (Aerated) Cell (B-EFF) Lagoon B Bulk Slurry from 2nd (Anaerobic) Cell (B-OV) pH 7.5 8.1 8.3 7.4 8 8.5 Soluble COD (mg/L) 1102 302 145 104 248 126 Dissolved Organic Carbon (mg/L) 385 117 73 359 80 42.7±5.2 Ammonia-N (mg/L) 141 390 165 120 20 14 Nitrate-N (mg/L) 2.9 3.8 3.7 3.2 3.97 3 Nitrite-N (mg/L) ND* ND* 0.6 ND* ND* 0.1 Alkalinity (mg/L) 513 1405 620 539 723 2351 Total Dissolved Solids (mg/L) 1370 2510 1360 1430 1570 680 Conductivity (uS) 2060 3760 2035 2140 2350 1030 UV 254 nm (m -1 ) 1.8 2.2 1.1 1.7 1.5 0.7 Specic UV Absorbance (L/mg-m) 0.5 1.9 1.6 0.5 1.8 1.5 Source: Qiang et al., Ozone Science and Engineering 26, 1–13, 2006. (With permission.) * ND = Not Detected © 2008 by Taylor & Francis Group, LLC 336 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems anaerobicdigestersmayincrease,however,asmoreemphasisisplacedonenergy recovery,odorcontrol,andmoreeffectivewastetreatmentthanisprovidedbyopen storagebasinsorlagoons. 14.3 SORPTION OF ANTIBIOTICS IN SWINE LAGOONS Sorption of antibiotics to biosolids is an important mechanism that affects whether an antibioticwouldlikelybeintheaqueousphasevs.sorbedtobiosolids.Furthermore, antibioticsthatstronglysorbtobiosolidsmaytendtoexistinthesettledsolids,while weaklysorbedantibioticsmaytendtoexistpredominantlyintheslurry.Ifalagoonis notmixedpriortolandapplication,onlytheantibioticsintheslurrymaybepredomi - na ntly introduced to the environment. If the lagoon is mixed prior to land application, allantibioticsinthelagoonmay,inthatcase,bereleasedtotheenvironment. Thelinearsorptioncoefcient(K D ) (L/kg) between an antibiotic and biosolids inatreatmentprocessrepresentstheconcentrationofanantibioticsorbed(µg/kg) relative to its concentration in the liquid phase (µg/L). The linear K D model is very often used to model sorption of pharmaceuticals in sediment, solids, and soils due to the linearity of isotherms at low adsorbate concentrations. Because there are a variety of mechanisms for sorption of pharmaceuticals on the organic and inorganic solids in treatment processes, prediction of K D is complex. Sorption onto solids can involve a variety of mechanisms, including absorption into organic carbon, adsorp- ti on to mineral surfaces, ion exchange, and chemical reactions (Schwarzenbachet a l.,2003).Similarly,equilibriumsolubilityoftheantibioticintheaqueousp hase can b eaffectedbymanyfactors,includingtemperature,dissolvedsolids,andpH. Kurwadkar et al. (2007) investigated the effects of sorbate speciation on the sorption of selected sulfonamides in three loamy soils. Sulfonamides predominantly existasanionsatpHlevelsabovetheirrespectivepK 2 values (5.3–7.5) (Qiang and Adams, 2004), as neutral species at pH between their respective pK 2 and pK 1 values (1.9–2.1)(QiangandAdams,2004),andascationsbelowtheirrespectivepK 1 values. An effective K D canbeestimatedusingaweightedK D value approach (Schwarzen- bachetal.,2 003; Kurwadkar et al., 2007), that is: K D,effective = B cationic ·K D,cationic + B neutral ·K D,neutral + B anionic ·K D,anionic where K D,cationic ,K D,neutral ,andK D,anionic are the linear partition coefcients for the cationic, neutral, and anionic species, respectively, and B cationic , B neutral ,andB anionic are the fractions of each species present at a specic pH. While this study addressed sorption to soils rather than biosolids, the same general principles are likely to apply inbiosolids.Extrapolatingtobiosolids,sulfonamidesmaybeexpectedtosorbmuch lessatahigherpH(abovetheirpK 2 )duetothepredominanceoftheanionicform andmuchmoreatalowerpH(betweentheirpK 1 and pK 2 ) where the neutral form predominatesandsorptiontoorganiccarboninbiosolidsmaybemoresignicant. TypicalvaluesforlogK D are4tetracyclines,3fortylosin,and1forsulfon- amides(Loftinetal.,2004).Thereforetetracyclinesandtylosinwouldtendtosorb strongly to settled biosolids in a lagoon, whereas sulfonamides may appear in the aqueousphasetoamuchlargerdegree. © 2008 by Taylor & Francis Group, LLC Treatment of Antibiotics in Swine Wastewater 337 RelatedworkbyVienoetal.(2007)examinedremovalofantibiotics,aswellas other pharmaceuticals, in a municipal wastewater treatment plant in Finland. The study concluded that the ciprooxacin is readily “eliminated” from wastewater by sorption to biosolids due to high K D or K OW values (e.g., >4). 14.4 HYDROLYSIS OF ANTIBIOTICS IN LAGOONS Antibiotics have opportunities to hydrolyze in storage basins, anaerobic lagoons, and othertreatmentsystems.HydrolysisstudiesbyLoftinetal.(2007)wereconducted indeionizedlabwaterandlteredlagoonslurryasafunctionofpH(2−11),tem- perature (7 to 35°C), and ionic strength. This study showed that lincomycin (LNC), trimethoprim (TRM), sulfadimethoxine (SDM), sulfathiazole (STZ), sulfachlorpyr- id azine(SCP),andtylosinA(TYL)wererecalcitranttohydrolysisinlagoonslurry forpH5,7,and9.AtahigherpHof11,limitedhydrolysisofTYLwasobserved. On the other hand, the tetracyclines—oxytetracycline (OTC), chlorotetracycline (CTC), and tetracycline (TET)—were all readily hydrolyzed under anaerobic lagoon conditions at pH levels of 5, 7, 9, and 11 (Figure 14.3). Researchers, including Loftin et al. (2007), have noted that a wide range of hydrolysis byproducts of the tetra- cy clines occur under different conditions, including epi-, iso-, epi-iso-, anhydro-, and epi-anhydro-analogues. More study is warranted of the partitioning behavior of these compounds to estimate their mobility relative to the corresponding parent tetracyclines. For a temperature of 22°C or greater, half-lives of OTC, CTC, and TETwere16hoursorless(Loftinetal.,2007).Atcoldertemperatures(e.g.,7°C), nearly an order-of-magnitude slower hydrolysis was observed. Due to the signicant seasonal temperature uctuations observed in many swine lagoons, a wide range of hydrolysis rates for tetracyclines would be expected, depending on both tempera - tu reandpH.However,duetolongholdingtimes,ontheorderofmonths,complete hydrolysistobelowdetectionwouldoftenbeexpected. TylosinunderwentnohydrolysisinthepHrange5to9,butwasreadilydegraded orlabileatalkalinepH(>11)attemperaturesof22°Corgreater.Thus,tylosinwould notbeexpectedtoundergoappreciablehydrolysisinswinelagoonpHlevels.These results suggest that tylosin, lincomycin, and the sulfonamides would be expected to be recalcitrant to abiotic degradation (hydrolysis) in swine lagoons. In warmer seasons or locations, oxytetratracycline and related compounds might be expected to hydrolyzetosomegreaterorlesserdegree. 14.5 BIOLOGICAL TREATMENT OF ANTIBIOTICS IN CONVENTIONAL SWINE TREATMENT SYSTEMS Whenantibioticsenteratreatmentlagoon,therearemanypotentialtransforma- tion and partitioning reactions that can potentially occur. Transformation reactions include anaerobic or aerobic biodegradation depending on redox conditions, hydro- ly sis,andphotolysis.Partitioningreactionsforantibioticsinacommontreatment lagoon are primarily to suspended and settled solids. In the subsequent sections, these potential removal mechanisms are discussed in more detail. © 2008 by Taylor & Francis Group, LLC 338 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 14.5.1 ANAEROBIC BIODEGRADATION Very few studies have investigated the biodegradation of antibiotics in anaerobic swinelagoons.AnaerobicbiodegradationinswinelagoonslurrywasstudiedbyLof- ti netal.(2004)inlaboratorymicrocosmexperiments.Inthiswork,solubleCOD was readily removed. In these microcosms, sulfathiazole exhibited little degradation over a 2-month period (half-life = 222 days), suggesting that sulfathiazole would likely be biorecalcitrant under anaerobic conditions. This persistence also suggests overall concerns with sulfonamides in swine lagoons, that is, their presence in slurry applied to the environment. Similarly, lincomycin also was persistent with a half-life of78daysinoneslurryandnodegradationinanother. Oxytetracycline, on the other hand, appears much more readily biodegradable under anaerobic conditions with half-lives of approximately 1 month in two different slurries. For example, with a 3-month treatment time, the concentrations of oxytetra - cyclinedecreasedtoonly12%ofitsinitialvalue.Tylosinewasobservedtodegrade even more readily under anaerobic conditions with a half-life of approximately 1 day OH OH OH HO Cl HCl OH OH NH 2 OH OO O N HO HO HO H HCl HO OH NH 2 HO OO O N H HO HCl OH NH 2 OH OO O N H FIGURE 14.3 Structures of chlorotetracycline (top), oxytetracycline (middle), and tetracy- cline (bottom). (Courtesy of ChemFinder 2004, Cambridgesoft Corp.) © 2008 by Taylor & Francis Group, LLC Treatment of Antibiotics in Swine Wastewater 339 in both swine lagoon slurries studies. Abiotic degradation rates were much slower (i.e.,approximately2weeks)inthesameautoclavedslurries. Thus, the amount of anaerobic biodegradation treatment of antibiotics that would be expected is highly dependent on the nature of the antibiotics. While the sulfonamide and lincosamide were relatively recalcitrant, the tetracycline and macrolide were rela - tively easily degraded. More studies are needed in order to be able to realistically estimate and model the anaerobic biodegradation of antibiotics in swine lagoons. 14.5.2 AEROBIC BIODEGRADATION Relatively little information is available on aerobic biodegradation of antibiotics in acti- vated sludge, aerated lagoons, or other processes. Wo rk by Ingersleveta l.(2001)suggests thatantibioticsmaygenerallydegrademuchmorerapidl yundera erobic conditions than under anaerobic conditions. They examined tylosin, oxytetracycline, metronidazole, and olaquindox in laboratory microcosms and demonstrated that for these antibiotics, aerobic biodegradation was signicantly more rapid than anaerobic biodegradation. The use of aerated lagoons, and aerated “caps” (an aerobic zone as the surface layer)onanaerobiclagoons,isapotentiallyviableoptionformoreeffectivelytreat - in gantibioticsinswinewastewatertreatmentsystems.Anaerated“cap”iscreatedby oxygenating the surface layer sufciently to maintain dissolved oxygen at the surface on an otherwise anaerobic lagoon. More research in needed to better develop, opti - mi ze, and implement this technology. 14.5.3 INHIBITION OF ANAEROBIC BIODEGRADATION BY ANTIBIOTICS IN SWINE LAGOONS Swinemanureconsistsofacomplexmixtureoffats,carbohydrates,andproteins. Anaerobicbiodegradationofswinemanureoccursbyaseriesofmetabolicsteps, specically:(1)conversionofcomplexorganicstovolatilefattyacidsbyfermenta- t i veorganisms;(2)conversionofvolatilefattyacidstoacetateandhydrogenbyfatty- acid oxidizing organisms; and (3) conversion of acetate and hydrogen to methane by methanogens (archea). Because antibiotics may often be present in swine manure and, hence, in t heswinelagoonslurry,thereispotentialfortheantibioticstonega - ti vely impact the anaerobic biodegradation of other waste constituents in a lagoon. WorkbyLoftinetal.(2005)investigatedtheinhibitionofanaerobicbiological activityinswinelagoonslurryinlab-scalemicrocosmexperiments.Thisworkmon - it ored the impacts of varying concentrations of sulfonamides, tetracycline, linco- my cin, and tylosin on the production of methane, hydrogen, and volatile fatty acids, including acetate. Thesestudiesshowedasignicant(20to50%)inhibitionofmethaneproduction foralloftheantibioticsstudied.Furthermore,antibioticdosagesof1,5,and25mg/L ofaspecicantibioticallcausedsimilarinhibitions,whichingeneralplateauedat approximately20to45%.Sanzetal.(1996)alsosawaplateauingeffectforampi - c i llin, novobiocin, penicillin, kanamycin, gentamicin, spectinomycin, streptomycin, tylosin,andtetracyclinesoverawiderangeofinhibition(from0to100%).Thisrapid plateauing in the inhibition of methane productions suggested that there exist certain © 2008 by Taylor & Francis Group, LLC 340 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems bacterial subpopulations within the slurry that are greatly inhibited by antibiotics (evenatlowantibioticconcentrations[e.g.,1mg/L]),whileothersareresistanttothe effects of the antibiotics. IntheworkbyLoftinetal.(2004),nobuildupofacetateorhydrogenwas observed, suggesting that the methanogens were the microbial population most sig - ni cantlyinhibitedasmightmostcommonlybeanticipated.S imi l arly, volatile fatty acids were not observed to build up in concentration, suggesting that the fatty-acid oxidizing organisms were not the most inhibited population. Thus this work sug - gested, but did not prove, that the fermentative organisms were the most signicantly inhibited microbial population. Akeyconsequenceofthisobservedinhibitionofanaerobicmetabolismin lagoons is that the presence of antibiotics may reduce the amount of manure degra - dation achieved in a swine waste treatment system. Furthermore, these ndings sug- g e st that if the amount of antibiotics entering a lagoon could be reduced then more effective treatment might be achieved. Finally this reduction in antibiotics could potentially be attained by pretreating the wastewater between a barn and the bio - l o gicaltreatmentsystemtoremoveantibiotics,orbyreducingtheapplicationrateof antibioticsgiventotheswine.Forexample,byeliminatingtheuseofantibioticsfor growthpromotion(whereitisstillpracticed),theproblemcouldpossiblybemini - m i zedorreduced. 14.6 CHLORINE TREATMENT FOR ANTIBIOTICS IN SWINE WASTEWATER 14.6.1 A NTIBIOTIC REMOVAL Chlorinetreatmentofwastewaterfromabarn,priortodischargeintoatreatment process,isapotentialmeansofremovingantibioticsthatcouldpromoteantibiotic- resistant bacterial growth within the lagoon, or may inhibit anaerobic activity within the lagoon. Chlorine treatment of treated wastewater (e.g., lagoon slurry) prior to eld application is, similarly, a potential method for removing antibiotics, thereby preventing their introduction into the environment. Chlorine treatment prior to eld application may also have potential for removing antibiotic-resistant bacteria, therebypreventingtheirreleaseintotheenvironment. ThepHhasbeenshowntohaveahighlysignicanteffectontheoxidationrates of selected antibiotics due to the speciation of the stronger hypochlorous acid (HOCl) to the weaker hypochlorite ion (OCl - ) (Chamberlain and Adams, 2006). Because the acid dissociation constant for HOCl/OCl - is approximately 7.6, at pH levels greater than 7.6, hypochlorite will be the most prevalent oxidant species of the two. Oxidation of antibiotics and disinfection of antibiotic resistant bacteria by indi - vidual addition of free chlorine or monochloramine were studied by Qiang et al. (2006). The study looked at the oxidation of sulfonamides (sulfamethizole [SML], STZ, sulfamethazine [SMN], sulfamethoxazole [SMX], and SDM) in inuents and efuentsfromtwolagoonsystems.Bothlagoonsystemshadtwocellsinseries, with one of the lagoons utilizing aeration in its rst cell. In laboratory experiments, © 2008 by Taylor & Francis Group, LLC [...]... FIGURE 14. 6 Decomposition of sulfonamides as a function of a free chlorine (FC) dose in the influent (B-INF) and effluent (B-EFF) from the first (aerated) cell, and effluent (B-OV) from the second cell (Qiang et al., 2006 With permission) © 2008 by Taylor & Francis Group, LLC 344 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems SML SMX Treatment of Antibiotics in Swine Wastewater... limited application in large-scale animal agriculture in the current economic and regulatory climate 14. 8 CONCLUDING REMARKS The most promising approaches to limiting the discharge of antibiotics into the environment during land application appear to include: (1) reducing of the use of antibiotics © 2008 by Taylor & Francis Group, LLC Treatment of Antibiotics in Swine Wastewater 347 in animal agriculture,... characteristics of each stream for both systems are shown in Table 14. 1 Oxidation using free chlorine, or preformed monochloramine for comparison, was studied in detail to determine its effectiveness in removing of the sulfonamides Addition of free chlorine (HOCl/OCl-) to swine wastewater results in rapid conversion of the free chlorine to monochloramine, a much weaker oxidant and disinfectant than... municipal wastewater treatment plant They found that a dosage of 3 mg/ © 2008 by Taylor & Francis Group, LLC 346 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems L or greater of ozone was able to remove at least 99% of the “fast-reacting antibiotics” (i.e., with second-order rate constants of at least 5(10 4) L·mole-1·sec–1) A strong pH dependency was observed for the removal of many... Francis Group, LLC 342 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems period in which free chlorine was dominant (Figure 14. 4A) This was followed by slow further oxidation of the antibiotics by monochloramine of other oxidant species (Figure 14. 4A) The work by Qiang et al (2006) suggested that application of chlorine dosages near the breakpoint (where all ammonia is converted.. .Treatment of Antibiotics in Swine Wastewater 341 antibiotics were spiked and then treated with chlorine (or monochloramine) for three sample matrices: (1) the influent to the first cell from the barn (INF); (2) the effluent from the first cell and influent to the second cell (EFF); and (3) bulk slurry from the second cell of a swine lagoon system (OV), which is generally field applied The characteristics... complete removal of both antibiotics and bacteria (including most antibiotic-resistant bacteria) The breakpoint generally occurs at a chlorine dosage near 7.6 mg/L of free chlorine per mg/L of ammonia present This results in generally high chlorine dosages being required for oxidation of sulfonamides in swine wastewater For example, chlorine dosages between 200 and 1000 mg/L of free chlorine were required... than the sulfonamides Thus, tetracyclines and tylosin may not pose as significant a threat to the environment as these other compounds due to reduced concentrations in lagoon slurry (at least with respect to exposure) While this treatment study focused on the oxidation of sulfonamides, clean water studies of the oxidation of other antibiotics with chlorine and chloramine provide some insight as to the. .. the removal of antibiotics The second two-cell swine lagoon (Lagoon B) studied by Qiang et al (2006) had aeration in its first cell The ammonia concentration in the effluent from the second cell was only 14 mg/L as NH3-N (Table 14. 1), while the ammonia concentrations were 120 and 200 mg/L as NH3-N in the influent and effluent from the first cell, respectively Therefore, much less chlorine was required... ciprofloxacin, enrofloxacin), trimethoprim, lincomycin, -lactams (i.e., cephalexim), tetracycline, and vancomycin Other antibiotics, including N(4)-acetylsulfamethoxazole, penicillin G, and amikacin, were not as readily removed (Dodd et al., 2006) Macauley et al (2006b) examined the disinfection of swine wastewater using ozone Their results showed that bacterial disinfection based on MPN varied greatly between . LLC 332 Fate of Pharmaceuticals in the Environment and in Water Treatment Systems 14. 2 TYPICAL MANURE HANDLING SYSTEMS FOR SWINE Swinemanureisamixtureofurineandfeces,whichoftencontainssignicantcon- centrations. Fate of Pharmaceuticals in the Environment and in Water Treatment Systems Lorgreaterofozonewasabletoremoveatleast99%ofthe“fast-reactingantibiot- ics” (i.e., with second-order rate constants of. conditions, including epi-, iso-, epi-iso-, anhydro-, and epi-anhydro-analogues. More study is warranted of the partitioning behavior of these compounds to estimate their mobility relative to the corresponding