Open Access RESEARCH. Tesfu Mengistu 1*, Heluf Gebrekidan 1, Kibebew Kibret 1, Kebede Woldetsadik 2, Beneberu Shimelis 1 and Hiranmai Yadav 1

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1 DOI /s RESEARCH Comprtive effetiveness of ifferent omposting methos on the stiliztion, mturtion n snitiztion of muniipl orgni soli wstes n rie fel sluge mixtures Tesfu Mengistu 1*, Heluf Gerekin 1, Kieew Kiret 1, Keee Woletsik 2, Beneeru Shimelis 1 n Hirnmi Yv 1 Open Aess Astrt Bkgroun: Composting is one of the integrte wste mngement strtegies use for the reyling of orgni wstes into useful prout. Composting methos vry in urtion of eomposition n poteny of stility, mturity n snittion. This stuy ws ime to investigte the omprtive effetiveness of four ifferent methos of omposting viz. winrow omposting (), Vermiomposting (), pit omposting () n omine winrow n vermiomposting (W) on the stiliztion, mturtion n snitiztion of mixtures of muniipl soli orgni wste n rie fel sluge. Methos: The omposting tretments were rrnge in ompletely rnomize lok esign with three replitions. The hnges in physio-hemil n iologil hrteristis of the ompost were exmine t 20 ys intervl for 100 ys using stnr lortory proeures. The nlysis of vrine ws performe using SAS softwre n the signifint ifferenes were etermine using Fisher s LSD test t P 0.05 level. Results: The evolution of omposting temperture, ph, EC, NH + 4, NO 3, NH+ 4 :NO 3 rtio, OC, C:N rtio n totl voltile solis vrie signifintly mong the omposting methos n with omposting time. The evolution of totl nitrogen n germintion inex lso vrie signifintly (P 0.001) with time, ut their vrition mong the omposting methos ws not signifint (P > 0.05). Exept for, ll other methos of omposting stisfie ll the inies for stility/mturity of ompost t the 60th y of smpling; wheres hieve the ritil limit vlues for most of the inies t the 80th y. A highly signifint ifferenes (P 0.001) were note mong the omposting methos with regr to their effetiveness in eliminting pthogens (fel oliforms n helminth eggs). The W metho ws most effiient in eliminting the pthogens omplying with WHO s stnr. Conlusion: Turne winrow omposting n omposting involving erthworms hstene the ioegrtion proess of orgni wstes n result in the proution of stle ompost erlier thn the tritionl pit metho of omposting. The W metho is most effiient in keeping the pthogens elow the threshol level. Thus, elimintion of pthogens from omposts eing ritil onsiertion, this stuy woul reommen this metho for omposting orgni wstes involving humn exret. *Corresponene: tesft.menge@gmil.om 1 Shool of Nturl Resoures Mngement n Environmentl Sienes, Hrmy University, P.O.Box 138, Dire Dw, Ethiopi Full list of uthor informtion is ville t the en of the rtile The Author(s) This rtile is istriute uner the terms of the Cretive Commons Attriution 4.0 Interntionl Liense ( whih permits unrestrite use, istriution, n reproution in ny meium, provie you give pproprite reit to the originl uthor(s) n the soure, provie link to the Cretive Commons liense, n inite if hnges were me.

2 Pge 2 of 16 Keywors: Composting, Fel oliform, Fel sluge, Helminth egg, Muniipl soli wste, Mturtion, Snitiztion, Stiliztion, Vermiomposting Bkgroun As in mny other ities of the eveloping ountries, the rpi urniztion n high popultion growth of Dire Dw (Ethiopi s 2n lrgest ity) hve resulte into signifint inrese in genertion of wstes from omesti n ommeril tivities, posing numerous questions onerning the equy of the urrent wste mngement systems, n their ssoite environmentl, eonomil n soil implitions. A report y Beneeru et l. (2012) epite tht, espite the gret efforts me y the Dire Dw ity muniiplity, it hs een hrly possile to meet the ever-inresing wste mngement servie emn of the ity equtely n effetively. The per pit wste genertion rte of the ity is reporte to e 0.3 kg y 1 n the ity genertes n estimte quntity of 77 tonnes of soli wstes per y (Community Development Reserh 2011). The sme report inite tht, s there is very limite or no effort to reyle, reuse or reover the wste tht is eing generte; wste isposl hs een the mjor moe of wste mngement prtie. It hs een oserve tht the inisriminte umping of wstes into the lnfill is resulting in unexpetely fster filling up of the ity s snitry lnfill whih woul, thus, likely e none in the ner future thn ntiipte 30 yers (Beneeru et l. 2012). In ition to the muniipl soli wstes (MSW), the humn exret lso onstitute signifint omponent of wstes generte from Dire Dw ity. Fel sluge (FS) umulting in the ommonly use on-site snittion systems re perioilly ollete n umpe inisrimintely into its well-engineere sluge ewtering n rying e. The fel sluge, fter eing rie in the es, sine it hs no purpose in Dire Dw, ws oserve to e exvte from the rying es n ispose in the lnfill site. It is, therefore, of prmount importne to estlish eonomilly vile, environmentlly sustinle n soilly eptle metho of wste mngement for the sustinle evelopment of the ity. Bunel et l. (2010) suggeste tht griulturl pplition of orgni soli wstes, s nutrient soure for plnts n s soil onitioner, is the most ost effetive muniipl soli wste (MSW) isposl option euse of its vntges over tritionl mens, suh s ln filling or ininertion. Though, humn wstes re rih soure of orgni mtter n inorgni plnt nutrients n therefore use to support foo proution, their use without prior stiliztion represents high risk euse of the potentilly negtive effets of ny phytotoxi sustnes or pthogens they my ontin (Gri et l. 1993). Applition of rw wstes my inhiit see germintion, reue plnt growth n mge rops y ompeting for oxygen or using phytotoxiity to plnts ue to insuffiient ioegrtion of orgni mtter (Brewer n Sullivn 2003; Coopern et l. 2003). Moreover, the reuse of untrete fees for griulturl purposes n use gret helth risk, euse gret numer of pthogens suh s teri, viruses n helminthes n e foun in humn exret (Gllizzi 2003). Therefore, the mngement of urn soli wstes involving humn exret for reyling in griulture shoul neessrily inorporte snitiztion, stiliztion n mturtion spets to minimize potentil isese trnsmission n to otin more stilize n mture prout for pplition to soil (Crr et l. 1995). Composting n vermiomposting re two of the estknown proesses for iologil stiliztion of soli orgni wstes y trnsforming them into sfer n more stilize mteril tht n e use s soure of nutrients n soil onitioner in griulturl pplitions (Lzno et l. 2008; Bernl et l. 2009; Domínguez n Ewrs 2010). Composting involves the elerte egrtion of orgni mtter y miroorgnisms uner ontrolle onitions, in whih the orgni mteril unergoes hrteristi thermophili stge tht llows snitiztion of the wste y elimintion of pthogeni miroorgnisms (Lung et l. 2001). Vermiomposting, on the other hn, is emerging s the most pproprite lterntive to onventionl eroi omposting (Yv et l. 2010) n it involves the io-oxition n stiliztion of orgni mteril y the joint tion of erthworms n miroorgnisms (Lzno et l. 2008). More reently, omining thermophili omposting n vermiomposting hs een onsiere s wy of hieving stilize sustrtes (Tognetti et l. 2007). Thermophili omposting results in snitiztion of wstes n elimintion of toxi ompouns while the susequent vermiomposting reues prtile size n inreses nutrient vilility (Muponi et l. 2010). Composting methos iffer in urtion of eomposition n poteny of stility n mturity (Iql et l. 2012). Due to the eologil n helth onerns of humn wstes, extensive reserh hs een onute to stuy the omposting proess n to evlute methos to esrie the stility, mturity n snittion of ompost prior to its griulturl use (Brewer n Sullivn 2003; Zmor-Nhum et l. 2005). Although severl stuies hve

3 Pge 3 of 16 resse the optimiztion of omposting, vermiomposting or omposting with susequent vermiomposting of vrious orgni wstes (Dominguez et l. 1997; Freerikson et l. 1997; Negw n Thompson 2001; Tognetti et l. 2005, 2007; Lzno et l. 2008; Muponi et l. 2010), informtion on the effetiveness of the ifferent omposting methos on ioegrtion n snitiztion of mixtures of MSW n rie fel sluge (DFS) is snt. Moreover, regring the snitiztion effiieny of the ifferent omposting tehniques, ontroversil reports hve een presente in ifferent litertures. Severl reserhers reporte the effetiveness of thermophili omposting in eliminting pthogeni orgnisms (Koné et l. 2007; Vinnerås 2007; Muponi et l. 2010). However, few stuies on omposting of soure-seprte fees lime tht suffiiently high temperture for pthogen estrution is iffiult to hieve (Bjorklun 2002; Niwg et l. 2009). Similrly, in vermiomposting, some stuies hve provie eviene of suppression of pthogens (Monroy et l. 2008; Roriguez-Cnhe et l. 2010; Estmn et l. 2001), while others (Bowmn et l. 2006; Hill et l. 2013) emonstrte the insignifint effet of vermiomposting in reuing Asris summ ov s ompre to omposting without worms. The effetiveness of vermiomposting for pthogen estrution ws still remining unler ue to onfliting informtion in the literture (Hill et l. 2013); the present senrio thus, lls for further explortion. Aoringly, the present stuy ttempte to investigte the omprtive effetiveness of four ifferent methos of omposting viz. winrow omposting (), Vermiomposting (), pit omposting (), n omine winrow n vermiomposting (W) on the stiliztion, mturtion n snitiztion of mixtures of MSW n rie fel sluge. Methos Experimentl site, wstes n erthworms utilize The stuy ws rrie out t Dire Dw, ity in Estern Ethiopi lote t 9 6 N, 41 8 E n t n ltitue of 1197 m ove se level. The Muniipl soli orgni wste use in this stuy ws otine from oor-tooor wste olletion servie provie y the Snittion n Beutifition Ageny (SBA) of Dire Dw ity, in whih the wstes were ollete from vrious lotions in the ity. The rie fel ke whih ws out to e exvte from the rying e n umpe to the lnfill site ws ollete from the umping site. The grge reeives mixe orgni n inorgni omesti wstes, upon rrivl to the omposting site; the wstes were spre flt on the groun n sorte mnully into orgni n non-orgni frtions. All the ompostle omponents were shree mnully into smll piees of prtile sizes rnging from 3 to 5 m s esrie y Pis n Wut (2013). The shree MSW n rie fel sluge were then mixe mnully in 2:1 mix rtio. The erthworm speies (Eiseni foeti) were otine from Hrmy University. Mture erthworms n their ooons were rought to Dire Dw, where they were me to e multiplie (rere) for out 4 months using ow ung s meium. Composting tretments The methos of omposting teste were: turne winrow omposting (), pit omposting () ( omposting metho ommonly prtie y frmers of the stuy re), vermiomposting () n omine winrow n vermiomposting (W). The omposting ws one in outoor ut uner she onition. Three replites of eh of the four omposting methos were me eing rrnge in ompletely rnomize lok esign. Eh omposting pile ws overe with lyer of ry grss (5 m) to prevent exessive loss of moisture. ) Winrow omposting: In the thermophili omposting, the homogenize feestok of 1 m 3 volume (~275 kg ry weight) ws hepe into onil piles in out 1 m 2 re fter eing wette with wter to 50 60% (Mso n Blsi 2008). ) Pit omposting homogenize feestok with the sme moisture level s in ws fille in pit with imension of m (length with n epth). ) Vermiomposting: Vermiomposting ws performe in vermiompost e mesuring m (length, with n height respetively) frme with riks where the wlls n ottom of the struture ws line with polyethylene sheet. In orer to rin the exess wter, the ottom of the polyethylene sheet ws me to hve tiny holes. Mture erthworms (E. foeti) were introue t the reommene stoking rte of 250 ult worms per 20 kg of io-wste (Pmvthimm et l. 2008). The moisture ontent of the mteril ws mintine etween 70 n 80% (Mso n Blsi 2008). ) Comine winrow omposting n vermiomposting: Thermophili omposting of the wstes ws one in sme mnner s in winrow omposting n the pile sustrte ws llowe to e omposte until the temperture ws roppe to mesophili phse. After the ompletion of the thermophili phse (15 ys fter the initition of the proess), the susequent vermiomposting ontinue using erthworms (E. foeti) s esrie uner vermiomposting (Muponi et l. 2010). The pille heps in were turne n mixe every week while the sustrtes in other methos of

4 Pge 4 of 16 omposting were left intt. The moisture ontent of eh pile ws heke every week n juste oringly. The ompost mss in W reeive the sme tretment s n uring the thermophili n mesophili phses of omposting respetively. The tempertures in eh hep ws mesure ily with temperture proe from rnomly selete ples (entre, ottom n top) throughout the proess. Compost smpling n nlysis Smpling proeure To evlute the vrious physil, hemil n iologil trnsformtions of the ompost, representtive smples were ollete from four ifferent points of the ompost pile (ottom, surfe, sie n entre) of eh pile t every 20 ys (20, 40, 60, 80 n 100 ys). All the smples were sele in plsti ontiners n trnsporte immeitely to the lortory using n ie ox. Up on their rrivl to the lortory, the smples were store in refrigertor t 4 C until they were nlyse. Physiohemil n miroil nlyses were rrie out t Hrmy University following stnr proeures. Physio hemil nlysis of ompost Moisture ontent ws etermine s weight loss upon rying in n oven t 105 C to onstnt weight (Lzno et l. 2008). Totl nitrogen (TN) n orgni ron (OC) were etermine using rie ompost smples whih were groun to pss through 2-mm sieve s esrie y Pis n Wut (2013). For the etermintion of totl N, smples were eompose using onentrte H 2 SO 4 n tlyst mixture in Kjelhl flsk n susequently, N ontent in the igest ws etermine following stem istilltion n titrtion metho (Bremner n Mulvney 1982). Orgni ron ws estimte y ihromte wet igestion n rpi titrtion methos s esrie y Wlkley n Blk (1934). Totl voltile solis ws etermine s weight loss on ignition t 550 C for 4 h in muffle furne s esrie y Lzno et l. (2008). Ammonium N (NH + 4 N) ws etermine from 0.2 ml liquot of 0.5 M K 2 SO 4 extrt of the filtrte fter olour evelopment with soium nitroprussie, wheres, Nitrte N (NO 3 N) ws etermine in seprte liquot (0.5 ml) fter olour evelopment with 5% sliyli i using spetrophotometer (Okleo et l. 2002). Anlysis for ph n eletril onutivity (EC) were performe in extrts of 1:10 (w/v) ompost: istille wter rtio s esrie y Negw n Thompson (2001). The C:N rtio ws lulte using the iniviul vlues of OC n TN. Compost phytotoxiity test For etermining ompost phytotoxiity, moifie phytotoxiity test employing see germintion ws use (Zuoni et l. 1981). A 10 g of sreene ompost smple ws shken with 100 ml of istille wter for n hour, then the suspension ws entrifuge t 3000 rpm for 15 min n the superntnt ws filtere through Whtmn No 42 filter pper. Numer 2 Whtmn filter pper ws ple insie sterilize petri ish n wette with 9 ml of the extrt, 30 tomto sees (Solnum esulentum L.) were ple on the pper. Nine ml of istille wter ws use s ontrol n ll experiments were run in triplite (Wu et l. 2000). The petri ishes were kept in the rk for 4 ys t room temperture. At the en of the 4th y, the germintion inex (GI) ws lulte using the following formul (Selim et l. 2012). Germintion Inex (%) See germintion (%) root elongtion (%) = 100 Fel oliform nlysis For the etermintion of fel oliforms in the initil rw mterils n in the omposts the proeures esrie y Muponi et l. (2010) were employe. Aseptilly weighe 10 g smples of either wste mixture or fresh ompost were e to 90 ml of istille wter previously utolve t 121 C for 15 min n the suspensions were then mixe using lener to ensure thorough mixing. Aitionl seril ilutions were me up to A 0.1 ml liquot of eh ilution ws plte, in triplite, in pproprite mei-violet Re Bile Agr (VBA) (Vuorinen n Shrinen 1997). The pltes were then mintine in n inutor t onstnt temperture of 44 C for 24 h. For eh of the tretment smples the numers of fel oliforms were expresse s log 10 CFU (olony forming unit) per grm of fresh smple n verge vlues were lulte. Helminth eggs reovery The etermintion of helminth egg in this stuy ws one se on the US EPA protool (1999) moifie y Shwrtzro (2003). The nlysis ws rrie out in triplite for the initil rw wste n ompost smples. The onentrtion of numer of eggs per grm of ry weight of smple ws ompute oring to the following formul (Ayres n Mr 1996): N = Y C M S, where N = numer of eggs per grm of ry weight of smple, Y = numer of eggs in the MMster slie (men of ounts from three slies), M = estimte volume of prout t finl entrifugtion, C = volume of the MMster slie, S = ry weight of the originl smple.

5 Pge 5 of 16 Dt nlysis The t otine from this stuy were sujete to sttistil nlysis of vrine (ANOVA) proeures using SAS softwre n the signifint ifferenes were etermine using Fisher s LSD test t P 0.05 level. Results n isussion Chrteristis of the rw wste mterils The results of the nlysis for the rw wstes re presente in Tle 1. The ph of the muniipl soli wste (MSW) ws lkline n tht of rie fel sluge (DFS) ws ii in retion. EC of MSW ws muh greter thn tht of DFS. The lkline ph n high EC vlue in MSW oul e ttriute to the presene of woo sh whih ws oserve to our in onsierle mount uring the sreening of the wste. The totl N ontent of DFS ws more oule thn tht of MSW, initing tht it oul e use to reue the C:N rtio of the MSW. The totl helminth egg ount for the rie fel sluge n mixture of fel sluge n MSW ws g 1 TS n g 1 TS respetively, whih is fr greter thn the reommene vlue for mterils use in griulture s per WHO s guielines ( 3 8 eggs g 1 TS) (Xnthoulis n Struss 1991). Similrly, the totl fel oliform ount of ll the rw mterils ws foun to exee the stnr threshol limit of <1000 fu g 1 (WHO 2006). Therefore, it suggests tht the rw wstes nnot e use iretly for griulture without eing trete s it my result in soil ontmintion. The germintion inex vlues of the wstes ws lso fr elow the stnr limit (>80%) sustntiting the presene of phytotoxi sustnes whih woul mke the rw wstes unfit for pplition in griulturl soils (Aitionl file 1: Tle S1). Evolution of omposting temperture Consierle vritions in temperture onitions were oserve mong the ifferent omposting methos on ourse of the omposting perio (Fig. 1). Though there were series of rise n fll in temperture, the generl pttern of temperture for tretments (prtiulrly for n ) ws similr. There ws rpi rise in temperture uring the first few ys of the omposting proess followe y fll with time n finlly it egn to grully reh to the mient temperture. These temperture ptterns enote the thermophili, mesophili n mturtion phses of omposting proess, respetively. The rpi progress from initil mesophili phse to thermophili phse in n inites high proportion of reily egrle sustnes n selfinsulting pity of the wste (Sunerg et l. 2004). The hnge in temperture pttern oserve in this stuy is in or with other omposting stuy (Tognetti et l. 2007). Tempertures rehe the thermophili rnge (>45 C) on the seon n thir y for the n whih lste for 15 n 19 ys, respetively fter initition of the proess. During these ys of the proess, higher temperture ws reore for the thn the. A pek verge temperture rnging etween 60.7 n C ws reore uring the 3r to 6th ys for. Corresponingly for, the highest verge temperture of C ws registere uring the 3r to 9th y (Aitionl file 1). The inrese in temperture Tle 1 Men vlues ± stnr error of the hemil n iohemil properties in the initil rw wstes use in the stuy Chemil n io-hemil property Rw mteril MSW DFS MSW:DFS (2:1) ph 7.39 ± ± ± 0.01 EC (µs/m) 2233 ± ± ± 7.94 Totl N (g kg 1 ) ± ± ± 0.19 Totl OC (g kg 1 ) ± ± ± 1.08 C:N rtio ± ± ± 0.17 TVS (g kg 1 ) ± ± ± 8.09 NH + 4 (mg kg 1 ) ± ± ± NO 3 (mg kg 1 ) ± ± ± 7.90 NH + 4 :NO 3 rtio ± ± ± 0.07 Germintion Inex ± ± ± 1.58 Fel oliforms (log 10 fu) 4.59 ± ± ± 0.04 Helminth egg g 1 TS ± ± 1.60 MSW muniipl soli wste, DFS rie fel sluge, OC orgni ron, EC eletril onutivity, TVS totl voltile solis, fu olony forming units, TS totl solis

6 Pge 6 of 16 Temperture ( o C) Amient W Composting time (Dys) Fig. 1 Chnges in mient ir temperture n temperture in the experimentl piles uring the omposting proess ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting) within the omposting mss ws use when the het generte from the respirtion n eomposition of sugr, strh n protein y the popultion of miroorgnisms umultes fster thn it is issipte to the surrouning environment (Jusoh et l. 2013). During the susequent mesophili phse (45 35 C), however, registere reltively higher temperture thn. This phse ws lste for 13 ys, from 16th to 28th y for n from 20th to 32n y for n from the respetive ys on temperture vlues <35 C n very lose to the mient temperture ws reore for oth omposting methos. The mient temperture uring the experimentl perio rnge from 23.7 to 33.7 C (Fig. 1). The vermiomposting unit (), where low temperture ws inue intentionlly y spreing the mteril in groun es, tene to show the lowest temperture ll through the proess. The temperture profile for the W uring the thermophili phse showe similr pttern s tht of the n hs tken ifferent trk uring the susequent vermiomposting proess resemling the sole vermiomposting unit. The size, initil moisture ontent n ertion of the pile sustrte might hve ttriute for the vrition in temperture of the ifferent omposting methos. Initilly, to protet the erthworms from extreme thermophili temperture n to keep n optimum onition for their performne, the height n moisture ontent of the pile in the vermiomposting unit were mintine to 30 m n 80% ompre to 1 m height/epth n 60%, respetively, in the n piles. As result, the vermiompost with smll volume of orgni pile n reltively high moisture ontent oes not het up s suh euse the het generte y the miroil popultion is lost quikly to the tmosphere, wheres in the n het uil-up prtiulrly in the entre of the pile might hve een insulte y the outer lyer letting the temperture insie the pile to e rise. It is well-estlishe ft tht, the smller the ioretor or ompost pile, the greter the surfe re-to-volume rtio, n therefore the lrger the egree of het loss to onution n rition ( invertertes.html). The possile explntion for the vrition in temperture profile of the n, given the sme volume n moisture ontent of the pile, my e the ifferenes in ertion (ir irultion) in the pile sustrtes. The weekly turning of the ompost mss in might hve promote the free irultion of ir to enhne the miroil tivity in the oxition proess n therey rise the temperture; wheres in, the sustrtes eing stke in the pit without eing turne the irultion of ir in the pile might hve een reltively restrite to impir the miroil tivity n therey the het generte uring the proess. Finstein et l. (1986) who emonstrte the liner reltionship etween the oxygen onsume n het proue uring eroi metolism, support the fining of this stuy. Evolution of ph The first ph reing eing tken t the 20th y fter the initition of the proess, shrp n signifint (P 0.001) rise in ph thn the initil stte ws oserve in ll the tretments. The rise in ph uring these ys is onsiere to e the result of the metoli egrtion of orgni mtter ontining nitrogen (proteins, mino is et.) leing to formtion of mines n mmoni slts through minerliztion of orgni nitrogen (Dumitresu et l. 2009). As Smith n Hughes (2002) n Muponi et l. (2006) suggeste, it might lso e ttriute to the eomposition of orgni is to relese lkli n lkli erth tions previously oun y orgni mtter. An inrese in ph uring omposting of ifferent sustrtes ws lso reporte in mny other stuies (Sunerg et l. 2004; Tognetti et l. 2007; Go et l. 2010). The nlysis of vrine (ANOVA) showe nonsignifint vrition (P > 0.05) of ph vlues mong the ifferent methos of omposting t the 20th y of smpling. Nevertheless, s omposting progresse, signifint vrition (P 0.01) in ph ws note mong the ifferent omposting methos (Fig. 2). Exept for, whih exhiite further rise in ph, ll other methos of omposting showe firly stle ph uring the 20th to 60th y of the proess. This ws followe y slight fll to nerly neutrl ph vlue uring 80th to 100th y. In, rise in ph vlue ws oserve to exten to the 60th

7 Pge 7 of 16 ph g W LSD (0.05) = 0.11 e ef ef Eletril onutivity (µs m -1 ) e eh hi e W ehi hijk ijk LSD (0.05) = ef ghij jk e hijk k Composting time (Dys) Fig. 2 Chnges in ph in ifferent omposting methos with time. ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting, LSD lest signifint ifferene). Different letters inite signifint ifferenes t P 0.05 y (8.03), fter whih it eline slightly t the 80th y n finlly roppe to 7.83 t the 100th y. Generlly, from the 20th y till the en of the proess (100th y), registere the highest ph vlue thn the rest of the omposting methos whih were note for their sttistil prity (P > 0.05) (Fig. 2). This my possily e use ue to the reltively higher onentrtion of mmonium ion mintine in. The reltive eline in ph uring the ltter stge of the omposting proess might e use ue to the nitrifition proess whih is responsile for the relese of H + ion (Hung et l. 2001). This is lso evient from NO 3 t whih ws oserve to inrese remrkly uring lter stges of the proess. Overll, the ph vlues hieve in ll tretments t the en of the experiment were within the rnge eptle for plnt growth s reommene y Tognetti et l. (2005). Evolution of eletril onutivity (EC) The eletril onutivity vlues vrie signifintly (P 0.01) mong the omposting methos n over the ifferent omposting perio. Generlly, s inite in Fig. 3, ll the tretments showe similr pttern of hnge in EC where the vlue erese steily with the progress in the omposting proess. It ws foun to e reue y out 55.53, 54.66, 47.97, n 37.40% respetively for, W,, n t the 100th y s ompre to the initil vlue of the rw mteril t y 0. The otine results re in greement with Yv et l. (2012) n Go et l. (2010) who reporte n eventul erese in EC vlue with progress in omposting n vermiomposting. However this is in ontrst with other stuies (Gómez-Brnón et l. 2008) whih reporte inrese EC vlues with omposting time. 600 Composting time (Dys) Fig. 3 Chnges in EC in omposting mixtures of ifferent omposting methos with time. ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 The progressive eline of EC vlue with time woul justify tht, firstly; there might e lehing of minerlize ions uring perioi showering of wter on the omposting mss, seonly; s omposting proess progresse, humifition woul inevitly proee n the resulting humi frtions might hve omplexe the solule slts whih in turn ten to erese the mount of moile free ions n therey the EC (Ro 2007). The ANOVA results revele tht the EC vlue uring the entire omposting perio ws signifintly higher (P 0.001) for followe y, wheres whih ws in sttistil prity with W reore the lowest vlue (Fig. 3). This woul justify tht the pile sustrtes in, n W whih were not turne, ut rther wtere perioilly on top to mintin the moisture t optimum; the solule ions might hve grully een lehe own. Moreover in n W, owing to the smller size of the pile n reltively lrge quntity of wter e, the lehing of those ions might hve een even more pronoune thn the. In on the other hn, the weekly turning n mixing up of the sustrte might hve helpe the reistriution of the minerlize ions in the ompost mss n hene the loss of those ions from the system through lehing might hve reltively een reue. This fining is in line with Lzno et l. (2008) n Freerikson et l. (2007) who reporte signifintly lower EC vlue for n W thn. The EC vlue in the finl prout of ll tretments ws fr elow the threshol vlue of 3000 µs m 1 initing mteril whih n e sfely pplie to soil (Soumré et l. 2002).

8 Pge 8 of 16 Evolution of totl orgni ron With vnement of the omposting proess, the totl orgni ron ontent of the ompost erese onsistently n signifintly (P 0.01) for ll the tretments (Fig. 4). The erese in orgni ron ontent t the en of the omposting proess with respet to W,, n ws 54.74, 54.52, 52.00, n 48.80%, respetively of their initil ron ontent. The present fining is lso in onsent with the finings of Tiqui et l. (2002), who reporte totl ron loss tht rnge from 50 to 63% in turne winrows n 30 54% in unturne winrows. Similrly, reviewing the works of other uthors, Yv et l. (2010) reporte totl orgni ron reution vlues rnging etween 26 n 66% uring vermiomposting of wstes of vrious soures. The vrition in the mount of OC lost from the ifferent omposting metho my possily e use y ifferenes in the ertion of the pile sustrte. Turning the ompost pile (in ) n ontinuous orrowing n frgmenting of the mteril y erthworms (in n W) might hve ltere the ertion of the ompost mss n elerte the egrtion proess to enhne the loss of ron s ron ioxie. The results re in greement with the finings of Guo et l. (2012) who emonstrte higher losses of ron in tretments reeiving higher rtes of ertion. Evolution of totl nitrogen Chnges in the totl nitrogen of the ifferent omposting methos vrie signifintly (P 0.01) with the ifferent smpling perio, while the vrition mong the omposting methos ws foun to e sttistilly insignifint (P > 0.05) (Fig. 5). The totl nitrogen ontent of the initil rw mteril of ll tretments ws reue signifintly (P 0.01) uring the first 20 ys of omposting. However, uring the susequent smpling, there ws grul inrement of totl nitrogen, the mximum vlue eing reore t the 100th y. The eline in the totl nitrogen uring the first 20 ys might e ttriute to the loss of nitrogen in the form of mmoni whih is pprent uring the tive phse of omposting. Witter n Lopez-Rel (1988) reporte nitrogen losses tht oul mount to 50% n onsiere tht nerly ll nitrogen lost is ue to mmoni voltiliztion. The rise in totl nitrogen fter the 20th y my e use ue to onentrtion effet tht resulte from egrtion of orgni C ompouns whih in turn les to weight loss n therefore, reltive inrese of N onentrtion (Dis et l. 2010). As Bernl et l. (1998) expline the onentrtion of N usully inreses uring omposting when the loss of voltile soli (orgni mtter) is greter thn the loss of NH 3. This woul generlly inite tht there ws reltively greter inrese in totl N ompre with the erese in the orgni ron ontent. The results of the present stuy woul, therefore, justify tht uring the first 20 ys of omposting, losses of N through NH 3 voltiliztion ourre t greter rte thn orgni mtter egrtion, while uring the susequent perios, the rte of N loss s NH 3 might e slower thn the rte of ry mtter loss s CO 2. In ition, the N level might hve lso een inrese ue to the fixtion of tmospheri N within the ompost hep y the free living N fixing miroorgnisms tivity tht ommonly ours uring the lter stge of the omposting proess (Sel et l. 2012). In their o-omposting Totl Orgni ron (g kg -1 ) ef e ghi e h hi Composting time (Dys) e LSD (0.05) = W ghi i Fig. 4 Chnges in totl orgni ron in omposting mixture of ifferent omposting methos with time. ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 Totl Nitrogen (g kg -1 ) hij ij j W ghij hij eh hi ghij LSD (0.05) = 1.74 e ef e Composting time (Dys) Fig. 5 Chnges in totl nitrogen in omposting mixture of ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05

9 Pge 9 of 16 stuy of pig mnure n orn stlks, Guo et l. (2012) reporte results tht were in greement with the trens of the present stuy generl erese of totl nitrogen uring the thermophili phse followe y n inrese then fter. Evolution of C:N Rtio The C:N rtio of the omposting mteril of ll the tretments nrrowe onsistently n signifintly (P 0.01) with the vnement of the omposting time (Fig. 6). The initil C:N rtio of the rw mteril t y 0 ws 19:1 whih ws within the reommene rnge suitle for omposting (35 12) (Epstein 1997). This ws foun to erese to nerly 11:1, 9:1, 10:1 n 9:1 t the 100th y of smpling for,, n W, respetively. Oviously, throughout the omposting proess the orgni mtter is eompose y miroorgnisms through whih the orgni ron ws oxiize to CO 2 gs to the tmosphere n thus lowers the C:N rtio (Jusoh et l. 2013). This is in onformity with the finings of other stuies (Kumr et l. 2009; Khwirkpm n Klmh 2011). C:N rtio vlue for ws signifintly (P 0.01) higher thn the other methos of omposting whih were sttistilly t pr (P > 0.05) with eh other (Fig. 6). The vrition seeme to rise minly ue to the ifferenes in the mount of totl orgni ron s oul e witnesse from previous isussion n the sme justifition given ove n lso e lime for the vrition in C:N rtio mong the ifferent omposting methos. Generlly, the C:N rtios in the finl prout of ll the tretments were foun to e stisftory euse mture ompost mteril usully hs C:N rtio of 15 or less (Hok et l. 2009). As Gómez-Brnón et l. (2008) pointe out C:N rtio my not e goo initor of ompost stility euse it n level off efore the ompost stilizes. When wstes rih in nitrogen re use s soure mteril for omposting, the C:N rtio n e within the vlues of stle ompost even though it my still e unstle. By the sme token, Zmor-Nhum et l. (2005) reporte C:N rtio lower thn the ut-off vlue of 15 very erly uring the omposting of ttle mnure, while importnt stiliztion proesses were still tking ple. Corresponingly, in the present stuy, three of the four tretments (, W n ) n hieve C:N rtio of <15 t the 40th n 60th y of smpling, respetively, while the egrtion of the orgni mteril ws still signifint till the 60th n 80th ys for the respetive tretments. As eviene erlier sttistilly stle vlues for totl orgni ron ws oserve uring the 60th to 100th n 80th to 100th y of smpling for the respetive tretments. Evolution of NH + 4, NO 3 n NH+ 4 :NO 3 rtio The onentrtion of NO 3 N n NH+ 4 N vrie signifintly (P 0.001) for the ifferent omposting methos n over the ifferent omposting perio, notwithstning tht ll the tretments hve generlly shown similr pttern of hnges in oth mmonium n nitrte onentrtions (Figs. 7, 8). As n e seen from the grph (Fig. 7), ll the omposting methos showe rise in NH + 4 N onentrtion uring the 20th y of smpling whih ws then eline shrply s eviene t the 40th y n oming to erese slightly from the 40th y until the en of the experiment (100th y). C:N Rtio LSD (0.05) = 1.53 W (mg kg -1 ) LSD (0.05) = W ef e Composting time (Dys) e e g Fig. 6 Chnges in C:N rtio of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 NH f e Composting time (Dys) Fig. 7 Chnges in NH + 4 onentrtion of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 gh g hi i i

10 Pge 10 of 16 (mg kg -1 ) NO LSD (0.05) = W Composting time (Dys) Fig. 8 Chnges in NO 3 onentrtion of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 The rise in NH + 4 N onentrtion uring the first 20 ys ws likely to e use s result of the minerliztion of orgni mtter (the onversion of orgni N to NH + 4 vi the mmonifition proess), thus refleting tive trnsformtion of orgni mtter n unstle sustrte (Tognetti et l. 2005; Guo et l. 2012). Wheres the erese in NH + 4 N uring the susequent smpling perios ws proly ue to NH 3 voltiliztion (Go et l. 2010), the miroil immoiliztion s nitrogenous ompouns suh s mino is, nulei is n proteins n/or its oxition to NO 3 through nitrifition proess (Guo et l. 2012). An inrese in NH + 4 N onentrtion uring the initil stge of omposting n its reution fterwrs ws reporte y Go et l. (2010). The nlysis of vrine inite tht registere the highest onentrtion of NH + 4 N uring ll the smpling perio. However, sttistilly signifint (P 0.01) vrition of NH + 4 N mong the tretments ws reore only t the 20th n 40th y of smpling (Fig. 7). Turning the pile sustrte in n the smller size n inrese surfe re of the vermie in n W might hve resulte in inrese loss of mmoni leing to reltively low level of mmonium t this y of smpling (20th y). The ompost pile in, on the other hn, eing not turne n mixe, the loss of N in the form of mmoni might hve reltively een reue n this might hve ontriute for the inrese level of mmonium nitrogen in thn the other methos of omposting. Similr results were reporte y Guo et l. (2012) who note highest level of ef e mmonium nitrogen in tretments with low thn high ertion rte. Regring the NO 3 N, for ll the tretments its level ws shrply n signifintly (P 0.01) erese t the 20th y smpling thn the initil. This might e use ue to either the lehing of nitrte y wter uring perioi wtering of the omposting mss or its immoiliztion y the eomposing miroorgnisms. During the susequent omposting perio (20th to 60th ys), however, the NO 3 N level me to e reltively stle n uring these ys the vrition in NO 3 N level mong ll the tretments ws insignifint (P > 0.05) (Fig. 8). This ws followe y shrp rise of NO 3 N fter the 60th y (for, n W) n 80th y (for ) s eviene on the 80th n 100th y of smpling, respetively. At the en of the proess (100th y), exhiite signifintly lower vlue of NO 3 N thn the other methos of omposting. It seems tht ue to the etter ertion y erthworms (in n W) n turning of the piles (in ), the oxition of NH + 4 to NO 3 might hve een enhne in the respetive methos of omposting thn in. The NH + 4 N ontent of the strting mteril ws lerly higher ( mg kg 1 ) thn the NO 3 N ontent (684.5 mg kg 1 ), giving the NH + 4 :NO 3 rtio to e On ourse of the omposting proess the rtio ws foun to e rise shrply t the 20th y of smpling for ll the tretments. This is followe y rsti eline uring the 40th y n oming to e elining grully uring the susequent perios of omposting ( ys) (Fig. 9). registere the highest rtio uring ll the smpling perios; however, sttistilly : NO 3 -Rtio NH f e LSD (0.05) = 0.75 e Composting time (Dys) gh W Fig. 9 Chnges in NH + 4 :NO 3 rtio of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 h h

11 Pge 11 of 16 signifint vrition mong the omposting tretments ws note only t the 20th n 40th y of smpling (Fig. 9). At the 20th y, the highest (13.57) n lowest (9.42) rtio ws reore for n W, respetively. At the 100th y of smpling the vlue ws foun to rop to 0.06, 0.026, n 0.02, respetively for,, n W. Critil limit vlues of <400 mg kg 1 for NH + 4 N (Zuoni n e Bertoli 1987), >300 mg kg 1 for NO 3 N (Forster et l. 1993) n <1 for NH + 4 -:NO 3 rtio (Brewer n Sullivn 2003) hs een estlishe s stility/ mturity inies for omposts of vrious origins. Conomitntly, exept for ll the other omposting tretments stisfie the ritil limits for stility/mturity t the 60th y of smpling. Wheres, hieve these vlues(no 3 N n NH+ 4 :NO 3 rtio) t the 80th y, implying tht ws lte to hieve the inex vlue for mturity thn the other three methos of omposting n the sme explntion given ove pertining to ifferenes in ertion woul lso e suggeste for the vrition in these vlues mong the tretments. Evolution of totl voltile solis (TVS) The verge totl voltile soli (TVS) ontent of the rw wste ws mg kg 1 whih steily eompose throughout the experimentl perio. The hnge in TVS with omposting time showe the sme pttern s the hnge in totl orgni ron in tht it ereses signifintly (P 0.01) with the vnement of omposting time. The gretest reution in TVS ws note uring the first 20 ys of omposting signifying the fst egrtion of the sustrte uring this tive phse of omposting (Fig. 10). The erese in TVS ontent of the smple inites the egrtion of orgni mtter of the wste uring the omposting proess (Levnon n Plu 2002). Vlues of TVS vrie signifintly (P 0.01) mong the ifferent methos of omposting (Fig. 10). On the ourse of omposting, the highest n lowest vlues of TVS were reore for n W, respetively. The nlysis of vrine revele tht the vlues of TVS for the three methos of omposting (, n W) fter the 60th y ws insignifint (P > 0.05) initing the stility of the prout t the 60th y. Wheres, for sttistilly stle vlue ws hieve t the 80th y of omposting, implying the reltively longer perio of time the ltter hs tken for the prout to e stle. This is ue to the reltively slow rte of egrtion of the orgni mtter in. The importnt role plye y the erthworms in reuing the TVS through egring wstes ws reporte y Yv et l. (2012). Phytotoxiity ssessment All the omposting tretments followe the sme generl pttern of hnges in germintion inex (GI) over the ifferent smpling perio n the vrition in GI vlues mong the tretments ws insignifint (P > 0.05; Fig. 11). However, the vlues vrie signifintly (P 0.01) with the omposting time. The lowest vlue of this vrile ws reore t the 20th y of smpling whih ws of ourse sttistilly not ifferent from the strting mteril (y 0). This ws oserve to inrese with the vnement of omposting perio up to the 60th y n from the 60th y on it me to more or less stle vlue with insignifint vrition (Fig. 11). Tiqui n Totl Voltile solis (g kg -1 ) e ef e LSD (0.05) = W e h ghij hi eh hi ij h j ij hij Composting time (Dys) Fig. 10 Chnges in totl voltile solis of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 Germintion inex LSD (0.05) = Composting time (Dys) W Fig. 11 Chnges in germintion inex (GI) of omposting mixture in ifferent omposting methos with time ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05

12 Pge 12 of 16 Tm (1998) lso reporte finings tht re similr to the results of this stuy. The reson for the low germintion inex vlue of in the initil smple n the smple tken t the 20th y of the omposting proess oul e ttriute to the presene of phytotoxi ompouns in the rw wstes n their proution in the sustrte uring the tive phse of omposting. Phytotoxi ompouns, suh s; mmonium ions, ftty is, n low moleulr weight phenoli is re reporte to impir see germintion n root elongtion (Delgo 2010; Gómez-Brnón et l. 2008). It ws lso evient from the hemil nlysis of the rw mteril n ompost smples of this stuy tht the highest level of mmonium ws reore t the 20th y of smpling followe y the initil sustrte t y 0. The etrimentl effet of high levels of mmonium to see germintion n root elongtion ws reporte in mny other stuies (Tiqui n Tm 1998; Selim et l n Guo et l. 2012). The rise in GI lte t the 60th y might e ue to the egrtion of the phytotoxi ompouns whih were present in the initil rw wstes or proue uring the tive phse of omposting s intermeite prouts of miroil metolism (Bernl et l. 1998). Aoring to Hq et l. (2014) ompost with GI of more thn 80% is onsiere to e mture n prtilly free of phytotoxi sustnes. In this stuy s inite in the grph (Fig. 11), ll the tretments were foun to hve GI vlue of >80% t the 60th y of smpling, implying tht, out 60 ys were neee to overome the threshol limit of 80% y reuing the phytotoxiity of the ompost to levels onsistent for sfe soil pplition (Sores et l. 2013). Pthogen intivtion Totl fel oliforms Exept for ll other methos of omposting showe sustntil reution in popultion of fel oliforms t the 20th y of smpling. These tretments were effetive in keeping the popultion of the fel oliforms in the ompost elow the minimum llowle limit (<1000 fu g 1 ) right t the 20th y. The reution in the popultion of fel oliforms in these methos of omposting might e relte to the high temperture generte in the ompost pile uring the thermophili phse. Perhps in this stuy the first smpling ws tken t the 20th y, ut it is likely tht these methos oul hve ttine suh low popultion even muh erlier thn the 20th y. As per the reports of WHO (2006) n Shönning n Stenström (2004), pthogen intivtion in omposting is hieve when tempertures ove 50 C re mintine for t lest 1 week. Tempertures exeeing 50 C were lso reore in those methos (, n W) involving thermophili phse of the urrent stuy. Some inonsistenies in reution pttern of the fel oliforms were etete in uring the mesophili n uring phse, where the popultion of these pthogens me to rise n fll t ifferent smpling perios (Fig. 12). This my e ue to the ontmintion of the ompost mss from the externl soure uring the perioi n mnul turning of the ompost pile. Regring, ontrry to the former methos, the numer of the fel oliforms ws foun to inrese remrkly t the 20th y of smpling, this ws then eline steily uring the susequent smpling perios (Fig. 12). The inresing of fel oliforms in uring the 20th y of smpling oul e ttriute to retion of goo environment for multiplition of this pthogen through rehyrtion n susequent vilility of esily egrle sustrtes y issolution following rehyrtion (Muponi et l. 2010). The reports y Shönning n Stenström (2004) n WHO (2006) lso inite tht ertin types of pthogeni teri n inrese in numers when onitions fvouring their growth re estlishe in their storge meium/environment. The reution of the fel oliforms popultion uring the susequent perio of vermiomposting my e ttriute to some tivities of erthworms whih possily inlue: seletive pretion/onsumption (Ewr n Bohlen 1996; Kumr n Shwet 2011); mehnil estrution through tion of gizzr (Ewrs n Suler 2011); miroil inhiition through humi n oelomi is or other enzymes serete within the igestive trt (Ewrs n Suler 2011); stimultion of miroil ntgonists (Kumr n Shwet 2011); n iniretly through stimultion of enemi or other Fel oliforms (log No. of fu/g smple) e jkl ijk ef ijk LSD (0.05) = 0.13 gh ij Composting time (Dys) g l ijk n W Fig. 12 Elimintion of fel oliform uring o-omposting of rie fel sluge n muniipl soli orgni wstes with time. ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting). Different letters inite signifint ifferenes t P 0.05 hi kl m o

13 Pge 13 of 16 miroil speies whih outompete, ntgonize, or otherwise estroy pthogens (Ewrs n Suler 2011). Helminth egg ount During the omposting proess, there ws generl reution in the numer of helminth eggs for ll the tretments (Fig. 13). The totl helminth egg ount ws foun to erese from g 1 TS of the strting mteril to 8.33 (), 19.44(), () n 2.78 (W) in the finl prout s eviene t the 100th y. These vlues orrespon to 78.57, 50, 61.9 n 92.86% totl reution of eggs for the respetive tretments. It hs een oserve tht the extent to whih the helminth eggs were eliminte vrie signifintly with time n mong the tretments (P 0.01). Those tretments involving thermophili omposting (, n W) emonstrte rsti reution of eggs uring the first 20 ys of the proess when the tive thermophili phse ws previling. This mounts to 84.85% (), 73.08% () n 74.36% (W) of the totl reutions reore in the respetive tretments. Wheres the tretment without thermophili phses (), the gretest reution of helminth eggs ws oserve uring the ltter stges of the omposting proess. More thn 75% of the totl reution ws reore fter the 60th y of the proess while only 23.81% of it ws reore uring the first 40 ys of the omposting proess. The highest reution of eggs ws hieve in W metho followe y winrow metho of omposting (), while the sole vermiomposting metho () registere the lowest vlue (Fig. 13). However, only the former tretment (W) is omplying with the WHO guielines of <3 8 Asris egg g 1 TS while ll the rest tretments were foun to hve egg ounts more thn the threshol Totl Helminth eggs (No. g -1 TS) ijk e hijk eh hi ijk LSD (0.05) = 4.63 Composting time (Dys) kl e jkl lm ghij jkl ef hi kl m W Fig. 13 Helminth eggs removl ynmis uring o-omposting of fel sluge n muniipl orgni soli wste. ( winrow omposting, vermiomposting, pit omposting, W omine winrow n vermiomposting LSD Lest signifint ifferene). Different letters inite signifint ifferenes t P 0.05 limit. The result of this stuy lerly emonstrte tht the high temperture proue in the thermophili phse of the omposting proess is muh more effetive in snitizing pthogeni prsites of fel sluge thn the erthworms i. It hs een suggeste tht high temperture my inrese the permeility of the Asris eggs shell, llowing trnsport of hrmful ompouns, s well s inresing the esition rte of the eggs (Koné et l. 2010). Even though numerous uthors reporte the full elimintion of prsiti eggs uner thermophili onition (Plym-Forshell 1995; Gntzer et l. 2001), this h not ome out in the present stuy where helminth eggs were still etete espite the ft tht the thermophili onition ( 45 C) ws mintine for out ys. It is likely tht the lethl temperture, eing not evenly istriute throughout the pile iomss, the omplete estrution of the eggs my not e ensure. The sustrtes tht ly on the top of the pile, eing expose to the open tmosphere, might hve experiene reltively ooler temperture thn the inner li ones. Struh (1991) suggeste tht omposting ensures hygieniztion of the mteril on onition tht ll iomss is expose to suffiiently high temperture (55 C for 14 ys). The temperture reing of the present stuy inites tht, on verge, high temperture of (>55 C) ws reore only for 8 ys in winrows n uring whih the pile ws turne only one letting it to experiene the high temperture of >55 C for only y fter this first turning. This woul therefore suggest tht, h the pile feestok een turne more frequently suh tht every 2 or 3 ys, the iomss woul hve enjoye the lethl high temperture uniformly n for reltively longer perio of time n thus woul hve resulte in inrese effiieny of helminth egg elimintion. This justifition is of ourse in rgument with the reports of Koné et l. (2007) who emonstrte the non-signifint effet of turning frequeny on the intivtion effiieny of helminths egg. However, it hs een expline tht the size of the pile feestok etermines the mgnitue of het generte n the time urtion in whih the thermophili phse woul e mintine uring the omposting proess. The lrger the size of the pile the higher the mgnitue of het generte n the longer the thermophili phse woul e mintine within the pile, n thus the less frequently it n e turne. In ses where the pile size is smller, the thermophili phse woul lst for short perio of time; therefore, unless turne frequently there woul e no hne for the out li iomss to enjoy the lethl high temperture whih is usully forme insie the pile. In the Unite Sttes of Ameri, the ompost is regre s hygienilly sfe if temperture >55 C is mintine in winrows for t lest 15 ys with minimum of 5 turnings uring the high temperture perio (USEPA 1999).