Process of Waste Sludge Facultative Metabolism

Journal of Dong Hua University (Eng. Ed.) Vol. 18 No .3(2001) 91Process of Waste Sludge Facultative MetabolismLi Yin(李茵)Callege旷Briroumenal Scieace & Enghering. Dong Hus Ualreriy, Shatphul, 20051Laboratory- scale experimentswere conducted to62- -65 t(0],determine new technology of waste sludge facultativeAnserobic sludge digsion may bc divided into two steps :metabolism . 10-L laboratory-scale facultative reactorshydrolysis- acidogenesis and methanogenesisl0.1ol. In the first step,were operated during 24-hour sludge residence timecomplex organie substrtes aro solubilzod and subsequenty(SRT) and in room temperature . Results show that theInetabolized t如 produce mainly volaile faty acide . This is calledlorganic matter in waste sludge after hydrolyais.the hydolysis-acidihcatio of faculative meabolisn。The secondacldilcatlon will be reduced by 75. 39%，the removalstep contains methane pouetort ,rate of COD。above 85%。Adrantage of the process isThe main chicie of this research is two invesigte a proceshydrolysis acidification in ambient air temperature asof wate sludge metabolismn， which 地tgard he hydrolysis-there is no need lor facilities to be sealed or heated. Inacldlfication器some preteatmneat, and therefore achite 2E70-additdon, the sludge will be recycled into the wastewaterdischarge of sluodge in the acrobic wastewater treatment system.treatment system and finally towards serodigcharge.Keyuwords : fulutive metaboliom ，hydrobysis acidjicarion ,Experimentalsludge treament, proees: anudy.1 Sludge propertyin this experiment, waste sludge was taken from 且cerainIntroductionwastcewaler trcatment station of Shanghai Chenical Fber FPactory.The sudge contained 50%一70% of sting volume ( SV )。hn order to provide better environmental prodecion, theWhreas he anount of mixed liquor suspended solis( MISS )amount of wasleswater treatment increaes in recent years. Sludgewas on avenage 11.553 g/L, with 67.35% volaole matter. Theproduction is consequently going up and sludge teanent costs arecontent of organic matter was up to 75%一-90%， while thealo rising.As a result it has become ncessry t如o improve organicconcenmtbon of caprolactam reached 4043 -4723 mg/L. .mater degndatbon ffciency。The most widely adopted method of2 Apparatus and materialssludgo teatrbent curenly 玛amnetobic digstiof'nl. Singl-stageBoth facllative rector and completely mixed aenaionsBtrobice thermophilie digestion processes are considered to lacksedimnentadon tank were made of plexiglass with a volume of 10process sabill and pathogen contof2-51， Dual-smagelitrs。The ractio under fasulative opeating condion requiredthemophilie/ mesophiliedigestionsystems have gainedemploying a set of low-speed gear agitator whose speed waspulrityle.], however, sludge resideace time will last 15reguinted to 40- -45 round/mindays'l and the systems 0e uncconormical to be opernated beecause3 Experimental processb digsion teoperature ia he thermophile age is u toThe experimental process flowsbet is sthown in Fg.1.hydolyriesidogcueilswaste sludgesoluble compoundsvolatile fatty acidsetrobis bopeal beatnent in seratian basimCO, ,HO, NH ,et.中国煤化工Sludge property tst iustates that most of orga.JYHCNMHG.B retuned 0o initial biochemicaland caprolactam wr adsorbed in loele of sctvwing the recyele with waslewalernot complotely metabolized. Paculatve microrganisms should betreatment, the shudpe will be decomposed. Eventualy, it reachedintroduced into the rector. Hyrolyxis acdficatio digstionztr0- discbarge. I ws for this purpose that laboratory-scule sudiesC8O coovert the complcated organic 0 volaile fatty acisl(Fig.were initiated.Receirnd Jul.28. 2000)2Journal of Dong Hua University ( Eng. Ed.) Vol. 18 No.3 (2001)faculative reactor was thenseoded with special bectris culivatedResults and Discussionby ouselves. With he agitaor stinring. varios trends ofdegradation during 24 bhour Treaction were shown in Hg.2.1 Facultative treatment of sludge inFng.2 shows te sludge has been decomaposed by faculativeambient air temperature and pressuremicrorgnims. The organic matter in the sludgc has decresed,Determination should be made in the course of degradingand the concentration of eaprolectam adsorbed by the sludge hasorganic mater and eaprolactam. Sludge taken into the openalso dropped gnadually alang with the reaction time .5「十Mixed liqpor suspendel solids营2-譬- Mixed liquor volatile suspended solids-士Caprolacam024 4.8， 72 9.6 120 144 168 19.2 21.6 24.0TimthFg.2 Fecalaive ureatnet of yate sludga2 Hydrolysis. acidification of sludge in thebiological activity . No extermal beat source was provided.facultative reactorThe cuhivated sludge was ucitedd to volatile faty acidsA furher experiment wa accomplishod 5o a to ascertain thedurtng 配acldifcarion sitp. soch as actie, propionic, butyrieduration of the byrolyis nidifictin p。The reactorand vateric acids. ete 10。These acids representedt a lutal value ofemperawre was maittained at about 33C hrough mixing andpH which ws measured in the tst every bour for twenty days .86告41624187276120 144168 248 328 408 488Sug residence timne/hg.3 Fyuyvlalifacio of wste sludgeIt can be seen from Fig.3 that the lowest point of pH, whenpredooninaced in the operation. Hyrolyte and adidifying organismsamived atS.2. was obuained at 24-hour SRT, This means the Talecrealed high conccntations of the enzymes especially in theof ddifieation i higher than that of coaventioal anserabicbydolysis reaction。 and teadily contacolot betwen excellulardigestion. The pH then recovors 0 the inia value, 明n the eighthenymes and complax subtrates. Many soluble solids were quiclydayest. A rise in the cure can be continuously observed withconveted t如 faty aclds by this bacerial action. The concentrationdecomposition of organic ftty scids. But酷w know the mehaneof organies and caprolactam decreased by 75.39名and 85. 68%would not be produced before undergoing cidifeation of fileentupetrvely . Whereas less compeiive scrobic bacteria oul of thefastergrowing acidgente organisms would autolyzs， henThe facutative reactor could be regarded as completcly mixedprobably be nurients to the others.device in the experimest . An upper Hiquid levedd and acidified sludge metab-the oir made it psie for sructure Dotto be s中国煤化工vaterthe fcilty w$s conveaicaly manged. At te s-ile ftty acids is for reyale and upe in hefound that the concentration of the sludge presecMYHdistribution sccording to the height of the reactor, i.e.. the loweron this pretmisc, the hydolyed and scidified sludge sould beof the height, the thinner of the concentation。So■natunl coverreumed to aeroble wastwater trealrnent systom 。 The organielayer of the dense sludge cake hindered from h oxygen of the armatler in he wastewater and acidified slndge will be molbolized0o the reactor, which resuiled in fostring the sludge hydrolysts,stmulbneously . The renlt of 3 monhs continwous operation wasacidicato and digertionWith mspect to microorganismsgivea in Fg.4，species distribuiom, faculaive and anserobic microbesJournal of Dong Hua University (Eng. Ed.) Vol. 18 No .3(2001) 93i 600--+-inle- -oulet600200,-■Time/hPug.4 Bloca of contos opeatconPig.4 shows he mixed treatment effects of sludge an4 Process of sludge treatnentwasiewaterane very good . When COD。of inlet wus controlledThe aim of this study was 0o determine the poces of wastebelow 1000 mg/L, COD。of oulet was almost less than 100 mg/sludgc trtatment ，According wo the axperimenal reulls, the waseL . At th same tine, he ratio of BOD/COD in the sysem roscstodge W就feculatively meablzed for 24 hours in the hydrolyisfrom 0.495 to 0.624, meaning the biodegrability enhanced andacidifcation tank, and then recydled to aerobic biologieal trentment0 shock lond to the idat biological treatment system formed.system( Pig.5)。wasitwaterconditioning tankacration basinsedimentation tank↑rcturned studwiaste sludgehydrolysis ucidification tankslodge tankFg.s Tech ologeal pocs of aludge tresnoentThe wse sludge enriches with 4 great quntity of organiedixchurgo of sludgepllataot。Usually the method of逝atroble blological treatment i(4) The ital and operaional costs of bydrolyisused for digestio and stblizaion of slodge。However, it semsacldlication process are much lower ( its volume oaly sbout oneimpossible for small-scale wasicwaler treatment plants to usepercent of wastewater Treatment device ) . This will have a greatanaerobic. proces because of the operaion snd capitalsignificance t切o small-scale wastewater treatment plants.etictios2l. Om the othber hand, the small amouat of methanegus would lack coaomie beneft ay way .References, charectriste of this proces is frcultative microbialpulatioos which aure not 80 strict i he demands as obligale1] Tspans, Ch. and Krshina, R.。J. Ensir. Eng.. 200, 126anaerobes for oxygea in the evironmeat。In addtion, the time of(9), 796 -801faculative metabolsm i very short in mere 24 bhous。Finaly.[2] Furbil, s. and Mavinte. D. s. J. Endr. Bng. 200, 126hyrolyed and sidified slndge is combined with inidsal wastewater(5), 289 -396[3] Tapena, an. and Krtshra R. P.. 1. Enuvir. Eag., 20000 126in此sume device wibout aditional energy consumption 。(9), 790-795[4] Alken, D.M. and Mllnr, R.W., Water Enir. Re.. 199.Conclusions64, 915-919[5]盐回完明等。 环境技术，999 28 (8).10-12Based on tbo rceults oburined from the lab-scale experinent,[6] Hu, Y. and Degu, R. R.. Water Enoir. Res., 1997. 69，毗fllowig ceoclusions can be made :(1) The process of waste studge feculate m中国煤化工o.s. Bnr. s. Hom. 196. su. .faculative pretrentment for sludge。was demonsttein nerobile treatment performance:YHC NM H Go.R.P.J. Bnw. Bnt., 199 125 .(2) Tho orgaric sobstmc in waste stadge wa touru by[9] Baicr u. nad Zictetholer. H.P. Warer Sd. and Techol..75.39强ather fculutive rexction and the total COD。removal race1991. 23.56-63in wastewater trestnent system wes sbove 855[10] Perot. c.. etal. Emtr. Technal. et, 1988, 7.741-751(3) This process can be applied to the waste sludge in whlch[1] Peot, C.al. Envdr 。Tctol. leir.. 1989， 10. 633 -644he ratbo of MLVSS/MLSS and/or the content of orgnie mater[12] Zhang Quan. a 1l. Shanphal Ensir. Sei.. 1995, 14《11). 15-are/i high. Advantages about the process aue less tmergy16( to Clincse )consumptioa, cepenisot 染2F严and to a grcat extent Mr0