[Rao, 2(10): October, 2013] ISSN: Impact Factor: 1.852

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1 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY Immobilized Bioeactos fo the Teatment of Industial Wastewate A Compaative Study D.L.Nageswaa Rao Associate Pofesso, Depatment of Chemical Engineeing, R.V.R.& J.C. College of Engineeing, Chowdavaam, Guntu,Andha Padesh, India lnao1978@gmail.com Abstact The vaious souces of incidence of vaious pollutants fom majo chemical pocess industies and thei dangeous effects have been epoted. The vaious chaacteistic composition of wastewate fom diffeent souces epesented. The methods of teatment of wastewate in bief discussed. Special attention has been paid to the biological teatment mentioning the dawbacks of the conventional methods. The elative advantages of vaious moden s functioning on immobilization technique have been pojected. A compaative epesentation with espect to vaious moden s has been pesented and the uniqueness of the fluidized and semifluidized bed s in the teatment of wastewate has been highlighted. Keywods: Pollution contol, wate pollution, wastewate, Immobilized cell, semifluidized bed, Bioeacto Intoduction Envionmental Pollution is a ising dange and immense disquiet in today s context petaining to its effect on the ecosystem. The woldwide ise in population and industialization duing the last few decades have esulted in ecological distub and degadation of the natual popety. One of the most vital natual esouces which have been the wost victim of population explosion and inceasing industialization is wate. In ecent yeas, consideable attention has been paid to industial wastes dischaged to land and suface wate. Industial effluents often contain vaious seveal oganic and inoganic compounds. Huge amount of wastewate geneated fom human esolution and industial sectos accompany the disposal system eithe as municipal waste wate of industial wastewate. This wastewate is eniched with vaied pollutants and hamful both to human being and the aquatic floa and fauna and its successive accumulation in the soil has advese effect on soil poductivity. Ove 5 million chemical substances poduced by industies have been ecognized and about of these ae maketed which amount to aound half of the total poduction. Due to dischage of contaminated effluents longtem consequences of expeience can cause cance, delayed nevous damage, defomity in uban childen, mutagenic chages, neuological disodes etc. vaious acid manufactuing industies dischage acidic effluent, which not only make the land infetile but make the wate of the ive acidic also. The high acidity causes stomach diseases and skin ailments in human beings. Alkaline effluents cause infetility of the soil and destoy floa and fauna of the vicinity. Contaminated wate by pesticides, such as DDT, aldin, dieldin, heptachlo etc is hamful fo aquatic life and human beings as well. Dischages of cyanidecontained wastewate to wate mass may lead to death of fish and othe aquatic life theein. Use of wate containing fluoide can causes mental disodes and stomach ailments and can also educes agicultual poduction. Chaacteistics of wastewate fom few pocess industies ae shown in table1(souce: H.M.Jena et al) Table 1: Chaacteistics of wastewate fom pocess industies: Paamete/souce &amount ange, mg/lt Fom steel industy Fom petoleum industy Fom LT coal cabonization Fom milk diay plants PH Total solids Dissolved solids Suspended solids http: // (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ]

2 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: Oils and geases Chloides as Cl Nil HS and mecaptans Nitogen Sulphates/sulfides Tace Cyanides Thiocyanates phenol Total alkality Phenolphthalein alkalinity Nil Tubidity tubid BOD ppm COD ppm In this way it is vey essential to puify and ecycle wastewate in vision of educed availability and deteioating wate quality. Phenol along with othe xenobiotic compounds is one of the most common contaminants pesent in effluents fom chemical pocess industies. Even at lowe concentation these compounds hamfully affect aquatic as well as human life. Also these compounds fom complexes with metal ions dischaged fom othe industies, which ae cacinogenic in natue. It is wate soluble and highly mobile. This impats medicinal taste and odo even at much lowe concentation of 2 micogam/lite and it is lethal to fish at concentation of 525 micogam/lite. The maximum pemitted concentation level of phenol being 0.51 mg/l fo industial wastewate and 1 µg/lite fo dinking wate. So it highly essential to save the wate esouces and aquatic life by emoving these compounds fom wastewate befoe disposal. The main souces of phenolic wastewate ae coal chemical plants, oil efineies,petochemical industies, fibes glass units, explosive manufactue phenolbased polymeization pocess, phamaceuticals, plastic, paints and vanish poducing units, textile units making use of oganic dyes, anticepticsm antiust poducts, biocides, photogaphic chemicals and smelting and elated metallugical opeations etc. Teatment Methods of Industial Waste Wate The conventional methods of teatment of phenolic and nitatenitogen wastewate ae lagely physical and chemical pocesses but these pocesses led to seconday effluent poblems due to configuation of toxic mateials such as cyanides, chloinated phenols, hydocabons, etc, these methods ae mainly chloination, ozonation, solvent extaction, incineation,chemical oxidation, membane pocess, coagulation, http: // flocculation, adsoption, ion exchange, evese osmosis, electolysis, etc.in solvent extaction thee is a dange of infectivity of teated wate by the solvent. The solvents used fo phenol ecovey ae benzene, isopopyl ethyl and butyl acetate. In addition to the pesence of solvent in teat wates the high cost of solvent is anothe disadvantage. In adsoption commonly activated cabon is used which is disposed by incineation. The pocess of incineation geneates many fuans have vey sevee consequences on human health. Chemical oxidation equies a eacto, which opeates high tempeatue and high pessue, ultimately huge enegy. Biological teatment is attactive due to the potential to almost degade phenol and othe pollutants while poducing innocuous and poducts, educed capital and opeating costs, maintains phenol concentations below the toxic limit. Howeve difficulty aises in such teatment due to the toxicity of phenol to the micobial population. In the biological denitification, in the wate is conveted into gaseous nitogen. The biological degadation of phenol is accomplished though benzene ing cleavage using the enzyme pesent in the micooganism. The bacteia expess diffeently when exposed to diffeent initial phenol concentations and othe conditions. The most efficient Pseudonomas Putida is capable of using phenol as the sole souce of cabon and enegy fo cell gowth and metabolism degade phenol via metapathway. That is the benzene ing of phenol is dehydoxylated to fom catechol deivative and the ing is then opened though metaoxidation. The final poducts ae molecules that can ente the ticaboxylic and cycle. The most common Bioeactos ae (1) Aeated lagoon (2) Oxidation Ditch (3) Activated sludge system (4) Anaeobic digestion system (5) Oxidation pond, (6) Tickling filtes (7) otating disc biological eactos (8) Basket type (9) Hollow fibe membane and (10) Fluidized bed. (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ]

3 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: Wastewate Teatment Using Bioeactos Teatment of industial and /o domestic wastewates equies a geat deal of space when using systems based on activated sludge o aeated lagoons in which etention time is many days. Wastewate having lowe phenol concentation in the ange 5500 mg/lt is coectly teated in the s like Activated sludge, Aeated lagoons, tickling filte, oxidation ponds. The majo constaints in using s with fee cells fo biodegadation of phenol include maintenance of pope cell concentation, emoval of cell sludge, settling and sedimentation of sludge, sludge ecycling etc. A integated to a membane module is efeed as membane s. The advantages with MBR s ae that they offe long cultue etention time and shot hydaulic etention time and educe numbe of the post teatment pocesses. The membane has the intention of emoval o paticulate substances that eplaces the gavitational claifie to sepaate the biomass fom the teated effluent and etainment of lowgowth micobes in the eacto fo high cell density opeation. The limitation of this eacto is high membane cost. In FeeCultue The micobes suffe fom substate Inhibition, wheeby gowth (and consequently pollutant degadation) is inhibited at high pollutant concentations. Biological fixed films exhibit popeties that make them pefeable to suspended cell systems fo a wide vaiety of wastewate teatment application. These popeties include high concentations, enhanced cell etention due to cell immobilization and an inceased esistance to the detiment effects of toxic shock loadings. Rotating biological contacto give vey good phenol emoval efficiency at modeate loading ate. It posses high suface aea, povide vigoous contact fo the biological gowth with wastewate and efficiently aeates the wastewate. Two phase patitioning (TPPBs) ae chaacteized by a cell containing aqueous phase and a second immiscible phase that contains toxic and /o hydophobic substates that patition to the cells at sub inhibitoy levels in esponse to the metabolic demand of the oganisms. This eacto is capable of degading the highly toxic chemical at vey concentation. Hollowfibe membane (HFMBR) with immobilized cultue (biofilm) is an extactive membane, could completely degade phenol up to 3000 mg/l with modeate hydaulic loading ate. Tickling bed eactos posses a vey good biomass concentation show high teatment efficiency at high hydaulic loading ates. But it has limitations like channeling, clogging and high enegy consumption Ove the conventional type feecultue s the immobilization cell s like CSTR, http: // PFR, Fluidized bed, ai lift type, etc, has the following advantages like continuous eacto opeation at any desied liquid thoughput without isk of cell washout, potection of cells fom toxic substates, highe gowth ate gives high concentation of cells in the eacto, easy cell teated wate sepaation, enhance gas liquid mass tansfe ate, plug flow opeation by maintaining the immobilized ells as a stationay phase. The fluidized bed s ae supeio in pefomance due to immobilization of cells on solid paticles educe the time of teatment, volume of ecto is extemely small, lack of clogging of biomass and emoval of phenol even at lowe concentations. Immobilization of Micobial Cells Cells of mixed cultue collected fom soils containing pollutants o specific cultue (pue) isolated fom the pollutant containing soil ae immobilized in/on solid matix. The specific cultues such as Pseudomonas Putida( NICM,SP,MTCC,Q5,DSM,KT etc) eithe psychotopic o mesophilic type, T cultaneum R57 used fo biodegadation of phenol, Catechol, Azo dyes emoval of ionic mecuy etc, Pseudomonas spp. and Bacillus spp used fo denitification, geen sulfu bacteia fo sulfide emoval etc. ae used fo immobilization. Acclimization of micooganisms is done by inceasing the pollutant concentation (say of phenol) gadually duing cultue pepaation. The aclimized cultue is used fo the immobilization in/on the solid matix. Immobilization of cells means that the cells have confined o localized so that it can be eused continuously. These exhibit totally diffeent hydodynamic chaacteistics that suounding envionment. Ling cells poduce enzyme (biological catalyst) to catalyze cellula eactions vital to the oganism, the micooganisms ae nomally immobilized on natual and synthetic suppots. Vaious types of solid matices like polyactylamide gel, Ca alginate, poous glass, plastic beads, activated cabon sand, chacoal, diatomaceous eath, cement balls made of coal ash, cellulose, polymeic mateials, polymeic ions, chitosan, lignin s, chitins, coal, collagens etc have been used fo immobilization of whole cells. In the ecent yeas, the immobilization of biocatalyst with polyvalent salts of alginic acids has eceived much attention because of low cost of alginate and the mild conditions of immobilization. The method of immobilization is boadly classified into fou categoies namely covalent bonding, cosslinking (chemical methods), entapment and adsoption (physical methods). Covalent bonding most extensively used technique, whee cells o enzymes ae covalently linked to the suppot though the goups in (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ]

4 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: them o though the functional goups in the suppot mateial. In the cosslinking technique, the cells ae immobilized though chemical cosslinking using agents. Adsoption is the simple of all techniques and does not alte the activity of the bound cells. Adsoption involves adhesion o condensation of the cells to the suface of a caie. The diving foce causing immobilization is the combined hydophobic inteactions, hydogen bonding and salt bidge fomation between the adsobent and cells. Entapment within the gels o fibe is a convenient method fo eactions involving low molecula weight substates and mainly used fo immobilization of whole cells. This method is nothing but the polymeization of the unsatuated monomes in the pesence of cells esults in the entapment of cells with in the intestitial spaces of the gel. Fludized Bed Bioeacto fo Wastewate Teatment This eacto had been successfully applied in the teatment of seveal kinds of wastewate such as ammonianitogen containing wastewate, photogaphic pocessing wastewate, phenolic wastewate, coke oven waste, and othe domestic and industial wastes. Also used successfully fo the eductive biotansfomation of mecuic ions to elemental mecuy pesent in the effluents fom industial amalgam pocess, combustos and powe stations. A fluidized bed (FBB) is capable of achieving teatment in low etention time because of the high biomass concentation., FBB offes distinct mechanical advantages, which allow small and high suface aea media to be used fo biomass gowth. Fluidization ovecomes opeating poblems such as bed clogging and the high pessue dop, which would occu if small and high suface aea media wee employed in packed bed opeation. Rathe than clog with new biomass gowth, the fluidized bed simply expands. Thus fo a compaable teatment efficiency, the equied volume is geatly educed. A futhe advantage is the possible elimination of the seconday claifie, although this must be weighed against the mediumbiomass sepaato. The supeio pefomance of the FBB stems fom the vey high biomass concentation (up to 3040 kg/m3) and its ability to poduce less amount of excess sludge compaed to activate sludge pocess. The limit on the opeating liquid flow ates imposed by the micobial maximum specific gowth ate, as encounteed in the continuous stied tank, is eliminated due to the decoupling of the esidence time of the liquid phase and the gowth of the cells. The use of biomass suppot http: // allows the patial eplenishment of the fluidized bed without inteupting the opeation in ode to maintain high micobial activity. An FBB has attacted consideable inteest as an altenative to the conventional suspended gowth and fixed film pocess in wastewate teatment application due to its high efficiency pefomance. Once fluidized, each paticle povides a lage suface aea fo biofilm fomation and gowth. The suppot media eventually become coveed with biofilm and the vast available gowth suface affoded by the media esults in a biomass concentation appoximately an ode of magnitude geated than that maintained in a suspended gowth system.a pactical appoach poblem, which occus in the opeation of an FBB, is the excessive gowth of biomass on suppot media. This can lead to the channeling of biopaticles in fluidized beds since biomass loading can incease to such extent that the biopaticle began to be caied ove fom a. The poblem of ove expansion of fluidized bed due to biomass gowth has geneally been solved by the emoval of heavily biomassladen paticles fom, followed by the addition of biomassfee paticles. Howeve this solution complicates opeation of a and intoduces the need fo additional equipment extenal to the, such as a vibating sceen o an incineato. One way to achieving the constant biomass loading in an FBB is the egulation of mass of cells gown on suface media so that a steady state is eached whee the ate of biomass gowth is equal to the ate of biomass attition. Livingston and Chase have demonstated that a pactically steady biomass loading can be achieved in a daft tube fluidized bed whee shea foces, occuing between the paticles and the liquid, slough off excess biomass fom suppot paticles. Anothe way is the application of a light (matix paticle density smalle than that of liquid) biomass suppot in a conventional FBB Sokol and Halfani have epoted that steady state biomass loading was achieved in a thee phase (gas liquidsolid)fluidized bed (TPFBB) with KMT paticles (made of poly popylene) fo ove a 9 month opeation. Rusten et al. have demonstated pactically in a with a biomass suppot made of polyethylene. Conventional FBB ae opeated in two diffeent ways. In a with a heavy (matix paticle density lage than that of liquid) biomass suppot(e.g. silica sand, coal), fluidization is commonly conducted with an upwad co cuent flow of gas and liquid though a bed of paticle. Unde fluidization condition, the bed is fluidized with an upwad flow of a liquid counte to the net gavitational foce of the paticle. Once fluidized, each paticle povides a lage suface aea fo biofilm fomation and gowth. (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ] The suppot media eventually

5 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: become coveed with biofilm and the vast available gowth suface affoded by the media esults in a biomass concentation appoximately an ode of magnitude geate than that maintained in a suspended gowth system. The use of biomass suppot allows the patial eplenishment of the fluidized bed without inteupting the opeation in ode to maintain high micobial activity. The limit on the opeating liquid flow ates imposed by the micobial maximum specific gowth ate, as encounteed in the continuous stied tank, is eliminated due to the decoupling of the esidence time of the liquid phase and of the gowth micobial cells. As a esult, loading ates that can be applied in FBBs is geate than those used in the suspended biomass gowth systems. Shieh and Keenan have epoted that fo FBB s a volumetic loading ate of 9.8 x 10 4 kg BOD 5 /m 3 can be applied to poduce effluent vales of 0.02 kg BOD 5 /m 3 and 0.03 kg suspended solids/m3. This value is faily high than the design value of appoximately 1.3x10 4 kg BOD 5 /m 3 s fo conventional ai activated sludge pocesses.the degadation of phenolic type liquos, deived fom coal pocesses, in a continuous stied tank CSTR, packed bed PBB and FBB shown in table. The degadation ates of 0.087,0.053, and kg phenol/m 3 wee achieved in the FBB,PBB and CSTR espectively. The effluent concentations poduced by thee s ae shown in table2. Table2: Typical assays of feed and effluent compositions fo the CSTR, PBR and FBB Constaints CSTB PBR FBR Concentation mg/l Factional convesion Concentation mg/l Factional convesion Concentation mg/l Factional convesion Feed poduct Feed poduct Feed poduct Phenol Thiocynate Cyanide Sulphate Chloide Phosphate Nitate Ammonium Nitogen Total cabon <1 < <10 < < < Table: 3 Compaison of FBB with competing s in municipal applications Paamete Tickling filte Rotating biological HFMBR FBB (PBB) contacto Specific suface aea pe volume(m 2 /m 3 ) 1200 Biomass concentation (kg/m 3 ) Upto 170 Upto 6 Upto http: // (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ]

6 [Rao, 2(10): Octobe, 2013] ISSN: Impact Facto: The basic nutients fo micobial gowth ae tanspoted fist fom bulk phase to the suface of the biofilm, and then tanspoted to the inne egions of the biofilm via diffusion. The limiting mass tanspot ate contols the pesentation of the biofilm eacto. Fom the liteatue it is seen that the extenal esistance can be neglected in the case of a high fluidization flow ate. In a theephase fluidized bed it is found eaction ate follows fist ode kinetics with espect to oxygen and zeoode one with espect to phenol. Fo chemical and biochemical pocess, whee mass tansfe is the atelimiting step, it is impotant to know the gas hold up as this is elated diectly to mass tansfe. the as hold up at high pessue is always lage than that at low pessues, egadless of the liquid velocity and paticle size in thee phase fluidization. SemiFluidized Bed Bioeacto fo Wastewate Teatment In this, simultaneous fomulation of packed bed and fluidized bed is achieved by the pevention of fee expansion of a fluidized bed with intoduction of an adjustable top sceen, which allows the fluid to pass though the bottom potion of the bed will be fluidized condition while the top potion of the bed will be a packed bed. In a fluidized bed the eacto is opeated at a liquid o gas velocity faily less than the washout velocity of the cells. But in semifluidized bed highe velocity of fluid is possible which will lessen the extenal mass tansfe esistance. As a top packed bed is fomed in such a, the eacto pessue dop is high that means it is opeated unde high pessue condition. Hence the gas holdup in the fluidizing section of the column will be moe this will enhance the mass tansfe ate. If the semi fluidized bed can be used as it will ovecome the disadvantages of fluidized bed, namely back mixing, attition and eosion of immobilized solids, eduction of concentation of cultue by elutiation, instability due to fluctuation in flow ate of wastewate, avoid agglomeation and also ovecome the dawbacks of packed bed such as paticles segegation, nonunifomity in tempeatue and channeling. As the top estaining plate is adjustable slugging by bacteial gowth can be pevented. Impoved mass tansfe in semifluidized bed at cost of highepessue dop is compensated by lowe opeation cost though efficient use of oxygen. The top packed bed potion complements the fluidized bed potion by acting as a polishing section, so that the level of contaminants low compaed to fluidized bed. The paametes, which goven the pefomance of a semifluidized ae (i) Popeties of paticles size, http: // shape, and density (ii)popeties of fluid; density, viscosity, and velocity(iii)dimension of the column and its configuations(iv)initial static bed height, height of top estaint and atio of top packed bed (v)to fluidized bed. The compaison of pefomance of diffeent s with espect to phenol degadation in wastewate is shown in table4 Table:4 Compaison of pefomance of Bioeactos with espect to phenol degadation of wastewate Conditi on of fee/effl uent 500 gm/lit of phenol Teate d effluen t CSTR 1.0 kg of Packed bed 4.7 kg of Fluidized bed 8.5 kg of Semifluidized 9.1 kg of Conclusions Immobilized cell s ae supeio than fee cultue s. Among the immobilized s, the semifluidized bed is a novel and efficient one, which can be adopted fo the teatment of industial wastewate containing phenolic compounds and othe pollutants even at lowe concentations. A ight choice of immobilized cultue, caeful delibeation of vaious design paametes fo semifluidized bed s will make teatment pocess cost effective in the long un. Refeences [1] H. M. Jena, G. K. Roy and B. C. Meikap, Compaative Study of Immobilized Cell Bioeactos fo Industial Wastewate Teatment, NIT, Roukela, WMCI2005, I st and 2 nd Oct 2005 [2] B. C. Meikap, G. K. oy, Recent advances in biochemical eactos fo teatment of wastewate, IJEP, vol15 (1), Jan1995, [3] A. V. Vinod, G. V. Reddy, Dynamic behaviou of a fluidised bed teating wastewate, Indian Chem. Eng., Section A, Vol.45, No.1, JanMa 2003, [4] T. K. Ghose, Envionment and Biotechnology, Indian Chem. Eng., Section B, Vol.43, No.2, ApJun 2001, [5] W. Jianping, P. L. H. Wei, D. Liping, M. Guozhu, The denitification of nitate contained wastewate in a gasliquidsoild thee (C) Intenational Jounal of Engineeing Sciences & Reseach Technology [ ]

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