Y. T. Puyate* and Z. R. Yelebe**

Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 Etimation Of Monod Kinetic Parameter During Aerobic Digetion Of Biodegradable Organic Wate, Part : Analyi Baed On Microbial Growth With Effect Of Bioaugmentation Y. T. Puyate* and Z. R. Yelebe** * Department of Chemical/Petro-chemical Engineering, River State Univerity of Science and Technology, P. M. B. 58, Port Harcourt, Nigeria. ** Department of Chemical/Petroleum Engineering, Niger-Delta Univerity, Wilberforce Iland Bayela State, Nigeria. ABSTRACT Monod kinetic parameter baed on microbial growth during aerobic digetion of biodegradable organic wate are etimated. The analyi involve non-bioaugmentation and bioaugmentation of aerobic biodegradation of organic wate in bioreactor labeled nonbioaugmented (i.e. control) bioreactor, and bioaugmented bioreactor repectively, uing a mixed culture of indigenou microorganim iolated from the wate for bioaugmentation. The maximum pecific growth rate ( m ) of microorganim during biodegradation of the wate are.17 and.15 day -1 for the control and bioaugmented bioreactor repectively. Dimenional yield coefficient ( ) for the control and bioaugmented bioreactor are 1 11.93 1 cfu/mg and 3. 1 cfu/mg repectively. It i hown that the ubtrate aturation contant, K, in Monod equation varie with time and microbial denity during microbial growth. Model for predicting K a a function of time, and microbial denity a a function of K, are alo preented. Prediction of the model are compared with experimental data and good agreement i obtained. Key word: Aerobic digetion, Bioaugmentation, Biodegradation, Monod kinetic, Organic wate. 1. INTRODUCTION In mot developing countrie like Nigeria, handling and treatment of municipal olid wate (MSW) i a major concern to the government and the people. Nigeria for example, produce approximately million tonne of municipal olid wate annually baed on an average of.5 kg olid wate generated by every Nigerian per day [1], majority of which i dumped in municipal landfill and/or heaped openly on the earth urface at variou location in the citie. Thee method of dipoing olid wate which are commonly practiced in thi part of the world have left an inheritance of abandoned dumpite, contaminated oil and groundwater, poioned lake and tream, and dipoal ite with toxic wate and methane exploion potential in many location []. The development and implementation of better engineering ytem for proper handling of olid wate generated by man, rather than jut dumping them into the environment, i extremely important in protecting urface water, groundwater, oil, and maintaining air quality tandard. According to Ogunbiyi [1], not le than 65% of our dometic wate i vegita, while the remaining 35% i made up of platic, rubber, cotton, leather, metal, glae, etc. With the ever-increaing cot of land, increae in human population, and difficultie in permitting new landfill ite, exiting landfill pace i becoming a valuable commodity. Biodegradation (or microbial degradation) of organic pollutant i a biological treatment proce accomplihed primarily by microorganim which utilize organic matter for metabolim [3,4]. Biological treatment of olid wate i a cot effective alternative to other wate treatment technique and many expert regard biotreatment a the technology of the future [5]. Wate containing ubtantial amount of biodegradable organic compound can be treated biologically under aerobic condition. The biological oxidation of organic wate by micro-organim under aerobic condition to produce table wate, water, and a mixture of carbon dioxide and other gae, i known a aerobic digetion and i one of the mot common wate treatment technique [6]. Although aerobic digetion i ued worldwide for the treatment of indutrial, agricultural, and municipal watewater a well a ludge becaue of the proven feaibility of the proce and the multitude of environmental benefit, the technology i alo applied to the treatment of municipal olid wate in recent year [6,7]. Bioremediation involve the ue of microorganim to remove pollutant, and the proce i becoming an increaingly important remedial option [8,9]. Adding nutrient to a contaminated ite to timulate the growth of the indigenou microbial community i known a biotimulation and it i ued extenively for retoration of the environment at petroleum-polluted ite. Injecting microorganim with extenive degrading activity into a contaminated ite to breakdown a pollutant i known a 93 P a g e

Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 bioaugmentation. Biotimulation and bioaugmentation either in-itu or ex-itu are variou modification of bioremediation [9]. Monod growth kinetic [1] i widely ued in modeling biodegradation of organic compound and microbial growth in pure culture, wate treatment ytem, and the natural environment. When Monod equation i coupled with bioma yield and decay, a number of kinetic parameter are required to decribe the operation of a ytem. Studie have hown that the kinetic of microbial degradation i bet repreented by a batch culture [11], and a lot of work ha been done on etimation of the kinetic parameter in Monod equation for variou ytem. For example, Lin and Weber [1] propoed a non-linear regreion procedure for obtaining unbiaed etimate of all Monod kinetic parameter uing batch tet data. Igoni et al. [13] etimated contant value of the kinetic parameter in Monod equation during anaerobic digetion of MSW. Simkin and Alexander [14] etimated the parameter of Monod kinetic that bet decribe mineralization of everal ubtrate concentration by diimilar bacterial denitie. Robinon and Tiedje [15] etimated the Monod growth kinetic parameter from a ingle ubtrate depletion curve, while Dang et al. [16] tudied biodegradation kinetic with repirometric data. Literature on the biokinetic of aerobic digetion of MSW i carce. Yelebe and Puyate [17] preented an approximate model for predicting microbial denity during aerobic biodegradation of MSW, where the ubtrate aturation contant ( K ) in Monod equation wa neglected. Prediction of the model how ignificant deviation from experimental data, which wa attributed to the neglected K in the analyi. Puyate and Yelebe [18] etimated Monod kinetic parameter baed on ubtrate utilization during aerobic digetion of biodegradable organic wate with and without the effect of bioaugmentation. In thi current paper, all kinetic parameter in Monod equation are etimated from experimental data [19] baed on microbial growth during aerobic digetion of biodegradable organic wate in bioaugmented and non-bioaugmenetd batch reactor. The difference between the preent analyi and the one preented in Puyate and Yelebe [18] lie in the kinetic of ubtrate utilization and microbial growth during biodegradation of organic wate in a batch reactor. Alo, the ubtrate aturation contant ( K ) in Monod equation, ubtrate concentration, and microbial denity are predicted by different equation in the preent analyi and in Puyate and Yelebe [18] thereby providing general alternative procedure for etimating Monod kinetic parameter during aerobic biodegration proce. A mixed microbial culture iolated from the wate i ued for the bioaugmentation ince mixed microbial population compoed of many different bacterial pecie often achieve a greater degree of biodegradation [-] than pure culture which generally degrade only a limited number of the compound found in a pollutant [3].. MATERIALS AND METHOD Biodegradable organic wate compoed of food wate, wood/leave, and paper, wa collected, chopped manually, and mahed to homogenize the mixture. Ten-fold erial dilution method [4] of analyi wa ued to enumerate and iolate three type of bacteria (Bacillu pecie, Staphylococcu pecie, and Peudomona pecie) from the wate. The iolated bacteria were then ued to prepare a broth culture (conortium of bacteria) required for bioaugmentation of the biodegradation proce. Detail of the preparation of the liquid wate and broth culture ued in the tudy are preented in Yelebe [19]. Fifty batch reactor, each coniting of 5 ml round bottom flak, were ued for the experiment conducted in the Laboratory of the Department of Chemical/Petro-chemical Engineering, River State Univerity of Science and Technology, Port Harcourt, Nigeria. Twenty-five of the bioreactor were labeled bioaugmented and each bioreactor wa charged with 37 ml of the prepared liquid wate, while each of the remaining twenty-five bioreactor were labeled control and charged with 4 ml of the prepared liquid wate. Thirty millilitre (3 ml) of the prepared broth culture wa added to each of the bioaugmented bioreactor which increaed the volume of the liquid in each of thee bioreactor to 4 ml. The broth culture raied the initial microbial denity in each of the bioaugmented bioreactor to 11.61 cfu/l, while the initial microbial denity in each of the twenty-five control-bioreactor with no 11 innoculum added wa 1.4 1 cfu/l. The bioreactor and their content were intrumented to monitor preure, temperature, and airflow rate. Air wa injected to the bottom of each flak for proper aerobic treatment, and the ga produced during the microbial degradation proce wa vented out from the open end of each flak. The flow rate of air wa approximately.15 l/min per 4 ml of the organic wate olution, and thi airflow rate wa choen to enure proper mixing/bubbling of the olution in each flak without plahing on the wall of the flak. During the natural proce of organic matter degradation in landfill, contaminated water called leachate i formed. In the preent cae, the leachate produced during the biodegradation proce wa not withdrawn from the bioreactor, and the experimental etup wa allowed to run for 5 day. Every day, one bioaugmented-flak and one control-flak were dimantled and a ample wa taken from each flak and analyed for microbial denity and chemical oxygen demand (COD) uing tandard method in Ofunne [4] and Cleceri et al. 94 P a g e

Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 [5], noting that COD (taken here to repreent ubtrate concentration) i normally ued to determine the degree of degradation of wate [7]. The ph of the medium in each dimantled flak wa alo meaured at the ame time interval a the other parameter (i.e. COD and microbial denity) uing a digital ph meter. rate of ubtrate utilization i related to the rate of cell formation in the form d dc (4) dt dt where i the fraction of ubtrate converted to cell (mg/l of cell per mg/l of ubtrate) and range typically from.4 to.8 for aerobic ytem, and.8 The fractional converion of ubtrate ( X ) baed on the meaured COD wa calculated a to. for anaerobic ytem []. The yield coefficient Initial COD Final COD X may (1) alo be expreed a Initial COD c co The temperature in each bioreactor wa meaured (5) twice daily at 9 and 16 hour uing a o thermometer. which can be rearranged to give ( c co) o (6) 3. KINETICS OF MICROBIAL GROWTH IN A BATCH REACTOR where co i the initial ma concentration of The batch growth of microorganim microorganim, and o i the initial ma involve adding a mall quantity of the microorganim or their pore (the eed culture or concentration of ubtrate. The ma concentration of inoculum) to a quantity of nutrient material (called microorganim at any time in the batch reactor i ubtrate) in a uitable veel. In the preent cae of obtained by olving eq. (3) in the form aerobic digetion of biodegradable organic wate, the K d c content of the bioreactor were aerated to create dt (7) m c aerobic condition for microbial growth. It i aumed that only oxygen from the air entering the veel Noting that i a function of c, and ubtituting enhance growth of microorganim, and the carbon from eq. (6) into eq. (7) and integrating the dioxide in the inlet air i ignored. For a batch reactor reulting expreion yield in which the inflow and outflow term are both zero, K the material balance for growth of microorganim o co c ln yield m( o co) co d V c rgv cv (1) (1) K o ln dt t (8) m ( o co) o co c where V i the volume of the reactor, r g i the growth rate of microorganim (ma/(volume Equation (8) can be ued to generate a graph time)), c i the microbial denity or ma howing change in microbial denity with time concentration of microorganim (cell), t i time, during batch biodegradation proce. The main and i the pecific growth rate of microorganim diadvantage of eq. (8) i that it i not explicit in c (time 1 ) which i related to ubtrate concentration in which require olving for c at a particular value of the form [1] t. We note in the preent analyi that i m () meaured () in mg/l; while ˆ c i meaured in cfu/l, K where the caret indicate the experimental unit (cfu/l) where i the ma concentration of ubtrate, m of ˆ c and not mg/l. Hence, the appropriate form of i the maximum pecific growth rate of, c, and co to be ued in eq. (8) are, ˆc, and microorganim, and K i the ubtrate aturation ˆ co repectively, where the prime indicate that i contant which i defined a the ubtrate dimenional and expreed in cfu/mg. concentration correponding to m /. Combining eq. (1) and () give the batch culture 3.1. Etimation of kinetic parameter during rate equation for microbial growth a aerobic digetion of biodegradable organic dc wate c m (3) (3) dt K In thi ection, all kinetic parameter ( m, If all the ubtrate i converted to cell, then K, ) in the Monod rate equation are etimated the rate of ubtrate utilization i ideal. However, uch an ideal condition doe not occur in practice due to inefficiencie in the converion proce. Hence, a yield coefficient ( 1) i introduced uch that the from experimental data [19] on microbial growth during aerobic digetion of biodegradable organic wate in bioaugmented and non-bioaugmented (i.e. control) batch reactor. It i hown in Yelebe [19] and Yelebe and Puyate [6] that microbial growth in the 95 P a g e

Subtrate conc. (mg/l) Subtrate conc. (mg/l) Specific growth rate (day 1 ) Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 bioaugmented and control bioreactor occurred during the firt day of the experiment, after which microorganim in the bioreactor begin to die. The lag phae of low microbial growth in each type of bioreactor occurred during the firt 1 day of the experiment, while the phae of very fat microbial growth (often called phae of exponential growth of microorganim) occurred between the 1 th and th day of the experiment. A dimenional yield coefficient ( ) i calculated from the experimental data [19] for the firt day uing eq. (5) a.93 1 cfu/mg for the control bioreactor, and 3.1 cfu/mg for the bioaugmented bioreactor. Since the dimenionle yield coefficient ( ) i the fraction of ubtrate converted to cell, the value of for the aerobic digetion proce conidered in thi tudy i.8 for the bioaugmented bioreactor, and.71 for the control bioreactor a hown in Fig. 1 and repectively. 7 6 5 4 3 1..4.6.8 1 Fractional converion of ubtrate Fig. 1. Plot of ubtrate concentration againt fractional converion of ubtrate (bioaugmented). 7 6 5 4 3 1.5.5.75 Fractional converio n of ubtrate Fig.. Plot of ubtrate concentration againt fractional converion of ubtrate (control). Thu the value of for the two type of bioreactor lie within the pecified range (.4.8) for aerobic ytem []. It i obviou from Fig. 1 and that the 1 11 ubtrate concentration in the two type of bioreactor decreae a the fractional converion of ubtrate increae. The pecific growth rate of microorganim ( ) wa calculated directly from the experimental data [19] uing eq. (1) for the firt day of the experiment, and Fig. 3 how plot of pecific growth rate againt ubtrate concentration in the bioaugmented and control bioreactor during the ame period. It may be een from Fig. 3 that the pecific growth rate of microorganim in the bioaugmented bioreactor i higher than in the control bioreactor and i attributable to the bioaugmentation of the ytem. Alo, Fig. 3 indicate that the pecific growth rate increae a the ubtrate concentration increae, which i due to abundant nutrient that promote and utain microbial growth..1.8.6.4. control bioaugumented 1 3 4 5 6 Subtrate conc. (mg/l) Fig.3. Plot of pecific growth rate againt ubtrate concentration Yelebe and Puyate [17] etimated m.17day -1 and.15 day -1 for the control and bioaugmented bioreactor repectively on the aumption that K i mall compared to, and K wa neglected in the analyi. But predicted microbial denitie in the two type of bioreactor baed on thi aumption did not compare well with experimental data. In the cae where K i not negligible, a contant value of K i normally etimated a the ubtrate concentration correponding to m / on a graph of pecific growth rate againt ubtrate concentration [11]. A contant value of K 4mg/l for the control bioreactor wa etimated from Fig. 3, while a contant value of K for the bioaugmented bioreactor cannot be etimated from Fig. 3 ince m / for thi type of bioreactor lie outide the experimental range of. However, K may not be contant and a general procedure for etimating K 96 P a g e

Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 which i applied in the current analyi i preented a follow. In order to invetigate the effect of K on microbial growth during the aerobic digetion proce, eq. (8) and experimental data [19] on microbial denity during the period of microbial growth were ued to generate value of K at pecified interval of time and correponding value of ˆ a hown in Table 1. c Table 1. Variation of time K with microbial denity and Time (day) Control bioreactor Bioaugmented bioreactor K 11 ˆ c 1 K ˆ c 1 (mg/l) (cfu/l) (mg/l) (cfu/l) 4. 1.4 4..6 3.46 1. 73.9.49 4 6.98 1.47 6.54 3.14 6.4 1.8 49.6 4.13 8 15.4.31 39.597 5.7 1 8.64 3.1 7.66 8.8 1.35 4.73 11.38 17.66 14-6.7 8.16-7.69 7. 16-5.96 1.78-6.44 18.5 18-3.53 1.57-3.6 138.1 -.16 13. -.1 15 11 It i obviou from Table 1 that K for each type of bioreactor varie with time and microbial denity, indicating that K i not contant for the aerobic biodegradation proce. The poitive value of K in Table 1 correpond to a region of low microbial growth uch a the lag phae, while the negative value of K correpond to a region of fat microbial growth uch a the phae of exponential growth [6]. Thu, the effect of K on microbial growth i conidered in two tage: (i) a firt tage of low microbial growth with poitive value of K, and (ii) a econd tage of fat microbial growth with negative value of K. Such tage-wie treatment of engineering procee where the different tage have unique characteritic are reported in the literature. For example, drying of olid i often conidered a a two-tage proce where a contant-rate period during which the drying rate i contant i followed by a falling-rate period when the drying rate gradually decreae with time [7,8]. Wick action in concrete i alo modeled a a two-tage tranport proce, where alt i tranported in olution from a wet face of the concrete in contact with a marine environment to a dry face of the concrete in contact with air of relative humidity le than 1%, reulting in the buildup of alt at a liquid-ga interface within the concrete where evaporation of water occur [9,3]. The initial microbial denity in each type of bioreactor (Table 1) i not predicted in thi tudy becaue it i contant and independent of any variable. Thi i jutified in the application of Newton divided difference interpolation polynomial to predict the flahpoint of bitumen blended with lighter petroleum product [31], and the flahpoint of keroene blended with mall quantitie of alcohol [3], where the flahpoint of the pure (unblended) material wa not predicted. Accordingly, the initial value of K in Table 1 i not predicted and the variation of K with time and microbial denity in each type of bioreactor are invetigated for t, where t i the time in day. 3.1.1. Relationhip between K, ˆc, and time for control bioreactor It i obviou from eq. (8) that microbial denity in the bioreactor depend on K and time, which i modeled in part a follow: (i) K a a function of time, and (ii) microbial denity a a function of K. Plotting the poitive value of K for the control bioreactor in Table 1 againt time for t 1 a hown in Fig. 4, give K ( ctrl ).991t 1.7895t 36.1 (9) where the ubcript ctrl refer to control bioreactor, and the poitive upercript indicate the ign of K. Plotting negative value of K for the control bioreactor in Table 1 againt time for 14 t a hown in Fig. 5, yield K ( ctrl ).174t 4.7338t 5.741 (1) where the negative upercript indicate the ign of K. Thu, K decreae with time in the lag phae (Fig. 4), but increae with time in the exponential growth phae (Fig. 5). Having known the functional relationhip between K and time, the equation relating microbial denity and K are obtained by plotting the microbial denitie in Table 1 againt the correponding value of K for the control bioreactor in the range t, to obtain ˆc ( ctrl).9k.16k 4.7471 (11) ˆc( ctrl).1854k.584k 13.131 (1) which are hown graphically in Fig. 6 and 7, where the poitive and negative upercript of ˆ c indicate value of thi parameter correponding to poitive and negative value of K repectively. 97 P a g e

Microbial denity (x1 11 cfu/l) Microbial denity (x1 11 cfu/l) Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 KS (mg/l) 35 3 5 15 1 5 y = -.991x - 1.7895x + 36.1 5 1 15 Time (day) Fig. 4. Plot of poitive value of K againt time for control bioreactor in the range t 1. KS (mg/l) -1 - -3-4 -5-6 -7-8 Time (day) 1 3 y =.174x - 4.7338x + 5.741 Fig. 5. Plot of negative value of K againt time for control bioreactor in the range 14 t. 5 4 3 1 y =.9x -.16x + 4.7471 4 K S (mg/l) Fig. 6. Plot of microbial denity againt poitive value of K for control bioreactor in the range t 1. y = -.1854x -.584x + 13.131 16 14 1 1-8 -6-4 - K S (mg/l) Fig. 7. Plot of microbial denity againt negative value of K for control bioreactor in the range 14 t. Fig. 6 indicate that microbial denity in the lag phae of the control bioreactor decreae a the value of K increae (or converely, microbial denity in the lag phae increae a while microbial denity increae a 8 6 4 K decreae), K increae in K the exponential growth phae (Fig. 7). Since decreae with time in the lag phae and increae with time in the exponential growth phae, it mean microbial denity increae with time in both the lag phae and exponential growth phae during microbial growth in the control bioreactor, which i conitent with the reult of Yelebe and Puyate [6]. 3.1.. Relationhip between K, ˆc, and time for bioaugmented bioreactor KS (mg/l) 8 7 6 5 4 3 1 y = -.491x 3 +.9483x - 11.85x + 9.75 4 6 8 1 1 14 Time (day) Fig. 8. Plot of poitive value of K againt time for bioaugmented bioreactor in the range t 1. 98 P a g e

Microbial denity (x1 11 cfu/l) Microbial denity (x1 11 cfu/l) Microbial denity (x1 11 cfu/l) Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 Plotting poitive and negative value of K in Table 1 for the bioaugmented bioreactor againt time in the 18 range t 1, yield 16 3 ( bioaug.) K.491t.9483t 11.85t 9.75 (13) ( bioaug.) K.1461t 3.6745t 15.71 (14) which are hown graphically in Fig. 8 and 9, where the ubcript bioaug indicate bioaugmented bioreactor. KS (mg/l) -1 - -3-4 -5-6 -7-8 -9 Time (day) 5 1 15 5 y =.1461x - 3.6745x + 15.71 Fig. 9. Plot of negative value of K againt time for bioaugmented bioreactor in the range 14 t. Like the control bioreactor, K in the lag phae of the bioaugmented bioreactor decreae with time, but increae with time in the exponential growth phae. Accordingly, plotting the microbial denitie in Table 1 againt correponding poitive and negative value of K for the bioaugmented bioreactor in the range t, give ˆ 5 3 c ( bioaug.) (8 1 ) K. 15 K data. 1.33K 7.59 (15) (15) ˆc ( bioaug.) 1.844K 4.49K 151.4 (16) (16) which are hown graphically in Fig. 1 and 11. 16 1 8 4 y = -8E-5x 3 +.15x - 1.33x + 7.59 4 6 8 K S (mg/l) Fig. 1. Plot of microbial denity againt poitive value of K for bioaugmented bioreactor in the range t 1. y = -1.844x - 4.49x + 151.4 14 1 1 8 6 4-1 -8-6 -4 - K S (mg/l) Fig. 11. Plot of microbial denity againt negative value of K for bioaugmented bioreactor in the range 14 t. A in the control bioreactor, microbial denity in the bioaugmented bioreactor increae with time in both the lag phae and exponential growth phae during microbial growth. 4. RESULTS AND DISCUSSION Figure 1 and 13 how the comparion between predicted microbial denity uing the current model (eq. (8) (16)), the approximate model by Yelebe and Puyate [17] when K i neglected, the K normal method of predicting a contant value of a the ubtrate concentration correponding to m / on a graph of againt ubtrate concentration (and repreented in the plot for control bioreactor a normal method ), and experimental 14 1 1 8 6 4 experiment current model Yelebe and Puyate [17] normal method 5 1 15 5 Time (day) Fig. 1. Experimental and predicted microbial denity in control bioreactor. 99 P a g e

Microbial denity (x1 11 cfu/l) Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 16 14 1 1 8 6 4 experiment current model Yelebe and Puyate [17] 5 1 15 5 Time (day) Fig. 13. Experimental and predicted microbial denity in bioaugmented bioreactor It may be een from Fig. 1 that the current model compare very well with experimental data, the approximate model by Yelebe and Puyate [17] partly over-predict and partly under-predict the experimental data, while the normal method compare fairly well only within the lag phae. In Fig. 13, the normal method i excluded becaue m / lie outide the experimental range of pecific growth rate of microorganim in the bioaugmented bioreactor (ee Fig. 3). Figure 1 and 13 how clearly that the contribution of K to the aerobic biodegradation proce i ignificant, and the normal method of etimating a contant value of K doe not apply in all cae epecially when contant a in the preent analyi. K i not 5. CONCLUSION Etimation of all Monod kinetic parameter baed on microbial growth during aerobic digetion of biodegradable organic wate in control and bioaugmented bioreactor ha been preented. The growth rate and pecific growth rate of microorganim in the bioaugmented bioreactor are higher than in the control bioreactor. It i hown that K i not contant in the preent analyi, neither i it equal to zero. The general procedure preented for etimating K a a function of time, and microbial denity a a function of K, i adequate and may be applied to biodegradation of organic compound. REFERENCES [1] A. Ogunbiyi, Local technology in olid wate management in Nigeria, Proceeding of the National Enginnering Conference and Annual General Meeting of Nigerian Society of Engineer, Port Harcourt, 73-75, 1. [] G. Kiely, Environmental Engineering, Irwin/McGraw-Hill, London, 653-66, 1997. [3] M. F. Gordon, J. C. Geyer, and D. A. Okun, Element of Water Supply and Watewater Dipoal, nd Ed., John Wiley, New York, 535-539, 1971. [4] E. N. Helmer, J. D. Frame, A. E. Greenbergh and C. N. Sawyer, Sewage and Indutrial Wate, 4, 884-887, 1951. [5] O Mara, M. K., 1996. Cae tudy of bioremediation of petroleum contaminated oil including nutrient addition at Kincheloe AFB, Kinro Michigan, Proceeding of the. 8th Mid-Atlantic Indutrial and Hazardou Wate Conference, New York State Center for Hazardou Wate Management, Department of Civil Engineering, Univerity at Buffalo, New York, 11-18, 1996, [6] T. D. Reynold, and P. A. Richard, Unit Operation and Procee in Environmental Engineering, nd Ed., PW Publihing Co., Boton, 573-58, 1996, [7] S. E. Borglin, T. C. Hazen, C. M. Oldenburg, and P.T. Zawilanki, Comparion of aerobic and anaerobic biotreatment of municipal olid wate, J. Air and Wate Manage. Aoc., 54, 815-8, 4. [8] S. Ozaki, N. Kihimoto, and T. Fujita, Iolation and plylogenetic characterization of microbial conortia able to degrade aromatic hydrocarbon at high rate, Microbe and Environ., 1, 44-5, 6. [9] K. Lee, G. H. Treamblay, and E. M. Levy, Bioremediation application of low releae fertilizer on low energy horeline, Proceeding of the 5 Oil Spill Conference, Miami Beach, Florida, 73-736, 5. [1] J. Monod, The growth of bacteria culture, Ann. Rev. Microbiol., 3, 535-54, 1949. [11] J. F. Richardon, and D. G. Peacock, Coulon and Richardon Chemical Engineering, Vol. 3, 3rd Ed., Elevier, New Delhi, 84-349, 6, [1] W. Lin, and A. S. Weber, Etimation of microbial kinetic parameter uing a nonlinear regreion method, Proceeding of the 8th Mid-Atlantic Indutrial and Hazardou Wate Conf., New York State Center for Hazardou Wate Management, Department of Civil Engineering, Univerity at Buffalo, New York, 547-554, 1996, [13] A. H. Igoni, M. F. N. Abowei, M. J. Ayotamuno, and C. L. Eze, Biokinetic of anaerobic digetion of municipal olid wate, Newview Eng. Analyi and Modeling J., 1, 98-99, 6. [14] S. Simkin and M. Alexander, Non-linear etimation of the parameter of Monod 91 P a g e

Y. T. Puyate, Z. R. Yelebe / International Journal of Engineering Reearch and Application (IJERA) ISSN: 48-96 www.ijera.com Vol., Iue 6, November- December 1, pp.93-911 kinetic that bet decribe mineralization of everal ubtrate concentration by diimilar bacterial denitie, Appl. Environ. Microbiol., 5, 816-8, 1985. [15] J. A. Robinon and J. M., Tiedje, Non-linear etimation of Monod growth kinetic parameter from a ingle ubtrate depletion curve, Appl. Environ. Microbiol., 45, 1453-1458, 1983. [16] J. S. Dang, D. M. Harvey, A. Jobaggy, and C. P. L. Grady, Evaluation of biodegradation kinetic with repirometric data, Re. J. Water Pollut. Contr. Fed., 61( 11/1), 1711-171, 1989. [17] Z. R. Yelebe and Y. T. Puyate, Biokinetic of aerobic digetion of municipal olid wate: An approximate analyi, J. Nigerian Soc. Chem. Engineer, 4, 8-39, 9. [18] Y. T. Puyate and Z. R. Yelebe, Etimation of Monod kinetic parameter during aerobic digetion of biodegradable organic wate, Part 1: Analyi baed on ubtrate utilization with effect of bioaugmentation, J. Nigerian Soc. Chem. Engineer, 5, 73-85, 1. [19] Z. R. Yelebe, Development of model for aerobic digetion of municipal olid wate, Ph.D. Thei, Department of Chemical/Petrochemical Engineering, River State Univerity of Science and Technology, Port Harcourt, Nigeria, 9. [] M. Vina, M. Grifoll, J. Sabate, and A. M. Solana, Biodegradation of a crude oil by three microbial conortia of different origin and metabolic capabilitie, J. Ind. Microbiol. Biotechnol., 8, 5-6,. [1] K. Sugiura, M. Ihihara, T. Shimauchi, and S. Harayama, Phyicochemical propertie and biodegradability of crude oil, Environ. Sci. Technol., 31, 45-51, 1997. [] P. Domde, A. Kapley, and H. J. Purohit, Impact of bioaugmentation with a conortium of bacteria on the remediation of watewater-containing hydrocarbon, Environ. Sci. Pollut. Re. Inter., 14, 7-11, 7. [3] J. R. Bragg, R. C. Prince, E. J. Harner, and R. M. Atla, Effectivene of bioremediation for the Exxon Valdez oil pill, Nature, 368, 413-418, 1994. [4] J. I. Ofunne, Bacteriological Examination of Clinical Specimen, Achugo Publication, Owerri, Nigeria, 4-35, 1999. [5] L. S. Cleceri, A. E. Greenberg and A. D Eaton, Standard Method for the Examination of Water and Watewater, th Ed., ALPHA/AWWA/WEF, Wahington DC, 1998. [6] Z. R. Yelebe and Y. T. Puyate Effect of bioaugmentation on aerobic digetion of biodegradable organic wate, J. Appl. Technol. Environ. Sanit., (3), 165-174, 1. [7] Y. T Puyate and C. J. Lawrence, Sherwood model for the falling-rate period: A miing link at moderate drying intenity, Chem. Eng. Sci., 61, 7177-718, 6. [8] Y. T. Puyate, Analogy between heat and ma tranfer for contant-rate period during non-convective drying: Application to waterbaed alumina upenion for tape cating, J. Appl. Sci., 8, 1511-1518, 8. [9] Y. T. Puyate and C. J. Lawrence, Steady tate olution for chloride ditribution due to wick action in concrete, Chem. Eng. Sci., 55, 339-3334,. [3] Y. T. Puyate, C. J. Lawrence, N. R. Buenfeld, and I. M. Mcloughlin, Chloride tranport model for wick action in concrete at large Peclet number, Phyic of Fluid, 1, 566-575, 1998. [31] S. N. Chigeru and Y. T. Puyate, Model for predicting flahpoint of penetration-grade bitumen blended with lighter petroleum product, AMSE J.: Modeling, Meaurement and Control C, 69(1-), 1, 8. [3] E. N. Wami, A general expreion for predicting flahpoint of keroene blended with mall quantitie of alcohol, AMSE J.: Modeling, Simulation and Control B, 48, 43-5, 1995 911 P a g e