Journal for Research| Volume 02| Issue 10 | December 2016 ISSN: 2395-7549
Feasibility Study of Treatment of Effluent from a Bulk Drug Manufacturing Industry using Aerobic Biological Treatment Mriganka Sekhar Mukhopadhyay Ph.D. Student Department of Civil Engineering National Institute of Technology, Durgapur - 713209, India
Dr. Vijay K. Dwivedi Professor Department of Civil Engineering National Institute of Technology, Durgapur -713209, India
Dr. Soumya Bhattacharyya Professor Department of Civil Engineering National Institute of Technology, Durgapur -713209, India
Dr. Sudit S. Mukhopadhyay Associate Professor Department of Bio Technology National Institute of Technology, Durgapur -713209, India
Abstract A study has been carried out on aerobic biological treatment of a bulk drug industrial effluent which is highly acidic in nature and shows high value of BOD5 (≈ 36000 mg/l), COD (≈ 84000 mg/l). Chemical treatment conducted for neutralizing the pH followed by biological treatment using a lab-scale reactor with acclimatized bacterial consortia isolated from natural soil has confirmed its feasibility for biological treatment. About 99% removal of COD from starting value of around 8000 mg/l has been achieved. The COD value in different hydraulic retention time (HRT) has been brought down to less than 100 mg/l in treated effluent, showing high removal of dissolved organics by aerobic biological treatment. Keywords: Aerobic Biological Treatment, Bio-kinetic Constants, Bulk Drug Effluent, COD _______________________________________________________________________________________________________ I.
INTRODUCTION
The modus operandi of a pharmaceutical industry has three main stages: (1) research and development; (2) conversion of organic and natural substances into bulk pharmaceutical substances or ingredients through fermentation, extraction, and/or chemical synthesis; and (3) formulation and assembly of the final pharmaceutical product. Chemical synthesis forms the basic process for preparing the compounds that are used today as pharmaceutical products [17]. The manufacture of Bulk Drug through chemical synthesis mainly involves a complex series of batch processes where many intermediate stages are present and many sequential chemical reactions take place. The processes use various raw materials and generate wastes and emissions [2, 3], including the wastewater. The wastewater is high in biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS), with a wide range of pH from 1 to 11 [16,8]. To keep the environment and ecology unaffected, the generated waste should be treated before disposal to the environment and the rate of generation of waste should also be minimized. Several processes have been proposed for the treatment of the pharmaceutical effluents which include physical, chemical and biological treatment [2, 5, 6, 16]. Biological treatment is a natural process and it plays a significant role in degradation of the organic compounds [4, 11]. Both the aerobic and anaerobic biological systems have been studied for the treatment of pharmaceutical effluents [9, 11, 17]. Installation cost of anaerobic system is very high which can hardly be afforded by small bulk drug producing industries [6, 9]. On the other hand, aerobic treatment is a conventional process having low installation cost and efficient for treatment of various types of pharmaceutical wastewaters [4]. This feasibility study for treatment has been carried out to develop a very simple wastewater treatment process which can be afforded by the small bulk drug producing industries [12]. This will also involve evaluation of bio-kinetic constants for understanding their potentialities in degrading the pharmaceutical effluents emanated specifically from the small bulk drug industries [1, 10, 15]. II. MATERIALS AND METHODS Materials All the chemicals used in this study are either AR grade or Molecular Biology grade. Double distilled water has been used for routine chemical analysis.
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Feasibility Study of Treatment of Effluent from a Bulk Drug Manufacturing Industry using Aerobic Biological Treatment (J4R/ Volume 02 / Issue 10 / 005)
Source and Characterization of wastewater The wastewater for the present study has been collected from the equalization tank of a small bulk drug producing industry. The Industry (situated at Behala, Kolkata) manufactures CALCIUM D-SACCHARATE USP (Calcium Glucarate) from dextrose to fulfill export and domestic requirement. During the production of CALCIUM D-SACCHARATE USP some waste is generated. The waste is mainly OXALIC ACID and un-reacted Dextrose. The sample was characterized using standard methods [13]. Chemical Treatment of Effluent Sample Collected from the Industry Effluent sample has been treated chemically by Lime [Ca(OH) 2] for neutralization [11]. Several trial experiments have been run with different strength of Ca(OH)2. Biological Treatment of Chemically Treated Effluent Sample Seed Preparation and Acclimatization The seed sample prepared from soil was taken in a 2000 ml measuring cylinder, where sugar, starch and peptone solution was added as feed to bacterial mass to initiate bacterial growth and afterwards the acclimatization of the microorganisms in presence of effluent sample was achieved by gradually increasing the dose of industrial effluent [5, 7, 14]. Reactor Aerobic oxidation was performed in the laboratory in a 2-litre measuring cylinder made of glass (Photo 1). The reactor was equipped externally with an air flow pump. It is also effective for uniform mixing [11].
Fig. 1: Reactor
Bacterial Degradation Experimental runs were conducted with the chemically treated effluent sample collected from the industry. Continuous aeration was done in the reactor. III. RESULTS AND DISCUSSIONS The results of analysis of (i) raw, (ii) chemically treated and (iii) diluted effluent sample are given in Table – 1.
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Feasibility Study of Treatment of Effluent from a Bulk Drug Manufacturing Industry using Aerobic Biological Treatment (J4R/ Volume 02 / Issue 10 / 005)
Parameters COD mg/lit BOD5 mg/lit pH
Table - 1 Results of Analysis of Effluent Sample of the Bulk Drug Industry Raw Effluent sample Chemically Treated Sample Four times diluted Chemically Treated Sample 84692 32400 8100 35982 14914 5671 4.2 7.1 7.1
It is observed from the Table-1 that pH value of the sample is too low, which indicates that the sample is highly acidic in nature. Simultaneously, it is observed that BOD and COD values are quite high. This sample is not suitable for biological treatment because of the acidic characteristic of the waste and the wastewater sample being high in organic content. For this reason the sample of wastewater is first neutralized by chemical treatment before subjecting it to biological treatment. It is obvious that by chemical treatment with some alkali material, pH will increase and become suitable for biodegradation and the organic content will also be reduced to a great extent. It has been found that after the neutralization of the acidic sample by calcium hydroxide, the sample still contains quite a good amount of COD value of the neutralized sample. The reduction in the COD value due to neutralization by calcium hydroxide is about 62% (Table-1). The effluent sample after being treated chemically by Ca(OH) 2 is diluted four times to obtain the low COD value before being subjected to biological treatment. The reduced COD value of sample after dilution is given in Table-1. As the chemically treated and diluted sample by nature is near to neutral, and it is suitable for biological treatment. The treatments of pharmaceutical wastewater were conducted during 7th March 2014 to 11th March 2014. During this study many parameters were analyzed for the characterization of raw wastewater and effluent after treatment. The results of biodegradation study are shown in Table-2. Parameters pH COD mg/lit BOD5 mg/lit
Table - 2 The Results of Biodegradation Study Pretreated and Diluted Wastewater Effluent after Bio-Degradation 7.1 7.3 8100 100 5671 20
The experimental results show the initial COD and BOD5 concentration to be 8100 mg/l and 5670 mg/l respectively. The concentration of COD and BOD5 of effluent after biological treatment are found to be 100 and 20 mg/l respectively confirming the high efficiency of bacterial removal of organic content from the wastewater. Evaluation of Biokinetic Constants With starting BOD5 concentration of 5670 mg/l, the BOD5 values at varying θc were considered for the evaluation of Biokinetic constants by using the following modified Monod’s equations. = (1) (2) (3) Where Ks = half-velocity constant mg/l, Y = yield coefficient, K = rate of substrate utilization per day, Kd = decay coefficient per day, μmax = maximum specific growth rate, θc = mean cell residence time, U = specific utilization rate, mg BOD applied / mg MLVSS / day. The values of S0 −S, Xθ, Xθ / (S0 −S), (S0 −S)/Xθ, 1/S, 1/θc were determined for the evaluation of biokinetic constants on BOD basis. In order to evaluate these constants a graphical method was adopted and the method of least squares was used to obtain the line of best fit. Considering the Monod equation Xθc / (S0 − S) = (Ks/K) (1/S) + (1/K), the term Xθ/ (S0 − S), which is reciprocal of F/M ratio, was plotted against effluent substrate concentration 1/S and a straight line of best fit was obtained on BOD basis. The ‘y’ intercept of the plot equals 1/K whose reciprocal gives the value of K. The slope of the plot is equal to Ks/K. By multiplying slope of K the value of Ks was obtained. The BOD based values for Ks, K, Kd and Y were 116.61mg/l, 2.41d-1 , 0.038 d-1and 0.31, respectively. Table - 3 Bio-kinetic Constants Evaluated Period of Experiment Temperature range Ks mg/lit 7th March 2014 to 11th March 2014 300C 116.61
K d-1 2.41
Kd d-1 0.038
Y 0.31
Temporal Variation of Percent COD Reduction and MLVSS Concentration, Interrelationship between Percent Increases in MLVSS Concentration vs. Percent COD Reduction during the Biodegradation Study Temporal variation of percent COD Reduction is graphically presented in Fig.-1. Temporal variation of MLVSS concentration is graphically presented in Fig.-2. Interrelationship between percent increase in MLVSS concentration and percent COD reduction is graphically presented in Fig.-3
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Feasibility Study of Treatment of Effluent from a Bulk Drug Manufacturing Industry using Aerobic Biological Treatment (J4R/ Volume 02 / Issue 10 / 005)
Fig. 2: Percent COD Reduction vs Time Curve
Fig. 2 shows the percent COD reduction with time during biodegradation of organic constituents present in the effluent from the industry. The temperature in the reactor during biodegradation has been maintained at 30 0C Âą 20C. It is observed that the percent COD reduction increases with time and reaches the value of 99% after 4 days. From this graph it is clearly noted that reduction rate of COD are not constant and it may vary from time to time. From day 1 to day 3 the COD reduction rate is very high, Whereas for next two days the rates decline as is evident from the blue lines. On the fourth day the rate is slower than that of third day and the same for the fifth day is further slower than that of fourth day. The percent COD reduction by bacterial degradation gradually decreases with time as bacteria present in the system acts at faster rate initially but after some time its activity reduces, because of the insufficiency in substrate concentration.
Fig. 3: MLVSS Concentration vs. Time
Fig - 3 shows the variation of MLVSS concentration with time curve biodegradation program at constant temperature (30 0 C). The graph shows that MLVSS concentration increases with time and reaches 2135.9mg/lit after 4 days. From this graph it is clearly noted that growth rates of bacteria are not constant but vary from time to time. The nature of curve suggests that the microorganism has taken some time to acclimatize and the growth rate is slow during the first two days. After that the growth rate becomes high (when F/M attains an optimum value) on the subsequent day (3rd day). On 4th day the rate again decreases because of low COD value.
Fig. 4: Percent Increase of MLVSS vs. Percent COD Reduction All rights reserved by www.journalforresearch.org
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Feasibility Study of Treatment of Effluent from a Bulk Drug Manufacturing Industry using Aerobic Biological Treatment (J4R/ Volume 02 / Issue 10 / 005)
Fig.-4 shows the variation of percent MLVSS concentration with percent COD reduction for biodegradation program at constant temperature (300C) for the effluent from the industry. The graph shows that there is a linear relationship with high correlation (R2 value of 0.9999) between percent increase in MLVSS concentration and percent COD reduction in the present experiment. IV. CONCLUSIONS Based on the findings of the physicochemical and biological treatment of effluent from Bulk Drug industry, the following conclusions may be drawn: The results obtained from the investigation revealed the biodegradability potential of the effluent from Bulk Drug Industry using mixed microorganisms to be cost-effective, as it takes less time for biodegradation of wastewater of bulk drug manufacturing industries. The reactor study performed for the industrial effluent shows that it can be successfully treated biologically without any inhibitory effect on bacterial growth. The high BOD5 and COD values are reduced by 99% by enriched microbial culture in aerobic system. It is possible to remove COD even up to 99.88% if temperature is maintained between 280C to320C which is conducive for bacterial growth. REFERENCES [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
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