International Journal of ChemTech Research CODEN( USA): IJCRGG ISSN : 0974-4290 Vol.6, No.1, pp 663-672, Jan-March 2014 Best Dilution ratio and GC-MS Analysis for the Removal of Nutrient from Municipal Wastewater by Microalgae R.Gokulan 1 * 1 Assistant professor, KPR Institute of Engineering and Technology, Coimbatore,India. *Corres.author: gokulravi4455@gmail.com Phone: 09487394153. Abstract: Treatment of wastewater by algae is receiving an ever increasing attention in the field of biofuel production, and carbon dioxide sequestration. In order to achieve environmental sustainability, a renewable, carbon free fuels are required that are also capable of sequestering atmospheric carbon dioxide. Algae are the major source of renewable energy. In addition, algae can be used for nutrient removal from the wastewater. Growing algae in wastewater are a potential source of low cost production of bioenergy In this study the prominent genera s namely Anabaena, Diatoms, Hyalophacus, Monoraphidium, Navicula, Oscillatoria and Spirogyra were tested for its ability to reduce the organic and inorganic pollutants present in the wastewater, at different dilution rations and the studies is carried out in a batch reactors with a working volume of 7 liters. The Nutrients namely phosphorus and Total kjeldhal Nitrogen were analyzed daily for a period of 13 days. At the end of 13 th day the reactor 01 showed the greater removal efficiency for Phosphorus and Total Kjeldhal Nitrogen and the removal efficiency were about 80% and 81%. The degradation of phosphorus and nitrogen has also been proved by GC-MS analysis. At the end of the experiment, it is found that, the nutrients were removed very effectively and biomass was produced, which can be used as a renewable energy. Key words: Wastewater, Algae, Nutrient, Renewable energy,gc-ms Analysis. Introduction: Wastewater derived from municipal, agricultural & industrial activities is a source of nutrients for microalgae cultivation [4]. In addition, microalgae-based systems can significantly reduce both organic matter and nutrients in municipal and piggery wastewater at minimal energy cost [2], [5], [7]. The use of wastewater could reduce the need for additional Nitrogen & phosphorus sources by approximately 55% [6]. Microalgae cultures offer an effective solution to tertiary & quaternary wastewater treatment due to the ability of microalgae to use inorganic nitrogen &phosphorus for their growth [3]. One promising way to make algal biofuel production more cost effective is to http://www.sphinxsai.com/framesphinxsaichemtech.htm
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 664 integrate wastewater treatment with algal biomass production [1]. This study focuses on the potential for using microalgae isolated from waste stabilization ponds in order to reduce the organic& inorganic pollutants from municipal wastewater. Methods and Materials: Municipal Wastewater Sample: The municipal wastewater sample is collected at the inlet of the sewage treatment plant. Algal Inoculum: The algal inoculum is collected from the waste stabilization pond and it is cultured under normal laboratory condition. The experiments were carried out in 10 liter plastic cans with a working volume of 7 liters Experimental Design Microalgae were inoculated at 20 %,16%,12%,10%,08% (V inoculation / V wastewater media ) in 10 liter capacity can with a working volume of 7 liters Table 1: Batch Reactors (Raw Sewage+ Algal Inoculum): Batch Reactor Raw Sewage (%) Algal Inoculum (%) Raw Sewage in (Litres) Algal Inoculum in (Litres) 01 8 2 5.6 1.4 02 8.4 1.6 5.88 1.12 03 8.8 1.2 6.16.84 04 9 1 6.3 0.7 05 9.2 8 6.44 0.56 Control 0 10 0 7 Results and Discussion: Microalgae Identification: The genera s responsible for the nutrient removal are Anabaena, Diatoms, Hyalophacus, Monoraphidium, Navicula, Oscillatoria and Spirogyra.
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 665 a)anabaena b) Diatoms c)hyalophacus d)monoraphidium e) Navicula f) Oscillatoria g) Spirogyra Figure 1: Photographic view of Microalgae s
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 666 Phosphorus Removal: The 0 th day phosphorus content of the batch reactors was varied between 44-63 mg/l. At the end of 13 th day it was found between 9-18 mg/l. There is a decrease in the Phosphorus content during algae cultivation. Of all the batch reactors, reactor 01 showed the greater removal efficiency of about 80%. Figure 2: variation of phosphorus Total Kjeldhal Nitrogen: The 0 th day total kjeldahl nitrogen of the batch reactors was varied between 36 68 mg/l. At the end of 13 th day it was found between 10 24 mg/l. There is a decrease in the Total kjeldhal nitrogen content during algae cultivation of all the batch reactors, reactor 01 showed the greater removal efficiency of about 81%. Figure 3: variation of Total Kjeldhal Nitrogen
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 667 Total Dissolved Solids: The biomass produced is measured in terms of Total Dissolved Solids. The 0 th day Total Dissolved Solids of the batch reactors were varied between 1080 1430 mg/l. At the end of 13 th day it was found between 1290-1530 mg/l. There is an increase in the total dissolved solids during algae cultivation. of all the batch reactors, Reactor control showed the greater increase in biomass. Figure 4: Variation of Total Dissolved solids GC-MS Analysis: The sample is analyzed for GCMS results, and it is done in Sophisticated Analytical Instrumentation Facility (SAIF), Indian institute of Technology Madras (IITM). The JEOL GCMATE II GC-MS with Data system is a high resolution, double focusing instrument. Maximum resolution: 6000 Maximum calibrated mass: 1500 Daltons. Source options: Electron impact (EI); Chemical ionization (CI). The raw municipal wastewater was found to contain 98 mg/l of nitrogen (estimated by Total kjeldhal Nitrogen method) and 41 mg/l of phosphorus (estimated by carrier method). This raw water subjected to GCMS analysis and it given eight chromatograms with different Retention Times as show in figure 5. These eight chromatograms when subjected to the mass spectrometric analysis gave no fragmentation patterns. The raw water was mixed with raw municipal wastewater in the ratio of 8:2 (municipal wastewater: algal inoculum). After mixing in this proportion, this mixture was subjected to estimation of nitrogen by kjeldhal nitrogen method and phosphorus by carrier s method. The estimation resulted, the presence of nitrogen (70 mg/l) and phosphorus (55 mg/l) on the zeroth day of mixing. The same sample was subjected to above estimation after 13 days. It revealed the presence of nitrogen (12 mg/l) and phosphorus (10 mg/l). The mixture containing (raw sewage: algal inoculum) 8:2 after 13 days was subjected to GCMS analysis. On GC it gave 11 chromatograms (figure 6), each of this 11 chromatograms were subjected to MS analysis. From the fragments ion peaks obtained, the presence of nitrate ion as NH 4 NO 3, KNO 3 and Mg (NO 3 ) 2 at m/z 77, m/z- 104, m/z- 146 respectively, in different Retention times. Similarly presence of phosphate ion as Mg 2 P 2 O 7,, Ca 3 and Ca 2 H 2 (PO 4 ) 2.CaSO 4.H 2 O At m/z-220.6, m/z-280.5, m/z-355.2 and m/z-427.7 respectively. The presence of nitrate as NH 4 NO 3, KNO 3 and Mg (NO 3 ) 2 in different chromatograms, with different Retention Times as given in the Table 2, respectively. The presence of phosphate ion in the form of Mg 2 P 2 O 7,, Ca 3 and Ca 2 H 2 (PO 4 ) 2.CaSO 4.H 2 O in different chromatograms with different retention times are given in the table 3 respectively
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 668 The high concentration chromatogram with RT 20.42 did not showed any peaks for the presence of Nitrate as NH 4 NO 3, KNO 3 and Mg (NO 3 ) 2 respectively. The low concentration GC with RT 17.61, 14.22 showed 22% as relative intensity of nitrate was in good agreement with value obtained for Nitrogen in the kjeldhal Nitrogen method of estimation (35 mg/l). The presence of phosphate Mg 2 P 2 O 7 in chromatograms with RT 20.42 was found 64% reduced to 34% in chromatograms with RT 14.22. The presence of phosphate as was reduced from 59% in GC with RT 20.42 to 33% in GC with RT 14.22. similarly the concentration of phosphate as Ca 3 and Ca 2 H 2 (PO 4 ) 2.CaSO 4.H 2 O are 100% relative intensity was reduced to 38%, this was also in good agreement with estimation of phosphorus by carriers method (12 mg/l). The GCMS analysis of 8:2 (Raw sewage: Algal inoculum) after 13 days revealed that the absence of any free nitrate and phosphate ions. It may be due to the degradation of NO 3- and PO 4 3- into other volatile compounds. The presence of nitrogen and phosphorus may be due to the presence of their residual molecules in very low concentration in 8:2 (Raw sewage: Algal inoculum). Hence the 8:2 (Raw sewage: Algal inoculum) was found to be better systems for the degradation of nitrate and phosphate ions. Hence it is suggested that algal blooms can be controlled in an effective manner by this ratio 8:2 (Raw sewage: Algal inoculum) for a treatment period of 13 days. Table 2: Concentration of NH 4 NO 3, KNO 3, Mg (NO 3 ) 2 at different GC Retention Times. SI No NH 4 NO 3 KNO 3 Mg(NO 3 ) GC- 2 Identific Identifi RT m/z % m/z % m/z % ation cation Identificat ion 01 14.22 - - - 104.5 23 KNO 3 146.82 33 Mg(NO 3 ) 2 02 16.01 - - - - - - - - - 03 17.61 74.1 22 NH 4 NO 3 - - - 146.80 67 Mg(NO 3 ) 2 04 19.08 - - - - - - 146.90 47 Mg(NO 3 ) 2 05 20.42 - - - - - - 147.17 59 Mg(NO 3 ) 2 06 21.72 - - - - - - 146.70 72 Mg(NO 3 ) 2 07 23.32 - - - - - - 146.78 67 Mg(NO 3 ) 2 08 25.48 - - - - - - 147.07 78 Mg(NO 3 ) 2 09 26.41 - - - - - - - - - 10 27.61 - - - - - - - - -
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 669 Table 3: Concentration of Mg 2 P 2 O 7,, Ca 3, Ca 2 H 2 at different GC Retention Times. Mg 2 P 2 O 7 Ca 3 Ca 2 H 2 (PO 4 ) 2.CaSO 4.H 2 O SI.N GC- 2 o RT m/z % Identifica m/z % Identification m/z % Identificatio m/z % Identification tion n Ca 01 14.22 220.60 34 Mg 2 P 2 O 7 280.50 33 Ca 2 H 2 3 355 100 02 16.01 - - - - - - - - - - - - 03 17.61 221.20 64 Mg 2 P 2 O 7 280.60 67 355 56 Ca 3 427.70 67 Ca 2 H 2 04 19.08 221.30 54 Mg 2 P 2 O 7 280.40 43 355 100 Ca 3 428.20 38 Ca 2 H 2 05 20.42 221.50 61 Mg 2 P 2 O 7 281.10 50 355 82 Ca 3 428.00 100 Ca 2 H 2 06 21.72 221.50 72 Mg 2 P 2 O 7 280.90 72 355 86 Ca 3 428.90 100 Ca 2 H 2 07 23.32 221.20 83 Mg 2 P 2 O 7 281.10 68 353 100 Ca 3 426.90 67 Ca 2 H 2 08 25.48 220.70 79 Mg 2 P 2 O 7 281.10 79 Ca 3 428.35 81 Ca 2 H 2 355 100 09 26.41 - - - - - - - - - - - - 10 27.61 - - - - - - - - - - - 11 28.47 220.50 10 Ca 3 428.00 98 Ca 2 H 2 Mg 2 P 2 O 7 281.80 98 355 100 0
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 670 Figure 5: Gas chromatogram Analysis for Raw sewage
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 671 Figure 6: Gas chromatogram Analysis for the sample 8:2 (sewage: algal inoculum) Conclusion: Acclimatization of the reactor has been observed for about 13 days, there is a decrease in the nitrogen and phosphorus content. The best dilution ratio for the maximum removal efficiency of nitrogen was found in Reactors 01 (81%) and for phosphorus in reactor 01(80%) and biomass increased for about 19% in reactor control. These algal cells can be harvested and it is utilized for various purposes according to the type of algal species. Simultaneously, Carbon dioxide can be bubbled into the Municipal wastewater for effective production of biomass, these results in the reduction of greenhouse gas carbon dioxide.
R.Gokulan /Int.J. ChemTech Res.2014,6(1), pp 663-672. 672 References 1. Clarens.A.F., Resurrection. E.P., White. M.A., Closi.L.M., 2010. Environmental life cycle comparison of algae to other bioenergy feedstock. Environmental Science and Technology 44, 1813-1819. 2. Gonzalez, C., Marciniak, J., Villaverde, S., Garcia-Encina, P.A., Munoz, R., 2008. Microalgae-based processes for the biodegradation of pretreated piggery wastewaters. Applied Microbiology and Biotechnology 80, 891-898. 3. Kumar. M.S., Zhihong. H.M., Sandy.K.W., 2010. Influence of nutrient loads, feeding frequency and inoculum source on growth of Chlorella vulgaris in digested piggery effluent culture medium. Bioresource Technology 101, 6012-6018. 4. Lardon, L., Helias, A., Sialve, B., Steyer, J.P., Bernard, O., 2009. Life cycle assessment and biodiesel production from microalgae. Environmental Science and Technology, 43, 6475-6481. 5. Mulbry, W., Kondrad, S., Buyer, J., 2008. Treatment of dairy and swine manure effluents using freshwater algae: fatty acid content and composition of algal biomass at different manure loading rates. Journal of Applied Phycology 20, 1079-1085. 6. Yang, J., Xu, M., Hu, Q., Sommerfeld, M., Chen, Y., 2011. Life-cycle analysis on bio-diesel production from microalgae: water footprint and nutrients balance. Bioresource Technology 102, 159-165. 7. Zhou, W., Min, Min, Li, Yecong, Hu, Bing, Ma, Xiaochen, Cheng, Yanling, Liu, Yuhuan, Chen, Paul, Ruan, Roger, 2012. A hetero-photoautotrophic two-stage cultivation process to improve wastewater nutrient removal and enhance algal lipid accumulation. Bioresource Technology 110, 448-455. 8. Soha S.M. Mostafa, Emad A. Shalaby, Ghada I. Mahmoud (2012), Cultivating Microalgae in Domestic Wastewater for Biodiesel Production, Notulae Scientia Biologicae, 4(1):56-65. 9. Soumya Pandit, Bikram Kumar Nayak, Debabrata Das (2012), Microbial carbon capture cell using cyanobacteria for simultaneous power generation, carbon dioxide sequestration and wastewater treatment, Bioresource Technology 107; 97 102. *****