Phycoremediation of Dairy Effluent by using the Microalgae Nostoc sp PDF

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International Journal of Environmental Research and Development. ISSN 2249-3131 Volume 2, Number 1 (2012), pp. 35-43 © Research India Publications http://www.ripublication.com/ijerd.htm Phycoremediation of Dairy Effluent by using the Microalgae Nostoc sp 1* Kotteswari M., Murugesan S. and 2Ranjith K...

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Phycoremediation of Dairy Effluent by using the Microalgae Nostoc sp Ramanathan RanjithKumar

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International Journal of Environmental Research and Development. ISSN 2249-3131 Volume 2, Number 1 (2012), pp. 35-43 © Research India Publications http://www.ripublication.com/ijerd.htm

Phycoremediation of Dairy Effluent by using the Microalgae Nostoc sp 1*

Kotteswari M., Murugesan S. and 2Ranjith Kumar R. 1

Unit of Algal Biotechnology and Bionanotechnology, PG and Research Dept of Botany, Pachaiyappa’s College, Chennai 600 030 India 2 Institute for Water and Wastewater Technology, Durban University of Technology, 19, Steve Biko Road, Durban 4000, South Africa *Corresponding Author E-mail: [email protected]

Abstract Increased urbanization and industrialization has given rise to serious water pollution and environmental problems. Discharge of industrial effluent as well as chemical spills, domestic sewage, and use of pesticides are the main cause of environmental pollution. Dairy industry is one of the important industries causing water pollution. There are many physico-chemical methods are available, but recent progress in bioremediation suggest that algae can play dual role to increase biomass by utilizing waste as nutrients and can be helped in solving problems of pollution created by effluents. Generally dairy effluent contains huge amount of milk constituents such as casein, lactose, fat and high amount of BOD and COD. In the present study, an attempt has been made to treat the dairy effluent by using the blue green alga Nostoc sp. The result revealed that the potential of Nostoc sp, to reduce TDS, TSS, BOD and COD. Keywords: Phycoremediation, Dairy effluent, Water pollution, Nostoc sp.

Introduction Microalgae play an important role during the tertiary treatment of domestic wastewater in maturation ponds or the treatment of small–middle-scale municipal wastewater in facultative or aerobic ponds (Aziz and Ng, 1993; Abeliovich, 1986; Mara and Pearson, 1986; Oswald, 1988, 1996). They enhance the removal of nutrients, heavy metals and pathogens and furnish O2 to heterotrophic aerobic bacteria to mineralize organic pollutants, using in turn the CO2 released from bacterial respiration. Photosynthetic aeration is therefore especially interesting to reduce operation costs and limits the risks for pollutant volatilization under mechanical

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aeration and recent studies have shown that microalgae can indeed support the aerobic degradation of various hazardous contaminants (Safonova et al., 2004). An innovative technology that is gaining momentum in the field of environmental studies is phycoremediation. This technology is a silent emerging trend going to be the answer for all environmental threats. Furthermore, most of these techniques are based on physical displacement or chemical replacement, generating yet another problem in the form of toxic sludge, the disposal which adds further burden on the techno-economic feasibility of the treatment process. In view of this, the development of new technique is necessary to meet the environmental standards at affordable costs. The main advantages of using micro algal species, is that it traps the solar energy in its chloroplast cell and absorbs CO2 along with nutrients from water to synthesis their biomass and produces oxygen. Algae release large amount of organic compounds which can be assimilated by bacteria (Bell, 1983). The bacteria, in turn constituent an important source of CO2 needed for algal growth, and its changing the pH of supporting medium. (Jean-Luc Moue, 1995). Filamentous cyanobacterium is an excellent nominee for wastewater treatment due to there variable unique characteristics Giorgos Markou and Dimitris Georgakakis (2011). India, a tropical country has got a plenty of sunshine and is rich in microalgal species. The parameters like nutrient requirement, tolerance to pollution, mixotophic growth tolerance to extreme temperature and presence of biochemical products of economic importance are to be investigated. Industries in India must be converted to this new technology by conducting meaningful help and field trials. The present study was focused on the phycoremediation of dairy effluent by using blue green microalgae. The role of blue green microalgae ideally fit to play a vital role in treating wastewater by utilizing different constituent’s essential chemical as nutrients for its growth metabolism.

Materials and Methods Effluent Characteristics and Analysis In dairy industry, primary and secondary treatment methods are quite common in the treatment of dairy wastewater, as they are efficient and dependable. The dairy effluent is predominantly organic in nature and due to its biodegradable constituents; it is amenable to conventional treatment. It is rich in nutrients, nitrate and phosphate, which is source of enhanced algal growth in natural waterways. Fresh dairy waste is highly alkaline and turns to acidic due to the fermentation of lactose to lactic acid. Due to these properties chemical treatment methods may not appropriate. It is probably due to this reason that most of the existing dairies have treatment plants based on activated sludge process. This type of treatment method is not effective in filtering the nutrients from the dairy wastewater. This waste water needs further polishing to remove the nutrients which can be effectively done through the use of aquatic macrophytes. Also dairy waste contains sufficient nutrients for biological growth, biological treatment methods are considered more ideal and economical.

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Isolation and Growth of Nostoc sp, under in vitro conditions Dairy effluent was collected from Madavaram Dairy Plant, Madavaram, suburb of Chennai. In order to select a suitable organism for the treatment process, cyanobacterial population was collected at different places from where the effluent was collected. Among the blue green microalgae Nostoc sp, responds well with dairy effluent, the viable potential microalgae Nostoc sp was selected further treatment process. The microalga, Nostoc sp, was isolated from dairy wastewater, and cultured BG 11 medium (Rippka et al., 1979). Microalgal cultures were examined under a microscope (Olympus HB) and identified according to the monograph of (Desikachary, 1959). The axenic culture of the isolated microalga, Nostoc sp was maintained in improvised BG11 medium (Rippka et al., 1979). For cultivation of microalgae. improvised BG11 medium (Na NO3, 1.5g; K2HPO4,0.04 g; MgSO47H20, 0.075g; CaCl22H20, 036 g; Citric acid, 0.036 g; ferric ammonium citrate, 0.006 g; EDTA disodium salt, 0.006 g; H3BO3, 2.86 g; MnCl2 4H20,1.81 g; ZnSO4 7H20, 0.222 g; Na2MO3 2H20,0.39g; CuSO4 5H20, 0.07 g; CO (NO3)2 6H20, 0.07 g; pH, 7.1), was used for culturing the microalga and the culture was incubated under laboratory conditions in an environmental chamber illuminated with cool white fluorescent light (3000 lux), in a 12 h light/12 h dark cycle at 24±1°C. Growth (divisions/day) was measured by weighing the algae. Selection of Viable Microalgae and Treatment Method in vitro Condition To study the role of blue green microalgae in dairy effluent, the following treatment were employed. (A) Effluent inoculated with Nostoc sp (B).Un inoculated Effluent (control), (C) BG 11 medium (Rippka et al., 1979) inoculated with Nostoc sp (to compare the growth of Nostoc sp, with that of dairy effluent). Initial physico chemical parameters were done by using standard method. APHA (2000). Experiments were conducted in triplicates and repeated at least three times. Two grams of uniform suspension of Nostoc sp, was inoculated as initial inoculums in each 3 liter raw effluent and BG 11 containing flasks (A & C). The experiment was conducted for a total duration of 15 days under open condition. Statistical Analysis All experiments were conducted in triplicates and mean differences ± 0.005.

Results and Discussion Phycoremediation under Laboratory Condition The experiments were carried out with amended with BG11 medium. Nostoc sp was inoculated in 2 gm amended BG11 media separately. The entire set of dairy effluent experiment was carried out for 15 days. Growth Rate The growth rates of Nostoc sp amended with dairy effluent wastewater. Nostoc sp showed maximum growth rate 330 mg on 15 day. The results were given in the figure.1.

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Figure 1: Growth rate of Nostoc sp amended with dairy effluent wastewater

Selection of Viable Microalgae for Effective Dairy Effluent Treatment Feasibility study was conducted by growing various microalgae in the diary effluent which included the native microalgae isolated from the effluent as well as the micro algal species from the (Algal Culture Laboratory, Pachaiyappa’s College, Chennai.) culture collection. The algae employed for the study are Nostoc sp. Physico-Chemical Parameters Before and After Treatment In the present study, colour of the effluent treated with Nostoc sp, changed from blackish gray on the 5th day and on 7th day it changed to greenish yellow on15th day it was completely turned to green. These changes in colour and odour of the dairy effluent may be due to the organic matter present in the effluent and made the water clear. These findings are in concordant with Verma and Madamwar (2002). The present study revealed that the dairy effluent was milky and grayish black in colour with disagreeable odour which may be due to decomposition of organic matter or presence of various aromatic and volatile organic compounds (Singh et al.,1998) and it may also be due to microbial activity (Nagarajan and Shasikumar, 2002). A large number of pollutants can impart colour, taste and odour to the receiving water there by making them unaesthetic and unfit for domestic consumption. The removal of colour from wastewater is often more important than the removal of soluble colourless organics, which normally contribute to the major BOD load. Often primary treatment and secondary treatment methods to remove colour of wastewater (McKay et al., 1981). The effluent was treated with microalgae the colour changed into green. Colour in dairy effluent is of aesthetic consideration rather than an actual pollutant. The result of the physico-chemical characteristic feature of dairy effluent is represented in Table.1.

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Table 1: Physico Chemical Characteristics of Dairy Effluent Parameter Before algal After algal % of Reduction mg/L Treatment Treatment TSS 356 164 -53.93 TDS 1128 1090 -20.21 pH 5.15 7.83 +34.22 Alkalinity total 356 386 -18.13 Phosphate 012 9.47 -21.08 COD 631 377 -40.25 BOD 216 120 -40.44

In the present study the amount of total suspended solids was reduced to 53.93 percent by Nostoc sp. The higher amount of total suspended solids present in raw effluent may be due to the presence of higher concentration of biodegradable organic matter in the dairy effluent which is in accordance with earlier reports. The high suspended solids in different industrial effluents were also reported earlier by Sinha (1993), Amudha and Mahalingam (1999) and Sundaramoorthy et al., (2000). Kotteswari et al., (2007) reported 74.37 percent reduction of total suspended solids, when the dairy effluent was treated with Spirulina platensis. The total dissolved solids (TDS) in the effluent with Nostoc sp was reduced to 20.21 percent. The TDS value of the dairy effluent was found to be exceeding the limits prescribed by (CPCB, 1995). Murugesan et al., (2007) reported 36.19 percent reduction of total dissolved solids, when the oil refinery effluent was treated with Spirulina platensis. Similarly, Veeralakshmi et al., (2007) reported 19.16 percent reduction of total dissolved solids, when the petroleum effluent was treated with Oscillatoria sp. pH of aqueous solution is an important controlling factor in the adsorption process and thus the role of hydrogen ion concentration was examined from solutions at different pH. It has been grouped in this annotation with other non-specific substances because it is a commonly measured “conventional” parameter, as the other substances. Because many treatment plants use biological systems for wastewater treatment, pH must be maintained within a range tolerated by the biomass involved in waste reduction. The pH of the untreated effluent was mostly acidic in nature due to decomposition of lactose into lactic acid under aerobic conditions and may cause corrosion of sewers (Joseph, 1995). In the present study interestingly, the pH of the dairy effluent wastewater increased from 5.15 to 7 83 by Nosotc sp. Murugesan et al., (2010) reported increase of pH in poultry wastewater treated with Chlorella vulgaris. In the present study, initially there was no carbonate, but fairly high levels of bicarbonates were present in the effluent. In the present study it was found that alkalinity was reduced to 18.13 percent when effluent was treated with Nostoc sp. Alkalinity related techniques for bicarbonate estimation are well developed in applications where CO2 is continuously generated by micro-organisms degrading organics. In the area of algal treatment, on the other hand, CO2 is consumed by the

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algae, resulting in relatively low or even limiting concentrations of bicarbonate in the water samples. Inorganic carbon (IC) is of major importance, because it is the only carbon source used by algae. Among the different forms of IC (CO2 (aq), HCO3-and CO2/3), only the first two ones were taken up by the algal biomass, and this was useful as a carbon substrate (Talbot et al., 1991). The ability to utilize bicarbonate has also been demonstrated in a variety of algae (Jolliffe and Tregunna (1970); (Beardall et al., 1976). Murugesan et al. (2010) reported 38.61 percent reduction of alkalinity when poultry wastewater treated with Chlorella vulgaris. Phosphate content in the wastewater was found to be reduced to 21.08 percent by Nostoc sp. Jing Shi et al., (2006) reported 90% removal of phosphate municipals wastewater. During summer when summer when the incident light intensities were high, a phosphorus removal efficiency of up to 100% could be reached with 17 cm deep cultures. During winter, however the performance with the bioreactor design used in the studies was much weaker and more uneven. Properly working phosphorus removal during winter would therefore require either i) more additional illumination than was used or ii) shallower cultures than those used plus the illumination used in the studies. As mentioned above however, shallower cultures demand more area, and illumination requires energy. If the algal biomass could render a product very high economic value, to use artificial light is good idea, but otherwise, such may energy demand may be too expensive (Borowtizka, 1996) and Tam and Wong (1990) have reported over 90 percent removal in total phosphorus within 10 days. The high content of organic matter results in high value of COD of wastewater because chemical oxygen demand measures the recalcitrant (non-biodegradable) organic matter in biologically treated industrial effluents (Malaviya et al., 2001). The discharged of BOD in the receiving environment with the limited assimilative aptitude sometimes reduce the dissolved oxygen concentration to the levels of below those required for aquatic life and it is in this condition that BOD and COD levels of the treated effluent were reduced significantly. In the present study the BOD levels was reduced to 40.25 percent by Nostoc sp and the COD level was reduced to 44.44 percent. COD is usually considered as a major indicate of organic pollution in water (Dash, and Mishra.1998). Reduction of BOD and COD levels high might occur due to the removal of dissolved organic compounds and derivatives to some extent from the effluent during the treatment process. It thus becomes evident that reduction in COD was less as compared to reduction in BOD. Thus it is obvious that the degradation sought was through biological activity and not through a chemical agent. Kotteswari et al., (2007) reported 47.34 percent of BOD and 24.69 percent reduction of COD when the dairy effluent was treated with Spirulina platensis.

Conclusion The result of the present study indicates, that the treatment of dairy effluent by Nostoc sp, is very efficient and it also proved to be cost effective and eco-friendly treatment. In this the Nostoc sp, play a vital role in the removal of COD, BOD, TSS, TDS and other metals. Microalgae can be used for tertiary treatment of wastewater due to their unique capacity to assimilate nutrients. Employing this technology in the treatment of

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industrial effluents presents an alternative tool to the current practice of using conventional methods, including physical and chemical methods. The timely and costeffective remediation of metal and organic contaminated sites mandate an understanding of the extent and mechanisms by which toxic metals inhibit organic biodegradation. The mechanisms by which metals inhibit biodegradation vary with the composition and complexity of the system under investigation and also include both physiological and ecological aspects. A thorough understanding of these systems, taking into account various levels of complexity is needed to develop new approaches to remediation of contaminated sites.

References [1] Abeliovich, A. 1986. Algae in wastewater oxidation ponds. In: Richmond, A. (Ed.), Handbook of Micro algal Mass Culture. pp. 331–338. CRC Press, Boca Raton, FL. [2] Allen, M.M. & Stanier, R.Y. 1968. Growth and division of some unicellular blue-green algae. J.Gen. Microbiol. 51: 199-202. [3] Amudha, P. and S. Mahalingam. 1999. Studies on the effect of dairy effluent on survival feeding energetics of Cyprinus carpio. J Environ.Biol. 20 (3): 275278. [4] Aziz, M.A., and Ng, W.J. 1993. Industrial wastewater treatment using an activated algae-reactor. WaterSci. Technol. 28, 71–76. [5] APHA American Public Health Association.2000. Standard method for the examination of water and wastewater, Washington, D.C, USA 21st edition. [6] Beardall, J.,D. Mukerji, H.E. Glover and I. Morris. 1976. The path of carbon in photosynthesis by marine phytoplankton. J. Phycol. 12: 409-417. Bell, W.H.1983. Bacterial utilization of algal extracellular produces. 3- The specificity of algal-bacterial interaction. Limnol. Oceanograph.28:1131-1143. [7] Borowitzka, M.A., 1996. Closed algal photobioreactors: Design considerations for large‐scale systems. Journal of Marine Biotechnology, 4: 185‐191. [8] CPCB.1995. Pollution control acts rules and modifications issued there under central pollution board, New Delhi. [9] Dash, A.K and Mishra, P.C. 1998. Role of the Blue green algae, Westiellopsis prolifica in Reducing pollution load from paper mill wastewater. IJEP 19(1) 1:5. [10] Desikachary. T.V. 1959. Cyanophyta. Indian Council of Agricultural Research, New Delhi. [11] Giorgos Markou, Dimitris Georgakakis.2011. Cultivation of filamentous cyanobacteria (blue-green algae) in agro-industrial wastes and wastewaters. Applied Energy. (In Press). [12] Jean-Lac, Mouget, et al., 1995. Algal growth enhancement by bacteria: is consumption of photosynthetic oxygen involved? FEMS Microbiol. Ecol. 18:35-44.

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[13] Jing Shi and Björn Podola & Michael Melkonian.2006. Removal of nitrogen and phospho...