Evaluation of microalgal consortia for treatment of primary treated sewage effluent and biomass production Nirmal Renuka & Anjuli Sood & Sachitra K. Ratha & Radha Prasanna & Amrik S. Ahluwalia Received: 26 August 2012 / Revised and accepted: 7 January 2013 # Springer Science+Business Media Dordrecht 2013 Abstract The present investigation was aimed towards an- alyzing the potential of consortia of native filamentous microalgal strains (MC2), native unicellular microalgal strains (MC3), and selected microalgae from germplasm (MC1) in terms of nutrient removal, water quality improve- ment, and biomass production using primary treated sewage water. Highest NO 3 -N (90 %) and PO 4 -P (97.8 %) removal was obtained with MC2-inoculated sewage water. Highest decrease in total dissolved solids to 806 from 1,120 mg L -1 and highest increase in dissolved oxygen of 9.0 from 0.4 mg L -1 were obtained using MC2-inoculated sewage water on the sixth day. The biomass production was also highest in MC2 (1.07 g L -1 ) followed by MC1 and MC3 (0.90 and 0.94 g L -1 , respectively) on the sixth day. The consortium of filamentous strains from native environment not only proved promising in nutrient removal efficiency but also led to enhanced biomass. The present study highlighted the utility of such a consortium for sewage wastewater treatment and the promise of sewage water as a growth medium for biomass production. Keywords Biomass . Consortium . Filamentous microalgae . Nutrient removal . Sewage water Introduction The increasing scarcity of water in the world, along with rapid population increase in urban areas, and improper dumping of wastes into aquatic bodies are areas of seri- ous concern, which emphasize the need for suitable and effective treatment options. According to a WHO report (2000), only 35 % of total sewage wastewater actually undergoes treatment to secondary level in Asia, while in African countries, no technique is being employed for the treatment of sewage wastewater (Singh et al. 2012). In India, a survey of Central Pollution Control Board stated that out of the total sewage generated from urban areas, only 35 % is being treated, with a capacity gap of 65 % (CPCB 2009). Apart from the lack of sufficient means to treat sewage water, another problem associated is the presence of excess of nutrients, especially N and P. This, in turn, leads to ecological problems such as eutrophication, algal blooms, uncontrolled spread of cer- tain aquatic macrophytes, oxygen depletion, and loss of key species, and degradation of fresh water ecosystems (Wang et al. 2010; Doria et al. 2012). Traditional treatment systems such as aerobic and anaerobic reactors are costly, involve complex operation, generate a great volume of waste sludge, and require a high-energy input. Therefore, there is a need to develop a cost-effective, eco-friendly technology that utilizes economically viable inputs, for its acceptability at commercial level. Phytoremediation or the use of plants or algae for treat- ment of wastewater is a suitable option (Sood et al. 2011). Microalgae, a broad category comprising of eukaryotic microalgae and cyanobacteria, has recently been exploited for the removal of nutrients from wastewater, because of their high requirement of N and P for their growth (Mata et al. 2012). Wastewaters also provide a suitable medium, supplying most of the necessary nutrients for algae growth, thereby, significantly reducing the cost associated with Electronic supplementary material The online version of this article (doi:10.1007/s10811-013-9982-x) contains supplementary material, which is available to authorized users. N. Renuka : A. S. Ahluwalia Department of Botany, Panjab University, Chandigarh 160014, India A. Sood Department of Botany, University of Delhi, Delhi 110007, India S. K. Ratha : R. Prasanna (*) Division of Microbiology, Indian Agricultural Research Institute, New Delhi 110012, India e-mail: radhapr@gmail.com J Appl Phycol DOI 10.1007/s10811-013-9982-x