CONCLUSION

Coupling algal wastewater treatment with biofuel production is a very attractive option for deriving bio-energy at low cost, reducing GHG emissions, nutrients (fertilisers for algal growth) and treatment of wastewater. The algal scums in surface waters is due to higher N and P in surface waters at C limiting conditions in the three valleys in Bangalore region. The mismanagement of nutrients has resulted in higher GHG emissions in the city accounting to 172 tonnes of N2O/yr and 3,10,795 tonnes of CH4/yr. The city wastewaters with a C:N:P ratio of 5:2:1 showed higher opportunities for algal treatment and subsequent algal harvest for biofuel production from wastewater algae. The algal blooms were found in regions with higher amm-N (~20-40 mg/l). The algal sp. being efficient devices for C capture were observed to transformed part of C into lipids in the wastewaters. The lipid accumulation in the cells was monitored through vibrational spectra obtained from ATR-FTIR analysis. The higher total lipid content was observed in Chlorococcum sp. (28%) that grows in obnoxious wastewaters in wastewater ponds and lagoons. Palmitate (C 16:0) was found out to be the most dominant among the analysed FAME. This analysis elucidated higher percentages of important fatty acids in the selected algal species that are necessary from biofuel combustion perspectives. With higher lipid content, a very high growth rate and having desirable fatty acids content wastewater grown algae foundin ponds and lagoons are excellent substrates for biofuel/lipid production and can be used as a cost effective option for sustainable biofuel production. Renewable energy can be drawn consistently from the wastewater grown algae as higher biomass productivities gives a real potential as a feasible way of biofuel generation. This renewable algal biofuel can supplement to the present fuel needs for transports and can reduce imports fostering sustainability for the nation.