Biomass and bioenergy production potential of microalgae consortium in open and closed bioreactors using untreated carpet industry effluent as growth medium

Improved wastewater management with beneficial utilization will result in enhanced sustainability and enormous cost savings in industries. Algae cultivation systems viz. raceway ponds, vertical tank reactors (VTR) and polybags were evaluated for mass production of algal consortium using carpet industry (CI) untreated wastewater. Overall areal biomass productivity of polybags (21.1 g m−2 d−1) was the best followed by VTR (8.1 g m−2 d−1) and raceways (5.9 g m−2 d−1). An estimated biomass productivity of 51 and 77 tons ha−1 year−1 can be achieved using 20 and 30 L capacity polybags, respectively with triple row arrangement. Biomass obtained from algal consortium was rich in proteins (∼53.8%) and low in carbohydrates (∼15.7%) and lipids (∼5.3%). Consortium cultivated in polybags has the potential to produce 12,128 m3 of biomethane ha−1 year−1. To be economically viable, the capital expenditure for polybag reactors needs to be reduced to $10 m−2 for bioenergy/biofuel production.