Uptake of Nutrients from Municipal Wastewater and Biodiesel Production by Mixed Algae Culture

Farooq Ahmad, Amin U. Khan and Abdullah Yasar

Eutrophication of water bodies is matter of concern for the last few decades because wastewater without treatment can cause serious health effects and disturb functioning of ecosystem. The objective of the current study was to utilize nutrient present in wastewater for algal growth and biodiesel production from harvested biomass of algae. Mixed algae culture (Microspora sp., Diatoms, Lyngbya sp., Cladophora sp., Spirogyra sp. and Rhizoclonium sp.) collected from Botanic Garden of Government College University Lahore was grown in artificial ponds of 13.5 L capacity. Algal growth was monitored for six days by measuring its fresh and dry weight which showed almost similar results of 3.34 g/day and 3 g/day respectively. Uptake of total Kjeldahl nitrogen (55%), total phosphorous (61%), nitrate (97%), phosphate (93%), sulphate (34%) and chloride (41%) was carried by mixed algae culture from wastewater. Seasonal variation in the absorption of nutrients in alternate months of the year showed higher uptake in March, September and November due to favorable conditions for algal growth. Yield of biodiesel produced by transesterification of dried algal biomass was calculated to be 15.13% on an average. Quality of biodiesel was analyzed for kinematic viscosity (4.5 mm2/s), flash point (167°C), specific gravity (0.895 g/ml), iodine value (80 mg/g), acid number (0.65 mg. KOH/g) and water contents (32 mg/kg). It was found that the quality of biodiesel was according to the ASTM standards for biodiesel.