ENERGY AND REVENUE CREATION FROM THE ANAEROBIC DIGESTION OF CHLORELLA VULGARIS CULTIVATED IN LIQUOR FROM CHEMICALLY TREATED SEWAGE SLUDGE

Abstract

Microalgae are a good alternative to fossil fuel for energy generation. Chlorella vulgaris (C.vulgaris) strain of the microalgae was cultivated on liquor from chemically treated sewage sludge samples, to estimate the economic worth of sludge liquor; from the anaerobic digestion of the generated biomass. Sample1 was conditioned with zetag66 polyelectrolyte (control sample), samples 2 and 3 were treated with lime at different concentrations and sample 4 was treated with ferric chloride. Biomass yield (dry solids) was 1.36 kg/m3, 2.94 kg/m3, 1 kg/m3 and 0.87 kg/m3 for media 1, 2, 3 and 4 respectively. The control had the highest energy and economic worth per m3 of 3.07 kWh and £1.12 respectively. Media from lime treatment had the same energy and economic worth per m3 of 2.51 kWh and £0.91 respectively. Media from ferric chloride treatment had the least energy and economic worth per m3 of 1.81 kWh and £0.66 respectively. Sludge liquor has potential for wealth creation and sustainable energy generation even after chemical sludge treatment when used to cultivate microalgae.