Microalgae Growth Using High Strength Wastewater Followed by Anaerobic Co-digestion

Authors: Xin Yuan, Meng Wang, Chul Park, Ashish K Sahu, Sarina J. Ergas

Publisher: Water Environment Federation

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Abstract:

Integration of algal biofuel production into wastewater anaerobic digestion infrastructurehas the potential to increase biogas production, decrease high and variable internalnitrogen loads and improve sludge digestibility and dewaterability. In this research, twospecies of microalgae, Spirulina platensis and Chlorella sp., were grown on sludgecentrate and a centrate/nitrified wastewater effluent mixture. Harvested algae were codigestedwith waste activated sludge (WAS) at varying ratios. High growth (6.8 g m-2 d- 101), nitrogen (36.5 g m-3 d-1) and phosphorous (6.5 g m-3 d-111 ) uptake rates were achieved with Chlorella on centrate. No growth was observed with S. platensis under the sameconditions; however, both organisms grew well on the centrate/effluent mixture. Co14digestion of algae with WAS improved volatile solids reduction. Co-digestion with S.platensis improved biosolids dewaterability; however, Chlorella had a slight negativeimpact on dewaterability compared to WAS alone. The efficiency of energy conversionfrom photons to biogas generated from Chlorella was estimated at 1.4%.83

Keywords: Algae, biofuel, Spirulina, Chlorella, centrate, wastewater, anaerobicdigestion.

Document Type:

DOI: http://dx.doi.org/10.2175/106143011X13233670703242

Appeared or available online: December 8, 2011