Crustacean zooplankton in aerated wastewater treatment lagoons as a potential feedstock for biofuel

Abstract

Zooplankton biomass productivity was estimated for two 64,000 m³ (1.7 ha) facultative aerated wastewater treatment lagoons to evaluate potential biodiesel production from zooplankton biomass. Lagoons were monitored bi-weekly during summer 2010. Lipid accumulated by crustacean zooplankton was considered the most efficient means by which to collect lipid produced by phytoplankton owing to the greater ease in the collection of these organisms (>0.153 mm) compared with unicellular algae (size<0.06 mm). In terms of biomass, the cladoceran Daphnia and the copepod Cyclops were the dominant zooplankton in these hypereutrophic lagoons, while unicellular chlorophytes dominated the phytoplankton community. Secondary productivity of these lagoons (250 g of dry weight m⁻² yr⁻¹) is comparable to the secondary productivity of other sewage lagoons. The potential biodiesel production for one lagoon was estimated to be 0.04±0.02 L m⁻² yr⁻¹, which results in a total of 1120±560 L from two lagoons. This study showed that there are organisms present in wastewater lagoons, besides algae, that can serve as a biofuel feedstock. Additionally, this research expands the current knowledge of facultative aerated wastewater lagoon ecology and waste stream-derived biofuel. Future research should include complete life cycle and economic analyses to determine if harvesting zooplankton from wastewater lagoons is a sustainable endeavour.

Keywords:

• facultative aerated wastewater treatment lagoon
• secondary productivity
• zooplankton
• Daphnia
• biodiesel

Acknowledgements

We thank the employees at the Canton Wastewater Treatment Plant for allowing access to their facility, the Center for Air Resources Science and Engineering and Dr B. Crimmins for lipid analyses, and D.E. Smith for assistance with field sampling. We thank Dr Kimberly L. Schulz for helpful comments on this research. This is Clarkson University Institute for a Sustainable Environment Contribution No. 547.

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