Up-scaling aquaculture wastewater treatment by microalgal bacterial flocs: from lab reactors to an outdoor raceway pond

Bioresour Technol. 2014 May:159:342-54. doi: 10.1016/j.biortech.2014.02.113. Epub 2014 Mar 6.

Abstract

Sequencing batch reactors with microalgal bacterial flocs (MaB-floc SBRs) are a novel approach for photosynthetic aerated wastewater treatment based on bioflocculation. To assess their technical potential for aquaculture wastewater treatment in Northwest Europe, MaB-floc SBRs were up-scaled from indoor photobioreactors of 4 L over 40 and 400 L to a 12 m(3) outdoor raceway pond. Scale-up decreased the nutrient removal efficiencies with a factor 1-3 and the volumetric biomass productivities with a factor 10-13. Effluents met current discharge norms, except for nitrite and nitrate. Flue gas sparging was needed to decrease the effluent pH. Outdoor MaB-flocs showed enhanced settling properties and an increased ash and chlorophyll a content. Bioflocculation enabled successful harvesting by gravity settling and dewatering by filtering at 150-250 μm. Optimisation of nitrogen removal and biomass valorisation are future challenges towards industrial implementation of MaB-floc SBRs for aquaculture wastewater treatment.

Keywords: Algae; Aquaculture wastewater; Bioflocculation; Biomass; Raceway pond.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aquaculture*
  • Bacteria / metabolism*
  • Batch Cell Culture Techniques / instrumentation
  • Biodegradation, Environmental
  • Biological Oxygen Demand Analysis
  • Biomass
  • Bioreactors / microbiology*
  • Electric Conductivity
  • Flocculation
  • Hydrogen-Ion Concentration
  • Microalgae / metabolism*
  • Nitrogen / analysis
  • Oxygen / analysis
  • Phosphorus / analysis
  • Photons
  • Photosynthesis
  • Ponds / microbiology*
  • Waste Disposal, Fluid
  • Wastewater / chemistry*
  • Wastewater / microbiology
  • Water Purification / methods*

Substances

  • Waste Water
  • Phosphorus
  • Nitrogen
  • Oxygen