Interactions between Microalgae and Bacteria in the Treatment of Wastewater from Milk Whey Processing

Abstract

Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content; the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. Different microalgal strains and populations were tested. Based on the obtained results, Scenedesmus acuminatus (SA) and a mixed population (PM) chiefly made of Chlorella, Scenedesmus, and Chlamydomonas spp. were grown in duplicate for 70 days in Plexiglas column photobioreactors (PBRs), fed continuously (2.5 L culture volume, 7 days hydraulic retention time). Nutrient removal, microalgae growth, photosynthetic efficiency, and the composition of microalgal populations in the columns were monitored. At steady state, the microalgal growth was similar for SA and PM. The average removal efficiencies for the main pollutants were: 93% (SA), 94% (PM) for COD; 88% (SA) and 90% (PM) for total N; and 69% (SA) and 73% (PM) for total P. The residual pollution levels in the effluent from the PBRs were low enough to allow their discharge into surface waters; such good results were achieved thanks to the synergy between the microalgae and bacteria in the CO2 and oxygen production/consumption and in the nitrogen mineralization.

Cyanobacterial Biomass Produced in the Wastewater of the Dairy Industry and Its Evaluation in Anaerobic Co-Digestion with Cattle Manure for Enhanced Methane Production

“…The highest RE was with the concentration of TN 1.1 mM, with 86.44%. Marazzi et al [74] evaluated the treatment of wastewater from whey processing with the microalgae Scenedesmus acuminatus (Lagerheim) Chodat 1902, and a consortium of microalgae consisting of Chlorella, Scenedesmus, and Chlamydomonas spp. The wastewater had a TN concentration of 3.71 mM and a TP of 0.42 mM.…”

Assessment of anammox, microalgae and white-rot fungi-based processes for the treatment of textile wastewater

“…photoinhibition, light limitation, temperature stress) affecting the photosynthetic rate of algal cultures [ 43 ], was used here to assess and compare the physiological state of the microalgae grown on textile wastewater and control medium. This parameter was determined according to Marazzi et al [ 17 ]. Microalgal suspensions were diluted in order to get an absorbance of 0.1 at 680 nm and adapted to dark conditions for 20 min prior to measurement.…”

Real-Time Behavior of a Microalgae–Bacteria Consortium Treating Wastewater in a Sequencing Batch Reactor in Response to Feeding Time and Agitation Mode

“…After each experimental phase, the microscopic analysis of consortiums showed a variety of microalgae as a major component of a microbial biomass complex, such as Chlorella, Scenedesmus, and Tetradesmus [34,35], as observed in Figure S2.…”