TY - JOUR
T1 - Effect of immobilized microalgal bead concentrations on wastewater nutrient removal
AU - Tam, N. F.Y.
AU - Wong, Y. S.
N1 - Funding Information:
The study was supported by the Hong Kong Research Grant Council and the City University Research Committee.
PY - 2000/1
Y1 - 2000/1
N2 - A unicellular green microalga, Chlorella vulgaris, entrapped in calcium alginate as algal beads were employed to remove nutrients (N and P) from simulated settled domestic wastewater. A significantly higher nutrient reduction was found in bioreactors containing algal beads (at concentrations ranging from 4 to 20 beads ml-1 wastewater) than the blank alginate beads (without algae). A complete removal of NH4/+-N and around 95% reduction of PO4/3--P was achieved within 24 h of treatment in bioreactors having the optimal algal bead concentration (12 beads ml-1, equivalent to 1:3 algal beads:wastewater, v/v). The NH4/+-N removal was significantly lower at low (around 4 beads ml-1) and high (>15 beads ml-1) algal bead concentrations. On the other hand, the effect of bead concentration on phosphate removal was less obvious, and bead concentrations ranging from 8 to 20 beads ml-1 showed comparable percentages of phosphate reduction. Algal uptake and adsorption on alginate gels were found to be the major processes involved in the removal of N and phosphate in the present study. In addition, NH4/+-N could be lost via ammonia volatilization while PO4/3--P was removed by chemical precipitation, as alkaline pH was recorded in the immobilized microalgal treatment system.
AB - A unicellular green microalga, Chlorella vulgaris, entrapped in calcium alginate as algal beads were employed to remove nutrients (N and P) from simulated settled domestic wastewater. A significantly higher nutrient reduction was found in bioreactors containing algal beads (at concentrations ranging from 4 to 20 beads ml-1 wastewater) than the blank alginate beads (without algae). A complete removal of NH4/+-N and around 95% reduction of PO4/3--P was achieved within 24 h of treatment in bioreactors having the optimal algal bead concentration (12 beads ml-1, equivalent to 1:3 algal beads:wastewater, v/v). The NH4/+-N removal was significantly lower at low (around 4 beads ml-1) and high (>15 beads ml-1) algal bead concentrations. On the other hand, the effect of bead concentration on phosphate removal was less obvious, and bead concentrations ranging from 8 to 20 beads ml-1 showed comparable percentages of phosphate reduction. Algal uptake and adsorption on alginate gels were found to be the major processes involved in the removal of N and phosphate in the present study. In addition, NH4/+-N could be lost via ammonia volatilization while PO4/3--P was removed by chemical precipitation, as alkaline pH was recorded in the immobilized microalgal treatment system.
KW - Alginate
KW - Ammonium
KW - Bead concentration
KW - Chlorella
KW - Immobilization
KW - Phosphate
UR - http://www.scopus.com/inward/record.url?scp=0033990447&partnerID=8YFLogxK
U2 - 10.1016/S0269-7491(99)00118-9
DO - 10.1016/S0269-7491(99)00118-9
M3 - Article
AN - SCOPUS:0033990447
SN - 0269-7491
VL - 107
SP - 145
EP - 151
JO - Environmental Pollution
JF - Environmental Pollution
IS - 1
ER -