TY - JOUR
T1 - Improving the removal of anions by coagulation and dissolved air flotation in wastewater reclamation
AU - Chuang, S. H.
AU - Chang, W. C.
AU - Chang, T. C.
AU - You, S. J.
N1 - Funding Information:
This study was part of an evaluation project sponsored by the Science-based Industrial Park Administration, Taiwan. The authors would like to thank J. Liou and K. Lin of the AXIOM Int’l Environmental Engineering Co. for providing assistance during the study.
PY - 2006/5
Y1 - 2006/5
N2 - This study investigated the feasibility of improving the removal of anions from a secondary effluent by coagulation/flocculation (Coag/Floc) and dissolved air flotation (DAF) using a pilot-scale wastewater reclamation plant in a high-tech industrial park. The pilot plant was equipped with units of Coag/Floc, DAF, activated carbon beds (AC), microfiltration modules (MF) and a reverse-osmosis membrane (RO). It was operated in-situ continuously for around one year to evaluate the performance of anion removal in two processes - the AC-RO process and the DAF-AC-RO process. Long-term experimental results indicated that combining Coag/Floc, DAF and AC units increased the potential of pretreatment to remove anions. The removal efficiencies in Coag/Floc-DAF units were in the order phosphate> fluoride> chloride> sulfate > silicate. The charged complex of PACl flocs revealed a higher affinity for adsorption onto phosphate and fluoride than on chloride, sulfate and silicate. Comparison of the performance of Coag/Floc-DAF-AC units in the DAF-AC-RO process with that of a single AC unit in the AC-RO process demonstrated that adding Coag/Floc-DAF units increased the removal efficiencies of phosphate, fluoride and silicate by approximately 70.0 %, 42.7 % and 70.1 %, respectively. Most of the phosphate and fluoride were removed in Coag/Floc-DAF units, while most of the silicate escaped from the Coag/Floc-DAF units, and was adsorbed and/or trapped in the AC unit. The quality of reclaimed water in the DAF-AC-RO process complied with the requirements of high-tech industries in cleaning processes. Combined units of Coag/Floc-DAF-AC were therefore recommended for use in pretreatment in wastewater reclamation in high-tech industrial parks.
AB - This study investigated the feasibility of improving the removal of anions from a secondary effluent by coagulation/flocculation (Coag/Floc) and dissolved air flotation (DAF) using a pilot-scale wastewater reclamation plant in a high-tech industrial park. The pilot plant was equipped with units of Coag/Floc, DAF, activated carbon beds (AC), microfiltration modules (MF) and a reverse-osmosis membrane (RO). It was operated in-situ continuously for around one year to evaluate the performance of anion removal in two processes - the AC-RO process and the DAF-AC-RO process. Long-term experimental results indicated that combining Coag/Floc, DAF and AC units increased the potential of pretreatment to remove anions. The removal efficiencies in Coag/Floc-DAF units were in the order phosphate> fluoride> chloride> sulfate > silicate. The charged complex of PACl flocs revealed a higher affinity for adsorption onto phosphate and fluoride than on chloride, sulfate and silicate. Comparison of the performance of Coag/Floc-DAF-AC units in the DAF-AC-RO process with that of a single AC unit in the AC-RO process demonstrated that adding Coag/Floc-DAF units increased the removal efficiencies of phosphate, fluoride and silicate by approximately 70.0 %, 42.7 % and 70.1 %, respectively. Most of the phosphate and fluoride were removed in Coag/Floc-DAF units, while most of the silicate escaped from the Coag/Floc-DAF units, and was adsorbed and/or trapped in the AC unit. The quality of reclaimed water in the DAF-AC-RO process complied with the requirements of high-tech industries in cleaning processes. Combined units of Coag/Floc-DAF-AC were therefore recommended for use in pretreatment in wastewater reclamation in high-tech industrial parks.
KW - Anion
KW - Coagulation
KW - Dissolved air flotation
KW - Polyaluminum chloride
KW - Wastewater reclamation
UR - http://www.scopus.com/inward/record.url?scp=33744971141&partnerID=8YFLogxK
U2 - 10.1080/09593332808618663
DO - 10.1080/09593332808618663
M3 - 期刊論文
C2 - 16749617
AN - SCOPUS:33744971141
SN - 0959-3330
VL - 27
SP - 493
EP - 500
JO - Environmental Technology (United Kingdom)
JF - Environmental Technology (United Kingdom)
IS - 5
ER -