Improving the performance of membrane bioreactors by powdered activated carbon dosing with cost considerations.
Effects of powdered activated carbon (PAC) dosing on the overall performance of membrane bioreactors (MBR) were investigated in two bench-scale submerged MBRs. Positive impacts of PAC dosing on membrane fouling and the removal of 17beta-estradiol (E2) and 17alpha-ethyinylestradiol (EE2) were demonstrated over a six-month stable operational period. PAC dosing in the MBR increased the removal rates of E2 and EE2 by 3.4% and 15.8%, respectively. The average soluble extracellular polymeric substances (EPS) and colloidal total organic carbon (TOC) concentrations in the PAC-MBR sludge was 60.1% and 61.8% lower than the control MBR sludge, respectively. Lower soluble EPS and colloidal TOC concentrations in the PAC-MBR sludge resulted in a slower rate of trans-membrane pressure (TMP) increase during MBRs operation, which could prolong the lifespan of membranes. Cost assessment showed that PAC dosing could reduce the operating cost for membrane cleaning and/or membrane replacement by about 25%. The operating cost for PAC dosing could be offset by the benefit from its reducing the cost for membrane maintenance.
Yang
W
W
Department of Biosystems Engineering, University of Manitoba, Winnipeg, Canada. wyang@trojanuv.com
Paetkau
M
M
Cicek
N
N
D019149:Bioreactors / Q000191:economics; D002606:Charcoal / Q000737:chemistry* / Q000191:economics; D003365:Costs and Cost Analysis; D052244:Endocrine Disruptors / Q000302:isolation & purification*; D004967:Estrogens / Q000302:isolation & purification*; D008567:Membranes, Artificial; D018505:Waste Management / Q000191:economics / Q000295:instrumentation / Q000379:methods*
D052244:Endocrine Disruptors; D004967:Estrogens; D008567:Membranes, Artificial; D002606:Charcoal