Drinking water denitrification using a membrane bioreactor.
A membrane bioreactor (MBR) was investigated for denitrification of nitrate (NO3(-)) contaminated drinking water. In the MBR, NO3(-) contaminated water flows through the lumen of tubular microporous membranes and NO3(-) diffuses through the membrane pores. Denitrification takes place on the shell side of the membranes, creating a driving force for mass transfer. The microporous membranes provide a high NO3(-) permeability, while separating the treated water from the microbial process, reducing carryover of organic carbon and sloughed biomass to the product water. Specific objectives of this research were to develop a model for NO3(-) mass transfer in the MBR, investigate the effect of shell and lumen velocity on NO3(-) mass transfer and investigate the effects of NO3(-) and organic carbon loading on denitrification rate and product water quality. A mathematical model of NO3(-) mass transfer was developed, which fit abiotic mass transfer data well. Correlations of dimensionless parameters were found to underestimate the overall NO3(-) mass transfer coefficient by 30-45%. The MBR achieved over 99% NO3(-) removal at an influent concentration of 200 mg NO3(-)-NL(-1). The average NO3- flux to the biomass was 6.1g NO3(-)-Nm(-2)d(-1). Low effluent turbidity was achieved; however, approximately 8% of the added methanol partitioned into the product water.
Ergas
Sarina J
SJ
Department of Civil and Environmental Engineering, University of Massachusetts, 18 Marston Hall, Amherst, MA 01003-5205, USA. ergas@ecs.umass.edu
Rheinheimer
David E
DE
D018533:Biomass; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry; D005374:Filtration; D008567:Membranes, Artificial; D000432:Methanol / Q000737:chemistry; D008962:Models, Theoretical; D009391:Nephelometry and Turbidimetry; D009573:Nitrites / Q000378:metabolism*; D009930:Organic Chemicals; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D014881:Water Supply
D008567:Membranes, Artificial; D009573:Nitrites; D009930:Organic Chemicals; D014874:Water Pollutants, Chemical; D002244:Carbon; D000432:Methanol