Nitrogen and phosphorus removal in biological aerated filters (BAFs)

dc.contributor.advisor Say Kee Ong Ha, Jeonghyub
dc.contributor.department Civil, Construction, and Environmental Engineering 2018-08-24T18:52:33.000 2020-06-30T07:22:05Z 2020-06-30T07:22:05Z 2006-01-01
dc.description.abstract <p>Three downflow pilot-scale biological aerated filters (BAFs) using different media, gravel, lava rock and plastic rings were operated to study their effectiveness as an add-on system or polishing process for aerated lagoons. Of the three media tested, gravel with a diameter of 5 mm was found to provide more than 96% nitrification at hydraulic retention time (HRT) as low as 0.5 hour with 200% recirculation. Experimental results showed that polishing BAF with gravel can be operated at 1 hour HRT without recirculation with nitrification as high as 83%;At a HRT of 2 hours and a wastewater temperature of 6.5°C, more than 98% of ammonia was nitrified in a gravel BAF. For a HRT of 1 hour at 6.5°C, ammonia removals (%) can be improved from 54.3 +/- 2.7% without recirculation to 76 +/- 3.8% with 100% recirculation. With 200% recirculation, ammonia removal improved further to 92 +/- 1.5%. C/N ratio of influent wastewater had a negative impact on nitrification with less than 5% ammonia removal for a C/N ratio of 8 at 6.5°C. Ammonia loading reached a maximum of 0.36 kg NH3-N/m3-day at 6.5°C while the maximum ammonia loading was 0.63 kg NH3-N/m3-day at 24°C;A pilot-scale partially aerated BAF was operated with an anaerobic, anoxic and oxic zone at a temperature of 24°C for the removal of nitrogen at various hydraulic loading rates and recirculation rates. With 300% recirculation at a HRT greater than 3 hours, the total nitrogen removed was approximately 80%. sCOD removals and nitrification at HRT of 3 hours with recirculation rates of 200% and 300% was more than 96%;By adding two alternating attached growth columns (diameter = 75 mm) after the partially aerated BAF, the phosphorus removal of more than 96% were obtained for influent phosphorus concentrations of 8 mg P/L and 16 mg P/L. The experimental results demonstrated that by using two alternating biofilm filters in conjunction with a partially aerated BAF, phosphorus removal can be achieved.</p>
dc.format.mimetype application/pdf
dc.identifier archive/
dc.identifier.articleid 2257
dc.identifier.contextkey 6093713
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/1258
dc.source.bitstream archive/
dc.subject Civil
dc.subject construction
dc.subject and environmental engineering
dc.subject Civil engineering (Environmental engineering)
dc.subject Environmental engineering
dc.title Nitrogen and phosphorus removal in biological aerated filters (BAFs)
dc.type dissertation
dspace.entity.type Publication Doctor of Philosophy
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