title: Remediation of nitrate-contaminated wastewater using denitrification biofilters with straws of ornamental flowers added as carbon source.
abstract: Straws of four ornamental flowers (carnation, rose, lily, and violet) were added into denitrification biofilters using gravel as matrix through vertically installed perforated polyvinylchloride pipes to provide organic carbon for the treatment of nitrate-contaminated wastewater operating in batch mode. Removal efficiencies of nitrate and phosphate, as well as temporal variations of nitrogen and carbon during batches 10 and 19, were investigated and assessed. Nitrate removal was efficiently enhanced by the addition of flower straws, but decreased gradually as the organic substances were consumed. Phosphate removal was also improved, although this very limited. High nitrate removal rates were achieved during the initial 12 h in the two batches each lasting for 3 days, along with the depletion of influent dissolved oxygen due to aerobic degradation of the organic compounds. NO2(-)-N of 0.01-2.83 mg/L and NH4(+)-N of 0.02-1.69 mg/L were formed and both positively correlated to the nitrate reduced. Inorganic carbon (IC) concentrations increased during the batches and varied conversely with the nitrate contents, and could be indicative of nitrate removal due to the highly significant positive correlation between NO3(-)-N removed and IC concentration (r(2) = 0.881, p < 0.0001). It is feasible and economical to use the denitrification biofilter to treat nitrate-contaminated wastewater, although further optimization of carbon source addition is still required.
authors.affiliation: Research Institute of Engineering and Technology, Yunnan University, Kunming 650091, China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Chang
authors.affiliation: Research Institute of Engineering and Technology, Yunnan University, Kunming 650091, China.
authors.forename: Luyao
authors.initials: L
authors.lastname: Ma
authors.affiliation: Research Institute of Engineering and Technology, Yunnan University, Kunming 650091, China.
authors.forename: Yuanyang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Resources and Environmental Science, South-Central University for Nationalities, Wuhan 430074, China E-mail: zhangshenghua@yahoo.com; aidun0408@163.com.
authors.forename: Shenghua
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Research Institute of Engineering and Technology, Yunnan University, Kunming 650091, China.
authors.forename: Weilu
authors.initials: W
authors.lastname: Wang
mesh_terms: D002244:Carbon / Q000378:metabolism*; D058440:Denitrification; D029749:Dianthus; D005374:Filtration / Q000295:instrumentation / Q000379:methods; D027762:Lilium; D009566:Nitrates / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018547:Plant Stems / Q000196:embryology; D027826:Rosa; D029649:Violaceae; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D002244:Carbon; D009566:Nitrates; D062065:Wastewater; D014874:Water Pollutants, Chemical