:: Volume 5, Issue 1 (Winter, 2018) ::
Environ. health eng. manag. 2018, 5(1): 1-7 Back to browse issues page
Autotrophic denitrification of synthetic nitrate-contaminated groundwater in up-flow fixed-bed bioreactor by pumice as porous media
Masoud Tourang , Behnoush Aminzadeh , Ali Torabian
Department of Environmental Engineering, Graduate Faculty of Environment, University of Tehran, Iran , bamin@ut.ac.ir
Abstract:   (1830 Views)
 Background: Increasing nitrate concentrations in groundwater resources is considered a common environmental and public health problem worldwide. In this research, an autotrophic up-flow bioreactor with pumice as media was used to study the effects of the sulfur-to-nitrogen (S/N) ratio and empty bed contact time (EBCT) on nitrate removal efficiency and byproducts.
Methods: Experiments were carried out in a 3.47 L up-flow, fixed-bed reactor with 3 sampling ports. To evaluate the overall impact of S/N ratio and EBCT on the performance of the bioreactor, several phases with different S/N ratios and EBCTs were applied.
Results: At a constant S/N ratio of 3.85 g/g, as EBCT decreased from 24 hours to 2 hours, the nitrate removal efficiency decreased from 98% to 64%. On the other hand, at the desired EBCT of 4 hr, as S/N ratio decreased from 3.85 to 1.51 g/g, nitrate removal efficiency was reduced from 85% to 32%. Changing the EBCT and S/N ratio also affected the effluent nitrite and sulfate concentrations as byproducts. At the S/N ratio of 3.85 g/g
and EBCT of 24 hours, effluent nitrite and sulfate concentrations were 0.1 mg NO2--N/L and 463 mg SO4 2-/L, respectively. Decreasing the S/N ratio to 1.51 g/g and the EBCT to 4 hours caused drastic changes in effluent nitrite and sulfate concentrations.
Conclusion: The results indicated that the autotrophic denitrification with thiosulfate as electron donor and pumice as media was feasible and applicable for nitrate contaminated groundwater.
Keywords: Autotrophic Denitrification, Pumice, Nitrate, Nitrite, Thiosulfate
eprint link: http://eprints.kmu.ac.ir/id/eprint/27029
Full-Text [PDF 551 kb]   (524 Downloads)    
Type of Study: Research | Subject: Special
Received: 2018/03/3 | Accepted: 2018/03/3 | Published: 2018/03/3

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Volume 5, Issue 1 (Winter, 2018) Back to browse issues page