Mathematical model for a batch aerated submerged biofilm reactor for organic carbon and nitrogen removal

The paper presents research of a prototype moving bed biofilm reactor (MBBR). The device was used for the post-denitrification process and was installed at the end of a technological system consisting of a septic tank and two trickling filters. The concentrations of suspended biomass and biomass attached on the EvU Perl moving bed surface were determined. The impact of the external organic carbon concentration on the denitrification rate and efficiency of total nitrogen removal was also examined. The study showed that the greater part of the biomass was in the suspended form and only 6% of the total biomass was attached to the surface of the moving bed. Abrasion forces between carriers of the moving bed caused the fast stripping of attached microorganisms and formation of flocs. Thanks to immobilization of a small amount of biomass, the MBBR was less prone to leaching of the biomass and the occurrence of scum and swelling sludge. It was revealed that the maximum rate of denitrification was an average of 0.73 gN-NO3/gDM·d (DM: dry matter), and was achieved when the reactor was maintained in external organic carbon concentration exceeding 300 mgO2/dm3 chemical oxygen demand. The reactor proved to be an effective device enabling the increase of total nitrogen removal from 53.5% to 86.0%.

Download Full-text

Examination on Influence Caused by Air Injection Manners Changing in Aerobic-Anaerobic Landfill Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.768.310 ◽

2015 ◽

Vol 768 ◽

pp. 310-317

Author(s):

Gang Zhen Jiao ◽

Lei Zhang ◽

Xiong Shi ◽

Gui Fu

Keyword(s):

Numerical Simulation ◽

Mathematical Model ◽

Organic Carbon ◽

Simulation Model ◽

Solid Phase ◽

Landfill Gas ◽

Air Injection ◽

Carbon And Nitrogen ◽

Speed Up ◽

Leachate Quality

In this study, aerobic-anaerobic landfill method (AANM) is focused on as a new way to speed up landfill stabilization, inhibit landfill gas flux, and ameliorate on leachate quality. Numerical simulation model is developed to guide the air injection craftwork and study its effect on achieving above goals. On basis of work finished in last period (0~310 days), air was injected into Lysimeters A (Lys.A) at 0.5 m, and at 2.5 m in Lys.B with the same rate of 1 L/min. In Lys.C there is no air injected. In order to interview the influence by air injection manners changing, from 310 days till 360 days, air injection manners are changed from Mono-site into Double-site in Lys.A and in Lys. B it will be changed from bottom-site (2.5m) into middle-site (1.5m). In Lys.C there will be no changing. By interviewing the comparisons on simulated results in 50 days with and without air injection manners changing, it was found that air injection manners changing in Lys.A causes TOC discharging amount increase more than 6 times, but T-N and GHE resulted from landfill gas decrease 24.1% and 71 % respectively. Air injection manners changing in Lys.B resulted in discharged TOC and T-N increase 108.1 % and 53.5 % respectively, while T-N decreases 3.7 %. On basis of mechanism assumption, mathematical model was developed and according to the simulated results for 5 years, air injected at 2.5 m achieved improvements on stabilization of solid phase organic carbon and nitrogen for 34 % and 13 %, amelioration on leachate quality for 35 % and 62 % of TOC and T-N, and the restraint of GHE for 14 times compared with no air injection case.

Download Full-text

Modeling dynamics of organic carbon and nitrogen removal during aeration interruption in aerated horizontal flow treatment wetlands

Water Science & Technology ◽

10.2166/wst.2019.304 ◽

2019 ◽

Vol 80 (3) ◽

pp. 597-606 ◽

Cited By ~ 1

Author(s):

Johannes Boog ◽

Thomas Kalbacher ◽

Jaime Nivala ◽

Manfred van Afferden ◽

Roland A. Müller

Keyword(s):

Steady State ◽

Organic Carbon ◽

Dynamic Response ◽

Nitrogen Removal ◽

Oxygen Demand ◽

Ammonia Nitrogen ◽

Treatment Wetlands ◽

Horizontal Flow ◽

Simulation Accuracy ◽

Carbon And Nitrogen

Abstract Despite recent developments in process-based modeling of treatment wetlands (TW), the dynamic response of horizontal flow (HF) aerated wetlands to interruptions of aeration has not yet been modeled. In this study, the dynamic response of organic carbon and nitrogen removal to interruptions of aeration in an HF aerated wetland was investigated using a recently-developed numerical process-based model. Model calibration and validation were achieved using previously obtained data from pilot-scale experiments. Setting initial concentrations for anaerobic bacteria to high values ( 35–70 mg L−1) and including ammonia sorption was important to simulate the treatment performance of the experimental wetland in transition phases when aeration was switched off and on again. Even though steady-state air flow rate impacted steady-state soluble chemical oxygen demand (CODs), ammonia nitrogen (NH4–N) and oxidized nitrogen (NOx–N) concentration length profiles, it did not substantially affect corresponding effluent concentrations during aeration interruption. When comparing simulated with experimental results, it is most likely that extending the model to include mass transfer through the biofilm will allow to better explain the underlying experiments and to increase simulation accuracy. This study provides insights into the dynamic behavior of HF aerated wetlands and discusses assumptions and limitations of the modeling approach.

Download Full-text

Phosphorus and Nitrogen Removal in Moving-Bed Sequencing Batch Biofilm Reactors

Water Science & Technology ◽

10.2166/wst.1999.0589 ◽

1999 ◽

Vol 40 (4-5) ◽

pp. 169-176 ◽

Cited By ~ 28

Author(s):

Giuseppe Pastorelli ◽

Roberto Canziani ◽

Luca Pedrazzi ◽

Alberto Rozzi

Keyword(s):

Organic Carbon ◽

Nitrogen Removal ◽

Municipal Wastewater ◽

Phosphorus Uptake ◽

Biofilm Reactor ◽

Municipal Wastewater Treatment ◽

Biological Phosphorus Removal ◽

Nitrogen And Phosphorus ◽

Limit Values ◽

Moving Bed

A pilot moving-bed sequencing batch biofilm reactor (MBSBBR) fed with primary settled wastewater, was used in order to study organic carbon, phosphorus and nitrogen removal with and without external carbon sources. Patented KMT® polyethylene biofilm carriers were used. Organic carbon uptake and phosphorus release has been achieved in the anaerobic phase of the cycle, while nitrification, simultaneous denitrification (i.e., anoxic respiration of sequestered COD in the inner layer of the biofilm) and phosphorus uptake was observed in the aerobic phase. A stable biological phosphorus removal could be achieved only with an external carbon source. Since the process proved flexible and reliable, it is suitable for full scale application to municipal wastewater treatment plants (WWTPs), in order to meet EU total nitrogen and phosphorus limit values for discharge into sensitive receiving waters.

Download Full-text