Performance of fixed film media integrated in activated sludge reactors to enhance nitrogen removal

1994 ◽  
Vol 30 (11) ◽  
pp. 13-24 ◽  
Author(s):  
Dipankar Sen ◽  
Pramod Mitta ◽  
Clifford W. Randall
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Biofilm Growth ◽  
Ammonium N ◽  
Suspended Growth ◽  
Fixed Film ◽  
The Media ◽  
Aerobic Zone ◽  
Sponge Media ◽  
Aerobic Cell

Nitrification and denitrification were evaluated in multiple CSTR continuous flow fixed film systems at 12°C. Three systems were operated with three types of media installations and a fourth as a control without media. The media configurations evaluated included: (i) frame mounted fine pore sponge media supported on wires; (ii) free floating fine pore sponge media; and (iii) fixed location frame mounted rope media (ringlace). The pore size for sponge media was 14 pores per centimeter. Each system included a two-cell anaerobic zone with 17 percent of total volume, two-cell anoxic zone with 17 percent of total volume, and a three-cell aerobic zone with 64 percent of total volume. The multi-cell configuration was used to maximize kinetics of removal with suspended growth biomass and evaluate improvements in nitrogen removal beyond the levels achieved with suspended growth. At the optimum location (aerobic cells 1 and 2), the nitrification in cells containing free-floating sponges was 143 percent of the control at aerobic MCRTs of 3.1 and 3.4 days, with 35 percent media volume to cell volume. The nitrification with rope media was 136 percent of the control in middle third of the aerobic zone. Removals with ringlace were poorer in the first aerobic cell operating at higher COD levels, and in the third aerobic cell which did not contain sufficient biofilm growth at low levels of COD. Nitrification was 14 percent higher in Systems 1 and 2 with fixed and free floating sponges, respectively, and 8 percent higher in System 3 (ringlace) when all systems were spiked with 20 mg/L additional ammonium over a 24 hour period. Optimizing location of the media, with higher density of media at locations where adequate COD and ammonium-N are available for biofilm growth increase nitrification on media. Studies in full scale systems show that COD and ammonium-N concentrations at downstream locations in the activated sludge basin increase during peak flows and with step feed of wastewater. This helps increase biofilm growth and improve nitrification on the media downstream locations. Denitrification observed in the aerobic cells of the fixed film systems was in excess of the control. All aerobic cells were operated at D.O. levels in excess of 6.0 mg/L. The fraction of total denitrification under aerobic conditions was 0.0 in the control as compared to 0.14 to 0.24 with ringlace media and fixed sponge media, respectively, at an aerobic MCRT 3.1 days. Fraction aerobic denitrification in all systems increased with an increase in MCRT of suspended growth - to 0.21 in the control and 0.35 and 0.39 with ringlace and sponges, respectively, at aerobic MCRTs of 3.4 to 7.7 days.

Full-scale evaluation of an integrated fixed-film activated sludge (IFAS) process for enhanced nitrogen removal

1996 ◽  
Vol 33 (12) ◽  
pp. 155-162 ◽  
Author(s):  
Clifford W. Randall ◽  
Dipankar Sen
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Plug Flow ◽  
Treatment Plant ◽  
Nitrification Rate ◽  
A Value ◽  
Fixed Film ◽  
Control Section ◽  
The Media ◽  
Retrofit Design

One of the two trains of the 37,000 m3/d Annapolis, Maryland step aeration activated sludge treatment plant was modified for single-sludge anoxic-aerobic operation, and then fixed-film media were integrated into the aerobic zone to enhance nitrification. Rope-like Ringlace media was selected for integration, and 30,000 meters were installed in a volume of 475 m3 for a pilot demonstration. The purpose of the integrated fixed-film media was to upgrade the short hydraulic retention time (HRT) basin (6 hrs nominal) for efficient, year-round nitrogen removal without construction to increase basin volume. An engineering study had concluded that upgrading the facility for year round complete nitrification, without nitrogen removal, would cost US$24 million. The modified train was operated for 12 months, six in the plug-flow MLE configuration, and six in a step-feed configuration. The integrated Ringlace media increased the nitrification rate per unit volume to 225% of that observed in the control section, attaining a value of 1.75 kg/d NH3-N per linear meter at 15°C. The media also increased denitrification in the aerobic media section to the extent that between 30 and 88% of the nitrates formed in the section were denitrified within it, permitting a potential 25% or more reduction in the volume of the anoxic zone. An IFAS retrofit design was developed which incorporated step-feed operation, and reduced the projected construction cost to US$9.2 million.

Understanding the contribution of biofilm in an integrated fixed-film-activated sludge system (IFAS) designed for nitrogen removal

2015 ◽  
Vol 71 (10) ◽  
pp. 1500-1506 ◽  
Author(s):  
P. Moretti ◽  
J. M. Choubert ◽  
J. P. Canler ◽  
O. Petrimaux ◽  
P. Buffiere ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Loading Rate ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Biofilm Growth ◽  
Operational Conditions ◽  
Solids Concentration ◽  
Fixed Film ◽  
Autotrophic Biomass

The objective of this study is to improve knowledge on the integrated fixed-film-activated sludge (IFAS) system designed for nitrogen removal. Biofilm growth and its contribution to nitrification were monitored under various operating conditions in a semi-industrial pilot-scale plant. Nitrification rates were observed in biofilms developed on free-floating media and in activated sludge operated under a low sludge retention time (4 days) and at an ammonia loading rate of 45–70 gNH4-N/kgMLVSS/d. Operational conditions, i.e. oxygen concentration, redox potential, suspended solids concentration, ammonium and nitrates, were monitored continuously in the reactors. High removal efficiencies were observed for carbon and ammonium at high-loading rate. The contribution of biofilm to nitrification was determined as 40–70% of total NOx-N production under the operating conditions tested. Optimal conditions to optimize process compacity were determined. The tested configuration responds especially well to winter and summer nitrification conditions. These results help provide a deeper understanding of how autotrophic biomass evolves through environmental and operational conditions in IFAS systems.

Estimation of Biomass Concentration and Population Dynamics in a Captor® Activated Sludge System

1994 ◽  
Vol 29 (7) ◽  
pp. 149-152 ◽  
Author(s):  
M. P. Reddy ◽  
K. R. Pagilla ◽  
P. R. Senthilnathan ◽  
H. W. Johnson ◽  
P. S. Golla
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Microbial Population ◽  
Biomass Concentration ◽  
Activated Sludge Process ◽  
Free Swimming ◽  
Activated Sludge System ◽  
Suspended Growth ◽  
Fixed Film ◽  
The Media

A technique was developed to measure the equivalent MLSS in the fixed film Captor® media-activated sludge process. The technique accounts for the wear in the media as well as unequal wear in different media. The microbial population variations encountered during three years of full scale operation of the Captor® process, at the Moundsville WWTP were recorded. It has been found that fixed film media seem to support predominantly rotifers, followed by free swimming ciliates, and single stalk ciliates. In contrast, the suspended growth activated sludge population contained lower level organisms, mostly free swimming ciliates, followed by stalk ciliates, flagellates, and a few rotifers.

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater

2017 ◽  
Vol 41 (2) ◽  
pp. 237-247 ◽  
Author(s):  
Paul Moretti ◽  
Jean-Marc Choubert ◽  
Jean-Pierre Canler ◽  
Pierre Buffière ◽  
Olivier Pétrimaux ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Dynamic Modeling ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Activated Sludge Process ◽  
Fixed Film

Enhancing nitrogen removal efficiency and reducing nitrate liquor recirculation ratio by improving simultaneous nitrification and denitrification in integrated fixed-film activated sludge (IFAS) process

2015 ◽  
Vol 73 (4) ◽  
pp. 827-834 ◽  
Author(s):  
Yang Bai ◽  
Yaobin Zhang ◽  
Xie Quan ◽  
Shuo Chen
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Electricity Consumption ◽  
Simultaneous Nitrification And Denitrification ◽  
Recirculation Flow ◽  
Fixed Film ◽  
Gradient Gel Electrophoresis ◽  
Nitrification And Denitrification

An integrated fixed-film activated sludge (IFAS) process (G1) and an activated sludge anoxic–oxic process (G2) were operated at nitrate liquor recirculation ratio (R) of 100, 200 and 300% to investigate the feasibility of enhancing nitrogen removal efficiency (RTN) and reducing R by improving simultaneous nitrification and denitrification (SND) in the IFAS process. The results showed that the effluent NH4+-N and total nitrogen (TN) of G1 at R of 200% were less than 1.5 and 14.5 mg/L, satisfying the Chinese discharge standard (NH4+-N < 5 mg/L; TN < 15 mg/L). However, the effluent NH4+-N and TN of G2 at R of 300% were higher than 8.5 and 15.3 mg/L. It indicated that better RTN could be achieved at a lower R in the IFAS process. The polymerase chain reaction–denaturing gradient gel electrophoresis results implied that nitrifiers and denitrifiers co-existed in one microbial community, facilitating the occurrence of SND in the aerobic reactor of G1, and the contribution of SND to TN removal efficiency ranged 15–19%, which was the main reason that the RTN was improved in the IFAS process. Therefore, the IFAS process was an effective method for improving RTN and reducing R. In practical application, this advantage of the IFAS process can decrease the electricity consumption for nitrate liquor recirculation flow, thereby saving operational costs.

Comparative study evaluating removal mechanisms of hydrocarbons by fixed film versus suspended growth reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 531-535 ◽  
Author(s):  
N. Galil
Keyword(s):  
Activated Sludge ◽  
Biological Treatment ◽  
Rotating Biological Contactor ◽  
Active Biomass ◽  
Parallel Processes ◽  
Petrochemical Complex ◽  
Removal Mechanisms ◽  
Suspended Growth ◽  
Fixed Film ◽  
Better Than

Biological treatment of wastewater from a petrochemical complex was performed in order to evaluate the removal mechanisms of hydrocarbons by two parallel processes: rotating biological contactor (RBC) and activated sludge. The influent contained 700 mg/L COD, 140 mg/L BOD, 7.5 mg/L phenols and 32 mg/L hydrocarbons in emulsified form. The hydraulic detention time was 14 to 18 hours for activated sludge and 4 to 5 hours for RBC. It was found that both units produced an effluent containing a residual hydrocarbon of about 10 percent from the initial effluent concentration. The distribution of the removed hydrocarbon was: in activated sludge 70 percent by attachment to biosolids and wasted with the removed sludge; in RBC 15 percent were stripped to the atmosphere, 25 percent by biodegradation and 50 percent were removed by wasted sludge. The higher fraction of hydrocarbon biodegraded by the fixed film seems to be the result of higher active biomass which could concentrate in the RBC reactor. The fact that RBC removes less hydrocarbon to the atmosphere is considered as an environmental advantage. Although the fixed film attached a major part of the hydrocarbons, the biosludge production and characteristics for the fixed film were substantially better than for the suspended growth.

Application of a sponge media (BioCube) process for upgrading and expansion of existing caprolactam wastewater treatment plant for nitrogen removal

2004 ◽  
Vol 50 (6) ◽  
pp. 163-171 ◽  
Author(s):  
K.J. Chae ◽  
S.K. Yim ◽  
K.H. Choi
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Treatment Plant ◽  
High Strength ◽  
Organics Removal ◽  
Large Fluctuations ◽  
The Media ◽  
Sponge Media

For the upgrade and expansion of an existing caprolactam wastewater treatment plant, a freely floating sponge media (BioCube) process was selected based on extensive pilot-plant tests, due to extreme space constraints. In order to protect nitrifier inhibition caused by high strength organics in caprolactam wastewater, the pilot plant consisted of an organics removal reactor, which functioned as a pretreatment for nitrification, and followed the nitrogen removal reactor. The suspended MLSS was 1,800-4,000 and the media attached MLSS was maintained at 22,000-26,000 mg/L. The final effluent COD was noticeably low, around 20.4-37 mg/L, even with fairly large fluctuations in the feed levels, between 1,400-6,770 mg/L. The removal of total nitrogen with the system, when denitrification was close to completion, was approximately 97.6%. For the entire run, complete nitrification of 99.6% was achieved, which might have been due to well-acclimatized nitrifiers attached in the BioCube media. Specifically, after adaptation, the nitrification continuously increased in the organics removal reactor, even under high residual organics conditions. From the numerous experimental results, the BioCube process seemed to be an effective method for the upgrading and expansion of the existing wastewater treatment plant, with minimum reactor enlargement.

Pilot scale study of sequencing batch reactor (SBR) retrofit with integrated fixed film activated sludge (IFAS): nitrogen removal and design consideration

2018 ◽  
Vol 4 (4) ◽  
pp. 569-581 ◽  
Author(s):  
Renzun Zhao ◽  
Hong Zhao ◽  
Rich Dimassimo ◽  
Guoren Xu
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Pilot Scale ◽  
Design Consideration ◽  
Fixed Film ◽  
Seeding Effect ◽  
Pilot Scale Reactor ◽  
Scale Reactor

IFAS process was coupled with SBR operation in a pilot-scale reactor to verify the feasibility and to evaluate the performance of IFAS-SBR. Significant nitrification improvement in the IFAS-SBR system was observed, which is attributed to both the introduction of attached-growth biomass on media carriers and the “seeding effect” by biofilm sloughing.

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