Nitrifier population dynamics in a bench-scale conventional activated sludge reactor following an induced perturbation

Three activated sludge reactors were operated to improve the removal of organic micropollutants such as Pharmaceutical and Personal Care Products (PPCPs). Reactor 1 (R1) was operated as a Conventional Activated Sludge reactor (CAS), Reactor 2 (R2) consisted of a CAS unit that was continuously fed with FeCl3 whereas granular activated carbon (GAC) was fed directly into the mixed liquor of Reactor 3 (R3) in order to attain concentrations in the range 100–1,000 mg/L. PPCPs removal rates varied depending on the compound present in each reactor during the entire 220 days of operation. Some substances showed the same behaviour in all reactors, such as the acidic pharmaceuticals naproxen and ibuprofen, which were almost completely removed (>90%). More hydrophobic organic substances, like musk fragrances, were about 90% removed after 40 days of operation in all of the reactors. The main difference between the three reactors was obtained in R3 when the GAC concentrations in the aeration tank were around 500–1,000 mg/L. Under these conditions, the more recalcitrant compounds like diazepam and carbamazepine could be removed by up to 40%, and diclofenac up to 85%. Adsorption isotherms for PPCPs were obtained with activated carbon, and the results were successfully fitted to the Freundlinch equation. The more recalcitrant compounds (carbamazepine, diazepam and diclofenac) had the highest adsorption capacities onto GAC, which is consistent with the behaviour observed in R3 and helps to identify the removal mechanism (adsorption for these compounds, whereas absorption for fragrances).

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Bench-Scale Testing of Activated Sludge Treatment for a TMP Wastewater

Water Quality Research Journal ◽

10.2166/wqrj.1993.030 ◽

1993 ◽

Vol 28 (3) ◽

pp. 571-596 ◽

Cited By ~ 1

Author(s):

Susan F. Liver ◽

Henry K. Miyamoto ◽

Steve A. Black

Keyword(s):

Activated Sludge ◽

Full Scale ◽

Operating Conditions ◽

Cold Weather ◽

Sludge Treatment ◽

Bench Scale ◽

Conventional Activated Sludge ◽

Initial Batch ◽

Treated Effluent ◽

Biokinetic Parameters

Abstract A continuous bench-scale treatability study determined the most desirable design and operating parameters for waste treament of effluent from an integrated Canadian TMP newsprint operation. An initial batch study indicated that the effluent was biologically treatable and provided initial biological kinetic (biokinetic) parameters for this wastewater. This information was used to design the continuous study. Conventional activated sludge treatment of the mill wastewater can produce an effluent which meets the federal regulations for BOD5, suspended solids, and toxicity to D. magna. Predictions using cumulative toxicity units (CTU) indicate that the treated effluent would also be non-toxic to O. mykiss as well. Analyses of ammonia in the treated effluent indicated that un-ionized ammonia concentrations would be non-toxic to rainbow trout. Mass balances incorporating the results of the bench-scale studies and the effect of fibre carry-over from the primary clarifier, defined the full-scale operating conditions selected as: an F/M of 0.35 d−1, HRT of 0.5 days, SRT of 6 days and an MLSS of 4400 mg/L (when no polymer is used at the primary clarifier). These conditions were arrived at by selecting the smallest HRT which still corresponded to an MLSS < 5000 mg/L, an F/M < 0.4 d−1 and an SRT > 5 days. Based on the kinetics for biological treatment of mill effluent, at the maximum mill production, adequate BOD5 removal will still easily be obtained under the above operating conditions, even during cold weather periods. Operational concerns identified by bench-scale testing indicated that a full-scale facility should incorporate an anoxic selector (although the anoxic selector did not show measurable improvement in the bench-scale tests) and micronutrient addition for filamentous bulking control.

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Optimal sludge retention time for a bench scale MBR treating municipal sewage

Water Science & Technology ◽

10.2166/wst.2008.118 ◽

2008 ◽

Vol 57 (3) ◽

pp. 319-322 ◽

Cited By ~ 21

Author(s):

A. Pollice ◽

G. Laera ◽

D. Saturno ◽

C. Giordano ◽

R. Sandulli

Keyword(s):

Activated Sludge ◽

Membrane Bioreactor ◽

Municipal Wastewater ◽

Operating Conditions ◽

Municipal Sewage ◽

Process Conditions ◽

Physical Parameters ◽

Municipal Wastewater Treatment ◽

Bench Scale ◽

Conventional Activated Sludge

Membrane bioreactors allow for higher sludge concentrations and improved degradation efficiencies with respect to conventional activated sludge. However, in the current practice these systems are often operated under sub-optimal conditions, since so far no precise indications have yet been issued on the optimal operating conditions of MBR for municipal wastewater treatment. This paper reports some results of four years of operation of a bench scale membrane bioreactor where steady state conditions were investigated under different sludge retention times. The whole experimental campaign was oriented towards the investigation of optimal process conditions in terms of COD removal and nitrification, biomass activity and growth, and sludge characteristics. The membrane bioreactor treated real municipal sewage, and four different sludge ages were tested (20, 40, 60, and 80 days) and compared with previous data on complete sludge retention. The results showed that the the biology of the system, as assessed by the oxygen uptake rate, is less affected than the sludge physical parameters. In particular, although the growth yield was observed to dramatically drop for SRT higher than 80 days, the biological activity was maintained under all the tested conditions. These considerations suggest that high SRT are convenient in terms of limited excess sludge production without losses of the treatment capacity. Physical characteristics such as the viscosity and the filterability appear to be negatively affected by prolonged sludge retention times, but their values remain within the ranges normally reported for conventional activated sludge.

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MICROBIOME ANALYSIS OF THE BACTERIAL POPULATION IN A BENCH-SCALE-ACTIVATED SLUDGE REACTOR EXPOSED TO AN ARTIFICIAL INSECTICIDE SPILL

Water Pollution XV ◽

10.2495/wp200031 ◽

2020 ◽

Author(s):

ÁNGELA BAEZA-SERRANO ◽

MARIA JOSÉ TÁRREGA ◽

JUAN F. MARTÍNEZ-BLANCH ◽

ANTONIA ROJAS ◽

MARTA TORTAJADA ◽

...

Keyword(s):

Activated Sludge ◽

Bacterial Population ◽

Bench Scale ◽

Microbiome Analysis ◽

Activated Sludge Reactor

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Short operational differences support granulation in a lab scale reactor in comparison to another conventional activated sludge reactor

Bioresource Technology ◽

10.1016/j.biortech.2018.09.111 ◽

2019 ◽

Vol 271 ◽

pp. 417-426 ◽

Cited By ~ 10

Author(s):

Sunayna Dasgupta ◽

Haydee De Clippeleir ◽

Ramesh Goel

Keyword(s):

Activated Sludge ◽

Conventional Activated Sludge ◽

Activated Sludge Reactor ◽

Scale Reactor

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Nitrification-denitrification of UASB effluents highly loaded with nitrogen in an activated sludge reactor operated with short cycled aeration

Water Science & Technology ◽

10.2166/wst.2001.0234 ◽

2001 ◽

Vol 44 (4) ◽

pp. 279-286 ◽

Cited By ~ 5

Author(s):

S. Villaverde ◽

M. L. Lacalle ◽

P. A. García-Encina ◽

F. Fdz-Polanco

Keyword(s):

Activated Sludge ◽

Total Nitrogen ◽

Nitrogen Removal ◽

Potato Starch ◽

Organic Carbon Content ◽

Conventional Activated Sludge ◽

Activated Sludge Reactor ◽

Total Nitrogen Removal ◽

Continuous Flow Reactors ◽

Activated Sludge Processes

A conventional activated sludge reactor operated with short cycled aeration was used for total nitrogen removal of UASB anaerobic reactor effluent containing nitrogen (up to 1,200 mg NKT/L) and organic matter (up to 2,000 mg COD/L). Initially the reactor was fed with synthetic water to progressively introduce the UASB effluent. This favored the acclimation of the microorganisms to the real environment. The results obtained throughout this study showed that initially the tested technology is feasible and can report significant cuts on operation and maintenance when compared to conventional activated sludge processes. Total nitrogen removal up to 66% was attained treating the effluent of an UASB process designed for treating the wastewater of a potato starch factory. Total nitrogen removal capacities ranging between 0.1 and 0.58 kg of nitrogen per cubic metre per day are reported. Short-cycled aeration allowed for a more efficient use of the oxygen supply for nitrification and the organic carbon content present in the wastewater for denitrification. This operating protocol has demonstrated serious advantages in terms of operation costs and simplicity when total nitrogen removal is wanted. Most of the existing activated sludge processes, i.e. single continuous flow reactors, can be updated for total nitrogen removal essentially at no cost, the inversion (aeration control system) is rapidly returned as reduction in energy expenditure.

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