Biosorption of LMW PAHs on activated sludge aerobic granules under varying BOD loading rate conditions

In this study it was investigated whether the CIRCOX® airlift technology with integrated denitrification was suitable to treat municipal wastewater. The standard CIRCOX® reactor was extended with an anoxic compartment. The sludge on carrier is circulated alternately over the anoxic and oxic compartments by means of an airlift pump. The study was performed in two pilot reactors, a standard CIRCOX® reactor and a CIRCOX® reactor with integrated denitrification. Concerning BOD conversion and nitrification, no differences between the two systems were observed. It was shown that both BOD and nitrogen were removed efficiently. In the effluent, mean soluble BOD concentrations of 7 mg/l were attained at varying COD loading rates. Nitrification was complete in both reactors at temperatures above 15°C and at COD conversion rates of more than 2.5 kg COD/m3/d. Nitrification rates below 15°C were higher as compared to a low loaded activated sludge system. Substrate conversion rates were found to be constant throughout the denitrifying reactor. Denitrification matched the rates theoretically feasible. This could be achieved by controlling the recirculation and the aeration in relation to the loading rate. It can be concluded that the denitrifying CIRCOX® airlift technology seems to be an interesting alternative to treat municipal wastewater.

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Impact of dissolved oxygen and loading rate on NH 3 oxidation and N 2 production mechanisms in activated sludge treatment of sewage

Microbial Biotechnology ◽

10.1111/1751-7915.13599 ◽

2020 ◽

Cited By ~ 1

Author(s):

Xueyu Zhang ◽

Shida Li ◽

Shaokui Zheng ◽

Shoupeng Duan

Keyword(s):

Dissolved Oxygen ◽

Activated Sludge ◽

Loading Rate ◽

Sludge Treatment ◽

Production Mechanisms

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Degradation of Nonylphenol Polyethoxylates and its Microflora Structure in an Anoxic-Oxic Activated Sludge Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.610-613.331 ◽

2012 ◽

Vol 610-613 ◽

pp. 331-336

Author(s):

Yuan Hua Xie ◽

Tong Zhu ◽

Xiao Jiang Liu ◽

Hui Liu ◽

Jin Han

Keyword(s):

In Situ Hybridization ◽

Activated Sludge ◽

Removal Efficiency ◽

Gel Electrophoresis ◽

Loading Rate ◽

Denaturing Gradient Gel Electrophoresis ◽

Oxygen Demand ◽

Activated Sludge Process ◽

Gradient Gel Electrophoresis

An anoxic-oxic activated sludge process (AOASP) was carried out to degrade nonylphenol polyethoxylates (NPEOs). The carbon source in influent was replaced stepwise by a mixture of nonylphenol decaethoxylate (M-NP10EO). The 2nd-derivative UV-spectrometry was applied to determine the total amount of M-NP10EO in water samples. Chemical oxygen demand (COD) removal efficiency achieves about 85% under the highest M-NP10EO loading rate, and M-NP10EO removal efficiency is about 80%. Denaturing gradient gel electrophoresis (DGGE) results of activated sludges show that the microbe species decrease but gradually stabilize with the increase of M-NP10EO concentration in influent. Fluorescence in situ hybridization (FISH) results of activated sludges showe that the dominant microflora under the highest M-NP10EO loading rate is β-Proteobacteria (35%), followed by α-Proteobacteria (15%), γ-Proteobacteria (5%) and Actinobateria (4%).

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

Water Science & Technology ◽

10.2166/wst.2015.127 ◽

2015 ◽

Vol 71 (10) ◽

pp. 1500-1506 ◽

Cited By ~ 8

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.

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Application of cigarette filter rods as biofilm carrier in an integrated fixed-film activated sludge reactor

Water Science & Technology ◽

10.2166/wst.2013.058 ◽

2013 ◽

Vol 67 (8) ◽

pp. 1793-1801 ◽

Cited By ~ 2

Author(s):

Ahmad Sabzali ◽

Mahnaz Nikaeen ◽

Bijan Bina

Keyword(s):

Activated Sludge ◽

Loading Rate ◽

Oxygen Demand ◽

Organic Loading Rate ◽

Organic Loading ◽

Cigarette Filter ◽

Biofilm Reactors ◽

Biofilm Carrier ◽

Fixed Film ◽

Activated Sludge Reactor

Bio-carriers are an important component of integrated fixed-film activated sludge (IFAS) processes. In this study, the capability of cigarette filter rods (CFRs) as a bio-carrier in IFAS processes was evaluated. Two similar laboratory-scale IFAS systems were operated over a 4-month period using Kaldnes-K3 and CFRs as IFAS media. The process performance was studied by using chemical oxygen demand (COD). The organic loading rate was in the range 0.5–2.8 kgCOD/(m3·d). The COD average removal efficiencies were 89.3 and 93.9% for Kaldnes-K3 (reactor A) and cigarette filters (reactor B), respectively. The results demonstrate that the performance of the IFAS reactor containing CFRs was comparable to the reactor using Kaldnes. The CFRs, which have a high porous surface area and entrapment ability for microbial cells, could be successfully used in biofilm reactors as a bio-carrier.

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