Full-Scale Studies with an Anaerobic/Aerobic RBC Unit Treating Brewery Wastewater

A full-scale combined anaerobic random packed-cage and aerobic disc rotating biological contactor was operated under fluctuating organic loading rates treating a brewery wastewater. The robustness of the combined system in coping with greatly fluctuating influent COD's and pH 's is demonstrated. Excessive turbulence along with the variable operating conditions are identified as the major reasons for the failure to establish a significant anaerobic biofilm attached to the media. The importance of suspended sludge and its retention within the anaerobic RBC is demonstrated by the changing biological population in the suspended solids.

Download Full-text

Effects of Complete Sludge Retention on Biomass Build-up in a Membrane Bioreactor

Water Science & Technology ◽

10.2166/wst.2005.0713 ◽

2005 ◽

Vol 52 (10-11) ◽

pp. 369-375 ◽

Cited By ~ 2

Author(s):

A. Pollice ◽

G. Laera

Keyword(s):

Membrane Bioreactor ◽

Suspended Solids ◽

Operating Conditions ◽

Municipal Sewage ◽

Equilibrium Conditions ◽

Load Variations ◽

Loading Rates ◽

Biomass Activity ◽

Two Parameters ◽

Volumetric Loading

The work reports the main results of an experimental activity aimed at evaluating the performance of a membrane bioreactor with complete sludge retention and the characteristics of its biomass. The bench scale system was started-up without any sludge inoculum and fed on real municipal sewage in order to favour biomass selection based on the imposed operating conditions. Process performance was evaluated in terms of COD removal (above 90% on average) and nitrification under two pre-determined volumetric loading rates (0.8 and 1.7gCOD Lreact.−1d−1 on average). The biomass was evaluated in terms of growth, accumulation of inert solids, and bacterial activity. The latter was measured through respirometric tests. The results showed that the suspended solids concentrations (SS) under equilibrium were proportional to the volumetric loading rates in both the experimental periods considered and a relationship between these two parameters was proposed. Also, the organic loading rates reached the same equilibrium value of 0.12gCOD gTSS−1d−1 in the two periods. Moreover, the system showed very limited sludge production under equilibrium conditions (0.12gVSS gCODrem−1) and low biomass activity, although it readily responded to load variations.

Download Full-text

Evaluation of the performance of full-scale packed saturators

Water Science & Technology ◽

10.2166/wst.2001.0466 ◽

2001 ◽

Vol 43 (8) ◽

pp. 67-74

Author(s):

M. Valade ◽

D. Nickols ◽

J. Haarhoff ◽

K. Barrett ◽

H. Dunn

Keyword(s):

Cold Water ◽

Full Range ◽

Cost Effective ◽

Full Scale ◽

Operating Conditions ◽

Comprehensive Model ◽

Loading Rates ◽

Saturator Efficiency ◽

Effective Saturation ◽

Saturation Systems

An evaluation of the performance of full-scale packed saturators was made. Measurements of saturator effluent air concentrations, saturator efficiency and precipitated are reported for both cold water and warm water operating conditions. Packed saturators were analyzed over a full range of operating pressures and loading rates. Measured results compared to predicted results based on a comprehensive model for the performance of packed saturators prove the model to be a useful tool in designing efficient and cost effective saturation systems.

Download Full-text

Integrated fixed-film activated sludge ANITA™Mox process – a new perspective for advanced nitrogen removal

Water Science & Technology ◽

10.2166/wst.2013.786 ◽

2013 ◽

Vol 69 (5) ◽

pp. 915-922 ◽

Cited By ~ 61

Author(s):

F. Veuillet ◽

S. Lacroix ◽

A. Bausseron ◽

E. Gonidec ◽

J. Ochoa ◽

...

Keyword(s):

Activated Sludge ◽

Suspended Solids ◽

Removal Rate ◽

Cost Effective ◽

Full Scale ◽

Operating Conditions ◽

Laboratory Scale ◽

Bulk Liquid ◽

N Removal ◽

Fixed Film

ANITA™Mox is a Veolia process using moving-bed biofilm reactor (MBBR) technology tested and validated in full-scale for energy- and cost-effective autotrophic N-removal from sidestream effluent using anammox (ANaerobic AMMonium OXidation) bacteria. In order to increase the ANITA™Mox process performances under different operating conditions (e.g. mainstream and sidestream application), substrate transport and accessibility inside the biofilm must be enhanced. In this work, (i) two laboratory scale biofilm ANITA™Mox reactors were operated using different configurations (IFAS – integrated fixed-film activated sludge – and MBBR) and (ii) the distribution of the anammox (AnAOB) and ammonia-oxidizing bacteria (AOB) in the suspended sludge and the biofilm was characterized using molecular tools (qPCR). This study showed that in IFAS configuration, the ANITA™Mox process achieved very high N-removal rate (up to 8 gN/m².d), which was three to four times higher than that achieved in the pure MBBR mode. The high concentration of suspended solids (mixed liquor suspended solids (MLSS)) in the bulk obtained within the IFAS mode induces a very efficient bacterial distribution between the AOB and AnAOB population. AnAOB activity mainly occurs in the biofilm (96% of total AnAOB in the reactor), whereas nitritation by AOB mostly takes place in the suspended phase (93% of total AOB). This spatial distribution observed in the IFAS reactor results from a natural selection due to more easily substrate accessibility for AOB in the bulk (NH4+, O2) creating higher nitrite concentration in the bulk liquid compare to pure MBBR mode. The efficient control of MLSS level in the IFAS reactor is a key parameter to enhance the nitrite production by AOB and increase the substrate availability in the AnAOB-enriched biofilm leading to higher N-removal rate. These promising results obtained at laboratory scale have been further confirmed in on-going full-scale IFAS ANITA™Mox trials opening new roads for the widespread application of a very compact and robust ANITA™Mox process for sidestream but also mainstream cost-effective N-removal.

Download Full-text

Investigations of Road Wear Caused by Studded Tires

Tire Science and Technology ◽

10.2346/tire.14.420101 ◽

2014 ◽

Vol 42 (1) ◽

pp. 2-15

Author(s):

Johannes Gültlinger ◽

Frank Gauterin ◽

Christian Brandau ◽

Jan Schlittenhard ◽

Burkhard Wies

Keyword(s):

Traffic Safety ◽

Test Bench ◽

Operating Conditions ◽

Test Method ◽

Analytical Models ◽

The Road ◽

Driving Speed ◽

Major Factors ◽

Tire Friction ◽

Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

Download Full-text

Behaviour of Alkylphenol Polyethoxylate Surfactants and of Nitrilotriacetate in Sewage Treatment

Water Science & Technology ◽

10.2166/wst.1987.0225 ◽

1987 ◽

Vol 19 (3-4) ◽

pp. 449-460 ◽

Cited By ~ 69

Author(s):

W. Giger ◽

M. Ahel ◽

M. Koch ◽

H. U. Laubscher ◽

C. Schaffner ◽

...

Keyword(s):

Activated Sludge ◽

Sewage Treatment ◽

Operating Conditions ◽

Municipal Sewage ◽

Sludge Treatment ◽

Loading Rates ◽

Treatment Conditions ◽

Physico Chemical ◽

Treated Sewage ◽

Removal Efficiencies

Effluents and sludges from several municipal sewage treatment plants in Switzerland were analyzed for nonylphenol polyethoxylates (NPnEO, n=3-20), nonylphenol mono- and diethoxylate (NPlEO, NP2EO), corresponding nonylphenoxy carboxylic acids (NP1EC, NP2EC) and nonylphenol (NP). These chemicals derive from nonionic surfactants of the NPnEO-type, and specific analitical techniques were used to study their behaviour during mechanical-biological sewage and subsequent sludge treatment. The parent NPnEO-surfactants, with concentrations in raw and mechanically treated sewage from 400-2200 mg/m3, were relatively efficiently removed by the activated sludge treatment. The abundances of the different metabolites varied depending on treatment conditions. The refractory nature of NPl/2EO, NP and NPl/2EC was recognized. Both biotransformations and physico-chemical processes determine the behaviour and fate of nonylphenolic substances in sewage treatment. Nitrilotriacetate (NTA) was found in primary effluents at concentrations between 430 and 1390 mg/m3. The various treatment plants showed different removal efficiencies for NTA depending on the operating conditions. Activated sludge treatment with low sludge loading rates and nitrifying conditions removed NTA with efficiencies between 95 and 99%. High sludge loading caused a decrease in NTA removal efficiencies from 70% to 39%.

Download Full-text

A Critical Look into the Deviation of Full Scale Performance from Design Expectations

Water Science & Technology ◽

10.2166/wst.1989.0336 ◽

1989 ◽

Vol 21 (10-11) ◽

pp. 1389-1402 ◽

Cited By ~ 2

Author(s):

R. Zaloum

Keyword(s):

Expert Systems ◽

Waste Treatment ◽

Full Scale ◽

Operating Conditions ◽

Organic Load ◽

Computer Assisted ◽

Uniform Load ◽

Effluent Quality ◽

Simulation Techniques ◽

Steady Level

Deviations from design expectations appear to stem from views which assume that a unique response should result from a given set of operating conditions. The results of this study showed that two systems operating at equal organic loads or F/M ratios and at the same SRT do not necessarily give equal responses. This deviation was linked to the manner in which the HRT and influent COD are manipulated to obtain a constant or uniform load, and to subtle interactions between influent COD, HRT and SRT on the biomass and effluent responses. Increases of up to 200% in influent COD from one steady level to the next did not significantly influence the effluent VSS concentration while an effect on filtered COD was observed for increases as low as 20%. Effluent TKN and filtered COD correlated strongly with the operating MLVSS while phosphorus residual depended on the operating SRT and the organic load removed. These results point to the inadequacy of traditional models to predict effluent quality and point to the need to consider these effects when developing simulation techniques or computer assisted expert systems for the control of waste treatment plants.

Download Full-text

Study on the performance of an up-flow aerated biofilter (UAB) in municipal wastewater treatments

Water Science & Technology ◽

10.2166/wst.1994.0543 ◽

1994 ◽

Vol 30 (11) ◽

pp. 25-33 ◽

Cited By ~ 7

Author(s):

Yoshimasa Watanabe ◽

Satoshi Okabe ◽

Tomochika Arata ◽

Yuji Haruta

Keyword(s):

Organic Matter ◽

Suspended Solids ◽

Municipal Wastewater ◽

Unique Feature ◽

Aeration Rate ◽

Loading Rates ◽

Hydraulic Loading ◽

Running Cost ◽

And Performance ◽

Activated Sludge Systems

A comprehensive wastewater treatment system that accomplishes oxidation of organic matter, nitrification, and denitrification was developed, and its characteristics and performance were investigated. A municipal wastewater was treated by an up-flow aerated biofilter (UAB), in which biofilms were developed on stainless meshes installed horizontally. This UAB exhibited a great potential ability of oxidation of organic matter, SS stabilization, and nitrification due to a unique aeration mechanism giving high DO concentrations with relatively low aeration rates. Another unique feature of the UAB was that attached biofilms on stainless meshes physically filtered out and/or adsorbed suspended solids in the wastewater in addition to the biological oxidation of organic matter. A stable nitrification could be achieved at HRT=10 hours corresponding to a hydraulic loading of 86 L m−2 d−1 and at a ratio of aeration rate to wastewater flow rate (A/W) of 2, which is considerably low as compared to aeration rates of typical activated sludge systems. This UAB system also could handle relatively high hydraulic loading rates. The UAB used in this study still have enough space to install more stainless meshes so as to reduce hydraulic loading rates resulting in the reduction of HRT and aeration rate, which leads to improvement of the system performance as well as reduction of the running cost.

Download Full-text

Treatment system response to transient AOX (adsorbable organic halogen) loadings

Water Science & Technology ◽

10.2166/wst.1997.0489 ◽

1997 ◽

Vol 35 (2-3) ◽

pp. 85-91

Author(s):

D. A. Barton ◽

J. D. Woodruff ◽

T. M. Bousquet ◽

A. M. Parrish

Keyword(s):

Paper Industry ◽

Model Development ◽

Operating Conditions ◽

System Response ◽

Additional Information ◽

Organic Halogen ◽

Aox Removal ◽

Variable Operating Conditions ◽

Plant Shutdown

If promulgated as proposed, effluent guidelines for the U.S. pulp and paper industry will impose average monthly and maximum daily numerical limits of discharged AOX (adsorbable organic halogen). At this time, it is unclear whether the maximum-day variability factor used to establish the proposed effluent guidelines will provide sufficient margin for mills to achieve compliance during periods of normal but variable operating conditions within the pulping and bleaching processes. Consequently, additional information is needed to relate transient AOX loadings with final AOX discharges. This paper presents a simplistic dynamic model of AOX decay during treatment. The model consists of hydraulic characterization of an activated sludge process and a first-order decay coefficient for AOX removal. Data for model development were acquired by frequent collection of influent and effluent samples at a bleach kraft mill during a bleach plant shutdown and startup sequence.

Download Full-text