Design of fine-bubble aeration systems for municipal WWTPs with high sea salt concentrations

2017 ◽  
Vol 75 (7) ◽  
pp. 1555-1563 ◽  
Author(s):  
S. Sander ◽  
J. Behnisch ◽  
M. Wagner
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Sea Salt ◽  
Favourable Effect ◽  
Municipal Wastewater Treatment ◽  
Fine Bubble ◽  
Municipal Wastewater Treatment Plants ◽  
The Impact

The impact of sea salt on the aeration coefficient kLa of fine-bubble aeration systems was investigated in clean water and in a model substance for simulating activated sludge. The investigations were carried out at laboratory and pilot scale. Sea salt was dosed in the form of artificial seawater, real seawater or simplified, by adding NaCl. The investigated media showed an increase of kLa with rising sea salt concentrations up to 10 g/L. The ratio between kLa and sea salt concentration is impaired by the air flow rate and the type of applied diffusers. Literature data show that the favourable effect of sea salt on kLa can also be found in the activated sludge of conventional municipal wastewater treatment plants. The results of this study allow the derivation of salt correction equations to be used in the design of fine-bubble aeration systems for taking into account the favourable impact of sea salt on kLa. By that means, a more precise design of respective systems will be enabled.

Biosensor-based control of nitrification inhibitor in municipal wastewater treatment plants

2006 ◽  
Vol 53 (4-5) ◽  
pp. 357-366 ◽  
Author(s):  
Y. Okayasu ◽  
H. Tanaka ◽  
T. Inui ◽  
Y. Tanaka
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Nitrification Inhibitor ◽  
Nitrifying Bacteria ◽  
Activated Sludge Process ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants ◽  
The Impact

The effect of potassium cyanide (KCN) on nitrification processes in municipal wastewater treatment plants was studied by batch nitrification tests, which indicated that nitrification processes tend to be inhibited at a lower KCN concentration than the present discharge standard to sewerage. The experiment of the biosensor using nitrifying bacteria was also conducted for continuous monitoring of nitrification inhibitor in influent wastewater, and demonstrated that the biosensor can detect KCN at as low as EC10 of the abovementioned batch nitrification test. Moreover, to determine the effectiveness of application of the biosensor to avoid the impact of KCN due to an accidental spillage in a sewerage system, KCN was intentionally injected into the experimental models of activated sludge process equipped both with and without the biosensor. The model with the biosensor that could detect KCN could divert the wastewater including KCN to a refuge tank, which resulted in the avoidance of upset of the activated sludge process. On the other hand, the model without the biosensor was upset in the nitrification process due to KCN. Such differences demonstrate the effectiveness of the biosensor applied to countermeasures of an accidental spillage of toxic chemicals to avoid upset of nitrification in municipal wastewater treatment plants.

PARAMETERS FOR DYNAMIC SIMULATION OF W ASTEW ATER TREATMENT PLANTS WITH HIGH-RATE AND LOW-RATE ACTIVATED SLUDGE TANKS

1994 ◽  
Vol 30 (4) ◽  
pp. 211-214 ◽  
Author(s):  
E. Brands ◽  
M. Liebeskind ◽  
M. Dohmann
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Dynamic Simulation ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
High Rate ◽  
Yield Coefficient ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants ◽  
Low Rate

This study shows a comparison of important parameters for dynamic simulation concerning the highrate and low-rate activated sludge tanks of several municipal wastewater treatment plants. The parameters for the dynamic simulation of the single-stage process are quite well known, but parameters for the high-ratellow-rate activated sludge process are still missi ng, although a considerable number of wastewater treatment plants are designed and operated that way. At present any attempt to simulate their operation is restricted to the second stage due to missing data concerning growth rate, decay rate, yield coefficient and others.

Characterization of wastewater and activated sludge from European municipal wastewater treatment plants using the NUR test

1998 ◽  
Vol 38 (1) ◽  
pp. 303-310 ◽  
Author(s):  
V. Naidoo ◽  
V. Urbain ◽  
C. A. Buckley
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Municipal Wastewater Treatment ◽  
Batch Tests ◽  
Denitrification Kinetics ◽  
Municipal Wastewater Treatment Plants

Denitrification kinetics and wastewater characterization of eight different plants in Europe are discussed. Denitrification batch tests revealed three distinct rates except in the cases of Plaisir, Rostock and Orense where 4 rates were observed. The latter three plants revealed atypical rapid initial rates which were between 7 and 21 mgN/gVSS.h. All denitrification kinetics under non-limiting carbon conditions revealed fast first rates which ranged between 3.0 and 7.3 mgN/gVSS.h. Acetate was used to simulate denitrification kinetics with readily biodegradable COD present. Two subsequent rates were observed. Rates 2 and 3 ranged between 2 and 3 mgN/gVSS.h, and 1 and 2 mgN/gVSS.h, respectively. The RBCOD fraction varied between 10 and 19%, except for one of the plants where the value determined was 7%.

Fate of sex hormones in two pilot-scale municipal wastewater treatment plants: Conventional treatment

Chemosphere ◽  
2007 ◽  
Vol 66 (8) ◽  
pp. 1535-1544 ◽  
Author(s):  
Mar Esperanza ◽  
Makram T. Suidan ◽  
Ruth Marfil-Vega ◽  
Cristina Gonzalez ◽  
George A. Sorial ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Sex Hormones ◽  
Conventional Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Municipal Wastewater Treatment Plants

scholarly journals Aeration control – a review

2013 ◽  
Vol 67 (11) ◽  
pp. 2374-2398 ◽  
Author(s):  
L. Åmand ◽  
G. Olsson ◽  
B. Carlsson
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Control Strategies ◽  
Pilot Scale ◽  
Special Focus ◽  
Municipal Wastewater Treatment ◽  
Optimal Controllers ◽  
Municipal Wastewater Treatment Plants ◽  
And Control ◽  
Published Research

This review covers automatic control of continuous aeration systems in municipal wastewater treatment plants. The review focuses on published research in the 21st century and describes research into various methods to decide and control the dissolved oxygen (DO) concentration and to control the aerobic volume with special focus on plants with nitrogen removal. Important aspects of control system implementation and success are discussed, together with a critical review of published research on the topic. With respect to DO control and determination, the strategies used for control span from modifications and developments of conventional control methods which have been explored since the 1970s, to advanced control such as model-based predictive and optimal controllers. The review is supplemented with a summary of comparisons between control strategies evaluated in full-scale, pilot-scale and in simulations.

On the effect of pharmaceuticals on bacterial nitrite oxidation

2004 ◽  
Vol 50 (5) ◽  
pp. 341-346 ◽  
Author(s):  
S.N. Dokianakis ◽  
M.E. Kornaros ◽  
G. Lyberatos
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Reduction Rate ◽  
Inhibitory Effect ◽  
Significant Inhibition ◽  
Nitrite Reduction ◽  
Municipal Wastewater Treatment ◽  
Nitrite Oxidizing Bacteria ◽  
Municipal Wastewater Treatment Plants

Pharmaceuticals or their metabolites are partially excreted with urine or faeces ending up in raw sewage. Many of these substances are not biodegradable and their presence in influents of municipal wastewater treatment plants may cause adverse effects to sensitive biological processes such as nitrification, while on the other hand, they may go through the activated sludge process unreacted. The second step of nitrification, i.e. oxidation of nitrite to nitrate is particularly sensitive. Inhibition of this step under uncontrolled conditions may lead to accumulation of nitrite nitrogen in the plant effluent, a form of nitrogen which is particularly toxic. The effects caused by the presence of seven different pharmaceuticals to a culture of nitrite-oxidizing bacteria isolated from activated sludge are presented. These pharmaceuticals were ofloxacin, propranolol, clofibrate, triclosan, carbamazepine, diclofenac and sulfamethoxazole. Different effects were observed for each of the pharmaceuticals tested in this study. In the cases of ofloxacin and sulfamethoxazole significant inhibition was observed. Triclosan presented a substantial inhibitory effect on the substrate (nitrite) reduction rate. The long-term effect of triclosan on nitrite oxidizers was also examined in a CSTR reactor and conclusions were drawn regarding the reversibility of the inhibition caused by this compound.

scholarly journals Innovative technologies in municipal wastewater treatment plants in Sweden to improve Baltic Sea water quality

2018 ◽  
Vol 45 ◽  
pp. 00113 ◽  
Author(s):  
Józef Trela ◽  
Elżbieta Płaza
Keyword(s):  
Wastewater Treatment ◽  
Baltic Sea ◽  
Municipal Wastewater ◽  
New Technologies ◽  
Sea Water ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Municipal Wastewater Treatment ◽  
Treatment Processes ◽  
Municipal Wastewater Treatment Plants

The article presents new trends in the treatment of municipal wastewater in Sweden caused by the constantly increasing requirements for discharging pollutants into Baltic Sea waters. The development of new technologies for nitrogen removal, pharmaceutical residues removal and the possibility of using membrane processes in wastewater treatment is presented. The state of research on innovative wastewater treatment processes at the level of pilot-scale tests and their implementation in full technical scale has been described. These technologies can allow the application of new, economical and environmentally friendly wastewater treatment processes based on biological, chemical and physical methods. Swedish wastewater treatment plants are preparing to meet the new conditions required for discharged wastewater with a value of 6 mg N/L for total nitrogen and 0.2 mg P/L for total phosphorus. This requires large investments in the reconstruction of municipal wastewater treatment plants and the introduction of new treatment processes.

Microsieving in primary treatment: effect of chemical dosing

2016 ◽  
Vol 74 (2) ◽  
pp. 438-447 ◽  
Author(s):  
J. Väänänen ◽  
M. Cimbritz ◽  
J. la Cour Jansen
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Municipal Wastewater Treatment ◽  
Chemically Enhanced Primary Treatment ◽  
Municipal Wastewater Treatment Plants

Primary and chemically enhanced primary wastewater treatment with microsieving (disc or drum filtration) was studied at the large pilot scale at seven municipal wastewater treatment plants in Europe. Without chemical dosing, the reduction of suspended solids (SS) was (on average) 50% (20–65%). By introducing chemically enhanced primary treatment and dosing with cationic polymer only, SS removal could be controlled and increased to >80%. A maximum SS removal of >90% was achieved with a chemical dosing of >0.007 mg polymer/mg influent SS and 20 mg Al3+/L or 30 mg Fe3+/L. When comparing sieve pore sizes of 30–40 μm with 100 μm, the effluent SS was comparable, indicating that the larger sieve pore size could be used due to the higher loading capacity for the solids. Phosphorus removal was adjusted with the coagulant dose, and a removal of 95–97% was achieved. Moreover, microsieving offers favourable conditions for automated dosing control due to the low retention time in the filter.

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