Intermittent feeding of wastewater in combination with alternating aeration for complete denitrification and control of filaments

2010 ◽  
Vol 61 (9) ◽  
pp. 2259-2266 ◽  
Author(s):  
Styliani Kantartzi ◽  
Paraschos Melidis ◽  
Alexander Aivasidis
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Settling Tank ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Anoxic Conditions ◽  
Total Nitrogen Removal

In the present study, a laboratory scale system, consisting of a primary settling tank, a continuous stirred tank reactor and a clarifier were constructed and operated, using wastewater from the municipal wastewater treatment plant in Xanthi, Greece. The system operated under intermittent aeration in aerobic/anoxic conditions and feeding of the wastewater once in every cycle. The unit was inoculated with sludge, which originated from the recirculation stream of the local wastewater treatment plant. The wastewater was processed with hydraulic retention time (HRT) of 12 h, in which various experimental states were studied regarding the combination of aerobic and anoxic intervals. The wastewater was fed in limited time once in every cycle of aerobic/anoxic conditions at the beginning of the anoxic period. The two states that exhibited highest performance in nitrification and total nitrogen removal were, then, repeated with HRT of 10 h. The results show that, regarding the nitrification stage and the organic load removal, the intermittent system achieved optimum efficiency, with an overall removal of biological oxygen demand (BOD5) and ammonium nitrogen in the range of 93–96% and 91–95% respectively. As far as the total nitrogen removal is concerned, and if the stage of the denitrification is taken into account, the performance of the intermittent system surpassed other methods, as it is shown by the total Kjeldahl nitrogen (TKN) removal efficiency of 85–87%. These operating conditions suppressed the growth of filamentous organisms, a fact reflected at the SVI values, which were lower than 150 ml/g.

Operational Results of the Wolfsburg Wastewater Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 203-209 ◽  
Author(s):  
R. Kayser ◽  
G. Stobbe ◽  
M. Werner
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Phosphate Removal ◽  
Total Nitrogen Content ◽  
Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

Intermittent Aeration for Nitrogen Removal in Small Aerated Lagoon

1993 ◽  
Vol 28 (10) ◽  
pp. 335-341 ◽  
Author(s):  
S. Koottatep ◽  
C. Leesanga ◽  
H. Araki
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Intermittent Aeration ◽  
Treatment Processes ◽  
Total Nitrogen Removal ◽  
Save Energy

Intermittent aeration has been proved to be an efficient method in nitrogen removal in many biological treatment processes. Aerated lagoon has been used as domestic wastewater treatment for a small housing estates in Thailand for quite sometime. The purpose of this study is to determine whether intermittent aeration of aerated lagoon could provide efficient nitrogen removal in domestic wastewater. The experiment was carried out using pilot scale aerated lagoon at Chiangmai University. The result showed that 45% of total nitrogen removal could be achieved by aeration and non-aeration of 12 hours each cycle. The intermittent aeration did not affect organic substances removal of the process. Sludge recycle during non-aeration period may improve total nitrogen removal. The method could be introduced to save energy of small wastewater treatment plant.

Nitrogen removal from wastewater in a pilot plant operated in the recirculation anoxic-oxic activated sludge mode

1996 ◽  
Vol 33 (12) ◽  
pp. 255-258 ◽  
Author(s):  
Olga Burica ◽  
Marjeta Strazar ◽  
Ivan Mahne
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Volume Ratio ◽  
Mineral Nitrogen ◽  
Operating Conditions ◽  
Effluent Quality

The recirculation activated sludge process with preanoxic treatment was applied for biological reduction of the nitrogen content in municipal wastewater at pilot plant level. The pilot plant of total volume 3 300 1 with an initial anoxic to aerobic volume ratio of 40 : 60 was fed with wastewater from the first heavily loaded aerobic stage of a local wastewater treatment plant. Experiments were run over the summer and winter periods, the influent wastewater temperature being approx 24°C and approx 10°C, respectively. Special attention was paid to the hydraulic retention time, the total as well as mineral nitrogen loading, the aerobic to anaerobic volume ratio, and to the energy demand for denitrification of oxidised mineral nitrogen forms. Under optimal operating conditions the effluent quality that could be achieved was about 10 mg/l of total nitrogen (74% removal) and less than 2 mg N/l mineral nitrogen (87% removal), while simultaneously 205 mg BOD5/l in the influent was reduced to less than 7mg O2/l in the effluent. It was found feasible from the pilot plant experiments to upgrade an existing two stage aerobic-anaerobic wastewater treatment plant to reduce nitrogen from the liquid fraction of municipal wastewater so as to meet effluent quality standards without much additional volume and without amending the energy source for bioconversion of oxidised mineral nitrogen to gaseous forms.

scholarly journals Novel Measurements in Primary Settling Tanks of Large Municipal Wastewater Treatment Plants

2013 ◽  
Vol 1 (1) ◽  
pp. 6-18 ◽  
Author(s):  
Katalin Kiss ◽  
Miklós Patziger
Keyword(s):  
Wastewater Treatment ◽  
Flow Pattern ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Settling Tank ◽  
Treatment Plant ◽  
Design Guidelines ◽  
Transport Processes ◽  
Municipal Wastewater Treatment ◽  
Cfd Modelling

Abstract This paper shows the in situ analysis of a primary settling tank (PST) at the Graz Municipal Wastewater Treatment Plant (500 000 PE). The study aims at the deeper understanding of primary settling tanks behaviour by measurement of flow pattern within the tank and suspended solids (SS) separation. Measurement campaigns were carried out at different surface overflow rates (a main measure of PST load), that ranged from low to even higher values than recommended ones by design guidelines. During the measurements the inflowing and outflowing SS concentrations and loads were registered on-line. The flow pattern (3D velocity measurements, turbulence characteristics) was measured by using Acoustic - Doppler - Velocimetry (ADV) in raster [1]. The settling function was carried out by laboratory test at Budapest Central Wastewater Treatment Plant, which was investigated at representative concentration of PST. The measurements provided detailed insight into the flow and mass transport processes within the PST and valuable calibration and verification data for further CFD modelling.

Pilot testing and preliminary design of moving bed biofilm reactors for nitrogen removal at the FREVAR wastewater treatment plant

2000 ◽  
Vol 41 (4-5) ◽  
pp. 13-20 ◽  
Author(s):  
B. Rusten ◽  
B.G. Hellström ◽  
F. Hellström ◽  
O. Sehested ◽  
E. Skjelfoss ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plant ◽  
Pilot Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Biofilm Reactor ◽  
Nitrification Rate ◽  
Total N ◽  
Moving Bed

A moving bed biofilm reactor (MBBR) pilot plant, using Kaldnes type K1 biofilm carriers, was tested for nitrogen removal at the FREVAR wastewater treatment plant. The pilot plant was fed primary treated municipal wastewater, at temperatures from 4.8 to about 20°C. The results showed that a reasonable design nitrification rate will be 190 g TKN/m3d, at 10°C and a reactor pH≥7.0. Pre-denitrification was very dependent on the concentration of readily biodegradable organic matter and the amount of oxygen in the influent to the first anoxic MBBR. It was found that a MBBR process for nitrogen removal at FREVAR will require a total reactor volume corresponding to an empty bed hydraulic retention time of 4–5 hours at average design influent flow. This was based on an influent concentration of 25 mg total N/l, 70% annual average removal of total N and a treatment process consisting of primary treatment, MBBRs with combined pre- and post-denitrification, and followed by coagulation/flocculation and a final solids separation stage.

scholarly journals A pilot study on suspended activated sludge process augmented with immobilized biomass for simultaneous nitrification and denitrification

2015 ◽  
Vol 5 (2) ◽  
pp. 157-165 ◽  
Author(s):  
Haon-Yao Chen ◽  
Pui-Kwan Andy Hong ◽  
Ping-Yi Yang ◽  
Kok Kwang Ng ◽  
Sheng-Fu Yang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Cellulose Triacetate ◽  
Domestic Wastewater Treatment ◽  
Total Nitrogen Removal ◽  
Nitrification And Denitrification

Concurrent nitrification and denitrification (CND) are natural phenomena in the soil environment that can be applied in wastewater treatment for enhanced total nitrogen removal. However, significant renovation is necessary for existing plants to equip them for nutrient removal. At a domestic wastewater treatment plant, we performed a pilot test by installing bioplates with entrapped biomass in a conventional aeration basin for CND, and investigated the effects of bioplate packing ratio (PR), hydraulic retention time (HRT), dissolved oxygen (DO) level, on/off aeration mode, and supplemental carbon and alkalinity on nitrogen removal. With the pilot aeration basin of 1.3 m3 loaded with mixed liquor suspended solids of 1,500–2,500 mg/L and bioplates at PR of 3.2% (3.2% basin volume) operated at HRT of 6 h and DO of 4–6 mg/L without supplemental carbon or alkalinity, nitrogen in the wastewater was removed to an effluent total nitrogen (TN) of 7.3 mg/L from an influent TN of 28 mg/L, achieving a specific TN removal of 25 g TN/m2/d. The bioplate, consisting of modular, robust cellulose triacetate structure carrying the biomass, shows promise in retrofitting conventional aeration basins for enhanced nutrient removal.

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