Development of 2-reactor intermittent-aeration activated sludge process for simultaneous removal of nitrogen and phosphorus

We have developed a new intermittently aerated anaerobic-aerobic activated sludge process. This process employs 2 reactors connected in series, and is capable of controlling the duration of aerobic, anoxic and anaerobic conditions in both reactors by utilizing the ORP bending point, which corresponds to the termination of denitrification. One cycle of aeration and agitation takes approximately 120 minutes. In the 1st reactor, nitrification and phosphorus uptake occur in the aeration period, followed by denitrification and phosphorus release in the agitation period. In the 2nd reactor, nitrification and phosphorus uptake are conducted during aeration, and denitrification and weak phosphorus uptake during agitation. A one-year pilot plant experiment using sewage (22 m3/day) showed stable and high removal ratios of 98% for BOD, 92% for T-N, and 85% for T-P under conditions of HRT 20 hours and water temperature 9∼33°C.

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Simultaneous Removal of Nitrogen and Phosphorus in Intermittently Aerated 2-Tank Activated Sludge Process Using DO and ORP-Bending-Point Control

Water Science & Technology ◽

10.2166/wst.1993.0691 ◽

1993 ◽

Vol 28 (11-12) ◽

pp. 513-521 ◽

Cited By ~ 13

Author(s):

Kousei Sasaki ◽

Yasuji Yamamoto ◽

Kazushi Tsumura ◽

Shigeru Hatsumata ◽

Masahiro Tatewaki

Keyword(s):

Control System ◽

Activated Sludge ◽

Phosphorus Uptake ◽

Material Balance ◽

Phosphorus Release ◽

Test Plant ◽

Activated Sludge Process ◽

Time Sharing ◽

Nitrogen And Phosphorus ◽

Time Control

The 2-tank intermittent aeration method is an anaerobic-aerobic activated sludge process of time-sharing type in which 2 complete mixing reaction tanks are connected in series, and aeration and agitation are periodically repeated in each tank. We have developed a new control system for the process which can secure anaerobic, anoxic and aerobic conditions through a combination of DO and ORP-Bending-point (corresponding to termination of denitrification) emergence time control. In the 1st tank, nitrification and phosphorus uptake occur in the aeration period, followed by denitrification and phosphorus release in the agitation. The 2nd tank performs nitrification and phosphorus uptake in the aeration and denitrification in the agitation. One cycle of aeration and agitation is approximately 2 hours. This control system was applied to the test plant (influent flow rate: 225 I/day) for two months under the conditions of HRT 16 hours and temperature 20 ±2 °C. We achieved stable and high removal ratios: TOC 94.9 %, T-N 89.4 %, and T-P 95.5 %. We also investigated the mechanisms of nitrogen and phosphorus removal and their material balance.

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Field investigations on reactive settling in an intermittent aeration sequencing batch reactor activated sludge process

Water Science & Technology ◽

10.2166/wst.2000.0021 ◽

2000 ◽

Vol 41 (1) ◽

pp. 127-135 ◽

Cited By ~ 5

Author(s):

A.A. Kazmi ◽

H. Furumai

Keyword(s):

Mass Transfer ◽

Activated Sludge ◽

Batch Reactor ◽

Phosphorus Release ◽

Activated Sludge Process ◽

Intermittent Aeration ◽

Mass Transfer Limitation ◽

Batch Tests ◽

Field Investigations ◽

Ph Decrease

The overall reactions during settling in an intermittent aeration SBR activated sludge process have been studied on a full scale. Several field investigations were conducted during settling in different seasons. Nitrate, MLSS, phosphate and TOC profiles were obtained at specified depths. Mass balances of nitrogen were made in order to evaluate the effect of different MLSS and seasonal conditions on nitrogen removal during settling. Total nitrogen reduction of more than 30% was achieved during settling by maintaining high MLSS in order of 3000 mg/L. Residual DO plays an important role in causing delay of denitrification for lower MLSS sludge concentration. Phosphorus release was observed in the bottom of the reactor and its occurrence was well coincident with the pH decrease. Denitrification rates and their temperature dependency were determined. Temperature coefficient θ was found to be 1.083 (valid in the range of 17–27°C). Mass transfer limitation during batch sludge settling was discussed. It was found out from batch tests with and without mixing, that denitrification rate was reduced by 40% under mass transfer limiting conditions.

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Development of 2-reactor intermittent-aeration activated sludge process for simultaneous removal of nitrogen and phosphorus

Water Science & Technology ◽

10.1016/0273-1223(96)00500-8 ◽

1996 ◽

Vol 34 (1-2) ◽

Cited By ~ 11

Keyword(s):

Activated Sludge ◽

Simultaneous Removal ◽

Activated Sludge Process ◽

Intermittent Aeration ◽

Nitrogen And Phosphorus

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Comparison of Aerobic and Anoxic-Aerobic Digestion of Waste Activated Sludge

Water Science & Technology ◽

10.2166/wst.1985.0068 ◽

1985 ◽

Vol 17 (8) ◽

pp. 1475-1478 ◽

Cited By ~ 6

Author(s):

A P. C. Warner ◽

G. A. Ekama ◽

G v. R. Marais

Keyword(s):

Experimental Data ◽

Activated Sludge ◽

Waste Activated Sludge ◽

Activated Sludge Process ◽

Cycle Times ◽

Waste Sludge ◽

Volatile Solids ◽

In Series ◽

Flow Through ◽

Theoretical Simulations

The laboratory scale experimental investigation comprised a 6 day sludge age activated sludge process, the waste sludge of which was fed to a number of digesters operated as follows: single reactor flow through digesters at 4 or 6 days sludge age, under aerobic and anoxic-aerobic conditions (with 1,5 and 4 h cycle times) and 3-in-series flow through aerobic digesters each at 4 days sludge age; all digesters were fed draw-and-fill wise once per day. The general kinetic model for the aerobic activated sludge process set out by Dold et al., (1980) and extended to the anoxic-aerobic process by van Haandel et al., (1981) simulated accurately all the experimental data (Figs 1 to 4) without the need for adjusting the kinetic constants. Both theoretical simulations and experimental data indicate that (i) the rate of volatile solids destruction is not affected by the incorporation of anoxic cycles and (ii) the specific denitrification rate is independent of sludge age and is K4T = 0,046(l,029)(T-20) mgNO3-N/(mg active VSS. d) i.e. about 2/3 of that in the secondary anoxic of the single sludge activated sludge stystem. An important consequence of (i) and (ii) above is that denitrification can be integrated easily in the steady state digester model of Marais and Ekama (1976) and used for design (Warner et al., 1983).

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High rate and compact single sludge pre-denitrification process for retrofit

Water Science & Technology ◽

10.2166/wst.1994.0250 ◽

1994 ◽

Vol 30 (6) ◽

pp. 31-40 ◽

Cited By ~ 11

Author(s):

Hiroyshi Emori ◽

Hiroki Nakamura ◽

Tatsuo Sumino ◽

Tadashi Takeshima ◽

Katsuzo Motegi ◽

...

Keyword(s):

Activated Sludge ◽

Sewage Treatment ◽

Treatment Plant ◽

High Rate ◽

Activated Sludge Process ◽

Nitrogen And Phosphorus ◽

Conventional Activated Sludge ◽

Treatment Techniques ◽

Conventional Activated Sludge Process ◽

Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

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Nitrogen and Phosphorus Removal by Activated Sludge Process: A Review

Mini-Reviews in Organic Chemistry ◽

10.2174/1570193x14666161130151411 ◽

2017 ◽

Vol 14 (2) ◽

pp. 99-106 ◽

Cited By ~ 6

Author(s):

Zhengan Zhang ◽

Shulin Pan ◽

Fei Huang ◽

Xiang Li ◽

Juanfang Shang ◽

...

Keyword(s):

Activated Sludge ◽

Phosphorus Removal ◽

Activated Sludge Process ◽

Nitrogen And Phosphorus ◽

Nitrogen And Phosphorus Removal

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Start-Up of A2/O Humic Activated Sludge Systemphosphorus Removal Efficiency Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.2201 ◽

2010 ◽

Vol 113-116 ◽

pp. 2201-2207 ◽

Cited By ~ 2

Author(s):

Jun Yin ◽

Lei Wu ◽

Ke Zhao ◽

Yu Juan Yu

Keyword(s):

Activated Sludge ◽

Removal Efficiency ◽

Phosphorus Removal ◽

Removal Rate ◽

Phosphorus Uptake ◽

Phosphorus Release ◽

Activated Sludge System ◽

Start Up ◽

Article Analysis ◽

Sludge Activity

In this article, analysis the start-up of A2/O humic activated sludge system phosphorus removal efficiency and the characteristics of anaerobic phosphorus release, aerobic phosphorus uptake, sludge activity and their change in the Series Technologies process. The results show that A2/O humic activated sludge system phosphorus removal rate stabilized at 90.7% ~ 97.6%. Sludge activity except for anoxic zone 2 increased, along the process showed a gradual decrease trend.

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Advanced Treatment of Domestic Wastewater Using Sequencing Batch Reactor Activated Sludge Process

Water Science & Technology ◽

10.2166/wst.1993.0243 ◽

1993 ◽

Vol 28 (10) ◽

pp. 267-274 ◽

Cited By ~ 6

Author(s):

M. Imura ◽

E. Suzuki ◽

T. Kitao ◽

S. Iwai

Keyword(s):

Activated Sludge ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Domestic Wastewater ◽

Experimental Period ◽

Small Scale ◽

Experimental Plant ◽

Activated Sludge Process ◽

Nitrogen And Phosphorus ◽

Experimental Apparatus

In order to apply a sequencing batch reactor activated sludge process to small scale treatment facilities, various experiments were conducted by manufacturing an experimental apparatus made of a factory-produced FRP cylinder transverse tank (Ø 2,500mm). Results of the verification test conducted for one year by leading the wastewater discharged from apartment houses into the experimental apparatus were as follows. Excellent performance was achieved without any addition of carbon source, irrespective of the organic compound concentration and the temperature of raw wastewater. Organic substances, nitrogen and phosphorus were removed simultaneously. Due to the automated operation format, stable performance was obtained with only periodic maintenance. Though water depth of the experimental plant was shallow, effective sedimentation of activated sludge was continued during the experimental period. Regarding the aerobic and anaerobic process, nitrification and denitrification occurred smoothly.

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