Treatment of a milkpowder/butter wastewater using the AAO activated sludge configuration

1997 ◽  
Vol 36 (10) ◽  
pp. 79-86 ◽  
Author(s):  
Michael J. Donkin ◽  
John M. Russell
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Synthetic Wastewater ◽  
Biological Nutrient Removal ◽  
In Series ◽  
Aerobic Reactor ◽  
Original Size

A laboratory-scale nutrient removal activated sludge system, based on the AAO configuration, was used to treat a synthetic wastewater from a milkpowder/butter factory. In this system, substrate is fed to anaerobic and anoxic selectors in series with an aerobic reactor. Sludge is returned to the anaerobic selector, and mixed liquor from the aerobic reactor is recycled to the anoxic selector. The overall system is operated at an HRT of 7 days and a nominal sludge age of 20 days. This system was prone to prolonged bulking periods, with filamentous bacteria Sphaerotilus natans, Type 0411 and Haliscomenobacter hydrossis being identified in the mixed liquors, although effective clarifier operation prevented loss of suspended solids. Theory suggests that selectors may be used to circumvent low F:M bulking, and to bring about enhanced biological nutrient removal. An investigation of the initial design revealed that relatively high nitrite levels were present in the system, and a larger anoxic selector with an HRT of 820 minutes was substituted for the original one with an HRT of 48 minutes. This resulted in a decrease in nitrite and a equivalent increase in nitrate in the system. Overall nitrogen removal remained unchanged at 66%, and SVI levels did not improve. On resetting the anoxic selector to its original size, the effect was not reversed. Phosphorus removal efficiency was detrimentally affected by the anoxic sizing experiment (49% to 20%), and this may be linked to the raised level of nitrate in the system. COD removal efficiency remained excellent throughout the trial at over 90% removal.

Practical Experience with Biological Phosphorus Removal Plants in Johannesburg

1983 ◽  
Vol 15 (3-4) ◽  
pp. 233-259 ◽  
Author(s):  
A R Pitman ◽  
S L V Venter ◽  
H A Nicholls
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Operating Experience ◽  
Practical Experience ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Factors Affecting ◽  
Process Improvements ◽  
Biological Phosphorus

This paper describes three years operating experience with two full-scale biological nutrient removal activated sludge plants. Factors affecting biological phosphorus removal are highlighted and possible process improvements suggested.

Influence of wastewater composition on biological nutrient removal in UniFed SBR process

2008 ◽  
Vol 58 (4) ◽  
pp. 803-810 ◽  
Author(s):  
C. H. Zhao ◽  
Y. Z. Peng ◽  
S. Y. Wang ◽  
X. G. Tang
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Domestic Wastewater ◽  
Biological Nutrient Removal ◽  
Detection Level ◽  
Maximum Value

The effects of influent C/N ratio and C/P ratio on biological nutrient removal performance were investigated in a lab-scale UniFed SBR apparatus treating real domestic wastewater. The results showed that TN removal efficiency increased as C/N ratio increased from 43.6% at 2.8 to 80.8% at 5.7. But when C/N ratio increased further, TN removal efficiency increased very slowly. This was because when C/N ratio was higher than 5.7, complete denitrification in the sludge blanket during feed/decant period had been achieved, TN removal efficiency during this period always kept the maximum value and only TN removal efficiency during aeration period rose as C/N ratio increased. PO43− removal efficiency increased as C/N ratio increased from 27.3% at 2.8 to 88.1% at 5.7. When C/N ratio was 6.5 and above, PO43− concentration couldn't be detected in the effluent. When influent C/N ratio and volumetric exchange ratio were fixed at 6 and 33% respectively, as C/P ratio was higher than 33, PO43− concentration of effluent always remained below the detection level and phosphorus removal efficiency kept stable at 100%, but as the C/P ratio was lower than 33, phosphorus removal efficiency increased as C/P ratio increased linearly. C/P ratio hardly affected TN removal efficiency, which always kept at 82.2%–85.8% in this study.

scholarly journals Simultaneous Biological Nutrient Removal from Municipal Wastewater and CO2-biofixation using Chlorella kessleri

2020 ◽  
Author(s):  
Mohammed Omar Faruque ◽  
Kazeem Ayodeji Mohammed ◽  
Mohammad Mozahar Hossain ◽  
Shaikh Abdur Razzak
Keyword(s):  
Removal Efficiency ◽  
Nutrient Removal ◽  
Municipal Wastewater ◽  
Biomass Concentration ◽  
Synthetic Wastewater ◽  
Biological Nutrient Removal ◽  
Fixation Rate ◽  
Chlorella Kessleri ◽  
Cultivation Period ◽  
Experimental Findings

Abstract Growing microalgae in tertiary wastewater offers a prospective avenue to remove and re-use the nutrients N and P simultaneously. Moreover, CO2 fixation via microalgae is a potential and promising approach of capturing and storing CO2. The impacts of various nitrogen to phosphorous ratios on the growth, nutrient removal from municipal wastewater, and the bio-fixation of CO2 using Chlorella kessleri were evaluated in this study. For this purpose, the microalgae was grown in synthetic wastewater, similar in composition to tertiary municipal wastewater, with NP ratios of 2:1, 4:1, 6:1, and 8:1 in batch photobioreactors for13 days. Biomass concentration increases at all NP ratios and the maximum biomass concentration is 606.79 mg/L at the NP ratio of 2:1. Nitrogen removal is more than 95% at all NP ratios except at 8:1, where it is only 72.4%. The removal efficiency of phosphorous is significantly affected by the NP ratio. The maximum phosphorous removal is about 97% for the NP ratio 6:1, whereas the lowest removal efficiency of about 20% is at the NP ratio of 2:1. The maximum CO2 bio-fixation rate of 89.36 mgL− 1d− 1 at the end of the first 7 days of the cultivation period is at the NP ratio of 6:1. In this study, Monod growth kinetic model based on a single substrate factor was used and the experimental findings agree well with the predictions by the model.

Sludge production and oxygen demand in nutrient removal activated sludge systems

1996 ◽  
Vol 34 (5-6) ◽  
pp. 43-50 ◽  
Author(s):  
P. S. Barker ◽  
P. L. Dold
Keyword(s):  
Oxygen Consumption ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Suspended Solids ◽  
Model Simulation ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Solids Concentration ◽  
Volatile Solids ◽  
Activated Sludge Systems

Results of model simulations indicate that without the assumption of COD loss, predictions of oxygen consumption and volatile suspended solids production are significantly over-estimated for biological excess phosphorus removal (BEPR) activated sludge systems (and to a lesser extent anoxic-aerobic systems). These systems apparently consume less oxygen and produce less volatile solids than aerobic systems for the same amount of COD removal. A general model for biological nutrient removal systems has recently been presented by Barker and Dold. Three mechanisms for COD loss are suggested, based on results of COD balances for different types of activated sludge system. Model simulation results with and without the assumption of COD loss are discussed, as well as the influence of influent COD composition on predictions of volatile suspended solids concentration/production and oxygen consumption.

Nutrient Removal Technology in North America and the European Union: A Review

2006 ◽  
Vol 41 (4) ◽  
pp. 449-462 ◽  
Author(s):  
Jan A. Oleszkiewicz ◽  
James L. Barnard
Keyword(s):  
European Union ◽  
North America ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
The European Union ◽  
The Impact

Abstract The European Union (EU) has implemented effluent (emission) standards since 1991, while North America practices a riskbased, imission approach. Progressing eutrophication and large fees for discharged loads push EU countries toward more stringent effluent concentrations, below total nitrogen (TN) levels of 10 mg/L and total phosphorus (TP) levels of 1 mg/L. In North America, the limit of treatment technology (LOT) concept has been defined as the lowest economically achievable effluent quality, which for TN is <1.5 to 3 mg/L and TP is <0.07 mg/L. These limits are becoming targets in fragile ecoregions in North America and drive the technology solutions towards a combination of advanced biological nutrient removal process trains, followed by chemical polishing and solids separation by granular or cloth filters or membranes. In Western Canada one-biomass biological nutrient removal processes are used, such as Westbank or Step-feed, often followed by filtration to achieve low effluent total phosphorus levels. Eastern Canada has a less stringent approach to nitrogen control and practices chemical phosphorus removal. Requirement for total nitrogen removal and rising costs of phosphorus precipitation drive designers towards advanced one-biomass processes and full utilization of carbon (for denitrification and phosphorus removal) available in raw wastewater and primary sludge. New processes are developed to take advantage of carbon available in waste activated sludge or even in the recycled activated sludge. Sludge treatment return streams have high nutrient loads and novel processes are introduced for their treatment, some utilizing generated nitrifier biomass for bio-augmentation of the main stream nitrification process. The impact of sludge processing on the liquid train and vice versa is now fully embedded in the design process.

Biological nutrient removal in membrane bioreactors: denitrification and phosphorus removal kinetics

2007 ◽  
Vol 56 (6) ◽  
pp. 125-134 ◽  
Author(s):  
V. Parco ◽  
G. du Toit ◽  
M. Wentzel ◽  
G. Ekama
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
Specific Rate ◽  
Mixed Liquor ◽  
Batch Tests ◽  
The Impact ◽  
Substrate Concentrations ◽  
P Removal

The impact of including membranes for solid liquid separation on the kinetics of nitrogen and phosphorus removal was investigated. To achieve this, a membrane bioreactor (MBR) biological nutrient removal (BNR) activated sludge system was operated. From batch tests on mixed liquor drawn from the MBR BNR system, denitrification and phosphorus removal rates were delineated. Additionally the influence of the high total suspended solids concentrations present in the MBR BNR system and of the limitation of substrate concentrations on the kinetics was investigated. Moreover the ability of activated sludge in this kind of system to denitrify under anoxic conditions with simultaneous phosphate uptake was verified and quantified. The denitrification rates obtained for different mixed liquor (ML) concentrations indicate no effect of ML concentration on the specific denitrification rate. The denitrification took place at a single specific rate (K2) with respect to the ordinary heterotrophic organisms (OHOs, i.e. non-PAOs) active mass. Similarly, results have been obtained for the P removal process kinetics: no differences in specific rates were observed for different ML or substrate concentrations. From the P removal batch tests results it seems that the biological phosphorus removal population (PAO) consists of 2 different sets of organisms denitrifying PAO and aerobic PAO.

Design Considerations for Nutrient Removal Activated Sludge Plants

1991 ◽  
Vol 23 (4-6) ◽  
pp. 781-790 ◽  
Author(s):  
A. R. Pitman
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Full Scale ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Anoxic Zone ◽  
Mixed Liquor ◽  
Design Considerations ◽  
Biological Phosphorus

Based on more than 10 years' experience with biological nutrient removal in Johannesburg, this paper highlights aspects which should be borne in mind in the design of such processes. Feed sewage quality and the question of treating raw or settled sewage are considered. More importantly, methods of rendering the feed more suitable for biological phosphorus removal are detailed. As nitrate feedback to the anaerobic zone can often mitigate against good phosphorus removal, methods of obviating this are covered. In this respect the need for, and placement of a second anoxic zone are discussed. Process type and configuration are covered as well as zone retention periods and the split of process volume into unaerated and aerated fractions. Aeration systems and the tailoring of aeration to process needs are also discussed. Two problems that have been experienced in many full-scale plants are bulking sludges and prolific growths of nuisance scums. Methods of minimising these problems are discussed. Finally, mixed liquor and return sludge recycles; aspects to be borne in mind in the design of final clarifiers and the provision of standby chemical addition are discussed.

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

2010 ◽  
Vol 113-116 ◽  
pp. 2201-2207 ◽  
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.

Improvment of nitrogen and phosphorus removal in the anaerobic-oxic-anoxic-OXIC (AOAO) process by stepwise feeding

2000 ◽  
Vol 42 (3-4) ◽  
pp. 89-94 ◽  
Author(s):  
H.Y. Chang ◽  
C.F. Ouyang
Keyword(s):  
Carbon Source ◽  
Phosphorus Removal ◽  
Removal Rate ◽  
Feeding Strategy ◽  
Synthetic Wastewater ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Kjeldahl Nitrogen ◽  
P Removal

This investigation incorporated a stepwise feeding strategy into the biological process containing anaerobic/oxide/anoxic/oxide (AOAO) stages to enhance nitrogen and phosphorus removal efficiencies. Synthetic wastewater was fed into the experimental reactors during the anaerobic and anoxic stages and the substrates/nutrients were successfully consumed without recycling either nitrified effluent or external carbon source. An intrinsic sufficient carbon source developed during the anoxic stage and caused the NOx (NO2-N+NO3-N) concentration to be reduced from 11.85mg/l to 5.65mg/l. The total Kjeldahl nitrogen (TKN) removal rate was between 81.81%∼93.96% and the PO4-P removal ratio ranged from 93%∼100%. The substrate fed into the anaerobic with a Q1 flow rate and a Q2 into the anoxic reactor. The three difference experiments contained within this study produced Q1/Q2 that varied from 7/3, 8/2, and 9/1. The AOAO process saved nearly one-third of the energy compared with typical biological nutrient removal (BNR) system A2O processes.

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