Improving the predictions of ASM2d through modelling in practice

2002 ◽  
Vol 45 (6) ◽  
pp. 199-208 ◽  
Author(s):  
L. Larrea ◽  
I. Irizar ◽  
M.E. Hildago
Keyword(s):  
Phosphorus Uptake ◽  
Pilot Scale ◽  
Phosphorus Release ◽  
Reduction Factor ◽  
Experimental Results ◽  
High Rate ◽  
Predictive Capacity ◽  
Kinetic Coefficients ◽  
Autotrophic Biomass ◽  
Rate Processes

The paper presents the adjustments carried out on the structure and in some default values of the kinetic coefficients of the ASM2d model in order to get an improved prediction for the experimental results obtained in pilot scale plants studies with different activated sludge treatment processes for carbon, nitrogen and phosphorous removal. In order to predict the high effluent filtered COD experimentally observed in high rate processes for carbon removal, a new model structure has been proposed, incorporating into the carbon model a soluble fraction of the slowly biodegradable substrate. Studies with the step feed and the alternating processes showed simultaneous nitrification-denitrification in aerated reactors which was predicted with increased values in the oxygen saturation coefficients for heterotrophic and autotrophic biomass. Both processes also showed loss of the denitrification capacity under unfavourable conditions, such us rains and low anoxic fraction, which required a very large decrease in the value of the reduction factor for denitrification so as to improve the predictions for effluent nitrate experimental results. Regarding phosphorus removal, the ASM2d model showed a satisfactory predictive capacity. For improved predictions of phosphorus release in anaerobic conditions, high values of the rate constant for storage of XPHA and low values of the anaerobic hydrolysis reduction factor were used. For phosphorus uptake in aerobic and anoxic conditions satisfactory predictions were obtained using the default values.

Water environment conservation in a closed water body by high concentrated oxygen water

2008 ◽  
Vol 58 (12) ◽  
pp. 2313-2318 ◽  
Author(s):  
Tsuyoshi Imai ◽  
Ramida Watanapokasin ◽  
Alissara Reungsang ◽  
Masahiko Sekine ◽  
Takaya Higuchi
Keyword(s):  
Bottom Sediment ◽  
High Efficiency ◽  
Water Environment ◽  
Pilot Scale ◽  
Phosphorus Release ◽  
High Rate ◽  
Effective Prevention ◽  
Closed Water ◽  
Scale Experiment ◽  
Set Up

In this study, the method of using high concentrated oxygen water to purify the bottom sediment was confirmed to be effective. The high concentrated oxygen dissolver was developed and the lab scale experiment was performed. High rate, high efficiency oxygen dissolver was developed, the optimum running condition of the apparatus and the method of producing high concentrated oxygen water was discussed and determined in this study. In addition, the effective prevention of phosphorus release from anaerobic bottom sediment was also studied. As a result, it is found that high concentrated oxygen water was effective for prevention of phosphorus release from anaerobic bottom sediment. On the basis of the fundamental knowledge from the laboratory-scale study, pilot scale apparatus was set up and the pilot study was carried out. It is showed that the introduction of high concentrated oxygen water did not destroy the thermocline of dam reservoir.

Evaluation of phosphorus removal in anaerobic-anoxic-aerobic system - via polyhydroxyalkonoates measurements

1998 ◽  
Vol 38 (1) ◽  
pp. 107-114 ◽  
Author(s):  
S. H. Chuang ◽  
C. F. Ouyang ◽  
H. C. Yuang ◽  
S. J. You
Keyword(s):  
Uptake Rate ◽  
Phosphorus Removal ◽  
Loading Condition ◽  
Phosphorus Uptake ◽  
Pilot Scale ◽  
Phosphorus Release ◽  
Biological Phosphorus Removal ◽  
Organic Loading ◽  
High Concentration ◽  
Aerobic Process

Accumulating and utilizing PHAs (polyhydroxyalkanoates), i.e. a major carbon reserve of polyphosphate accumulating organisms (PAOs), is a prerequisite for phosphorus removal in an enhanced biological phosphorus removal (EBPR) system. To evaluate phosphorus removal, this study investigates the behavior of PHAs in a hybrid anaerobic-anoxic-aerobic process, operating under various sludge retention times (5, 10, 12 and 15 days) and dissolved oxygen conditions (0.5, 1.0 and 2.0 mg/l in aerobic stage). PHAs and phosphorus measurements in the pilot-scale experiments demonstrate that the PHAs content of sludge closely relates to phosphorus release and uptake behavios under anaerobic and aerobic conditions, respectively. The aerobic specific-phosphorus-uptake-rate is directly proportional to PHAs content of sludge in the anoxic stage. When the process is under a high organic loading condition, the sludge exhibits a large amount of PHAs having accumulated in the anoxic stage and a high phosphorus uptake rate in the subsequent aerobic stage. However, experimental results confirm that anoxic phosphorus release, leading to a high concentration of phosphorus flow into the aerobic stage, causes deficient phosphorus removal under a high organic loading condition. Moreover, a low PHAs content of sludge causes incomplete phosphorus removal; the phenomenon occurs when the process is under a low organic loading condition. Based on the results presented herein, we can conclude that the organic loading should be carefully controlled for phosphorus removal in the anaerobic-anoxic-aerobic process.

Modeling and Simulation of Pollutants Removal in the Modified Oxidation Ditch

2013 ◽  
Vol 777 ◽  
pp. 201-205
Author(s):  
Fan Kai Su ◽  
Jing Jie Yu ◽  
Li Ping Sun ◽  
Shao Po Wang ◽  
Jian Feng Zheng
Keyword(s):  
Modeling And Simulation ◽  
Kinetic Models ◽  
Phosphorus Uptake ◽  
Reaction Rates ◽  
Phosphorus Release ◽  
Cod Removal ◽  
Experimental Results ◽  
Oxidation Ditch ◽  
Anaerobic Zone ◽  
Pollutants Removal

The kinetic models of COD removal and phosphorus release in anaerobic zone, and phosphorus uptake, nitrification, denitrification and COD removal in circulating corridors were established in this work, in order to provide the guidance on design and running of the modified oxidation ditch. At the same time, the coefficients of reaction rates were calculated. Using the kinetic models already been established and the coefficients already been calculated to simulate the experimental results, the results showed that the models can well simulate the removal effect of pollutants in the modified oxidation ditch.

Viability of nematode eggs in high rate algal ponds: the effect of physico-chemical conditions

2000 ◽  
Vol 42 (10-11) ◽  
pp. 371-374 ◽  
Author(s):  
S. Araki ◽  
J. M. González ◽  
E. de Luis ◽  
E. Bécares
Keyword(s):  
Hydraulic Retention Time ◽  
Pilot Scale ◽  
High Rate ◽  
Sterile Water ◽  
Egg Viability ◽  
High Rate Algal Ponds ◽  
Helminth Eggs ◽  
Physico Chemical ◽  
Nematode Eggs ◽  
Chemical Conditions

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

On-site and in situ bioremediation of wood-preservative contaminated groundwater

2000 ◽  
Vol 42 (5-6) ◽  
pp. 371-376 ◽  
Author(s):  
J.A. Puhakka ◽  
K.T. Järvinen ◽  
J.H. Langwaldt ◽  
E.S. Melin ◽  
M.K. Männistö ◽  
...  
Keyword(s):  
Iron Oxidation ◽  
Wood Preservative ◽  
Pilot Scale ◽  
High Rate ◽  
Contaminated Groundwater ◽  
Groundwater Temperature ◽  
In Situ Bioremediation ◽  
Contaminated Aquifer ◽  
Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

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.

Tilapia rearing with high rate algal pond effluent: ammonia surface loading rates and stocking densities effects

2018 ◽  
Vol 78 (1) ◽  
pp. 49-56
Author(s):  
I. A. Sánchez ◽  
R. K. X. Bastos ◽  
E. A. T. Lana
Keyword(s):  
Weight Gain ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonia Nitrogen ◽  
High Rate ◽  
Surface Loading ◽  
Loading Rates ◽  
Total Weight Gain ◽  
Low Weight ◽  
Total Ammonia

Abstract In two pilot-scale experiments, fingerlings and juvenile of tilapia were reared in high rate algal pond (HRAP) effluent. The combination of three different total ammonia nitrogen (TAN) surface loading rates (SLR1 = 0.6, SLR2 = 1.2; SLR3 = 2.4 kg TAN·ha−1·d−1) and two fish stocking densities (D1 = 4 and D2 = 8 fish per tank) was evaluated during two 12-week experiments. Fingerlings total weight gain varied from 4.9 to 18.9 g, with the highest value (equivalent to 0.225 g·d−1) being recorded in SLR2-D1 treatment; however, high mortality (up to 67%) was recorded, probably due to sensitivity to ammonia and wide daily temperature variations. At lower water temperatures, juvenile tilapia showed no mortality, but very low weight gain. The fish rearing tanks worked as wastewater polishing units, adding the following approximate average removal figures on top of those achieved at the HRAP: 63% of total Kjeldahl nitrogen; 54% of ammonia nitrogen; 42% of total phosphorus; 37% of chemical oxygen demand; 1.1 log units of Escherichia coli.

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

1993 ◽  
Vol 28 (11-12) ◽  
pp. 513-521 ◽  
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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