Model-based evaluation of struvite recovery from an in-line stripper in a BNR process (BCFS)

2006 ◽  
Vol 53 (3) ◽  
pp. 191-198 ◽  
Author(s):  
X.-D. Hao ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Nutrient Removal ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Carbon Oxidation ◽  
P Efficiency ◽  
Effluent Quality ◽  
P Recovery ◽  
Struvite Precipitation ◽  
Removal And Recovery ◽  
P Removal

Phosphate removal and recovery can be combined in BNR processes. This may be realised by struvite precipitation from the supernatant of the sludge in anaerobic compartments. This can be beneficial for either improving bio-P removal effluent quality or lowering the influent COD/P ratio required for bio-P removal. For this reason, a patented BNR process, BCFS®, was developed and applied in The Netherlands. Several questions relating to P-recovery and behaviour of the system remain unclear and need to be ascertained. For this purpose, a modelling technique was employed in this study. With the help of a previous developed model describing carbon oxidation and nutrient removal, three cases were fully simulated. The simulations demonstrated that there was an optimal stripping flow rate and P-recovery would increase in costs and bio-P activity might be negatively affected due to decreased bio-P efficiency if this value was exceeded. The simulations indicated that the minimal CODbiod/P ratio required for the effluent standard (1 g P/m3) could be lowered from 20 to 10 with 36% of P-recovery. A simulation with dynamic inflow revealed that the dynamic influent loads affected slightly the anaerobic supernatant phosphate concentration but the effluent phosphate concentration would not be affected with regular P-recovery.

Phosphate Removal and Recovery with Seed Crystals in Low Concentrated Phosphate Wastewater

2011 ◽  
Vol 374-377 ◽  
pp. 865-868 ◽  
Author(s):  
Li Ping Qiu ◽  
Guang Wei Wang ◽  
Shou Bin Zhang ◽  
Tao Yu
Keyword(s):  
Reaction Time ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Xrd Analysis ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Reaction Conditions ◽  
Seed Crystals ◽  
Furnace Slag ◽  
Removal And Recovery

The phosphate removal and recovery from lower concentrated phosphate wastewater with the quartz sand, ceramsite, blast furnace slag and steel slag as seed crystals were investigated. The results showed that the steel slag performed a better phosphate removal performance than the other threes. The phosphate crystallization occurred under the reaction conditions of Ca/P 2.0, pH 9.0, phosphate concentration 10 mg/L and reaction time 12h. The steel slag could be employed as an effective seed crystal, of which the phosphate concentration decreased drastically in 12h and almost had been removed completely in 48h. The XRD analysis showed that the main crystallization products were hydroxyapatite (HAP) and the crystallinity increased with the reaction time.

Considerations in the Process Design of Nutrient Removal Activated Sludge Processes

1983 ◽  
Vol 15 (3-4) ◽  
pp. 283-318 ◽  
Author(s):  
G A Ekama ◽  
I P Siebritz ◽  
G V R Marais
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Concentration Ratio ◽  
Oxygen Demand ◽  
Biological Nutrient Removal ◽  
Nitrogen And Phosphorus ◽  
Effluent Quality ◽  
Biological Nitrogen ◽  
Activated Sludge Processes ◽  
P Removal

The average influent wastewater characteristics - (i) the COD concentration, (ii) the TKN/COD concentration ratio, (iii) the rapidly biodegradable COD concentration, (iv) the maximum specific growth rate of the nitrifiers at 20°C attainable in the wastewater, (v) the maximum and minimum temperatures, and (vi) the P/COD concentration ratio - are shown to govern the design of, and effluent quality from single sludge activated sludge processes for both biological nitrogen and phosphorus removal. The TKN/COD ratio governs the selection of the process type: For the Phoredox process, complete denitrification is essential to obtain excess P removal, and this is shown to be feasible only for TKN/COD ratios less than 0,07 to 0,08 mgN/mgCOD; as the TKN/COD ratio increases above 0,08, complete denitrification becomes increasingly unlikely, and the UCT or Modified UCT processes are appropriate because in these processes complete denitrification is not essential to achieve excess P removal - in these processes N and P removal can be traded off against each other depending on the critical nutrient to be removed. Primary sedimentation significantly reduces the biological nutrient removal potential of activated sludge process because it increases the TKN/COD and P/COD ratios and reduces the COD load; however it significantly reduces the process volume and total oxygen demand.

Enhancing bio-P removal by phosphate recovery from anaerobic supernatant

2006 ◽  
Vol 6 (6) ◽  
pp. 11-18
Author(s):  
X.-D. Hao ◽  
J. Dai ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Ph Value ◽  
Phosphate Removal ◽  
Biological Nutrient Removal ◽  
Effluent Quality ◽  
Phosphate Recovery ◽  
Previous Modeling Study ◽  
Modeling Prediction ◽  
Minor Form ◽  
A Minor ◽  
P Removal

A previous modeling study predicted that phosphate removal and recovery could be combined in biological nutrient removal (BNR) processes, which would be beneficial for either improving bio-P removal effluent quality or lowering the influent COD/P ratio required for bio-P removal. To confirm the modeling prediction, an experiment with a traditional A2/O process was initiated. The experimental results were qualitatively in agreement with the modeling prediction. The minimal COD/P ratio required for the effluent standard (1 mg P/L) could be lowered from 35 to 25 with a stripping ratio of 20% at a phosphate recovery efficiency of 34%, which means a COD saving of 25–30% in bio-P removal. A practical experiment for phosphate recovery in a WWTP identified that HAP was a major form of precipitated compounds and that MAP was a minor form. Due to the higher contents of Ca2 +  and Mg2 +  in the influent to the WWTP (with groundwater mainly used for portable water), it was unnecessary to dose any extra chemicals for phosphate precipitation, and a pH value increased to ≥9 in the supernatant was all to be done.

A Promising Combination of Two Phosphate Removal Techniques: Biological P-Removal and the Crystalactor

1991 ◽  
Vol 24 (10) ◽  
pp. 329-332
Author(s):  
P. M. J. Janssen ◽  
J. H. Rensink ◽  
E. Eggers
Keyword(s):  
Phosphate Removal ◽  
P Removal

Experiences with sludge settleability in different process alternatives for nutrient removal

1996 ◽  
Vol 33 (12) ◽  
pp. 137-146 ◽  
Author(s):  
Kjær Andreasen ◽  
Lars Sigvardsen
Keyword(s):  
Nutrient Removal ◽  
Plant Layout ◽  
Filamentous Microorganisms ◽  
Positive Effect ◽  
Sludge Settleability ◽  
Settling Characteristics ◽  
P Removal

SVI and DSVI were measured three times at almost 100 Danish nutrient removal plants and the filamentous microorganisms were subsequently characterized in the laboratory. Information about the plant layout and the operation was collected by means of a questionnaire. In general, the sludge settleability index becomes worse by the introduction of nutrient removal. Among nutrient removal plants the best settling characteristics are found among plants with biological P removal and the poorest among the plants that perform simultaneous denitrification. When compared to iron products, aluminium products in some cases seem to reduce the filament number and improve the settling characteristics in plants that apply simultaneous precipitation for P removal. Selectors may have a positive effect on the filament number but the effect may not be enough to prevent bulking.

Survey of filamentous populations in nutrient removal plants in four European countries

1998 ◽  
Vol 37 (4-5) ◽  
pp. 281-289 ◽  
Author(s):  
Dick H. Eikelboom ◽  
Andreas Andreadakis ◽  
Kjaer Andreasen
Keyword(s):  
Nutrient Removal ◽  
Seasonal Pattern ◽  
Plug Flow ◽  
Phosphate Removal ◽  
Particulate Fraction ◽  
Biological Nutrient Removal ◽  
Process Conditions ◽  
Minor Importance ◽  
Filamentous Microorganisms ◽  
Short Period

A joint EU research project aimed at solving activated sludge bulking in nutrient removal plants was initiated in 1993. The project started with a survey of the size and composition of the filamentous population in nutrient removal plants in Denmark, Germany, Greece and the Netherlands. The results show that biological nutrient removal process conditions indeed favour filamentous microorganisms in their competition with floc forming organisms. An increase in the size of the filamentous population resulted in a deterioration of the settling properties of the biomass, except for plants with Bio-P removal conditions. It is assumed that in the latter case the dense clusters of Bio-P bacteria increase the weight of the flocs, and compensate for the effect of the larger number of filaments. Although exceptions frequently occur, the following sequence in decreasing filamentous organism population size was observed for the process conditions indicated: - completely mixed + simultaneous denitrification; - completely mixed + intermittent aeration/denitrification; - alternating anoxic/oxic process conditions, with an anaerobic tank for biological phosphate removal (Bio-Denipho); - alternating anoxic/oxic process conditions (Bio-Denitro); - predenitrification The surveys provided little information about the effect of nutrient removal in plants with plug flow aeration basins. Simultaneous precipitation with aluminium salts nearly always resulted in a low number of filaments and a good settling sludge. The size of the filamentous organism population showed a seasonal pattern with a maximum in winter/early spring and a minimum during summer (in Greece: during autumn). This seasonal variation is primarily caused by the effect of the season on the population sizes of M. parvicella, N. limicola and Type 0092. M. parvicella is by far the most important filamentous species in nutrient removal plants. In Denmark only, Type 0041 also frequently dominates the filamentous population, but seldom causes severe bulking. Considering their frequency of occurrence, approx. 10 other filamentous micro-organisms are of minor importance. Growth of some of these species, viz. those which use soluble substrate, can be prevented by the introduction of Bio-P process conditions. M. parvicella and Type 0041 (and probably also Actinomycetes and the Types 1851 and 0092) seem to compete for the same substrates i.e. the influent particulate fraction. Most of the differences in composition of the filamentous microorganism population can be explained by whether or not premixing of influent and recycled sludge is used. In general, premixing for a short period of time followed by anoxic conditions favours Type 0041. M. parvicella seems to proliferate if the particulate fraction is first hydrolysed or if it enters the plant via an oxic zone. It is concluded that bulking in nutrient removal plants is mainly caused by filamentous species requiring the particulate fraction for their growth.

Effect of addition of anaerobic fermented OFMSW (organic fraction of municipal solid waste) on biological nutrient removal (BNR) process: preliminary results

1998 ◽  
Vol 38 (1) ◽  
pp. 327-334 ◽  
Author(s):  
P. Pavan ◽  
P. Battistoni ◽  
P. Traverso ◽  
A. Musacco ◽  
F. Cecchi
Keyword(s):  
Nutrient Removal ◽  
Fermentation Process ◽  
Organic Waste ◽  
Anaerobic Fermentation ◽  
Pilot Scale ◽  
Biological Nutrient Removal ◽  
Organic Fraction ◽  
P Release ◽  
Pure Methanol ◽  
P Removal

The paper presents results coming from experiments on pilot scale plants about the possibility to integrate the organic waste and wastewater treatment cycles, using the light organic fraction produced via anaerobic fermentation of OFMSW as RBCOD source for BNR processes. The effluent from the anaerobic fermentation process, with an average content of 20 g/l of VFA+ lactic acid was added to wastewater to be treated in order to increase RBCOD content of about 60-70 mg/l. The results obtained in the BNR process through the addition of the effluent from the fermentation unit are presented. Significant increase of denitrification rate was obtained: 0.06 KgN-NO3/KgVSS d were denitrified in the best operative conditions studied. -Vmax shows values close to those typical of the pure methanol addition (about 0.3 KgN-NO3/KgVSS d). A considerable P release (35%) was observed in the anaerobic step of the BNR process, even if not yet a completely developed P removal process.

scholarly journals Phosphate Removal Using Polyethylenimine Functionalized Silica-Based Materials

2021 ◽  
Vol 13 (3) ◽  
pp. 1502
Author(s):  
Maria Xanthopoulou ◽  
Dimitrios Giliopoulos ◽  
Nikolaos Tzollas ◽  
Konstantinos S. Triantafyllidis ◽  
Margaritis Kostoglou ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Removal Rate ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Equilibrium Studies ◽  
Maximum Sorption Capacity ◽  
Algae Blooms ◽  
Maximum Sorption ◽  
Phosphate Anions ◽  
Adsorbent Dose

In water and wastewater, phosphate anions are considered critical contaminants because they cause algae blooms and eutrophication. The present work aims at studying the removal of phosphate anions from aqueous solutions using silica particles functionalized with polyethylenimine. The parameters affecting the adsorption process such as pH, initial concentration, adsorbent dose, and the presence of competitive anions, such as carbonate, nitrate, sulfate and chromate ions, were studied. Equilibrium studies were carried out to determine their sorption capacity and the rate of phosphate ions uptake. The adsorption isotherm data fitted well with the Langmuir and Sips model. The maximum sorption capacity was 41.1 mg/g at pH 5, which decreased slightly at pH 7. The efficiency of phosphate removal adsorption increased at lower pH values and by increasing the adsorbent dose. The maximum phosphate removal was 80% for pH 5 and decreased to 75% for pH 6, to 73% for pH 7 and to 70% for pH 8, for initial phosphate concentration at about 1 mg/L and for a dose of adsorbent 100 mg/L. The removal rate was increased with the increase of the adsorbent dose. For example, for initial phosphate concentration of 4 mg/L the removal rate increased from 40% to 80% by increasing the dose from 0.1 to 2.0 g/L at pH 7. The competitive anions adversely affected phosphate removal. Though they were also found to be removed to a certain extent. Their co-removal provided an adsorbent which might be very useful for treating waters with low-level multiple contaminant occurrence in natural or engineered aquatic systems.

scholarly journals Modification and Validation of the Phosphate Removal Model: A Multicenter Study

2021 ◽  
pp. 1-10
Author(s):  
Weichen Zhang ◽  
Qiuna Du ◽  
Jing Xiao ◽  
Zhaori Bi ◽  
Chen Yu ◽  
...  
Keyword(s):  
Polynomial Regression ◽  
External Validation ◽  
Original Model ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Internal Validation ◽  
Modified Model ◽  
New Model ◽  
Significant Difference ◽  
Removal Model

<b><i>Background:</i></b> Our research group has previously reported a noninvasive model that estimates phosphate removal within a 4-h hemodialysis (HD) treatment. The aim of this study was to modify the original model and validate the accuracy of the new model of phosphate removal for HD and hemodiafiltration (HDF) treatment. <b><i>Methods:</i></b> A total of 109 HD patients from 3 HD centers were enrolled. The actual phosphate removal amount was calculated using the area under the dialysate phosphate concentration time curve. Model modification was executed using second-order multivariable polynomial regression analysis to obtain a new parameter for dialyzer phosphate clearance. Bias, precision, and accuracy were measured in the internal and external validation to determine the performance of the modified model. <b><i>Results:</i></b> Mean age of the enrolled patients was 63 ± 12 years, and 67 (61.5%) were male. Phosphate removal was 19.06 ± 8.12 mmol and 17.38 ± 6.75 mmol in 4-h HD and HDF treatments, respectively, with no significant difference. The modified phosphate removal model was expressed as Tpo<sub>4</sub> = 80.3 × <i>C</i><sub>45</sub> − 0.024 × age + 0.07 × weight + β × clearance − 8.14 (β = 6.231 × 10<sup>−3</sup> × clearance − 1.886 × 10<sup>−5</sup> × clearance<sup>2</sup> – 0.467), where <i>C</i><sub>45</sub> was the phosphate concentration in the spent dialysate measured at the 45th minute of HD and clearance was the phosphate clearance of the dialyzer. Internal validation indicated that the new model was superior to the original model with a significantly smaller bias and higher accuracy. External validation showed that <i>R</i><sup>2</sup>, bias, and accuracy were not significantly different than those of internal validation. <b><i>Conclusions:</i></b> A new model was generated to quantify phosphate removal by 4-h HD and HDF with a dialyzer surface area of 1.3–1.8 m<sup>2</sup>. This modified model would contribute to the evaluation of phosphate balance and individualized therapy of hyperphosphatemia.

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