Conditions Influencing Struvite Precipitation from Anaerobic Sludge Digestion Filtrate in a Batch Reactor

2011 ◽  
Vol 183-185 ◽  
pp. 1432-1436
Author(s):  
Xiang Sheng Cao ◽  
Xue Zheng Meng ◽  
Yin Zhong Wang
Keyword(s):  
Reaction Time ◽  
Batch Reactor ◽  
Anaerobic Sludge ◽  
Precipitation Process ◽  
Operational Conditions ◽  
Sludge Digestion ◽  
Stirring Rate ◽  
Struvite Precipitation ◽  
Positive Effect ◽  
Sedimentation Time

Struvite precipitation in sludge dewatering filtrate was achieved in a lab-scale sequencing batch reactor. The influence of the operational conditions on the struvite precipitation process has been studied. These operational conditions include stirring rate of the reactor, reaction time and sedimentation time. Experiments indicated that stirring rate of the reactor within 50 rpm to 250 rpm had no strong influence on the formation of struvite. As reaction time increased, there was a slight positive effect on the removal of Mg2+, NH4+ and PO43-. Suggested reaction time is 40-80 minutes based on our experiments. In order to obtain the lower turbidity and the lower PO43- concentration in the decanting filtrate of the batch reactor, the minimum sedimentation time should be more than 30 minutes.

scholarly journals Simultaneous Nitrification and Denitrification in an SBR with a Modified Cycle During Reject Water Treatment

2013 ◽  
Vol 39 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Katarzyna Bernat
Keyword(s):  
Batch Reactor ◽  
Anaerobic Sludge ◽  
Simultaneous Nitrification And Denitrification ◽  
Low Oxygen ◽  
Total Removal ◽  
Operational Conditions ◽  
Reject Water ◽  
Do Concentration ◽  
Nitrification And Denitrification ◽  
Low Oxygen Concentration

Abstract In this study, the dependence between volumetric exchange rate (n) in an SBR (Sequencing Batch Reactor) with a modified cycle and simultaneous nitrification and denitrification (SND) efficiency during the treatment of anaerobic sludge digester supernatant was determined. In the SBR cycle alternating three aeration phases (with limited dissolved oxygen (DO) concentration up to 0.7 mg O2/L) and two mixing phases were applied. The lengths of each aeration and mixing phases were 4 and 5.5 h, respectively. Independently of n, a total removal of ammonium was achieved. However, at n = 0.1 d-1 and n = 0.3 d-1 nitrates were the main product of nitrification, while at n = 0.5 d-1, both nitrates and nitrites occurred in the effluent. Under these operational conditions, despite low COD/N (ca. 4) ratio in the influent, denitrification in activated sludge was observed. A higher denitrification efficiency at n = 0.5 d-1 (51.3%) than at n = 0.1 d-1 (7.8%) indicated that n was a crucial factor influencing SND via nitrite and nitrate in the SBR with a low oxygen concentration in aeration phases.

scholarly journals Nutrients Recovery from Dairy Wastewater by Struvite Precipitation Combined with Ammonium Sorption on Clinoptilolite

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5822
Author(s):  
Claver Numviyimana ◽  
Jolanta Warchoł ◽  
Bartosz Ligas ◽  
Katarzyna Chojnacka
Keyword(s):  
Environmental Impact ◽  
Sorption Capacity ◽  
Natural Zeolite ◽  
Dairy Wastewater ◽  
Ammonium Concentration ◽  
Precipitation Process ◽  
Struvite Precipitation ◽  
Complex Solutions ◽  
Ammonium Level ◽  
Positive Effect

Struvite precipitation from Wastewater involves an excess of ammonium to create a supersaturated initial solution. The remaining fraction can be a threat to the environment. This work combined struvite precipitation and ammonium sorption using natural zeolite to decrease the ammonium level in the effluent. Two approaches of estimation of feed sample doses were used. One consisted of gradient experiments for ammonium precipitation to the asymptotic level and was combined with clinoptilolite to lower the ammonium level in the effluent. This approach used doses of 0.05:1.51:0.61:1 of Ca:Mg:NH4+:PO43− mole ratios, respectively. In contrast, three level design with narrowed NH4+:PO43− range reached 0.25:1.51:0.8:1 for Ca:Mg:NH4+:PO43− mole ratios. The addition of zeolite decreased effluent ammonium concentration. In both ways, the P and N recoveries were higher than 94% and 72%, respectively. The complexity of the precipitation mixture decreased the ammonium sorption capacity (Qe) of clinoptilolite from Qe of 0.52 to 0.10 meq∙g−1 in single and complex solutions, respectively. Thermodynamically, the addition of 1.5 % of clinoptilolite changed the struvite precipitation spontaneity from ∆G of −5.87 to −5.42 kJ·mol−1 and from 9.66 to 9.56 kJ·mol−1 for gradient and three level experimental procedures, respectively. Thus, clinoptilolite demonstrated a positive effect on the struvite precipitation process and its environmental impact.

scholarly journals Modeling and optimization of the photocatalytic degradation of Tartrazine in aqueous solution

2021 ◽  
pp. 133-145
Author(s):  
Mirvet Assassi ◽  
Farid Madjene ◽  
Sara Harchouche ◽  
Hind Boulfiza
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Heterogeneous Photocatalysis ◽  
Active Species ◽  
Influential Factor ◽  
Solar Irradiation ◽  
Uv Lamp ◽  
Positive Effect

The application of heterogeneous photocatalysis process using ZnO photocatalyst for the degradation of Tartrazine (TRZ) dye in aqueous solution was investigated in a batch reactor. The estimation, the comparison of the parameter?s effects and the optimization of the removal yield of TRZ were realized by using Box-Behnken experimental design (BBD). The results suggested that the most influential factor on the photocatalytic degradation of the dye was the initial TZR concentration with an effect of (-23.24), the second in the order was the amount of the catalyst with an effect of (+18.09), the third was the reaction time with an effect of (+15.38) and the fourth was stirring speed with a positive effect of (+4.41). The model obtained by BBD led to the following optimal conditions for degradation yield of TRZ: initial concentration of TZR equal to 20.035 mg/L, reaction time equal to 88.635 min, 0.6409 mg/L of ZnO amount and 404.9 rpm for the stirring speed, which gave 98.576% of degradation efficiency. The study of irradiation type effect shows that a solar irradiation gave higher yield than photocatalysis by UV lamp. The O2?- radicals were the principal active species responsible of the degradation of TRZ. The BOD5/COD ratio increased from 0.26 to 0.41 after 60 minutes of photocatalysis under solar light, indicating the feasibility of coupling the photocatalysis process to biological treatment for the removal of TRZ.

scholarly journals Achieving Efficient and Stable Deammonification at LowTemperatures—Experimental and Modeling Studies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3961
Author(s):  
Hussein Al-Hazmi ◽  
Xi Lu ◽  
Dominika Grubba ◽  
Joanna Majtacz ◽  
Przemysław Kowal ◽  
...  
Keyword(s):  
Sequencing Batch Reactor ◽  
Energy Savings ◽  
Batch Reactor ◽  
Phase Changes ◽  
Intermittent Aeration ◽  
Short Term ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
The Mathematical Model ◽  
Positive Effect

The short-term effects of temperature on deammonification sludge were evaluated in a laboratory-scale sequencing batch reactor (SBR). Mathematical modeling was used for further evaluations of different intermittent aeration strategies for achieving high and stable deammonification performance at decreasing temperatures. As for the biomass cultivated at high temperatures (e.g., 30 °C), a higher temperature dependency (the adjusted Arrhenius coefficient θ for 11–17 °C = 1.71 vs. θ for 17–30 °C = 1.12) on the specific anammox growth rates was found at lower temperatures (11–17 °C) in comparison with higher temperatures (17–30 °C). Further evaluations of recovering the nitrogen removal efficiency at decreasing temperatures with the mathematical model by modifying the intermittent aeration strategies (aeration frequency (F) and the ratio (R) between non-aerated (non-aer) phase and aerated (aer) phase durations) indicated that intermittent aeration with a prolonged non-aerated phase (e.g., R ≥ 4 regardless of F value) would help to maintain high and stable deammonification performance (~80%) at decreasing temperatures (14–22 °C). Extending the non-aerated phases (increasing R) and reducing the frequency (F) of off/on phase changes have a positive effect on increasing energy savings, leading to increasing interest in this method.

scholarly journals Morphogenesis and evolution mechanisms of bacterially-induced struvite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tian-Lei Zhao ◽  
Han Li ◽  
Hao-Fan Jiang ◽  
Qi-Zhi Yao ◽  
Ying Huang ◽  
...  
Keyword(s):  
Time Course ◽  
Carboxyl Groups ◽  
Precipitation Process ◽  
Phosphate Content ◽  
Biomimetic Mineralization ◽  
Struvite Precipitation ◽  
Growth Habits ◽  
Two Stages ◽  
Relevant Work ◽  
Insight Into

AbstractBacteria are able to induce struvite precipitation, and modify struvite morphology, leading to the mineral with various growth habits. However, the relevant work involving the morphogenesis is limited, thereby obstructing our understanding of bacterially mediated struvite mineralization. Here, an actinomycete Microbacterium marinum sp. nov. H207 was chosen to study its effect on struvite morphology. A combination of bacterial mineralization and biomimetic mineralization techniques was adopted. The bacterial mineralization results showed that strain H207 could induce the formation of struvite with grouping structure (i.e., a small coffin-like crystal grown on a large trapezoid-like substrate crystal), and the overgrowth structure gradually disappeared, while the substrate crystal further evolved into coffin-like, and quadrangular tabular morphology with time. The biomimetic experiments with different organic components confirmed that the soluble macromolecules rich in electronegative carboxyl groups secreted by strain H207 dominate the formation of the struvite grouping. The time-course biomimetic experiments with supernatant testified that the increase in pH and NH4+ content promoted the evolution of crystal habits. Moreover, the evolution process of substrate crystal can be divided into two stages. At the first stage, the crystal grew along the crystallographic b axis. At the later stage, coupled dissolution–precipitation process occurred, and the crystals grew along the corners (i.e., [110] and [1-10] directions). In the case of dissolution, it was also found that the (00-1) face of substrate crystal preferentially dissolved, which results from the low initial phosphate content and high PO43− density on this face. As a result, present work can provide a deeper insight into bio-struvite mineralization.

High process activity of a two-phase UASB (upflow anaerobic sludge blanket) receiving ethanol wastewater: Operational conditions in relation to granulation development

2021 ◽  
Vol 148 ◽  
pp. 106012
Author(s):  
Achiraya Jiraprasertwong ◽  
Pattaratorn Karnchanapaisal ◽  
Kessara Seneesrisakul ◽  
Pramoch Rangsunvigit ◽  
Sumaeth Chavadej
Keyword(s):  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Two Phase ◽  
Operational Conditions ◽  
Anaerobic Sludge Blanket

Biolixiviation des métaux lourds et stabilisation des boues d'épuration : essai en bioréacteur opéré en mode cuvée

1993 ◽  
Vol 20 (1) ◽  
pp. 57-64 ◽  
Author(s):  
R. D. Tyagi ◽  
J. F. Blais ◽  
N. Meunier ◽  
D. Kluepfel
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Suspended Solids ◽  
Elemental Sulfur ◽  
Batch Reactor ◽  
Fecal Coliforms ◽  
Sludge Stabilization ◽  
Sludge Digestion ◽  
Batch Time ◽  
Phosphorus And Potassium

A biological process of heavy metals solubilization and sewage sludge stabilization was studied in a batch reactor of 30-L capacity. The acclimatized leaching microflora was composed of two major groups of thiobacilli: less acidophilic and acidophilic. A batch time of 10 days allows a substantial metal solubilization: cadmium (100%), copper (80%), manganese (80%), nickel (46%), and zinc (100%). The bioleaching process also causes a significative decrease in sludge total suspended solids (25%) and volatile suspended solids (32%), and a considerable reduction (under the detection limit of 10 cfu∙mL−1) of indicator bacteria (total coliforms, fecal coliforms, fecal streptococci). After filtration or centrifugation of the leached sludge, the solubilized metals were precipitated by lime neutralization. The phosphorus and potassium sludge contents were not affected by bioleaching process. These results indicate that the process of sludge digestion and metal leaching can be conducted in parallel in the same reactor. Key words: sewage sludge, heavy metals, bioleaching, stabilization, thiobacilli, elemental sulfur.

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