Nitrate and Phosphate Removal by Co-immobilized Chlorella pyrenoidosa and Activated Sludge at Different pH Values

2003 ◽  
Vol 38 (3) ◽  
pp. 541-551 ◽  
Author(s):  
Guolan Huang ◽  
Yuan Wang
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Ph Value ◽  
Nitrate Removal ◽  
Chlorella Pyrenoidosa ◽  
Phosphate Removal ◽  
Ph Values ◽  
Pva Gel ◽  
Influence Of Ph ◽  
Immobilization Method

Abstract A new immobilization method, the simplifying modified polyvinyl alcohol (PVA)-sulfate method, has been evaluated. The influence of pH value on nitrate and phosphate removal by co-immobilized Chlorella pyrenoidosa and activated sludge was studied. The results showed that the co-immobilized system was adaptable to the environment; the micro-algae reproduced rapidly inside a PVA gel carrier under pH ranging from 5.0 to 10.0. Phosphate removal efficiency of the co-immobilized system was distinctly affected by pH but nitrate removal efficiency was not affected very much. The co-immobilized system had a higher removal efficiency in the water when close to neutral. Under suitable circumstances, the removal efficiency of nitrate reached 80% in all four experimental periods; meanwhile, the highest removal efficiency of phosphate was 88% but decreased to 56% from the first period to the fourth period in the experiment.

scholarly journals The Influence of pH Values on the Crystallite Size of ZnO by Solvothermal Synthesis

2017 ◽  
Vol 2 (2) ◽  
pp. 118 ◽  
Author(s):  
Ahmadi Jaya Permana ◽  
Dian Wulandari ◽  
Hartati Hartati ◽  
Harsasi Setyawati ◽  
Mochammad Zakki Fahmi
Keyword(s):  
Heat Treatment ◽  
Zinc Oxide ◽  
Crystallite Size ◽  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Ph Value ◽  
Semiconductor Material ◽  
X Ray ◽  
Ph Values ◽  
Influence Of Ph

 Zinc oxide (ZnO) is a semiconductor material that widely used in various applications due to its unique properties. Synthesis of ZnO by solvothermal method has been conducted with controlled pH values. The variations of pH value were 10, 11 and 12 by adjusting NaOH content. Crystall structure of the synthesis products after heat treatment at 110oC and 600oC has characterised by X-ray Diffratometer (XRD). Crystallite size of ZnO was measured by Scherrer equation. Crystall phase of ZnO has been observed on all pH value variations at 110 oC with 22,98-37,06 nm of crystallite size, whereas ZnO has been observed on all pH value variations at 600 oC with 41,39-71,77 nm of crystallite size.Keywords: ZnO, pH values, crystallite size, solvothermal

scholarly journals Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM)

2018 ◽  
Vol 77 (6) ◽  
pp. 1765-1776 ◽  
Author(s):  
Gagik Badalians Gholikandi ◽  
Khashayar Kazemirad
Keyword(s):  
Response Surface Methodology ◽  
Activated Sludge ◽  
Response Surface ◽  
Removal Efficiency ◽  
Ph Value ◽  
System Optimization ◽  
Waste Activated Sludge ◽  
Operational Conditions ◽  
Sludge Stabilization ◽  
Rsm Optimization

Abstract In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H2O2 concentration and the retention time were 3, 3.2 mA/cm2, 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8–2.5 kWh (kg VSS removed)−1) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2–3 kWh (kg VSS removed)−1). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe2+ concentrations into the system and the VSS removal efficiency of the process precisely.

Effect of Environment Factors on Phosphorus Removal Efficiency of Phosphate Reduction System

2011 ◽  
Vol 255-260 ◽  
pp. 2797-2801
Author(s):  
Chen Yao ◽  
Chun Juan Gan ◽  
Jian Zhou
Keyword(s):  
Removal Efficiency ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Removal Rate ◽  
Mass Rearing ◽  
Phosphate Removal ◽  
Environment Factors ◽  
Reduction System ◽  
Initial Ph ◽  
The Impact

Effect of environment factors such as initial pH value, dissolved oxygen (DO) and temperature on phosphorus removal efficiency of phosphate reduction system was discussed in treating pickled mustard tube wastewater. Results indicate that environment factors have significant influence on dephosphorization efficiency. And, the impact of DO on phosphate reduction is mainly by affecting the distribution of micro-environment inner biofilm, manifest as phosphate removal rate decreased with a fall in DO concentration, while overhigh DO can lead to detachment of biofilm, thus causing the increase of effluent COD concentration, and so DO need to be controlled in the range of 6 mg/L. Moreover, a higher temperature is more beneficial to phosphorus removal by PRB. Unfortunately, exorbitant temperature can result in mass rearing of Leuconostoc characterized with poor flocculability in reactor, and that cause turbidity in effluent appeared as a rise in COD of effluent. Hence, the optimal temperature is found to be about 30°C.

Influence of pH on the Morphology and Luminescence Properties of Europium-Doped Hydroxyapatite Nanoparticles

2011 ◽  
Vol 391-392 ◽  
pp. 1132-1137
Author(s):  
Su Ping Huang ◽  
Jun Zhu ◽  
Ke Chao Zhou
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Doping Concentration ◽  
Ph Value ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Ph Values ◽  
Influence Of Ph

Luminescence behaviors and morphology of Eu3+doped hydroxyapatite synthesized under different pH values were well investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Inductively Coupled Plasma (ICP) (ICP–PLASMA 1000), and photoluminescence (PL) spectroscopy. Results revealed that With pH values increased from 6.5 to 10.0, the morphology of nano-Eu:HA particles changes from rod particles to equiaxed particles. The actual doping concentration and aspect ratio of Eu3+-doped HA decreased with the increasing of pH value. At the same time, the fluorescence intensity also tends to weakly lower with the increasing of pH value, which indicated that the luminescence properties mainly depended on the actual Eu3+doping concentration, the influences of morphology on the luminescence properties were slight.

Two novel mixed Eu3+/Y3+ Ln MOFs: influence of pH on the topology, Eu/Y ratio and energy transfer

CrystEngComm ◽  
2014 ◽  
Vol 16 (25) ◽  
pp. 5681-5688 ◽  
Author(s):  
Yu Zhang ◽  
Weiwei Ju ◽  
Xiao Xu ◽  
Yun Lv ◽  
Dunru Zhu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Ph Value ◽  
Ph Values ◽  
Influence Of Ph

Two mixed europium–yttrium MOFs with different interesting structures and doping proportions have been successfully synthesized by adjusting the pH values. The pH value largely affects the topologies and Eu/Y ratios of the two compounds.

scholarly journals Influence of pH and ionic strength on the aggregation behaviors of xylan rich hemicelluloses with alkaline lignins

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7608-7622
Author(s):  
Guichun Hu ◽  
Jinguang Hu ◽  
Honglei Chen ◽  
Shunxi Song ◽  
Fuqiang Chu
Keyword(s):  
Particle Size ◽  
Self Assembly ◽  
Main Chain ◽  
Ph Value ◽  
Low Ph ◽  
Ph Values ◽  
Wide Range ◽  
Nacl Concentration ◽  
Aggregation Behaviors ◽  
Influence Of Ph

The evolution of xylan-rich hemicelluloses (XH) aggregation behaviors in the presence of alkaline lignins (AL) under a wide range of pH values and NaCl concentration were investigated via dynamic light scattering and turbidity measurements. XH isolated from wheat straw contain a xylose backbone with arabinose side chains and a small amount of phenol groups. XH tend to aggregate in solution due to their low ratio of arabinose to xylose and hydrophobic phenol groups. AL interact with XH through the phenol groups bonded to the hemicellulose main chain to form an AL-XH complex. As the pH value decreases, the particle size and turbidity of AL, XH and their bonded complex all increase. The size of the AL-XH complex agglomerate is greater than the size of a XH at the same pH value, which indicates that the self-assembly of lignin molecules initiate the aggregation of XH. The particle size and turbidity of XH and AL-XH complexes increase as the XH concentration increase. At low pH values, e.g., 6.0, the particle size of the AL-XH complex more obviously increases compared to the XH particles. The size and turbidity of the AL, XH, and AL-XH complex agglomerates increased as the NaCl concentration increased.

The Role of Acetate in Denitrification and Biological Phosphate Removal in Modified Bardenpho Systems

1989 ◽  
Vol 21 (4-5) ◽  
pp. 375-385 ◽  
Author(s):  
C. T. Winter
Keyword(s):  
Sodium Acetate ◽  
Ph Value ◽  
Phosphate Removal ◽  
Organic Substances ◽  
Phosphate Release ◽  
Ph Values ◽  
Experimental Systems ◽  
Removal Capacity ◽  
Equivalent Sequence

The importance of easily biodegradable organic substances such as acetate and propionate in biological phosphate removal has been recognised by many researchers. Laboratory-scale studies on the performance of three-stage modified Bardenpho nutrient removal systems, fed with settled sewage supplemented with 0, 50, 100 and 200 mg/l sodium acetate respectively are described. Particular attention is given to the effects of these additions on biological phosphate release and uptake and also to the fate of parameters such as pH, calcium, potassium, ammonia and nitrate. Additional phosphate of 10 mg/l (as P) was initially introduced into the feed in order to burden the experimental systems beyond their normal phosphate removal capacity. This was increased to 20 mg/l and eventually to 40 mg/l of phosphate (as P). Increasing concentrations of sodium acetate resulted in distinct increases in pH values, increase in phosphate release in the anaerobic zones and significantly improved overall phosphate removal in the experimental units. The correlation of phosphate removal on acetate concentration was found to be 0.9886. In some instances the unit receiving 200 mg/l acetate removed up to an average of 30 mg/l of phosphate (as P), constituting an improvement of up to 200% compared with the unit receiving no acetate. The alternating release and uptake of phosphate was accompanied by an equivalent sequence for potassium and magnesium. The high pH value plus the disappearance of phosphate, ammonia and magnesium places doubt on a purely biological phosphate removal but could point at the crystallization of ammonium magnesium phosphate.

scholarly journals Investigation of Electro-coagulation Process for Phosphate and Nitrate Removal From Sugarcane Wastewaters

2021 ◽  
Vol 15 (1) ◽  
pp. 19-26
Author(s):  
Majid Ebadi ◽  
◽  
Ali Asareh ◽  
Reza Jalilzadeh Yengejeh ◽  
Najaf Hedayat ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Nitrate Removal ◽  
Phosphate Removal ◽  
Septic Tank ◽  
Industrial Complex ◽  
Khuzestan Province ◽  
Coagulation Process ◽  
Aluminum Electrodes ◽  
Electro Coagulation

Background: Highly-concentrated phosphate and nitrate anions from sugarcane wastewater are often discharged into public waters without standardized treatments. This study assessed the effects of electrical coagulation, initial pH and reaction time in the removal of phosphate and nitrate pollutants. Methods: We used aluminum electrodes to remove the pollutants at Hakhim Farabi Agricultural and Industrial complex, Khuzestan Province, Iran. A septic tank was used for collecting water samples followed by measuring the pH, and the concentrations of phosphate and nitrate in the samples. The pH was set at 5, 7, 9 or 11. Six aluminum electrodes were placed perpendicular to the water flow and were connected to power in a single-polar method. They were used to assess the effects of pH changes, electrical power at 10 and 30 volts and the water retention time at 15, 30, 45 or 60 min. on the efficiency of the pollutants’ removal. Results: The results indicated that under equal retention time and varying pH values, as voltage increased from 10 to 30, the phosphate and nitrate removal increased progressively. It was further demonstrated that the maximum phosphate removal efficiency was achieved at pH7, while it declined at higher pH levels. The highest possible nitrate removal efficiency was achieved under alkaline pH levels. The overall results showed that at every pH and voltage, the percentage of phosphate and nitrate removal increased over time. Conclusion: This study demonstrated that electro-coagulation process is an appropriate and efficient method to remove phosphate and nitrate pollutants from sugarcane wastewaters.

Influence of pH on the Morphology of Yttrium Oxide Hydroxide Nitrate Nanocrystal

2007 ◽  
Vol 336-338 ◽  
pp. 2176-2178 ◽  
Author(s):  
Zhang Lian Hong ◽  
Huang Guo ◽  
Li Xia Peng ◽  
Min Quan Wang
Keyword(s):  
Hydrothermal Method ◽  
Yttrium Oxide ◽  
Ph Value ◽  
High Ph ◽  
Ph Values ◽  
Starting Solution ◽  
Primary Mechanism ◽  
Oxide Hydroxide ◽  
Influence Of Ph

Yttrium oxide hydroxide nitrate (Y4O(OH)9NO3), which was prepared by polyvinyl alcoholassisted hydrothermal method from the Y(NO3)3 and KOH starting solution, was characterized by XRD and FE-SEM. The results revealed that pH value of the starting solution is an important factor which determines the morphology and size of the products. The obtained products varied from lamina microprisms to circular nanorods when the pH value increased from 7.0 to 8.0. In the high pH value above 8.0, the size of nanorods decreased with increasing pH value. A primary mechanism was proposed to explain the evolution of morphology and size of Y4O(OH)9NO3 products prepared under various pH values.

Precipitation of Ferric Phosphate in Activated Sludge: A Chemical Model and Its Verification

1989 ◽  
Vol 21 (4-5) ◽  
pp. 325-337 ◽  
Author(s):  
Cornelia Luedecke ◽  
Slawomir W. Hermanowicz ◽  
David Jenkins
Keyword(s):  
Activated Sludge ◽  
Adsorption Mechanism ◽  
Solubility Product ◽  
Ferric Hydroxide ◽  
Phosphate Removal ◽  
Chemical Model ◽  
Additional Mechanism ◽  
Ph Values ◽  
Ferric Phosphate ◽  
Proposed Model

A chemical model of ferric phosphate precipitation was developed describing ferric hydroxy-phosphate precipitation either alone or together with ferric hydroxide. Conditions for formation of one or two precipitates are examined. The model also incorporates an additional mechanism for phosphate removal through adsorption of PO43− ions on the precipitate. Experimental verification of the proposed model was carried out in lab-scale batch and continuous activated sludge units fed with municipal primary effluent and at five pH values in the range of 6.5 to 8.0. Solubility of ferric phosphate in the activated sludge system was significantly different from that reported in the literature for distilled water systems and was pH-dependent with a minimum at pH of approx. 7.0. It is proposed that the composition of precipitating ferric hydroxy-phosphate can be represented by the empirical formula Fe2.5PO4(OH)4.5. Corresponding solubility product was estimated at pKsp=96.7. The adsorption mechanism has an important effect on total phosphate removal, especially at low residual phosphate concentrations.

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