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1.
Artigo em Inglês | MEDLINE | ID: mdl-30935101

RESUMO

Soil contamination with petroleum hydrocarbons and heavy metals is a widespread environmental problem. In recent years, cyclodextrin has attracted research interest because of its special hole structure that can form inclusion complexes with certain small molecules. However, the solubility of ß-cyclodextrin (ß-CD) in water is low and it crystallizes easily, leading to its low utilization in practice. In this experiment, we connected ß-CD with glycine under alkaline conditions to prepare glycine-ß-cyclodextrin (G-ß-CD), which is water soluble, has stronger coordinating ability with heavy metals, and is more suitable for treating oil-contaminated soil. The results show that G-ß-CD provides better desorption of petroleum hydrocarbons and heavy metals in soils with low organic matter content (1%) and NaNO3 of 0.25 mol/L at 70 g/L G-ß-CD under mildly acidic (pH 5⁻6) conditions. The results indicate that petroleum hydrocarbons and heavy metals were removed simultaneously by means of pretreatment with G-ß-CD, and the results can provide a theoretical basis for remediation of petroleum-contaminated soil.


Assuntos
Glicina/química , Metais Pesados/química , Petróleo/análise , Poluentes do Solo/química , beta-Ciclodextrinas/química , Concentração de Íons de Hidrogênio , Inativação Metabólica
2.
Ecotoxicol Environ Saf ; 158: 162-170, 2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-29684746

RESUMO

Sulfate-reducing bacteria (SRB), a group of anaerobic prokaryotes, can use sulfur species as a terminal electron acceptor for the oxidation of organic compounds. They not only have significant ecological functions, but also play an important role in bioremediation of contaminated sites. Although numerous studies on metabolism and applications of SRB have been conducted, they still remain incompletely understood and even controversial. Fully understanding the metabolism of SRB paves the way for allowing the microorganisms to provide more beneficial services in bioremediation. Here we review progress in bioenergetics mechanisms and application of SRB including: (1) electron acceptors and donors for SRB; (2) pathway for sulfate reduction; (3) electron transfer in sulfate reduction; (4) application of SRB for economical and concomitant treatment of heavy metal, organic contaminants and sulfates. Moreover, current knowledge gaps and further research needs are identified.


Assuntos
Bactérias Anaeróbias/metabolismo , Metabolismo Energético , Sulfatos/metabolismo , Bactérias Redutoras de Enxofre/metabolismo , Biodegradação Ambiental , Transporte de Elétrons , Hidrocarbonetos Clorados/análise , Hidrogênio/metabolismo , Metais Pesados/análise , Oxirredução , Águas Residuárias/química , Águas Residuárias/microbiologia , Poluentes da Água/análise
3.
Environ Sci Pollut Res Int ; 22(8): 5887-94, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25354439

RESUMO

Previous research has demonstrated that post-anoxic denitrification and biological nutrient removal could be achieved in the oxic/anoxic/extended-idle wastewater treatment regime. This study further investigated the effect of different carbon sources on post-anoxic denitrification and biological nutrient removal. Acetate, propionate (volatile fatty acids (VFAs)), glucose (carbohydrate), methanol, and ethanol (alcohol) were used as the sole carbon source, respectively. The experimental results showed that VFA substrates led to an improvement in nitrogen and phosphorus removal. The total nitrogen and phosphorus removal efficiency values driven by acetate achieved 93 and 99%, respectively. In contrast, glucose present in mixed liquor deteriorated total nitrogen and phosphorus removal efficiency values to 72 and 54%. In the reactors cultured with methanol and ethanol, 66 and 63% of the total nitrogen were removed, and phosphorus removal efficiency values were 78 and 71%, respectively. The mechanism studies revealed that different carbon sources affected the transformations of intracellular polyhydroxyalkanoates (PHAs) and glycogen. PHAs are the dominant storages for microorganisms cultured with VFA substrates. Though glycogen is not the favorable energy and carbon source for polyphosphate-accumulating organisms, it can be consumed by microorganisms related to biological nitrogen removal and is able to serve as the electron donor for post-anoxic denitrification.


Assuntos
Reatores Biológicos , Carbono/metabolismo , Desnitrificação/fisiologia , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Águas Residuárias/química , Purificação da Água/métodos , Acetatos/metabolismo , Análise de Variância , Etanol/metabolismo , Glucose/metabolismo , Glicogênio/metabolismo , Hibridização in Situ Fluorescente , Indóis , Metanol/metabolismo , Poli-Hidroxialcanoatos/metabolismo , Polifosfatos/metabolismo , Propionatos/metabolismo , Esgotos/microbiologia
4.
Bioresour Technol ; 179: 8-12, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25514396

RESUMO

In this study, a novel algal biofilm membrane photobioreactor (BMPBR) equipped with solid carriers and submerged membrane module was developed for attached growth of Chlorella vulgaris and secondary effluent treatment. The volumetric microalgae production achieved in BMPBR was 0.072 g L(-1) d(-1), which was 1.44-fold larger than that in suspended growth membrane photobioreactor (MPBR). Furthermore, 72.4% of the total produced algal biomass was immobilized as algal biofilm in BMPBR. Advanced nutrients removal from secondary effluent was achieved both in BMPBR and MPBR, with average reduction of about 85% for PO4(3-)-P in the stable stage. Additionally, BMPBR showed better nitrogen removal performance than MPBR due to its higher algal biomass productivity. Moreover, with the filtration effect of the submerged membrane module in the reactor, suspended microalgae could be completely isolated from the effluent and a low average SS concentration of 0.28 mg L(-1) was achieved in the effluent of BMPBR.


Assuntos
Biofilmes , Membranas Artificiais , Microalgas/crescimento & desenvolvimento , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Fotobiorreatores/microbiologia , Eliminação de Resíduos Líquidos , Purificação da Água/instrumentação , Biodegradação Ambiental , Biomassa , Chlorella vulgaris/crescimento & desenvolvimento , Clorofila/metabolismo
5.
Chemosphere ; 117: 27-32, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25433991

RESUMO

Short-term and long-term effects of Cd(II) on wastewater biological nitrogen and phosphorus removal were investigated with respect to microorganism abundances, enzyme activities, and polyhydroxyalkanoates (PHAs) and glycogen transformations. Though no obvious effects on wastewater biological nutrient removal were observed after short-term exposure, the long-term exposure of 10 mg L(-)(1) Cd(II) inhibited nitrification and phosphorus uptake. Compared with the absence of Cd(II), the presence of 10 mg L(-1) of Cd(II) decreased total nitrogen and phosphorus removal efficiencies from 97% and 98% to 88% and 18%, respectively. Mechanism studies revealed that Cd(II) affected the transformations of intracellular PHAs and glycogen, and the activities of oxidoreductase and polyphosphate kinase, resulted in the decrease of nitrite oxidizing bacteria and polyphosphate accumulating organisms abundance, which might be the major reason for the negative effects of long-term exposure to 10 mg L(-1) Cd(II) on biological nitrogen and phosphorus removal.


Assuntos
Bactérias/efeitos dos fármacos , Compostos de Cádmio/toxicidade , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Águas Residuárias , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Aerobiose , Anaerobiose , Bactérias/enzimologia , Compostos de Cádmio/análise , Nitrificação , Esgotos/microbiologia , Águas Residuárias/química , Águas Residuárias/microbiologia , Poluentes Químicos da Água/análise
6.
Environ Sci Pollut Res Int ; 21(9): 6034-43, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24464081

RESUMO

Previous researches have demonstrated that biological phosphorus removal (BPR) from wastewater could be driven by the aerobic/extended-idle (A/EI) regime. This study further investigated temperature effects on phosphorus removal performance in six A/EI sequencing batch reactors (SBRs) operated at temperatures ranging from 5 to 30 °C. The results showed that phosphorus removal efficiency increased with temperature increasing from 5 to 20 °C but slightly decreased when temperature continually increased to 30 °C. The highest phosphorus removal rate of 97.1 % was obtained at 20 °C. The biomass cultured at 20 °C contained more polyphosphate accumulating organisms (PAO) and less glycogen accumulating organisms (GAO) than that cultured at any other temperatures investigated. The mechanism studies revealed that temperature affected the transformations of glycogen and polyhydroxyalkanoates, and the activities of exopolyphosphatase and polyphosphate kinase activities. In addition, phosphorus removal performances of the A/EI and traditional anaerobic/oxic (A/O) SBRs were compared at 5 and 20 °C, respectively. The results showed the A/EI regime drove better phosphorus removal than the A/O regime at both 5 and 20 °C, and more PAO and less GAO abundances in the biomass might be the principal reason for the higher BPR in the A/EI SBRs as compared with the A/O SBRs.


Assuntos
Fósforo/metabolismo , Temperatura , Eliminação de Resíduos Líquidos/métodos , Hidrolases Anidrido Ácido/análise , Hidrolases Anidrido Ácido/metabolismo , Aerobiose , Reatores Biológicos/microbiologia , Glicogênio/análise , Glicogênio/metabolismo , Fósforo/análise , Poli-Hidroxialcanoatos/análise , Poli-Hidroxialcanoatos/metabolismo , Polifosfatos/análise , Polifosfatos/metabolismo , Águas Residuárias/química , Águas Residuárias/microbiologia
7.
Chemosphere ; 105: 75-81, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24393562

RESUMO

Previous researches have demonstrated that biological phosphorus removal from wastewater could be induced by oxic/extended-idle (O/EI) regime. In this study, an anoxic period was introduced after the aeration to realize biological nutrient removal. High nitrite accumulation ratio and polyhydroxyalkanoates biosynthesis were obtained in the aeration and biological nutrient removal could be well achieved in oxic/anoxic/extended-idle (O/A/EI) regime for the wastewater used. In addition, nitrogen and phosphorus removal performance in O/A/EI regime was compared with that in conventional anaerobic/anoxic/aerobic (A(2)/O) and O/EI processes. The results showed that O/A/EI regime exhibited higher nitrogen and phosphorus removal than A(2)/O and O/EI processes. More ammonium oxidizing bacteria and polyphosphate accumulating organisms and less glycogen accumulating organisms containing in the biomass might be the principal reason for the better nitrogen and phosphorus removal in O/A/EI regime. Furthermore, biological nutrient removal with O/A/EI regime was demonstrated with municipal wastewater. The average TN, SOP and COD removal efficiencies were 93%, 95% and 87%, respectively.


Assuntos
Reatores Biológicos , Nitrogênio/metabolismo , Oxigênio/análise , Fósforo/metabolismo , Poluentes Químicos da Água/metabolismo , Bactérias/enzimologia , Bactérias/isolamento & purificação , Carga Bacteriana , Proteínas de Bactérias/metabolismo , Reatores Biológicos/microbiologia , Eliminação de Resíduos Líquidos
8.
Chemosphere ; 92(10): 1349-55, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23769322

RESUMO

Recently, it was found that excess phosphorus removal could be induced by aerobic/extended-idle regime. In this study, an anoxic period was introduced after the aeration to realize simultaneous nitrogen and phosphorus removal. The results demonstrated that stable partial nitrification could be achieved by controlling the aeration duration at 2.5h because it could not only obtain a desirable ammonia oxidation to nitrite but also avoid the extensive aeration converting nitrite to nitrate, and moreover, the accumulated poly-3-hydroxybutyrate still remain in a relative sufficient concentration (1.5mmolCg(-1) VSS), which could subsequently served as internal carbon source for post-anoxic denitrification. The nitrite accumulation ratio was observed to have relatively high correlation with biological nutrient removal. Over stages with stable high-level nitrite accumulation, the process achieved desirable and stable nitrogen and phosphorus removal efficiencies averaging 95% and 99% respectively. Fluorescence in situ hybridization analysis showed that the faster growth rate of the ammonia oxidizing bacteria than the nitrite oxidizing bacteria was the main reason for achieving nitrite accumulation. In addition, the secondary phosphorus release was negligible and the process maintained excellent nutrient removal under low influent ammonia nitrogen.


Assuntos
Hidroxibutiratos/metabolismo , Nitritos/metabolismo , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Poliésteres/metabolismo , Águas Residuárias/microbiologia , Amônia/metabolismo , Anaerobiose , Desnitrificação , Nitrogênio/metabolismo , Oxigênio/química , Fósforo/metabolismo , Águas Residuárias/análise
9.
Water Sci Technol ; 67(3): 485-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23202551

RESUMO

Recently, it has been found that biological phosphorus removal can be achieved in an aerobic/extended-idle (AEI) process using both glucose and acetate as the sole substrate. However, the microbial consortiums involved in glucose-fed and acetate-fed systems have not yet been characterized. Thus the aims of this paper were to investigate the diversities and dynamics of bacterial communities during the acclimation period, and to quantify polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in the systems. The phylogenetic analysis showed that the microbial communities were mainly composed of phylum Proteobacteria, Bacteroidetes, Chlorobi and another six kinds of unclassified bacteria. Fluorescence in-situ hybridization (FISH) analysis revealed that PAOs and GAOs accounted for 43 ± 7 and 16 ± 3% of all bacteria in the glucose-fed system, and 19 ± 4 and 35 ± 5% of total bacteria in the acetate-fed system, respectively. The results showed that the conventional PAOs could thrive in the AEI process, and a defined anaerobic zone was not necessarily required for putative PAOs growth.


Assuntos
Reatores Biológicos/microbiologia , Consórcios Microbianos , Fósforo/metabolismo , Poluentes Químicos da Água/metabolismo , Eletroforese em Gel de Gradiente Desnaturante , Hibridização in Situ Fluorescente , Fósforo/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Poluentes Químicos da Água/isolamento & purificação
10.
J Hazard Mater ; 186(2-3): 2138-43, 2011 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-21247693

RESUMO

To improve the removal efficiency of heavy metals from wastewater, the surface of a fungal biomass was modified to obtain a high-capacity biosorbent for Cr(VI) in wastewater. The effects of pH, initial concentration, and sorption time on Cr(VI) removal by polyethylenimine (PEI)-modified Phanerochaete chrysosporium were investigated. The biomass adsorption capacity was significantly dependent on the pH of the solution, and the optimum pH was approximately 3.0. The maximum removal for Cr(VI) was 344.8 mg/g as determined with the Langmuir adsorption isotherm. Pseudo-first-order Lagergren model is better than pseudo-second-order Lagergren model when simulating the kinetic experiment results. Furthermore, an amount of Cr(VI) was reduced to Cr(III), indicating that some reactions occurred on the surface of the biomass leading to the reduction of Cr(VI). The point of zero potential for the modified biomass increased from an initial pH of 3.0 to a much higher value of 10.8, indicating that the PEI-modified biomass is better than the pristine biomass for adsorption of anionic adsorbates. Results showed that the PEI-modified biosorbent presented high efficiency in treating Cr(VI)-contaminated wastewater.


Assuntos
Cromo/química , Phanerochaete/química , Eliminação de Resíduos Líquidos , Água/análise , Adsorção , Algoritmos , Meios de Cultura , Eletroquímica , Concentração de Íons de Hidrogênio , Cinética , Modelos Estatísticos , Solanum tuberosum , Termodinâmica
11.
Appl Biochem Biotechnol ; 164(1): 103-14, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21052863

RESUMO

The effects of two biosurfactants, tea saponin (TS) and rhamnolipid (RL), on the production of laccase and the degradation of phenol by P. simplicissimum were investigated in solid-state fermentation consisting of rice straw, rice bran, and sawdust. Firstly, the effects of phenol on the fermentation process were studied in the absence of surfactants. Then, a phenol concentration of 3 mg/g in the fermentation was selected for detailed research with the addition of biosurfactants. The results showed that TS and RL at different concentrations had stimulative effects on the enzyme activity of laccase. The highest laccase activities during the fermentation were enhanced by 163.7%, 68.2%, and 23.3% by TS at concentrations of 0.02%, 0.06%, and 0.10%, respectively. As a result of the enhanced laccase activity, the efficiency of phenol degradation was also improved by both biosurfactants. RL caused a significant increase of fungal biomass in the early stage of the fermentation, while TS had an inhibitory effect in the whole process. These results indicated that RL could mitigate the negative effects of phenol on fungal growth and consequently improve laccase production and phenol degradation. TS was potentially applicable to phenol-polluted solid-state fermentation.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas Fúngicas/metabolismo , Lacase/metabolismo , Fenol/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Biomassa , Camellia sinensis/química , Fermentação/efeitos dos fármacos , Glicolipídeos/farmacologia , Oryza , Penicillium/efeitos dos fármacos , Penicillium/enzimologia , Fenol/toxicidade , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/enzimologia , Saponinas/farmacologia , Tensoativos/farmacologia
12.
Water Sci Technol ; 62(1): 15-20, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20595748

RESUMO

This study aims at coupling coal cinder filter with biological process to improve pharmaceutical wastewater quality and reduce the disposal cost. In the coal cinder filter, the removal efficiencies of COD, BOD(5), SS and color were 90+/-2%, 72+/-2%, 95+/-2% and 80+/-2%, respectively. The results attribute to the big specific surface area and strong adsorption ability. Coal cinder filter removes a large portion of the pollutants in the influent wastewater, which would strongly stable the effluent waste water quality, and reduce the load of follow-up biological treatment process. The average removal efficiencies for COD, BOD(5), SS and color of the combined process were about 99.7+/-3%, 98.2+/-4%, 98.5+/-3% and 96.3+/-2%, respectively, with the average effluent quality of COD 16+/-1 mg/L, BOD(5) 11+/-1 mg/L, SS 10+/-0.6 mg/L and color 22+/-1 (multiple), which are consistent with the national requirements of the waste pollutants for pharmaceutical industry of chinese traditional medicine discharge standard (GB 21906-2008). The results indicated that the combined procedure could offer an attractive solution for pharmaceutical wastewater treatment with considerable low cost.


Assuntos
Filtração/métodos , Resíduos Industriais , Preparações Farmacêuticas/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Óxido de Alumínio/química , Hidrólise , Oxirredução , Preparações Farmacêuticas/metabolismo , Dióxido de Silício/química , Poluentes Químicos da Água/metabolismo
13.
Huan Jing Ke Xue ; 31(1): 124-8, 2010 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-20329527

RESUMO

To investigate the performances of phosphorus removal in a sequencing batch reactor (SBR) with single-stage oxic process using synthetical wastewater, glucose (R1) and acetate (R2) were fed to two SBRs as the sole carbon source, respectively. The operation run mode was determined to be: influent --> aeration (4 h) --> settling (8 h) --> effluent. The results showed that the performance of phosphorus removal in R1 was higher than that in R2 after steady-operation. Total phosphorus (TP) removed per MLVSS in R1 and R2 were 7.2-7.7 and 3.8-4.6 mg x g(-1) during aeration, respectively, but the rate of phosphorus release at the two reactors were 3.6-3.8 and 2.7-3.1 mg x g(-1) during the idle zone, respectively. The energy storage of poly-beta-hydroxyalkanoates (PHA) was constant nearly in R1 during the whole period, but glycogen was accumulated to the maximum value at 30 minutes of aeration, and then was decreased to the initial level. However in R2, PHA and glycogen were both accumulated at about 45 minutes of aeration. This phenomenon suggested that glycogen is the main energy source for metabolism during aerobic period in R1, and the main energy resource come from the decomposition of PHA and the hydrolysis of glycogen in R2. The facts showed that glycogen could replace PHAs to supply energy for phosphate uptake and polyphosphate accumulation in such a single-stage oxic process. Since glycogen accumulated in R1 was more than that in R2, the efficiency of phosphorus removal in R1 was higher than that in R2.


Assuntos
Reatores Biológicos/microbiologia , Carbono/metabolismo , Fósforo/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Anaerobiose , Glicogênio/metabolismo , Oxirredução , Fósforo/metabolismo , Poli-Hidroxialcanoatos/metabolismo
14.
Talanta ; 80(2): 991-5, 2009 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-19836584

RESUMO

A two-probe tandem DNA hybridization assay including capture DNA(1), probe DNA(2), and target DNA(3) was prepared. The long-lived luminescent europium complex doped nanoparticles (NPs) were used as the biomarker. The complex included in the particle was Eu(TTA)(3)(5-NH(2)-phen)-IgG (ETN-IgG), the europium complex Eu(TTA)(3)(5-NH(2)-phen) linking an IgG molecule. Silica NPs containing ETN-IgG were prepared by the reverse microemulsion method, and were easy to label oligonucleotide for time-resolved fluorescence assays. The luminophores were well-protected from the environmental interference when they were doped inside the silica network. The sequences of Staphylococcus aureus and Escherichia coli genes were designed using software Primer Premier 5.0. Amino-modified capture DNA(1) was covalently immobilized on the common glass slides surface. The detection was done by monitoring the fluorescence intensity from the glass surface after the hybridization reaction with the NPs labeled probe DNA(2) and complementary target DNA(3). The sensing system presented short hybridization time, satisfactory stability, sensitivity, and selectivity. This approach was successfully employed for preliminary application in the detection of pure cultured E. coli, it might be an effective tool for pathogen DNA monitoring.


Assuntos
DNA/química , Európio/química , Nanopartículas/química , Dióxido de Silício/química , DNA/análise , DNA/genética , DNA Bacteriano/análise , DNA Bacteriano/química , DNA Bacteriano/genética , Escherichia coli/genética , Fluorescência , Imunoglobulina G/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Nanopartículas/ultraestrutura , Hibridização de Ácido Nucleico , Sondas de Oligonucleotídeos/química , Sondas de Oligonucleotídeos/genética , Fenantrolinas/química , Reprodutibilidade dos Testes , Espectrometria de Fluorescência , Staphylococcus aureus/genética , Tenoiltrifluoracetona/química , Fatores de Tempo
15.
Recent Pat Food Nutr Agric ; 1(3): 236-42, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20653545

RESUMO

Excessive nitrogen and phosphorus supply to freshwater negatively affects water quality and ecosystem balance through a process known as eutrophication. This can lead to increased wastewater treatment costs, a reduction in the biological diversity and recreational value of natural water bodies. Besides, algal blooms can result in loss of livestock and human health issues. Therefore, efficient and reliable nitrogen and phosphorus removal methods are required. In wastewater containing relatively high concentrations of nitrogen and phosphorus (e.g. wastewater from chemical fertilizer plant, the supernate of dewatered sludge, etc.), these elements are difficult to remove economically to reach the appropriate compliance limits by biological methods. On the other hand, both nitrogen and phosphorus are nutrients for the plants, and recently, nitrogen and phosphorus recovery by precipitation (e.g. struvite) has drawn much attention, because nitrogen and phosphorus precipitates can be utilized as a fertilizer and both phosphorus and ammonium can be simultaneously removed. Thus, this review summarized nitrogen and phosphorus recovery methods, during which nitrogen and phosphorus compounds can be used as a raw material for the fertilizer industry, including the options of struvite and hydroxyapatite formation and other feasible using options. In this article most important patents are also discussed.


Assuntos
Conservação dos Recursos Naturais , Nitrogênio , Fósforo , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água , Purificação da Água/métodos , Precipitação Química , Eutrofização , Fertilizantes , Resíduos Industriais , Esgotos/química
16.
Huan Jing Ke Xue ; 29(7): 1867-73, 2008 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-18828368

RESUMO

The performance of phosphorus removal with a sequencing batch reactor was investigated by simulated municipal wastewater. The experimental results showed that phosphorus removal could be achieved in sequencing batch reactor without anaerobic phase, which was conventionally considered as a key phase for phosphorus removal. Phosphorus concentration in the effluent was 1.0 mg x L(-1) below after 4 h aeration, during which pH was 7.0 +/- 0.2. Which indicated the removal rate of phosphorus was above 90% when the COD and phosphorus concentrationof influent were about 400 mg x L(-1), 15-20 mg x L(-1), respectively. Intracellular storage of poly-phosphate (poly-P) was increasing in the aeration after decreasing in first hour aeration (the content of poly-P was 83.034 mg x g(-1) at the beginning of aerobic phase, 79.980 mg x g(-1) in first aeration and 83.086 mg x g(-1) in end), but the energy storage poly-beta-hydroxyalkanoates (PHA) was constant nearly and the content was very low (PHA concentration was about 5 mg x L(-1)). The researches indicated that phosphate could be transformed to poly-P by poly-phosphate-accumulating organisms without anaerobic zone and PHA, biological phosphorus removal was obtained by removing sludge with rich phosphorus, and this phenomenon could not be explained by conventional theory.


Assuntos
Bactérias Aeróbias/metabolismo , Reatores Biológicos/microbiologia , Fósforo/metabolismo , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Fósforo/isolamento & purificação , Polifosfatos/metabolismo
17.
Water Res ; 42(10-11): 2629-39, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18308365

RESUMO

This study advances an integrated simulation, inference, and optimization method (ISIOM) for optimizing groundwater remediation systems. SIOM has the advantages of (i) automotive screening of potential explanatory variables (e.g., the pumping rates at various remediation wells), (ii) providing a flexible manner for investigating the linear, interactive, and quadratic effects of operating conditions on the benzene levels, and (iii) mitigating the computational efforts in optimization processes. The method is applied to a petroleum-contaminated site in western Canada for identifying the optimal remediation strategies under a given set of remediation durations and environmental standard levels. To examine the effect of pumping duration on contaminants removing efficiency, 4 duration options are considered including 5, 10, 15, and 20 years, respectively. The results indicate that the pumping duration would have effect on the optimized scheme. It is suggested that the 10-year duration would be more desirable than the 15-year one. The simulation results demonstrate that the peak benzene concentrations would be reduced to satisfy the environmental standard when the optimal remediation strategy is carried out.


Assuntos
Simulação por Computador , Recuperação e Remediação Ambiental/métodos , Petróleo/análise , Solo , Poluentes Químicos da Água/isolamento & purificação , Abastecimento de Água , Biodegradação Ambiental , Canadá
18.
Bioresour Technol ; 99(13): 5466-73, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18082396

RESUMO

The performance of biological phosphorus removal (BPR) in a sequencing batch reactor (SBR) with single-stage oxic process was investigated using simulated municipal wastewater. The experimental results showed that BPR could be achieved in a SBR without anaerobic phase, which was conventionally considered as a key phase for BPR. Phosphorus (P) concentration 0.22-1.79 mg L(-1) in effluent can be obtained after 4h aeration when P concentration in influent was about 15-20 mg L(-1), the dissolved oxygen (DO) was controlled at 3+/-0.2 mg L(-1) during aerobic phase and pH was maintained 7+/-0.1, which indicated the efficiencies of P removal were achieved 90% above. Experimental results also showed that P was mainly stored in the form of intracellular storage of polyphosphate (poly-P), and about 207.235 mg phosphates have been removed by the discharge of rich-phosphorus sludge for each SBR cycle. However, the energy storage poly-beta-hydroxyalkanoates (PHA) was almost kept constant at a low level (5-6 mg L(-1)) during the process. Those results showed that phosphate could be transformed to poly-P with single-stage oxic process without PHA accumulation, and BPR could be realized in net phosphate removal.


Assuntos
Fosfatos/isolamento & purificação , Fósforo/isolamento & purificação , Polifosfatos/isolamento & purificação , Esgotos , Acetobacter , Aerobiose , Anaerobiose , Reatores Biológicos , Ciclo do Ácido Cítrico , Polimetil Metacrilato
19.
Huan Jing Ke Xue ; 28(3): 534-9, 2007 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-17633629

RESUMO

The performance of simultaneous nitrogen and phosphorus removal with an inner loop sequencing batch reactor were investigated by simulated municipal wastewater. The experimental results showed that COD, NH4(+) -N, and TP can be removed efficiently after four hours aeration, during which dissolved oxygen concentration was at 6 mg/L at the beginning of aerobic phase and pH was in the rang of 7 - 8. The COD and NH4+ -N as well as TP concentration in the effluent were about at 4 - 48 mg x L(1), 0 - 2.0 mg x L(-1), and 0 - 1.4 mg x L(-1) respectively, which indicated the removal rate for each item were about 89.7% +/- 6.5%, 97.4% +/- 3.6%, 95.6% +/- 4.4% when the concentration of influent were about 170 - 260 mg x L(-1), 20 - 30 mg- L(-1), 8 - 20 mg L(-1), respectively. The removal rate of TIN( NH4 -N + NO3(-) -N + NO2(-) -N) was also reached about 70%. It was found during the research process that phosphorus removal can be achieved without anaerobic phase, which was conventionally considered as a key phase for phosphorus removal, and this phenomena can not be explained by traditional theory.


Assuntos
Bactérias Aeróbias/metabolismo , Reatores Biológicos , Nitrogênio/metabolismo , Fósforo/metabolismo , Eliminação de Resíduos Líquidos/métodos , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Poluentes da Água/metabolismo
20.
J Hazard Mater ; 141(3): 736-44, 2007 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-16949746

RESUMO

Three kinds of adsorbents-potassium dihydrogen phosphate, sawdust and mixture of potassium dihydrogen phosphate and sawdust were added respectively into composting to investigate their adsorption effect on ammonia. The experimental results showed that all the adsorbents could restrain ammonia volatilizing, with the sorption of potassium dihydrogen phosphate adsorbents being the best of all, the sorption of mixture adsorbent with potassium dihydrogen phosphate and sawdust being the second and the sorption of sawdust adsorbent being the last. Therefore, the total nitrogen loss ratios respectively reduced from 38% to 13%, 15% and 21% after adding these three kinds of adsorbents into composting. However, potassium dihydrogen phosphate produced negative influence on composting properties as its supplemented amount exceeded a quantity basis equivalent to 18% of total nitrogen in the composting, for example: pH value had been lessened, microorganism activity reduced, which finally resulted in the reduction of biodegradation ratio of organic matter. But it did not result in these problems when using the mixture of potassium dihydrogen phosphate and sawdust as adsorbent, in which the amount of potassium dihydrogen phosphate was under a quantity basis equivalent to 6% of total nitrogen in the composting. Moreover, the mixture adsorbent produced better adsorption effect on ammonia, and raised biodegradation ratio of organic matter from 26% to 33%.


Assuntos
Amônia/química , Poeira , Fosfatos/química , Compostos de Potássio/química , Eliminação de Resíduos/métodos , Solo , Adsorção , Aerobiose , Reatores Biológicos , Nitrogênio/química , Nitrogênio/metabolismo , Madeira
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